@article{dutta_houdinet_nandakafle_kafle_hawkes_garcia_2023, title={Agrobacterium tumefaciens-mediated transformation of Nigrospora sp. isolated from switchgrass leaves and antagonistic toward plant pathogens}, volume={215}, ISSN={["1872-8359"]}, url={http://dx.doi.org/10.1016/j.mimet.2023.106849}, DOI={10.1016/j.mimet.2023.106849}, abstractNote={Nigrospora is a diverse genus of fungi colonizing plants through endophytic, pathogenic, or saprobic interactions. Endophytic isolates can improve growth and development of host plants, as well as their resistance to microbial pathogens, but exactly how they do so remains poorly understood. Developing a reliable transformation method is crucial to investigate these mechanisms, in particular to identify pivotal genes for specific functions that correlate with specific traits. In this study, we identified eight isolates of Nigrospora sp. internally colonizing the leaves of switchgrass plants cultivated in North Carolina. Using an Agrobacterium tumefaciens-mediated transformation approach with control and GFP-expressing vectors, we report the first successful transformation of two Nigrospora isolates. Finally, we demonstrate that wild-type and transgenic isolates both negatively impact the growth of two plant pathogens in co-culture conditions, Bipolaris maydis and Parastagonospora nodorum, responsible for the Southern Leaf Blight and Septoria Nodorum Blotch diseases, respectively. The GFP-transformed strains developed here can therefore serve as accurate reporters of spatial interactions in future studies of Nigrospora and pathogens in the plant. Finally, the transformation method we describe lays the foundation for further genetic research on the Nigrospora genus to expand our mechanistic understanding of plant-endophyte interactions.}, journal={JOURNAL OF MICROBIOLOGICAL METHODS}, author={Dutta, Summi and Houdinet, Gabriella and NandaKafle, Gitanjali and Kafle, Arjun and Hawkes, Christine V. and Garcia, Kevin}, year={2023}, month={Dec} }
 @article{das_kafle_ho-plagaro_zimmermann_bucking_garcia_2023, title={Importance of root symbiomes for plant nutrition: new insights, perspectives and future challenges, volume II}, volume={14}, ISSN={["1664-462X"]}, DOI={10.3389/fpls.2023.1296604}, abstractNote={EDITORIAL article Front. Plant Sci., 04 October 2023Sec. Plant Pathogen Interactions Volume 14 - 2023 | https://doi.org/10.3389/fpls.2023.1296604}, journal={FRONTIERS IN PLANT SCIENCE}, publisher={Frontiers Media SA}, author={Das, Debatosh and Kafle, Arjun and Ho-Plagaro, Tania and Zimmermann, Sabine D. and Bucking, Heike and Garcia, Kevin}, year={2023}, month={Oct} }
 @article{garcia_cloghessy_cooney_shelley_chakraborty_kafle_busidan_sonawala_collier_jayaraman_et al._2023, title={The putative transporter MtUMAMIT14 participates in nodule formation in Medicago truncatula}, volume={13}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-023-28160-8}, abstractNote={AbstractTransport systems are crucial in many plant processes, including plant–microbe interactions. Nodule formation and function in legumes involve the expression and regulation of multiple transport proteins, and many are still uncharacterized, particularly for nitrogen transport. Amino acids originating from the nitrogen-fixing process are an essential form of nitrogen for legumes. This work evaluates the role of MtN21 (henceforth MtUMAMIT14), a putative transport system from the MtN21/EamA-like/UMAMIT family, in nodule formation and nitrogen fixation in Medicago truncatula. To dissect this transporter’s role, we assessed the expression of MtUMAMIT14 using GUS staining, localized the corresponding protein in M. truncatula root and tobacco leaf cells, and investigated two independent MtUMAMIT14 mutant lines. Our results indicate that MtUMAMIT14 is localized in endosomal structures and is expressed in both the infection zone and interzone of nodules. Comparison of mutant and wild-type M. truncatula indicates MtUMAMIT14, the expression of which is dependent on the presence of NIN, DNF1, and DNF2, plays a role in nodule formation and nitrogen-fixation. While the function of the transporter is still unclear, our results connect root nodule nitrogen fixation in legumes with the UMAMIT family.}, number={1}, journal={SCIENTIFIC REPORTS}, publisher={Springer Science and Business Media LLC}, author={Garcia, Kevin and Cloghessy, Kaylee and Cooney, Danielle R. and Shelley, Brett and Chakraborty, Sanhita and Kafle, Arjun and Busidan, Aymeric and Sonawala, Unnati and Collier, Ray and Jayaraman, Dhileepkumar and et al.}, year={2023}, month={Jan} }
