@article{liao_montalban_panwala_totsline_hernandez_guedira_huerta_2024, title={First Report of Xanthomonas perforans Causing Bacterial Spot of Pepper (Capsicum annuum) in North Carolina}, volume={7}, ISSN={["1943-7692"]}, DOI={10.1094/PDIS-02-24-0444-PDN}, abstractNote={North Carolina (NC) is the fifth largest producer of bell pepper (Capsicum annuum) in the US with an estimated 2,400 acres in production (NASS-USDA, 2022). A survey of bacterial diseases of peppers was initiated in 2020 after numerous bacterial spot outbreaks were reported in NC. Bacterial spot is caused by a complex of four Xanthomonads: X. euvesicatoria, X. vesicatoria, X. perforans, and X. hortorum pv. gardneri (Larrahondo-Rodríguez et al., 2022). If not preemptively managed, bacterial spot can cause up to 40% yield loss (Kousik and Ritchie, 1998). During the 2020 and 2021 growing seasons, 103 yellow mucoid colonies were isolated from plants representing 51 pepper cultivars symptomatic of bacterial spot, i.e., water-soaked leaf lesions that become necrotic spots on leaves and fruits across 22 commercial fields in NC following published methods (Klein-Gordon et al., 2021). All colonies were characterized to species using the qPCR species-specific primers and probes described by Strayer et al. 2016. Of the 103 colonies, 12 isolates tested positive for X. perforans. To confirm qPCR results, a Multi-Locus Sequence Analysis (MLSA) was run using fusA, gapA, gltA, gyrB, and lacF following previously described methods (Almeida et al., 2010) on three representative isolates: AHX61, collected in September 2020 from a field with 20% disease severity in Wake County on cv. Canary Bell; AHX261, collected in July 2021 from a field with 50% disease severity in Sampson County on Jalapeño; and AHX426, collected in August 2021 from a field with 50% disease severity in Dublin County on Jalapeño. All gene sequences were deposited to NCBI (GenBank Accessions: OQ799538-OQ799552) and compared to those from X. euvesicatoria, X. hortorum pv. gardneri, X. perforans, and X. vesicatoria type strains (Almeida et al., 2010). The MLSA showed AHX61, AHX261, and AHX426 cluster with X. perforans ICMP16690T, sharing 99-100% nucleotide similarity. Koch's postulates were performed with the three strains, Xp1484T [ X. perforans type strain, (Wilson 1987)], and water as a negative control. Three 10-week-old bell pepper plants (cv. Early Cal Wonder) were dip-inoculated in 600 mL of a bacterial suspension at an OD600 of 0.3 (~5x108 CFU/mL) and 0.04% Silwet L-77 per strain or water. All 18 plants were individually incubated in a plastic bag for 48 h post-inoculation at 28°C, 80% relative humidity, and 14 h:10 h light-dark cycle in a growth chamber, after which plastic bags were removed. Water-soaking and necrotic spots characteristic of bacterial spot were first observed at six days post-inoculation (dpi). At 14 dpi, symptomatic leaves were removed from treated plants to attempt pathogen re-isolation. Yellow mucoid colonies similar in morphology to those originally inoculated were recovered from all plants and confirmed to be X. perforans through sequencing; no isolates were recovered from water-treated plants. To our knowledge, this is the first time X. perforans is isolated in commercial bell pepper and specialty pepper fields in the state. This is an indication that the Xanthomonas population on peppers in the state is more diverse than previously reported and that pathogen populations will require monitoring for possible species shifts for this crop in NC.}, journal={PLANT DISEASE}, author={Liao, Ying-Yu and Montalban, Kimberly and Panwala, Roshni and Totsline, Noah and Hernandez, Kimberly and Guedira, Anisa and Huerta, Alejandra I.}, year={2024}, month={Jul} }
@article{duin_montalban_joglekar_d՚amico-willman_ritchie_fagen_huerta_2024, title={First Report of Bacterial Leaf Spot Disease on Sesame (Sesamum indicum) Caused by Pseudomonas syringae pv. sesami in North Carolina}, volume={108}, ISSN={0191-2917 1943-7692}, url={http://dx.doi.org/10.1094/PDIS-02-24-0292-PDN}, DOI={10.1094/PDIS-02-24-0292-PDN}, abstractNote={In July 2022, dark brown to black, angular, water-soaked lesions were observed on sesame leaves (Sesamum indicum L.) in a research plot established to assess yield potential for eight varieties at the North Carolina (NC) Sandhills Research Station (Chavez 2023). Symptoms were indicative of a bacterial leaf spot (BLS). At early flowering stage, leaf spots were present on scattered plants; varieties ES108, SS3301, and ES201 exhibited up to 75% disease prevalence, with lower frequency in ES103, S39, S4302, S3251, and S3276. Symptomatic leaves from 3-4 plants were collected on four different dates from July through September. A section of symptomatic tissue was excised and macerated in sterile deionized water (SDW). A 10 µL aliquot was streaked onto SPA medium (15 g sucrose, 5.0 g proteose peptone, 0.50 g MgSO4 7H2O, 0.25 g K2HPO4, 15 g agar per liter of SDW) and incubated at 28ºC. After 72 h, numerous, smooth, white-cream colored, convex-shaped, colonies were individually isolated. Five randomly selected isolates from the different collection dates, designated as AHP108-AHP111 and AHP116, were genotyped. The 16S rRNA, gyrB, rpoD, and gapA genes were sequenced (Heuer et al. 1997; Hwang et al. 2005) and deposited