@article{qian_wang_zhang_sun_luo_posny_xu_tang_ma_zhang_et al._2021, title={Investigation of proline in superficial scald development during low temperature storage of 'Dangshansuli' pear fruit}, volume={181}, ISSN={["1873-2356"]}, DOI={10.1016/j.postharvbio.2021.111643}, abstractNote={The role of proline in superficial scald development in pear fruit was investigated in this study. During low temperature storage of 'Dangshansuli' pear fruit, superficial scald incidence and index accumulated in association with the alternation of α-farnesene and conjugated trienols (CTols). 14 out of 17 free amino acids were identified; proline content gradually decreased, which was consistent with the up-regulation of PbrP5CS activity and down-regulation of PbrProDH activity in its metabolic pathway. A total of 14 genes involved in proline metabolism were identified based on transcriptome annotation with diverse expression profiles. Results from correlation analysis among proline content further indicate that enzyme activity and gene expression profile, PbrProDH2, PbrProDH4, PbrProDH5 & PbrP5CS5 might play a critical role in proline metabolism during low temperature storage of 'Dangshansuli' fruit; thus, influencing superficial scald development which was then functionally validated using the transgenic pear fruit. Postharvest 1-MCP and diphenylamine (DPA) treatment inhibited the accumulation of CTols, and thus, mitigated superficial scald development and maintained higher proline content, in association with the up-regulated PbrP5CS activity, PbrP5CS4 & PbrP5CS5 mRNAs as well as the down-regulated PbrProDH activity & PbrProDH4 transcripts. In a further study, we found that exogenous application of proline alleviated superficial scald incidence and index. To that end, the results of our study confirmed that proline was involved in superficial scald development during pear storage.}, journal={POSTHARVEST BIOLOGY AND TECHNOLOGY}, author={Qian, Ming and Wang, Libin and Zhang, Suling and Sun, Liqiong and Luo, Weiqi and Posny, Drew and Xu, Shanshan and Tang, Chao and Ma, Min and Zhang, Chen and et al.}, year={2021}, month={Nov} }
 @article{gottwald_poole_taylor_luo_posny_adkins_schneider_mcroberts_2020, title={Canine Olfactory Detection of a Non-Systemic Phytobacterial Citrus Pathogen of International Quarantine Significance}, volume={22}, ISSN={["1099-4300"]}, DOI={10.3390/e22111269}, abstractNote={For millennia humans have benefitted from application of the acute canine sense of smell to hunt, track and find targets of importance. In this report, canines were evaluated for their ability to detect the severe exotic phytobacterial arboreal pathogen Xanthomonas citri pv. citri (Xcc), which is the causal agent of Asiatic citrus canker (Acc). Since Xcc causes only local lesions, infections are non-systemic, limiting the use of serological and molecular diagnostic tools for field-level detection. This necessitates reliance on human visual surveys for Acc symptoms, which is highly inefficient at low disease incidence, and thus for early detection. In simulated orchards the overall combined performance metrics for a pair of canines were 0.9856, 0.9974, 0.9257 and 0.9970, for sensitivity, specificity, precision, and accuracy, respectively, with 1–2 s/tree detection time. Detection of trace Xcc infections on commercial packinghouse fruit resulted in 0.7313, 0.9947, 0.8750, and 0.9821 for the same performance metrics across a range of cartons with 0–10% Xcc-infected fruit despite the noisy, hot and potentially distracting environment. In orchards, the sensitivity of canines increased with lesion incidence, whereas the specificity and overall accuracy was >0.99 across all incidence levels; i.e., false positive rates were uniformly low. Canines also alerted to a range of 1–12-week-old infections with equal accuracy. When trained to either Xcc-infected trees or Xcc axenic cultures, canines inherently detected the homologous and heterologous targets, suggesting they can detect Xcc directly rather than only volatiles produced by the host following infection. Canines were able to detect the Xcc scent signature at very low concentrations (10,000× less than 1 bacterial cell per sample), which implies that the scent signature is composed of bacterial cell volatile organic compound constituents or exudates that occur at concentrations many fold that of the bacterial cells. The results imply that canines can be trained as viable early detectors of Xcc and deployed across citrus orchards, packinghouses, and nurseries.}, number={11}, journal={ENTROPY}, author={Gottwald, Timothy and Poole, Gavin and Taylor, Earl and Luo, Weiqi and Posny, Drew and Adkins, Scott and Schneider, William and McRoberts, Neil}, year={2020}, month={Nov} }