 @article{kafle_garcia_2022, title={Cesium could be used as a proxy for potassium in mycorrhizal Medicago truncatula}, volume={17}, ISSN={["1559-2324"]}, url={https://doi.org/10.1080/15592324.2022.2134676}, DOI={10.1080/15592324.2022.2134676}, abstractNote={ABSTRACT Arbuscular mycorrhizal (AM) fungi interact with the roots of most land plants and help them to acquire various mineral resources from the soil, including potassium (K+). However, tracking K+ movement in AM symbiosis remains challenging. Recently, we reported that rubidium can be used as a proxy for K+ in mycorrhizal Medicago truncatula. In the present work, we investigated the possibility of using cesium (Cs+) as another proxy for K+ in AM symbiosis. Plants were placed in growing systems that include a separate compartment only accessible to the AM fungus Rhizophagus irregularis isolate 09 and in which various amounts of cesium chloride (0 mM, 0.5 mM, 1.5 mM, or 3.75 mM) were supplied. Plants were watered with sufficient K+ or K+-free nutrient solutions, and shoot and root biomass, fungal colonization, and K+ and Cs+ concentrations were recorded seven weeks after inoculation. Our results indicate that Cs+ accumulated in plant tissues only when K+ was present in the nutrient solution and when the highest concentration of Cs+ was used in the fungal compartment. Consequently, we conclude that Cs+ could be used as a proxy for K+ in AM symbiosis, but with serious limitations.}, number={1}, journal={PLANT SIGNALING & BEHAVIOR}, author={Kafle, Arjun and Garcia, Kevin}, year={2022}, month={Dec} }
 @article{wei-ge_xiao-fen_xi-he_batchelor_kafle_gu_2022, title={Indigenous arbuscular mycorrhizal fungi play a role in phosphorus depletion in organic manure amended high fertility soil}, volume={21}, ISSN={["2095-3119"]}, DOI={10.1016/j.jia.2022.07.045}, abstractNote={The species richness and propagule number of arbuscular mycorrhizal fungi (AMF) are high in intensively managed agricultural soils. Past research has shown that AMF improve crop phosphorus (P) uptake under low soil P conditions, however it is unclear if AMF play a role in high Olsen-P soils. In this study, we investigated whether native fungal benefits exist under high P input field conditions in-situ and contribute to P utilization. We installed in-grow tubes which were sealed with different membrane pore sizes (30 or 0.45 μm) to allow or prevent AMF hyphae access to the hyphal compartment and prevent cotton roots from penetrating the chamber. We used the depletion of soil available P (Olsen-P) in the hyphae accessed compartment to indicate P uptake by the native AMF community. Our results showed that the native AMF mediated P depletion and microbial biomass P (MBP) turnover and caused the largest Olsen-P depletion ratio and MBP turnover ratio in the high P treatments (Olsen-P: 78.29 mg kg−1). The cotton roots in each fertilization regime were colonized by a unique AMF community and Glomus and Paraglomus were the dominant genera, implying the long-term fertilization regimes domesticated the AMF community. We conclude that native AMF caused the P depletion and P turnover even under high soil Olsen-P conditions.}, number={10}, journal={JOURNAL OF INTEGRATIVE AGRICULTURE}, author={Wei-Ge, Huo and Xiao-Fen, Chai and Xi-He, Wang and Batchelor, William David and Kafle, Arjun and Gu, Feng}, year={2022}, month={Oct}, pages={3051–3066} }
 @article{kafle_cooney_shah_garcia_2022, title={Mycorrhiza-mediated potassium transport in Medicago truncatula can be evaluated by using rubidium as a proxy}, volume={322}, ISSN={["1873-2259"]}, DOI={10.1016/j.plantsci.2022.111364}, abstractNote={Arbuscular mycorrhizal (AM) fungi considerably improve plant nutrient acquisition, particularly phosphorus and nitrogen. Despite the physiological importance of potassium (K+) in plants, there is increasing interest in the mycorrhizal contribution to plant K+ nutrition. Yet, methods to track K+ transport are often costly and limiting evaluation opportunities. Rubidium (Rb+) is known to be transported through same pathways as K+. As such our research efforts attempt to evaluate if Rb+ could serve as a viable proxy for evaluating K+ transport in AM symbiosis. Therefore, we examined the transport of K+ in Medicago truncatula colonized by the AM fungus Rhizophagus irregularis isolate 09 having access to various concentrations of Rb+ in custom-made two-compartment systems. Plant biomass, fungal root colonization, and shoot nutrient concentrations were recorded under sufficient and limited K+ regimes. We report that AM plants displayed higher shoot Rb+ and K+ concentrations and a greater K+:Na+ ratio relative to non-colonized plants in both sufficient and limited K+ conditions. Consequently, our results indicate that Rb+ can be used as a proxy to assess the movement of K+ in AM symbiosis, and suggest the existence of a mycorrhizal uptake pathway for K+ nutrition in M. truncatula.}, journal={PLANT SCIENCE}, author={Kafle, Arjun and Cooney, Danielle R. and Shah, Garud and Garcia, Kevin}, year={2022}, month={Sep} }