to NCBI (GenBank Accessions: P213467- PP213470; OQ628040-OQ628042; PP214983-PP214994; and PP255798). These five isolates shared 100% sequence identity for gyrB and rpoD. AHP108-AHP111 shared 100% sequence identity for 16S rRNA and gapA, with 99.7% and 90.8% identity, respectively, for AHP116. A phylogenetic tree was inferred from a maximum-likelihood analysis of concatenated gyrB, rpoD, and gapA sequences of the five isolates and the top 11 hts from a blastn search of the NCBI nucleotide database. Those hits included closely related sequences from Pseudomonas syringae pv. sesami type strains ICMP 763T and ICMP 7459T. Based on this phylogenetic analysis AHP108-AHP111 and AHP116 are P. syringae pv. sesami. Recent genomic analysis suggests this pathovar is part of P. amygdali (Gomila et al. 2017), but an official name change has not been proposed. Each of the five isolates were infiltrated into leaves of sesame varieties ES108, ES103, and S327, consistently resulting in similar symptoms. Thus, strain AHP116, as a representative, was used to fulfill Koch's postulates using five, 30-day-old potted sesame plants (var. S3301). Plants were spray-inoculated with a bacterial suspension of ~108 CFU/ml until runoff; plants were incubated in moist chambers 24 h pre and post inoculation at 28ºC with 80% relative humidity and a 12 h photoperiod. At 13 days post inoculation, symptoms resembling those on plants at the Sandhills Research Stations in 2022 were evident. Reisolated bacteria were confirmed to be AHP116 through 16S rRNA and gyrB amplification and sequencing. No symptoms were observed on the five water-inoculated plants. BLS of sesame has been reported in Asia and is thought to be seedborne (Firdous et al. 2009; Prathuangwong and Yowabutra 1997). To our knowledge, this is the first report of P. syringae pv. sesami causing BLS on sesame in North Carolina. Sesame cultivation in the state increased from approximately 2,000 acres in 2022 to 13,000 acres in 2023 and there is interest in cultivating sesame as a rotational and alternative crop because it requires minimal input costs. Potential outbreaks of BLS in this warm, humid region could negatively affect sesame production, where little is known about the economic impact of the disease.}, number={6}, journal={Plant Disease}, publisher={Scientific Societies}, author={Duin, Izabela Moura and Montalban, Kimberly M. and Joglekar, Prasanna and D՚Amico-Willman, Katherine and Ritchie, David F. and Fagen, Jennie R. and Huerta, Alejandra I.}, year={2024}, month={Jun}, pages={1880} }
@article{d'amico-willman_montalban_joglekar_duin_ritchie_fagen_huerta_2024, title={Whole-Genome Sequence Resources for Pseudomonas amygdali pv. sesami and Xanthomonas arboricola Isolated from Sesame (Sesamum indicum) in North Carolina in 2022}, volume={7}, ISSN={2690-5442}, url={http://dx.doi.org/10.1094/PHYTOFR-11-23-0148-A}, DOI={10.1094/PHYTOFR-11-23-0148-A}, abstractNote={Sesame ( Sesamum indicum) is a specialty crop with increasing interest as an alternative, rotational crop for U.S. agricultural systems. This crop is susceptible to several pathogens, including Pseudomonas and Xanthomonas species. Two bacterial isolates were recently cultured from sesame in North Carolina symptomatic of bacterial spot and identified as Pseudomonas amygdali pv. sesami (Pas) and Xanthomonas sp. These isolates were used for hybrid whole-genome sequencing and assembly using Illumina and PacBio to develop robust genomic resources for these disease-causing strains. The results provide the most complete Pas genome available and placed the Xanthomonas sp. isolate into the X. arboricola species designation. Improved genomic resources for pathogens of sesame are needed to accurately detect, characterize, and employ timely management of the disease. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .}, journal={PhytoFrontiers™}, publisher={Scientific Societies}, author={D'Amico-Willman, Katherine M. and Montalban, Kimberly M. and Joglekar, Prasanna and Duin, Izabela Moura and Ritchie, David F. and Fagen, Jennie and Huerta, Alejandra I.}, year={2024}, month={Jul} }
@article{flores-lopez_olalde-portugal_vidaver_morales-galvan_hernandez-rosales_huerta_2024, title={Unlocking a Mystery: Characterizing the First Appearance of Clavibacter nebraskensis in Mexican Cornfields}, volume={5}, ISSN={["1943-7692"]}, DOI={10.1094/PDIS-08-23-1493-RE}, abstractNote={The Goss's wilt and leaf blight is a disease of maize (}, journal={PLANT DISEASE}, author={Flores-Lopez, Luis Fernando and Olalde-Portugal, Victor and Vidaver, Anne K. and Morales-Galvan, Oscar and Hernandez-Rosales, Maribel and Huerta, Alejandra I.}, year={2024}, month={May} }
@article{d’amico-willman_joglekar_luna_ritchie_fagen_huerta_2022, title={Complete Genome Sequence of Xanthomonas arboricola pv.
pruni
Strain Xcp1 Isolated in 1984 from a Bacterial Spot Spring Canker on Prunus persica var.
nucipersica
cv. “Redgold”}, volume={11}, ISSN={2576-098X}, url={http://dx.doi.org/10.1128/mra.00209-22}, DOI={10.1128/mra.00209-22}, abstractNote={
Xanthomonas arboricola
pv.
pruni
is an important plant pathogen and the causal agent of bacterial spot of stone fruits (
Prunus
spp). Here, we report a complete genome of
X. arboricola
pv.
pruni
strain Xcp1 generated from hybrid PacBio Sequel and Illumina NextSeq2000 sequencing.