 @article{gottwald_poole_mccollum_hall_hartung_bai_luo_posny_duan_taylor_et al._2020, title={Canine olfactory detection of a vectored phytobacterial pathogen, Liberibacter asiaticus, and integration with disease control}, volume={117}, ISSN={["0027-8424"]}, url={https://publons.com/wos-op/publon/39596623/}, DOI={10.1073/pnas.1914296117}, abstractNote={
            Early detection and rapid response are crucial to avoid severe epidemics of exotic pathogens. However, most detection methods (molecular, serological, chemical) are logistically limited for large-scale survey of outbreaks due to intrinsic sampling issues and laboratory throughput. Evaluation of 10 canines trained for detection of a severe exotic phytobacterial arboreal pathogen,
            Candidatus
            Liberibacter asiaticus (
            C
            Las), demonstrated 0.9905 accuracy, 0.8579 sensitivity, and 0.9961 specificity. In a longitudinal study, cryptic
            C
            Las infections that remained subclinical visually were detected within 2 wk postinfection compared with 1 to 32 mo for qPCR. When allowed to interrogate a diverse range of in vivo pathogens infecting an international citrus pathogen collection, canines only reacted to Liberibacter pathogens of citrus and not to other bacterial, viral, or spiroplasma pathogens. Canines trained to detect
            C
            Las-infected citrus also alerted on
            C
            Las-infected tobacco and periwinkle,
            C
            Las-bearing psyllid insect vectors, and
            C
            Las cocultured with other bacteria but at
            C
            Las titers below the level of molecular detection. All of these observations suggest that canines can detect
            C
            Las directly rather than only host volatiles produced by the infection. Detection in orchards and residential properties was real time, ∼2 s per tree. Spatiotemporal epidemic simulations demonstrated that control of pathogen prevalence was possible and economically sustainable when canine detection was followed by intervention (i.e., culling infected individuals), whereas current methods of molecular (qPCR) and visual detection failed to contribute to the suppression of an exponential trajectory of infection.
          }, number={7}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Gottwald, Timothy and Poole, Gavin and McCollum, Thomas and Hall, David and Hartung, John and Bai, Jinhe and Luo, Weiqi and Posny, Drew and Duan, Yong-Ping and Taylor, Earl and et al.}, year={2020}, month={Feb}, pages={3492–3501} }
 @article{luo_posny_kriss_graham_poole_taylor_mccollum_gottwald_bock_2020, title={Seasonal and post-harvest population dynamics of the Asiatic citrus canker pathogen Xanthomonas citri subsp. citri on grapefruit in Florida}, volume={137}, ISSN={["1873-6904"]}, DOI={10.1016/j.cropro.2020.105227}, abstractNote={Asiatic citrus canker (ACC, caused by Xanthomonas citri subsp. citri, [Xcc]) is a serious disease of citrus, reducing yield and impacting marketability of fresh fruit. ACC has phytosanitary implications for fresh fruit trade. Lesions on fruit, leaves, and shoots in an orchard of ACC-susceptible grapefruit were monitored for production of Xcc from June to the following January in 2009 and 2010. Lesions on fruit post-harvest either packingline-treated or not treated were also monitored for production of Xcc on fruit harvested in November 2013 and January 2014. Shoot lesions generally produced fewer bacteria and had a smaller proportion of active lesions compared to leaf and fruit lesions. As the season progressed the proportion of active lesions on fruit and shoots gradually declined. Bacterial flux density (BFD) in surviving lesions was >103 on all organs at all sample times. A window-pane analysis revealed weather variables associated with bacterial survival within the lesion. The packingline treatment had no effect in reducing the proportion of active lesions, and had only a small, transient effect reducing BFD (~1.5 log units). Lesion size affected survival – small lesions (<10 mm2) declined in activity more rapidly compared to larger lesions, both in the field pre-harvest, and post-harvest in storage. Although lesions of ACC on fruit, leaves, and shoots are a constant source of inoculum, steps that can be taken to minimize early infection of fruit which often results in larger lesions will reduce the risk of inoculum dispersal. Current packingline treatments do not reduce activity of lesions of ACC. Based on these and other previously reported results, lesions on fruit post-harvest can be deemed a limited risk for spread of canker.}, journal={CROP PROTECTION}, author={Luo, Weiqi and Posny, Drew and Kriss, Alissa B. and Graham, Jim H. and Poole, Gavin H. and Taylor, Earl L. and McCollum, Greg and Gottwald, Tim R. and Bock, Clive H.}, year={2020}, month={Nov} }
 @article{gottwald_luo_posny_riley_louws_2019, title={A probabilistic census-travel model to predict introduction sites of exotic plant, animal and human pathogens}, volume={374}, ISSN={["1471-2970"]}, url={http://dx.doi.org/10.1098/rstb.2018.0260}, DOI={10.1098/rstb.2018.0260}, abstractNote={