 @article{cope_kafle_yakha_pfeffer_strahan_garcia_subramanian_bucking_2022, title={Physiological and transcriptomic response of Medicago truncatula to colonization by high- or low-benefit arbuscular mycorrhizal fungi}, volume={32}, ISSN={["1432-1890"]}, url={https://doi.org/10.1007/s00572-022-01077-2}, DOI={10.1007/s00572-022-01077-2}, abstractNote={Arbuscular mycorrhizal (AM) fungi form a root endosymbiosis with many agronomically important crop species. They enhance the ability of their host to obtain nutrients from the soil and increase the tolerance to biotic and abiotic stressors. However, AM fungal species can differ in the benefits they provide to their host plants. Here, we examined the putative molecular mechanisms involved in the regulation of the physiological response of Medicago truncatula to colonization by Rhizophagus irregularis or Glomus aggregatum, which have previously been characterized as high- and low-benefit AM fungal species, respectively. Colonization with R. irregularis led to greater growth and nutrient uptake than colonization with G. aggregatum. These benefits were linked to an elevated expression in the roots of strigolactone biosynthesis genes (NSP1, NSP2, CCD7, and MAX1a), mycorrhiza-induced phosphate (PT8), ammonium (AMT2;3), and nitrate (NPF4.12) transporters and the putative ammonium transporter NIP1;5. R. irregularis also stimulated the expression of photosynthesis-related genes in the shoot and the upregulation of the sugar transporters SWEET1.2, SWEET3.3, and SWEET 12 and the lipid biosynthesis gene RAM2 in the roots. In contrast, G. aggregatum induced the expression of biotic stress defense response genes in the shoots, and several genes associated with abiotic stress in the roots. This suggests that either the host perceives colonization by G. aggregatum as pathogen attack or that G. aggregatum can prime host defense responses. Our findings highlight molecular mechanisms that host plants may use to regulate their association with high- and low-benefit arbuscular mycorrhizal symbionts.}, number={3-4}, journal={MYCORRHIZA}, publisher={Springer Science and Business Media LLC}, author={Cope, Kevin R. and Kafle, Arjun and Yakha, Jaya K. and Pfeffer, Philip E. and Strahan, Gary D. and Garcia, Kevin and Subramanian, Senthil and Bucking, Heike}, year={2022}, month={May} }
 @article{wang_wang_maimaitiaili_kafle_khan_feng_2021, title={Breeding Practice Improves the Mycorrhizal Responsiveness of Cotton (Gossypium spp. L.)}, volume={12}, ISSN={["1664-462X"]}, DOI={10.3389/fpls.2021.780454}, abstractNote={Maximizing the function of indigenous arbuscular mycorrhizal (AM) fungi by choosing specific crop genotypes offers one of the few untapped opportunities to improve the sustainability of agriculture. In this study, the differences in mycorrhizal responsiveness (MR) in plant growth and shoot phosphorus (P) content among cotton (Gossypium spp. L.) genotypes from different release dates were compared and then the relationships between MR and P uptake-related traits were determined. The experimental design in a greenhouse included 24 genotypes released from 1950 to present in Xinjiang Province, inoculation with or without AM fungi, and P levels (15 and 150 mg P kg–1 added as KH2PO4). Results showed that the modern cotton genotypes exhibited a higher degree of mycorrhizal colonization, the hyphal length density (HLD), and mycorrhizae-induced changes in shoot growth than the old genotypes when inoculated with indigenous AM fungi at both the P levels. Moreover, MR was highly correlated with the HLD at low P levels and the HLD may provide useful insights for future cotton breeding aimed at delivering crop genotypes that can benefit more from AM fungi.}, journal={FRONTIERS IN PLANT SCIENCE}, author={Wang, Letian and Wang, Xihe and Maimaitiaili, Baidengsha and Kafle, Arjun and Khan, Khuram Shehzad and Feng, Gu}, year={2021}, month={Dec} }