}, number={12}, journal={Microbiology Resource Announcements}, publisher={American Society for Microbiology}, author={D’Amico-Willman, Katherine M. and Joglekar, Prasanna and Luna, Emily K. and Ritchie, David F. and Fagen, Jennie and Huerta, Alejandra I.}, editor={Dunning Hotopp, Julie C.Editor}, year={2022}, month={Dec} }
@article{larrahondo-rodriguez_liao_huerta_2022, title={Diagnostic Guide for Bacterial Spot of Tomato and Pepper}, volume={23}, ISSN={["1535-1025"]}, DOI={10.1094/PHP-11-21-0140-DG}, abstractNote={ Bacterial spot of tomato and pepper, caused by four Xanthomonas species, X. euvesicatoria, X. vesicatoria, X. perforans, and X. gardneri (renamed X. hortorum pv. gardneri), is a disease that affects pepper and tomato production worldwide. Symptomatic plants often show dark brown or black lesions on all aboveground tissue including fruit, stems, and foliage. Defoliation, fruit spots, and fruit drop are the most important symptoms that contribute to yield loss. To manage the disease, a combination of cultural management tactics is recommended. Unfortunately, effective commercially available copper-based agrochemicals are limited due to the pathogen’s ability to develop tolerance in the field. Multiple breeding efforts have focused on generating genetically resistant cultivars; however, host resistance has been observed to be lost over time due to the pathogen’s adaptation to a deployed genotype and the evolution of new pathogenic races. Isolation of the pathogen from infected tissue can be performed by surface sterilization followed by tissue maceration and streaking the supernatant on nutrient agar or yeast–dextrose–calcium carbonate agar. Identification tools for these pathogens include semiselective media (i.e., Chang Kama Tween Medium and Tween agar), serological methods, biochemical tests, and molecular techniques. For the latter method, one can use species-specific primers to run conventional PCR, qPCR, and multiplex PCR. Lastly, differential genotypes can be used for identifying races. }, number={3}, journal={PLANT HEALTH PROGRESS}, author={Larrahondo-Rodriguez, Erika and Liao, Ying-Yu and Huerta, Alejandra I}, year={2022}, month={Sep}, pages={355–361} }
@article{zhao_cheng_wang_gao_huang_kong_antwi-boasiako_zheng_yan_chang_et al._2022, title={Identification of Novel Genomic Regions for Bacterial Leaf Pustule (BLP) Resistance in Soybean (Glycine max L.) via Integrating Linkage Mapping and Association Analysis}, volume={23}, ISSN={["1422-0067"]}, url={https://www.mdpi.com/1422-0067/23/4/2113}, DOI={10.3390/ijms23042113}, abstractNote={Bacterial leaf pustule (BLP), caused by Xanthornonas axonopodis pv. glycines (Xag), is a worldwide disease of soybean, particularly in warm and humid regions. To date, little is known about the underlying molecular mechanisms of BLP resistance. The only single recessive resistance gene rxp has not been functionally identified yet, even though the genotypes carrying the gene have been widely used for BLP resistance breeding. Using a linkage mapping in a recombinant inbred line (RIL) population against the Xag strain Chinese C5, we identified that quantitative trait locus (QTL) qrxp–17–2 accounted for 74.33% of the total phenotypic variations. We also identified two minor QTLs, qrxp–05–1 and qrxp–17–1, that accounted for 7.26% and 22.26% of the total phenotypic variations, respectively, for the first time. Using a genome-wide association study (GWAS) in 476 cultivars of a soybean breeding germplasm population, we identified a total of 38 quantitative trait nucleotides (QTNs) on chromosomes (Chr) 5, 7, 8, 9,15, 17, 19, and 20 under artificial infection with C5, and 34 QTNs on Chr 4, 5, 6, 9, 13, 16, 17, 18, and 20 under natural morbidity condition. Taken together, three QTLs and 11 stable QTNs were detected in both linkage mapping and GWAS analysis, and located in three genomic regions with the major genomic region containing qrxp_17_2. Real-time RT-PCR analysis of the relative expression levels of five potential candidate genes in the resistant soybean cultivar W82 following Xag treatment showed that of Glyma.17G086300, which is located in qrxp–17–2, significantly increased in W82 at 24 and 72 h post-inoculation (hpi) when compared to that in the susceptible cultivar Jack. These results indicate that Glyma.17G086300 is a potential candidate gene for rxp and the QTLs and QTNs identified in this study will be useful for marker development for the breeding of Xag-resistant soybean cultivars.}, number={4}, journal={INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES}, author={Zhao, Fangzhou and Cheng, Wei and Wang, Yanan and Gao, Xuewen and Huang, Debao and Kong, Jiejie and Antwi-Boasiako, Augustine and Zheng, Lingyi and Yan, Wenliang and Chang, Fangguo and et al.}, year={2022}, month={Feb} }
@article{xue-liang_jia-jia_quan-cheng_xin-yao_yong_huerta_jian-bing_hui_wen-de_2022, title={The effects of soil properties, cropping systems and geographic location on soil prokaryotic communities in four maize production regions across China}, volume={21}, ISSN={["2095-3119"]}, DOI={10.1016/S2095-3119(21)63772-3}, abstractNote={The diversity of prokaryotic communities in soil is shaped by both biotic and abiotic factors. However, little is known about the major factors shaping soil prokaryotic communities at a large scale in agroecosystems. To this end, we undertook a study to investigate the impact of maize production cropping systems, soil properties and geographic location (latitude and longitude) on soil prokaryotic communities using metagenomic techniques, across four distinct maize production regions in China. Across all study sites, the dominant prokaryotes in soil were Alphaproteobacteria, Gammaproteobacteria, Betaproteobacteria, Gemmatimonadetes, Acidobacteria, and Actinobacteria. Non-metric multidimensional scaling revealed that prokaryotic communities clustered into the respective maize cropping systems in which they resided. Redundancy analysis (RDA) showed that soil properties especially pH, geographic location and cropping system jointly determined the diversity of the prokaryotic communities. The functional genes of soil prokaryotes from these samples were chiefly influenced by latitude, soil pH and cropping system, as revealed by RDA analysis. The abundance of genes in some metabolic pathways, such as genes involved in microbe–microbe interactions, degradation of aromatic compounds, carbon fixation pathways in prokaryotes and microbial metabolism were markedly different across the four maize production regions. Our study indicated that the combination of soil pH, cropping system and geographic location significantly influenced the prokaryotic community and the functional genes of these microbes. This work contributes to a deeper understanding of the composition and function of the soil prokaryotic community across large-scale production systems such as maize.}, number={7}, journal={JOURNAL OF INTEGRATIVE AGRICULTURE}, author={Xue-liang, Tian and Jia-jia, Liu and Quan-cheng, Liu and Xin-yao, Xia and Yong, Peng and Huerta, Alejandra I. and Jian-bing, Yan and Hui, Li and Wen-de, Liu}, year={2022}, month={Jul}, pages={2145–2157} }