            International travel offers an extensive network for new and recurring human-mediated introductions of exotic infectious pathogens and biota, freeing geographical constraints. We present a predictive census-travel model that integrates international travel with endpoint census data and epidemiological characteristics to predict points of introduction. Population demographics, inbound and outbound travel patterns, and quantification of source strength by country are combined to estimate and rank risk of introduction at user-scalable land parcel areas (e.g. state, county, zip code, census tract, gridded landscapes (1 mi
            2
            , 5 km
            2
            , etc.)). This risk ranking by parcel can be used to develop pathogen surveillance programmes, and has been incorporated in multiple US state/federal surveillance protocols. The census-travel model is versatile and independent of pathosystems, and applies a risk algorithm to generate risk maps for plant, human and animal contagions at different spatial scales. An interactive, user-friendly interface is available online (https://epi-models.shinyapps.io/Census_Travel/) to provide ease-of-use for regulatory agencies for early detection of high-risk exotics. The interface allows users to parametrize and run the model without knowledge of background code and underpinning data.
          
          This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control’. This theme issue is linked with the earlier issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’.}, number={1776}, journal={PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES}, author={Gottwald, Tim and Luo, Weiqi and Posny, Drew and Riley, Tim and Louws, Frank}, year={2019}, month={Jul} }
 @misc{mcroberts_figuera_olkowski_mcguire_luo_posny_gottwald_2019, title={Using models to provide rapid programme support for California's efforts to suppress Huanglongbing disease of citrus}, volume={374}, ISSN={["1471-2970"]}, DOI={10.1098/rstb.2018.0281}, abstractNote={We describe a series of operational questions posed during the state-wide response in California to the arrival of the invasive citrus disease Huanglongbing. The response is coordinated by an elected committee from the citrus industry and operates in collaboration with the California Department of Food and Agriculture, which gives it regulatory authority to enforce the removal of infected trees. The paper reviews how surveillance for disease and resource allocation between detection and delimitation have been addressed, based on epidemiological principles. In addition, we describe how epidemiological analyses have been used to support rule-making to enact costly but beneficial regulations and we highlight two recurring themes in the programme support work: (i) data are often insufficient for quantitative analyses of questions and (ii) modellers and decision-makers alike may be forced to accept the need to make decisions on the basis of simple or incomplete analyses that are subject to considerable uncertainty.This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control’. This theme issue is linked with the earlier issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’.}, number={1776}, journal={PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES}, author={McRoberts, Neil and Figuera, Sara Garcia and Olkowski, Sandra and McGuire, Brianna and Luo, Weiqi and Posny, Drew and Gottwald, Tim}, year={2019}, month={Jul} }
 @article{wang_posny_wang_2016, title={A REACTION-CONVECTION-DIFFUSION MODEL FOR CHOLERA SPATIAL DYNAMICS}, volume={21}, ISSN={["1553-524X"]}, DOI={10.3934/dcdsb.2016073}, abstractNote={In this paper, we propose a general partial differential equation (PDE) model of 
cholera epidemics that extends previous mathematical cholera studies. Our new 
formation concerns the impact of the bacterial and human diffusion, bacterial 
convection, and their interaction with the intrinsic bacterial growth and multiple 
disease transmission pathways. A sensitivity analysis for a few key model parameters 
indicates the significance of diffusion and convection in shaping cholera epidemics. 
We then investigate the traveling wave solutions of our PDE model based on 
analytical derivation and numerical simulation, with a focus on the interplay of 
different biological, environmental and physical factors that determines the spatial 
spreading speeds of cholera. In addition, disease threshold dynamics are studied 
by computing the basic reproduction number associated with the 
PDE model, using both asymptotic analysis and numerical calculation.}, number={8}, journal={DISCRETE AND CONTINUOUS DYNAMICAL SYSTEMS-SERIES B}, author={Wang, Xueying and Posny, Drew and Wang, Jin}, year={2016}, month={Oct}, pages={2785–2809} }