 @article{salomon_demarmels_watts-williams_mclaughlin_kafle_ketelsen_soupir_buecking_cavagnaro_heijden_2022, title={Global evaluation of commercial arbuscular mycorrhizal inoculants under greenhouse and field conditions}, volume={169}, ISSN={["1873-0272"]}, DOI={10.1016/j.apsoil.2021.104225}, abstractNote={Arbuscular mycorrhizal fungi (AMF) are plant symbionts that promote plant growth and provide important plant and ecosystem functions. These abilities have great economical potential which has resulted in an increasing number of commercially available AMF inoculants. Here, we present the results of a global study in which we evaluate the effectiveness of 28 commercial AMF inoculants to colonize host plants under greenhouse and field conditions. This evaluation includes three independent studies across three continents (Australia, Europe, and North America). The Australian and European studies tested 25 different commercial AMF inoculants in non-sterilized and sterilized soils under greenhouse conditions and compared them against laboratory cultures of the AMF Rhizophagus irregularis. This is supplemented by the North American study which evaluated the effects of three commercial inoculants under field conditions. In the greenhouse trials using non-sterilized soil, we observed that the addition of commercial inoculants did not lead to enhanced mycorrhizal colonization and inoculation increased plant biomass in only one out of 25 treatments. In sterilized soil, 84% of the mycorrhizal inoculants did not lead to mycorrhizal root colonization, demonstrating that these products did not contain viable propagules. In contrast, the laboratory cultures of the AM fungus Rhizophagus irregularis resulted in substantial root colonization (48% and 79%) in the Australian and European bioassay. Moreover, only five out of 25 treatments enhanced plant biomass when added to sterilized soil. Metagenomic analysis of field roots in the North American field trial revealed changes in the mycorrhizal community after inoculation. For one inoculant, this was accompanied by increased biomass production. This global evaluation of commercial inoculants raises concerns over unreliable products which do not contain viable propagules and do not result in mycorrhizal root colonization. Under field conditions, effects on plant growth are dependent on changes within the mycorrhizal community. The results of this study highlight the need for standardized quality control of AMF inoculants and further research on their establishment and effects under field conditions.}, journal={APPLIED SOIL ECOLOGY}, author={Salomon, M. J. and Demarmels, R. and Watts-Williams, S. J. and McLaughlin, M. J. and Kafle, A. and Ketelsen, C. and Soupir, A. and Buecking, H. and Cavagnaro, T. R. and Heijden, M. G. A.}, year={2022}, month={Jan} }
 @misc{kafle_frank_rose_garcia_2022, title={Split down the middle: studying arbuscular mycorrhizal and ectomycorrhizal symbioses using split-root assays}, volume={73}, ISSN={["1460-2431"]}, url={https://doi.org/10.1093/jxb/erab489}, DOI={10.1093/jxb/erab489}, abstractNote={Abstract
               Most land plants symbiotically interact with soil-borne fungi to ensure nutrient acquisition and tolerance to various environmental stressors. Among these symbioses, arbuscular mycorrhizal and ectomycorrhizal associations can be found in a large proportion of plants, including many crops. Split-root assays are widely used in plant research to study local and systemic signaling responses triggered by local treatments, including nutrient availability, interaction with soil microbes, or abiotic stresses. However, split-root approaches have only been occasionally used to tackle these questions with regard to mycorrhizal symbioses. This review compiles and discusses split-root assays developed to study arbuscular mycorrhizal and ectomycorrhizal symbioses, with a particular emphasis on colonization by multiple beneficial symbionts, systemic resistance induced by mycorrhizal fungi, water and nutrient transport from fungi to colonized plants, and host photosynthate allocation from the host to fungal symbionts. In addition, we highlight how the use of split-root assays could result in a better understanding of mycorrhizal symbioses, particularly for a broader range of essential nutrients, and for multipartite interactions.}, number={5}, journal={JOURNAL OF EXPERIMENTAL BOTANY}, publisher={Oxford University Press (OUP)}, author={Kafle, Arjun and Frank, Hannah E. R. and Rose, Benjamin D. and Garcia, Kevin}, editor={Gifford, MiriamEditor}, year={2022}, month={Mar}, pages={1288–1300} }