@article{zhao_maren_kosentka_liao_lu_duduit_huang_ashrafi_zhao_huerta_et al._2021, title={An optimized protocol for stepwise optimization of real-time RT-PCR analysis}, volume={8}, ISSN={["2052-7276"]}, url={https://doi.org/10.1038/s41438-021-00616-w}, DOI={10.1038/s41438-021-00616-w}, abstractNote={AbstractComputational tool-assisted primer design for real-time reverse transcription (RT) PCR (qPCR) analysis largely ignores the sequence similarities between sequences of homologous genes in a plant genome. It can lead to false confidence in the quality of the designed primers, which sometimes results in skipping the optimization steps for qPCR. However, the optimization of qPCR parameters plays an essential role in the efficiency, specificity, and sensitivity of each gene’s primers. Here, we proposed an optimized approach to sequentially optimizing primer sequences, annealing temperatures, primer concentrations, and cDNA concentration range for each reference (and target) gene. Our approach started with a sequence-specific primer design that should be based on the single-nucleotide polymorphisms (SNPs) present in all the homologous sequences for each of the reference (and target) genes under study. By combining the efficiency calibrated and standard curve methods with the 2−ΔΔCt method, the standard cDNA concentration curve with a logarithmic scale was obtained for each primer pair for each gene. As a result, an R2 ≥ 0.9999 and the efficiency (E) = 100 ± 5% should be achieved for the best primer pair of each gene, which serve as the prerequisite for using the 2−ΔΔCt method for data analysis. We applied our newly developed approach to identify the best reference genes in different tissues and at various inflorescence developmental stages of Tripidium ravennae, an ornamental and biomass grass, and validated their utility under varying abiotic stress conditions. We also applied this approach to test the expression stability of six reference genes in soybean under biotic stress treatment with Xanthomonas axonopodis pv. glycines (Xag). Thus, these case studies demonstrated the effectiveness of our optimized protocol for qPCR analysis.}, number={1}, journal={HORTICULTURE RESEARCH}, author={Zhao, Fangzhou and Maren, Nathan A. and Kosentka, Pawel Z. and Liao, Ying-Yu and Lu, Hongyan and Duduit, James R. and Huang, Debao and Ashrafi, Hamid and Zhao, Tuanjie and Huerta, Alejandra I and et al.}, year={2021}, month={Dec} }
@article{liao_huang_carvalho_choudhary_da silva_colee_huerta_vallad_freeman_jones_et al._2021, title={Magnesium Oxide Nanomaterial, an Alternative for Commercial Copper Bactericides: Field-Scale Tomato Bacterial Spot Disease Management and Total and Bioavailable Metal Accumulation in Soil}, volume={55}, ISSN={["1520-5851"]}, DOI={10.1021/acs.est.1c00804}, abstractNote={Copper (Cu) is the most extensively used bactericide worldwide in many agricultural production systems. However, intensive application of Cu bactericide have increased the selection pressure toward Cu-tolerant pathogens, including Xanthomonas perforans, the causal agent of tomato bacterial spot. However, alternatives for Cu bactericides are limited and have many drawbacks including plant damage and inconsistent effectiveness under field conditions. Also, potential ecological risk on nontarget organisms exposed to field runoff containing Cu is high. However, due to lack of alternatives for Cu, it is still widely used in tomato and other crops around the world in both conventional and organic production systems. In this study, a Cu-tolerant X. perforans strain GEV485, which can tolerate eight tested commercial Cu bactericides, was used in all the field trials to evaluate the efficacy of MgO nanomaterial. Four field experiments were conducted to evaluate the impact of intensive application of MgO nanomaterial on tomato bacterial spot disease severity, and one field experiment was conducted to study the impact of soil accumulation of total and bioavailable Cu, Mg, Mn, and Zn. In the first two field experiments, twice-weekly applications of 200 μg/mL MgO significantly reduced disease severity by 29-38% less in comparison to a conventional Cu bactericide Kocide 3000 and 19-30% less in comparison to the water control applied at the same frequency (p = 0.05). The disease severity on MgO twice-weekly was 12-32% less than Kocide 3000 + Mancozeb treatment. Single weekly applications of MgO had 13-19% higher disease severity than twice weekly application of MgO. In the second set of two field trials, twice-weekly applications of MgO at 1000 μg/mL significantly reduced disease severity by 32-40% in comparison to water control applied at the same frequency (p = 0.05). There was no negative yield impact in any of the trials. The third field experiment demonstrated that application of MgO did not result in significant accumulation of total and bioavailable Mg, Mn, Cu, or Zn in the root-associated soil and in soil farther away from the production bed compared to the water control. However, Cu bactericide contributed to significantly higher Mn, Cu, and Zn accumulation in the soil compared to water control (p = 0.05). This study demonstrates that MgO nanomaterial could be an alternative for Cu bactericide and have potential in reducing risks associated with development of tolerant strains and for reducing Cu load in the environment.}, number={20}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Liao, Ying-Yu and Huang, Yuxiong and Carvalho, Renato and Choudhary, Manoj and Da Silva, Susannah and Colee, James and Huerta, Alejandra and Vallad, Gary E. and Freeman, Joshua H. and Jones, Jeffrey B. and et al.}, year={2021}, month={Oct}, pages={13561–13570} }
@article{gonzalez-akre_piponiot_lepore_herrmann_lutz_baltzer_dick_gilbert_he_heym_et al._2021, title={allodb: An R package for biomass estimation at globally distributed extratropical forest plots}, volume={11}, ISSN={["2041-2096"]}, DOI={10.1111/2041-210X.13756}, abstractNote={Abstract
Allometric equations for calculation of tree above‐ground biomass (AGB) form the basis for estimates of forest carbon storage and exchange with the atmosphere. While standard models exist to calculate forest biomass across the tropics, we lack a standardized tool for computing AGB across boreal and temperate regions that comprise the global extratropics.
Here we present an integrated R package, allodb, containing systematically selected published allometric equations and proposed functions to compute AGB. The data component of the package is based on 701 woody species identified at 24 large Forest Global Earth Observatory (ForestGEO) forest dynamics plots representing a wide diversity of extratropical forests.
A total of 570 parsed allometric equations to estimate individual tree biomass were retrieved, checked and combined using a weighting function designed to ensure optimal equation selection over the full tree size range with smooth transitions across equations. The equation dataset can be customized with built‐in functions that subset the original dataset and add new equations.
