Research > System Plant Physiology


The Systems Plant Physiology program is developing crops with enhanced nutritional qualities and identifying new methods to improve environmental attributes. This program focuses on plant biology and its integrations with micro and macro environments, utilizing physiological, molecular, or metabolic traits to understand associated biological processes. Our broad goal is developing crop varieties with enhanced crop productivity, nutritional qualities and tolerance to abiotic stresses for greater adaptability. The critical areas of research we focus on are:

  • Nitrogen use efficiency, nitrogen sensing, transport and assimilation
  • Molecular and genetic aspects of plant metabolism

Advancing the Sustainability Practices of Organic Vegetable Production

Poor productivity of organic crops is in part attributed to the lack of nutrient management strategy, a lack of genetics designed for optimal utilization of resources, and ineffective methods to enhance nutrient uptake.  To improve yield stability, we are investigating biochemical aspects of nutrient uptake, their interactions with soil microbiomes and evaluation of nutraceutical potential of organic vegetables for human consumption and processing.

Enhancing the Nutraceutical Potential of Plants

Non-protein amino acid “citrulline” is universal in animals, plants, bacteria, and fungi. It has extensive clinical and therapeutic implications for human and animal health. We focus on many intriguing aspects of its metabolism; such as synthesis, regulation, long-distance transport, its role as an N-carrier, and as an osmolyte using molecular and metabolic cues. We are using Arabidopsis and watermelon systems to characterize citrulline metabolism.


Photo of Spinach

Enhancing the nutrient use efficiency of plants

The leaching of excessive nitrogenous fertilizers applied to commercial crops leads to environmental problems. To understand the dynamics of nutrient use efficiency we are using cutting-edge tools in genomics to identify spinach genotypes efficient in nutrient uptake, assimilation, utilization. We are using natural variation as a tool to identify the genetic variation for the anti-microbial compounds in spinach and variation in the indigenous microbiota for it’s effectiveness against food-borne pathogens.

Dr. Vijay Joshi

Assistant Professor of Systems Plant Physiology

830-278-9151 ext. 236

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Team Members

  • Ashley Rubio, Non-Affiliated Student Assistant
  • Miranda Schott, Non-Affiliated Student Assistant
  • Amit Kumar Mishra, Post Doc Student
  • Qiushuo Song, MS Student

Kudos to Ms. Qiushuo Song on her graduation.


  • Q Song, M Joshi, S Wang, C Johnson, and V Joshi* 2020. Comparative analysis of root transcriptome profiles of sesame (Sesamum indicum) in response to osmotic stress. J Plant Growth Regulation (accepted).
  • Q Song, M Joshi and V Joshi* 2020. Transcriptomic analysis of short-term salt stress response in watermelon seedlings. Int J Molecular Sciences (Special Issue- Molecular Aspects of Plant Salinity Stress and Tolerance) 21, 6036; doi:10.3390/ijms21176036
  • Q Song, M Joshi, J DiPiazza, V Joshi* (2020) Functional relevance of citrulline in the vegetative tissues of watermelon during abiotic stresses. Frontiers in Plant Science 11. DOI 10.3389/fpls.2020.00512 
  • V Joshi*, M Joshi, A Penalosa (2020) Comparative analysis of tissue-specific transcriptomic responses to nitrogen stress in spinach (Spinacia oleracea). PLOS ONE 15, e0232011. DOI 10.1371/journal.pone.0232011
  • Shi T, Joshi V, Joshi M, Vitha S, Gibbs H, Wang K, Okumoto S (2019) Broad-spectrum amino acid transporters ClAAP3 and ClAAP6 expressed in watermelon fruits. Int J Molecular Sciences. 20(23). pii: E5855. doi: 10.3390/ijms20235855.
  • Awika HO, Cochran K, Joshi V, Bedre R, Mandadi KK, Avila CA (2019) Single‐marker and haplotype‐based association analysis of anthracnose (Colletotrichum dematium) resistance in spinach (Spinacia oleracea). Plant Breed.; 1– 17.
  • Joshi, V, Shinde S., Nimmakayala P, Abburi VL, Alaparthi SB, Lopez-Ortiz C, Levi A, Panicker G, Reddy UK (2019) Haplotype Networking of GWAS Hits for Citrulline Variation Associated with the Domestication of Watermelon. Int. J. Molecular Sciences. 20, 5392.
  • Joshi V*, Joshi M, Silwal D, Noonan K, Rodriguez S*, Penalosa A* (2019) Systematized biosynthesis, and catabolism regulates citrulline accumulation in watermelon. Phytochemistry 162: 129-140.
  • Joshi V*, Fernie A (2017) Citrulline Metabolism in Plants. Amino Acids 49(9): 1543-1559.
  • Huang T, Joshi V, Jander G (2014) The catabolic enzyme MGL methionine gamma-lyase limits methionine accumulation in potato tubers. Plant Biotechnology Journal 12(7): 883-893
  • Adio AM, Casteel CL, De Vos Martin, Kim J, Joshi, V et al., (2011) Biosynthesis and defensive function of Nd-acetylornithine, a jasmonate induced Arabidopsis metabolite. Plant Cell 23(9): 3303-18
  • Jander, G and Joshi, V. (2010) Deciphering the biosynthesis of aspartate-derived amino acids in plants: Metabolic networks and molecular mechanisms. Molecular Plant 3:54-65.
  • Joshi V, Joung J, Fei Z., Jander G (2009) Transcriptional regulation and synthesis of branched chain amino acids as osmolytes in plants under drough tand cold stress. Amino Acids 39(4):933-47.
  • Joshi V, Jander G (2009) Arabidopsis thaliana methionine gamma-lyase is regulated according to isoleucine biosynthesis needs but plays a subordinate role to threonine deaminase. Plant Physiology 151:367-378.
  • Joshi V, Laubengayer K, Schauer N, Fernie A, Jander G (2006) Two Arabidopsis threonine aldolases are non-redundant and compete with threonine deaminase for a common substrate pool. Plant Cell 18: 3564-3575
  • Jander G, Norris SR, Joshi V*, Fraga M, Rugg A, Yu S, Li L, Last R (2004) Application of a high throughput HPLC-MS/MS assay to Arabidopsis mutant screening; evidence that threonine aldolase plays a role in seed nutritional quality. Plant Journal 39 (3) 465-475.
  • Telang M, Srinivasan A, Patankar A, Harsulkar A, Joshi V, Damle, Deshpande, Sainani, Ranjekar, Gupta G, Birah A, Rani S, Kachole M, Giri A, Gupta V (2003) Bitter gourd proteinase inhibitors: potential growth inhibitors of Helicoverpa armigera & Spodoptera litura. Phytochemistry 63(6) 643-652.
  • Joshi, V, Ugale SD (2002) Involvement of higher order gene interactions addressing complex polygenetically controlled the inheritance of downy mildew (Sclerospora graminicola S), resistance in pearl millet (P glaucum). Euphytica 127(2): 149-161
  • Shetty S, Joshi V, Vasanthi NS, Sarosh BR, Kini KR, Ugale SD (2001) Inheritance of downy mildew resistance, beta-1,3 glucanases and peroxidases in pearl millet (Pennisetum glaucum) crosses. Theoretical and Applied Genetics 103:1311


  • Grant #1