Although equations were curated based on a limited set of forest communities and number of species, this resource is appropriate for large portions of the global extratropics and can easily be expanded to cover novel forest types.
}, journal={METHODS IN ECOLOGY AND EVOLUTION}, author={Gonzalez-Akre, Erika and Piponiot, Camille and Lepore, Mauro and Herrmann, Valentine and Lutz, James A. and Baltzer, Jennifer L. and Dick, Christopher W. and Gilbert, Gregory S. and He, Fangliang and Heym, Michael and et al.}, year={2021}, month={Nov} }
@article{dundore-arias_eloe-fadrosh_schriml_beattie_brennan_busby_calderon_castle_emerson_everhart_et al._2020, title={Community-Driven Metadata Standards for Agricultural Microbiome Research}, volume={4}, ISSN={["2471-2906"]}, DOI={10.1094/PBIOMES-09-19-0051-P}, abstractNote={ Accelerating the pace of microbiome science to enhance crop productivity and agroecosystem health will require transdisciplinary studies, comparisons among datasets, and synthetic analyses of research from diverse crop management contexts. However, despite the widespread availability of crop-associated microbiome data, variation in field sampling and laboratory processing methodologies, as well as metadata collection and reporting, significantly constrains the potential for integrative and comparative analyses. Here we discuss the need for agriculture-specific metadata standards for microbiome research, and propose a list of “required” and “desirable” metadata categories and ontologies essential to be included in a future minimum information metadata standards checklist for describing agricultural microbiome studies. We begin by briefly reviewing existing metadata standards relevant to agricultural microbiome research, and describe ongoing efforts to enhance the potential for integration of data across research studies. Our goal is not to delineate a fixed list of metadata requirements. Instead, we hope to advance the field by providing a starting point for discussion, and inspire researchers to adopt standardized procedures for collecting and reporting consistent and well-annotated metadata for agricultural microbiome research. }, number={2}, journal={PHYTOBIOMES JOURNAL}, author={Dundore-Arias, J. P. and Eloe-Fadrosh, E. A. and Schriml, L. M. and Beattie, G. A. and Brennan, F. P. and Busby, P. E. and Calderon, R. B. and Castle, S. C. and Emerson, J. B. and Everhart, S. E. and et al.}, year={2020}, pages={115–121} }
@article{stahr_butler_huerta_ritchie_quesada-ocampo_2020, title={First Report of Bacterial Root Rot, Caused by Dickeya dadantii, on Sweetpotato (Ipomoea batatas) in North Carolina}, volume={104}, url={https://doi.org/10.1094/PDIS-03-20-0568-PDN}, DOI={10.1094/pdis-03-20-0568-pdn}, abstractNote={HomePlant DiseaseVol. 104, No. 10First Report of Bacterial Root Rot, Caused by Dickeya dadantii, on Sweetpotato (Ipomoea batatas) in North Carolina PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Bacterial Root Rot, Caused by Dickeya dadantii, on Sweetpotato (Ipomoea batatas) in North CarolinaM. N. Stahr, S. Butler, A. I. Huerta, D. F. Ritchie, and L. M. Quesada-OcampoM. N. Stahr†Corresponding author: M. N. Stahr; E-mail Address: mnstahr@ncsu.eduhttp://orcid.org/0000-0001-6027-9611North Carolina State University, Department of Entomology and Plant Pathology, Raleigh, NC 27695, S. ButlerNorth Carolina State University, Department of Entomology and Plant Pathology, Raleigh, NC 27695Plant Disease and Insect Clinic, North Carolina State University, Raleigh, NC 27695, A. I. HuertaNorth Carolina State University, Department of Entomology and Plant Pathology, Raleigh, NC 27695, D. F. RitchieNorth Carolina State University, Department of Entomology and Plant Pathology, Raleigh, NC 27695, and L. M. Quesada-Ocampohttp://orcid.org/0000-0002-9072-7531North Carolina State University, Department of Entomology and Plant Pathology, Raleigh, NC 27695AffiliationsAuthors and Affiliations M. N. Stahr1 † S. Butler1 2 A. I. Huerta1 D. F. Ritchie1 L. M. Quesada-Ocampo1 1North Carolina State University, Department of Entomology and Plant Pathology, Raleigh, NC 27695 2Plant Disease and Insect Clinic, North Carolina State University, Raleigh, NC 27695 Published Online:4 Aug 2020https://doi.org/10.1094/PDIS-03-20-0568-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat North Carolina (NC) produces over 50% of sweetpotatoes grown in the United States. In May of 2019, sweetpotato storage roots with soft rot symptoms from Johnston County, NC, were submitted to the NC State University Plant Disease and Insect Clinic (PDIC). The epidermis of some roots had light brown, water-soaked lesions with a dark black margin, and these roots also had internal rotted decay. Internal decay was also found in roots with no external symptoms. A gram-negative bacterium was isolated from symptomatic tissue. The colonies grew at 39°C and were small, off-white, circular, flat, and had smooth margins when grown on nutrient agar. Following the protocol of Stahr and Quesada-Ocampo (2020), five Covington variety storage roots were wounded with a toothpick and injected with 10 µl of a 107 CFU/ml suspension of isolated bacteria. Inoculated roots were stored without light at 29°C, and after 3 days they developed symptoms consistent with bacterial soft rot on the roots sent to the PDIC. The isolate was biochemically profiled using a BIOLOG GEN III MicroPlate and was found to utilize D-melibiose, raffinose, and mannitol, indicating Dickeya dianthicola (SIM 0.810) as the putative causal agent. To confirm BIOLOG results, DNA of the unknown isolate was extracted using a phenol-chloroform method (He 2011). Extracted DNA was screened using polymerase chain reaction (PCR) alongside a DNA panel of previously characterized strains of Dickeya dadantii, D. dianthicola, and Erwinia amylovora, Xanthomonas arboricola pv. pruni, and Pseudomonas syringae pv. syringae as outgroups, with diagnostic primers specific for the following: Dickeya and Pectobacterium spp. (Df-Dr, pelADE1-pelADE2, SR3F-SR1cR) (Laurila et al. 2010; Nassar et al. 1996; Toth et al. 1999); Pectobacterium carotovorum subsp. carotovorum (ExpccF-ExpccR) (Kang et al. 2003); P. atrosepticum (Y45-Y46) (Fréchon et al. 1998); and D. dianthicola (DIA-Cf-DIA-Cr and DDI-F1-DDI-R1) (Karim et al. 2019; Pritchard et al. 2013). Outgroup DNA failed to amplify in all reactions. The unknown isolate, D. dadantii and D. dianthicola, amplified a 130-, 150-, and 420-bp amplicon for the Df-Dr, SR3F-SR1cR, and pelADE1-pelADE2 primer sets, respectively, confirming the unknown isolate as Dickeya. The D. dianthicola primer set DIA-Cf and DIA-Cr amplified a 120-bp band only in the presence of D. dianthicola, contradicting the results of primer set DDI-F1-DDI-R1, for which the unknown isolate, D. dadantii and D dianthicola, amplified a positive 120-bp band. PCR amplicons of the unknown isolate were cleaned following the ExoSap-IT protocol, sequenced, and compared with the GenBank database using BLASTn. The Df-Dr (MT140883) and pelADE1-pelADE2 (MT140884) amplicons were 100 and 94.77% identical to D. dadantii strain DSM 18020 (CP023467.1), respectively. The DDI-F1-DDI-R1 amplicon (MT140886) was 99.37% identical to D. dadantii strain 3937 (CP002038.1), and the SR3F-SR1cR amplicon (MT140885) was 98.63% identical to the D. dadantii 16S ribosomal RNA gene (KX870942.1). From these results, the unknown isolate was determined to be D. dadantii, formerly known as E. chrysanthemi, which has not been previously reported on sweetpotato in NC. This pathogen was responsible for a severe epidemic that threatened the Georgia sweetpotato industry in the 1970s (Schaad and Brenner 1976); thus, more research is needed to evaluate the risk of a new epidemic occurring.The author(s) declare no conflict of interest.References:Fréchon, D., et al. 1998. Potato Res. 41:163. https://doi.org/10.1007/BF02358439 Crossref, ISI, Google ScholarHe, F. 2011. Bio Protoc. 101:e97. https://doi.org/10.21769/BioProtoc.97 Google ScholarKang, H. W., et al. 2003. Plant Pathol. 52:127. https://doi.org/10.1046/j.1365-3059.2003.00822.x Crossref, ISI, Google ScholarKarim, S., et al. 2019. Plant Dis. 103:2893. https://doi.org/10.1094/PDIS-10-18-1819-RE Link, ISI, Google ScholarLaurila, J., et al. 2010. Eur. J. Plant Pathol. 126:249. https://doi.org/10.1007/s10658-009-9537-9 Crossref, ISI, Google ScholarNassar, A., et al. 1996. Appl. Environ. Microbiol. 62:2228. https://doi.org/10.1128/AEM.62.7.2228-2235.1996 Crossref, ISI, Google ScholarPritchard, L., et al. 2013. Plant Pathol. 62:587. https://doi.org/10.1111/j.1365-3059.2012.02678.x Crossref, ISI, Google ScholarSchaad, N. W., and Brenner, D. 1976. Phytopathology 67:302. https://doi.org/10.1094/Phyto-67-302 ISI, Google ScholarStahr, M. N., and Quesada-Ocampo, L. M. 2020. Plant Dis. 104:930. https://doi.org/10.1094/PDIS-12-18-2224-RE Link, ISI, Google ScholarToth, I. K., et al. 1999. J. Appl. Microbiol. 87:770. https://doi.org/10.1046/j.1365-2672.1999.00929.x Crossref, ISI, Google ScholarThe author(s) declare no conflict of interest.Funding: Funding was provided by NC State Hatch Project (NC02628).DetailsFiguresLiterature CitedRelated Vol. 104, No. 10 October 2020SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionSymptoms of yellow leaf disease of Areca catechu caused by areca palm velarivirus 1 (H. X. Wang et al.). Photo credit: X. Huang. Fungal fruiting bodies of Phyllachora maydis on corn foliage resemble spots of tar (J. Valle-Torres et al.). Photo credit: C. Cruz. Geranium (Pelargonium hortorum) showing pale green and little leaves, phyllody, virescence, and witches’-broom (A. R. Amirmijani et al.). Photo credit: M. Azadvar. Metrics Article History Issue Date: 25 Sep 2020Published: 4 Aug 2020First Look: 5 May 2020Accepted: 4 May 2020 Pages: 2723-2723 Information© 2020 The American Phytopathological SocietyFundingNC State Hatch ProjectGrant/Award Number: NC02628Keywordsprokaryotesvegetablesepidemiologydisease development and spreadThe author(s) declare no conflict of interest.Cited bySweetpotato Root Development Influences Susceptibility to Black Rot Caused by the Fungal Pathogen Ceratocystis fimbriataC. H. Parada-Rojas, Kenneth Pecota, C. Almeyda, G. Craig Yencho, and L. M. Quesada-Ocampo3 October 2021 | Phytopathology®, Vol. 111, No. 9Effects of Water Temperature, Inoculum Concentration and Age, and Sanitizers on Infection of Ceratocystis fimbriata, Causal Agent of Black Rot in SweetpotatoMadison N. Stahr and Lina M. Quesada-Ocampo30 March 2021 | Plant Disease, Vol. 105, No. 5}, number={10}, journal={Plant Disease}, publisher={Scientific Societies}, author={Stahr, M. N. and Butler, S. and Huerta, A. I. and Ritchie, D. F. and Quesada-Ocampo, L. M.}, year={2020}, month={Oct}, pages={2723–2723} }
@article{huerta_delorean_bossa-castro_tonnessen_raghavan_corral_perez-quintero_leung_verdier_leach_2021, title={Resistance and susceptibility QTL identified in a rice MAGIC population by screening with a minor-effect virulence factor fromXanthomonas oryzaepv.oryzae}, volume={19}, ISSN={["1467-7652"]}, url={https://doi.org/10.1111/pbi.13438}, DOI={10.1111/pbi.13438}, abstractNote={SummaryEffective and durable disease resistance for bacterial blight (BB) of rice is a continuous challenge due to the evolution and adaptation of the pathogen, Xanthomonas oryzae pv. oryzae (Xoo), on cultivated rice varieties. Fundamental to this pathogens’ virulence is transcription activator‐like (TAL) effectors that activate transcription of host genes and contribute differently to pathogen virulence, fitness or both. Host plant resistance is predicted to be more durable if directed at strategic virulence factors that impact both pathogen virulence and fitness. We characterized Tal7b, a minor‐effect virulence factor that contributes incrementally to pathogen virulence in rice, is a fitness factor to the pathogen and is widely present in geographically diverse strains of Xoo. To identify sources of resistance to this conserved effector, we used a highly virulent strain carrying a plasmid borne copy of Tal7b to screen an indica multi‐parent advanced generation inter‐cross (MAGIC) population. Of 18 QTL revealed by genome‐wide association studies and interval mapping analysis, six were specific to Tal7b (qBB‐tal7b). Overall, 150 predicted Tal7b gene targets overlapped with qBB‐tal7b QTL. Of these, 21 showed polymorphisms in the predicted effector binding element (EBE) site and 23 lost the EBE sequence altogether. Inoculation and bioinformatics studies suggest that the Tal7b target in one of the Tal7b‐specific QTL, qBB‐tal7b‐8, is a disease susceptibility gene and that the resistance mechanism for this locus may be through loss of susceptibility. Our work demonstrates that minor‐effect virulence factors significantly contribute to disease and provide a potential new approach to identify effective disease resistance.}, number={1}, journal={PLANT BIOTECHNOLOGY JOURNAL}, publisher={Wiley}, author={Huerta, Alejandra I and Delorean, Emily E. and Bossa-Castro, Ana M. and Tonnessen, Bradley W. and Raghavan, Chitra and Corral, Rene and Perez-Quintero, Alvaro L. and Leung, Hei and Verdier, Valerie and Leach, Jan E.}, year={2021}, month={Jan}, pages={51–63} }
@inbook{molecular genetics of bacterial blight and bacterial leaf streak and their impact on future control strategies._2018, url={http://rice-diseases.irri.org/home/contents}, booktitle={Rice diseases: Biology and selected management practices.}, year={2018} }
@article{triplett_cohen_heffelfinger_schmidt_huerta_tekete_verdier_bogdanove_leach_2016, title={A resistance locus in the American heirloom rice variety Carolina Gold Select is triggered by TAL effectors with diverse predicted targets and is effective against African strains ofXanthomonas oryzaepv.oryzicola}, volume={87}, DOI={10.1111/tpj.13212}, abstractNote={SummaryThe rice pathogens Xanthomonas oryzae pathovar (pv.) oryzae and pv. oryzicola produce numerous transcription activator‐like (TAL) effectors that increase bacterial virulence by activating expression of host susceptibility genes. Rice resistance mechanisms against TAL effectors include polymorphisms that prevent effector binding to susceptibility gene promoters, or that allow effector activation of resistance genes. This study identifies, in the heirloom variety Carolina Gold Select, a third mechanism of rice resistance involving TAL effectors. This resistance manifests through strong suppression of disease development in response to diverse TAL effectors from both X. oryzae pathovars. The resistance can be triggered by an effector with only 3.5 central repeats, is independent of the composition of the repeat variable di‐residues that determine TAL effector binding specificity, and is independent of the transcriptional activation domain. We determined that the resistance is conferred by a single dominant locus, designated Xo1, that maps to a 1.09 Mbp fragment on chromosome 4. The Xo1 interval also confers complete resistance to the strains in the African clade of X. oryzae pv. oryzicola, representing the first dominant resistance locus against bacterial leaf streak in rice. The strong phenotypic similarity between the TAL effector‐triggered resistance conferred by Xo1 and that conferred by the tomato resistance gene Bs4 suggests that monocots and dicots share an ancient or convergently evolved mechanism to recognize analogous TAL effector epitopes.}, number={5}, journal={The Plant Journal}, publisher={Wiley}, author={Triplett, Lindsay R. and Cohen, Stephen P. and Heffelfinger, Christopher and Schmidt, Clarice L. and Huerta, Alejandra I. and Tekete, Cheick and Verdier, Valerie and Bogdanove, Adam J. and Leach, Jan E.}, year={2016}, month={Aug}, pages={472–483} }
@article{tran_jacobs_huerta_milling_weibel_allen_2016, title={Sensitive, Secure Detection of Race 3 Biovar 2 and Native U.S. Strains of Ralstonia solanacearum}, volume={100}, DOI={10.1094/pdis-12-14-1327-re}, abstractNote={ Detecting and correctly identifying Ralstonia solanacearum in infected plants is important because the race 3 biovar 2 (R3bv2) subgroup is a high-concern quarantine pathogen, while the related sequevar 7 group is endemic to the southeastern United States. Preventing accidental import of R3bv2 in geranium cuttings demands sensitive detection methods that are suitable for large-volume use both onshore and offshore. However, detection is complicated by frequent asymptomatic latent infections, uneven pathogen distribution within infected plants, pathogen viable-but-not-culturable state, and biosecurity laws that restrict transport of R3bv2 strains for diagnosis. There are many methods to detect R3bv2 strains but their relative utility is unknown, particularly in the realistic context of infected plant hosts. Therefore, we compared the sensitivity, cost, and technical complexity of several assays to detect and distinguish R3bv2 and sequevar 7 strains of R. solanacearum in geranium, tomato, and potato tissue in the laboratory and in naturally infected tomato plants from the field. The sensitivity of polymerase chain reaction (PCR)-based methods in infected geranium tissues was significantly improved by use of Kapa3G Plant, a polymerase with enhanced performance in the presence of plant inhibitors. R3bv2 cells were killed within 60 min of application to Whatman FTA(R) nucleic acid-binding cards, suggesting that samples on FTA cards can be safely transported for diagnosis. Overall, culture enrichment followed by dilution plating was the most sensitive detection method (101 CFU/ml) but it was also most laborious. Conducting PCR from FTA cards was faster, easier, and sensitive enough to detect approximately 104 CFU/ml, levels similar to those found in latently infected geranium plants. }, number={3}, journal={Plant Disease}, publisher={Scientific Societies}, author={Tran, Tuan Minh and Jacobs, Jonathan M. and Huerta, Alejandra and Milling, Annett and Weibel, Jordan and Allen, Caitilyn}, year={2016}, month={Mar}, pages={630–639} }
@article{huerta_milling_allen_2015, title={Tropical Strains of Ralstonia solanacearum Outcompete Race 3 Biovar 2 Strains at Lowland Tropical Temperatures}, volume={81}, DOI={10.1128/aem.04123-14}, abstractNote={ABSTRACT
Bacterial wilt, caused by members of the heterogenous
Ralstonia solanacearum
species complex, is an economically important vascular disease affecting many crops. Human activity has widely disseminated
R. solanacearum
strains, increasing their global agricultural impact. However, tropical highland race 3 biovar 2 (R3bv2) strains do not cause disease in tropical lowlands, even though they are virulent at warm temperatures. We tested the hypothesis that differences in temperature adaptation and competitive fitness explain the uneven geographic distribution of
R. solanacearum
strains. Using three phylogenetically and ecologically distinct strains, we measured competitive fitness at two temperatures following paired-strain inoculations of their shared host, tomato. Lowland tropical strain GMI1000 was only weakly virulent on tomato under temperate conditions (24°C for day and 19°C for night [24/19°C]), but highland tropical R3bv2 strain UW551 and U.S. warm temperate strain K60 were highly virulent at both 24/19°C and 28°C. Strain K60 was significantly more competitive than both GMI1000 and UW551 in tomato rhizospheres and stems at 28°C, and GMI1000 also outcompeted UW551 at 28°C. The results were reversed at cooler temperatures, at which highland strain UW551 generally outcompeted GMI1000 and K60
in planta
. The superior competitive index of UW551 at 24/19°C suggests that adaptation to cool temperatures could explain why only R3bv2 strains threaten highland agriculture. Strains K60 and GMI1000 each produced different bacteriocins that inhibited growth of UW551 in culture. Such interstrain inhibition could explain why R3bv2 strains do not cause disease in tropical lowlands.
}, number={10}, journal={Applied and Environmental Microbiology}, publisher={American Society for Microbiology}, author={Huerta, Alejandra I. and Milling, Annett and Allen, Caitilyn}, editor={Drake, H. L.Editor}, year={2015}, month={Mar}, pages={3542–3551} }
@article{bull_huerta_koike_2009, title={First Report of Blossom Blight of Strawberry (Fragaria × ananassa) Caused by Pseudomonas marginalis}, volume={93}, DOI={10.1094/pdis-93-12-1350b}, abstractNote={ In 2003, a new disease was observed on commercial strawberries (Fragaria × ananassa Duch.) grown in multiple fields in Watsonville, CA. Initial symptoms consisted of brown lesions on the undersides of the sepals of strawberry flowers. The lesions coalesced and spread to upper sepal surfaces and anther bases. No leaf symptoms were observed. Fields affected with this disease appeared to have a greater number of deformed fruit, though incidence data were not collected. A gram-negative, blue-green fluorescent pseudomonad was isolated from lesions on King's medium B agar from both sepals and anthers from 23 of 24 samples from three different fields. All isolates were levan, oxidase, and arginine dihydrolase positive. The strains did rot potato slices but did not induce a hypersensitive reaction in tobacco (Nicotiana tabacum L. cv. Sansun), indicating that the bacteria belonged to Lelliot's LOPAT group IVa, P. marginalis (3). Isolates from strawberry were compared with pathotype strains of Pseudomonas marginalis pv. marginalis, P. marginalis pv. alfalfae, and P. marginalis pv. pastinaceae. The 16S rDNA sequence of type strain of P. marginalis (Z76663) was 97 to 99% similar to the four strawberry isolates sequenced (GQ845121). Identity was further supported by analysis of fatty acid methyl esters (MIS-TSBA version 4.10; MIDI, Inc., Newark, DE). Polymerase chain reaction using BOX-A1R primers (repetitive sequence-based (rep)-PCR [1]) resulted in DNA fragment banding patterns that were identical among strawberry isolates. These banding patterns were different from the three distinct patterns of the P. marginalis pathotypes. Pathogenicity on strawberry (cv. Albion) was confirmed in three experiments using four strawberry isolates originally isolated from plants from three different fields and the P. marginalis pathotype strains. Inoculum was produced by growing bacteria in nutrient broth shake cultures for 48 h (24°C) and washing and suspending the cultures in 0.01 M phosphate buffer (pH 7.0). Three to five attached strawberry flowers on separate plants were dipped in the bacterial suspensions (106 CFU/ml) or sterile buffer for 1 min. To maintain high humidity, flower buds were enclosed in plastic bags for 36 to 48 h and then incubated in the greenhouse (24 to 26°C). After 7 days, approximately half of the flowers inoculated with the strawberry isolates had symptoms on sepals that were identical to symptoms seen in the field. Additionally, reisolates obtained from the symptomatic, inoculated flowers were identical to those used to inoculate the plants as confirmed by LOPAT reactions and rep-PCR, thus completing Koch's postulates. Flowers dipped in phosphate buffer or the P. marginalis pathotype strains did not develop symptoms and no bacteria were reisolated. To our knowledge, this is the first report of blossom blight of strawberry caused by P. marginalis and the first report of P. marginalis on strawberry in California. P. marginalis causes leaf bud rot of strawberry in Japan (2). Further research is needed to determine if the strawberry isolates represent a new or previously described pathovar of P. marginalis. References: (1) N. A. Cintas et al. Plant Dis. 86:992, 2002. (2) T. Kijima et al. Bull. Tochigi. Agric. Exp. Stn. 36:59, 1989. (3) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966. }, number={12}, journal={Plant Disease}, publisher={Scientific Societies}, author={Bull, C. T. and Huerta, A. I. and Koike, S. T.}, year={2009}, pages={1350–1350} }