Research Projects

Mungbean is an important protein-rich pulse crop in Asia [1]. India is the world’s largest producer of mungbean, with an overall yield of 685 Kg/Ha in 2024-25 (Unified portal for agricultural statistics, 2025). The growth and productivity of mungbean is significantly hampered by biotic factors. Powdery mildew and anthracnose, caused by Erysiphe polygonii and Colletotrichum lindemuthianum, respectively, are among the major fungal diseases impacting mungbean yield in India [2,3]. Current disease-resistant varieties are limited and often race-specific, emphasizing a need to identify novel sources of resistance against these pathogens. Host plant resistance is rapidly overcome by constantly evolving pathogen populations. Nonhost resistance (NHR) is an immune response exhibited by plant species against all strains of a non-adapted pathogen [4]. NHR is multilayered, involving pre- and post-invasive defenses such as recognition of conserved pathogen molecules, cell wall reinforcement, hypersensitive response, and downstream defense activation. Unlike host resistance, which is often strain-specific and short-lived, NHR is generally broad-spectrum and more durable [5]. Understanding NHR mechanisms in crops holds a great potential for engineering disease resistant crops [6], but remains underexplored in legumes, particularly mungbean. Nucleotide-binding leucine-rich repeat receptors (NLRs) are intracellular immune receptors in plants that play a key role in host and NHR [7]. Recent studies have shown that NLRs can recognize effectors secreted by non-adapted pathogens and trigger a hypersensitive response, contributing to NHR in nonhost plants. Notably, NLRs recognizing non-adapted pathogen effectors may provide more durable resistance, as NLRs derived from a nonhost may be more tolerant to pathogen-mediated immune suppression than those derived from host plants [8]. These NLRs, therefore, serve as untapped resources that can be harnessed for the development of broad-spectrum resistance against adapted pathogens in susceptible hosts. Identification of NLR networks that recognize effectors from non-adapted pathogens and their functional validation in susceptible host plants against adapted pathogens are essential first steps in this process. This study aims to elucidate the molecular mechanisms underlying NHR in mungbean against two non-adapted fungal pathogens: Erysiphe pisi (a biotroph) and Colletotrichum siamense (a hemibiotroph) with distinct lifestyles and to identify candidate defense genes using histochemical and omics approaches. Since functional NLRs typically exhibit high expression in uninfected plants [9] and are induced in response to pathogen infection, particularly in resistant plants [10], we expect the omics approach to identify NLRs with high basal and pathogen-responsive expression. Further, we aim to use in silico structure-based predictions to identify NLR candidates that recognize candidate effector proteins secreted by non-adapted fungal pathogens and functionally validate their ability to confer resistance against adapted pathogens in a related susceptible legume host through transient expression assays. We expect the outcomes of this project to provide novel insights into NHR in mungbean and have a direct translational potential for contributing robust disease resistance in legume crops. This will be the first comprehensive study to reveal complex regulatory pathways associated with NHR in mungbean. References: 1 Nair & Schreinemachers, 2020, The mungbean genome. 2 Pandey et al., 2021, Plant Dis. 3 Behera et al., 2024, Indian Phytopathol. 4 Panstruga & Moscou, 2020, Mol. Plant-Microbe Interact. 5 Thordal-Christensen, 2003, Curr. Opin Plant Biol. 6 Fonseca et al., 2019, Plant Sci. 7 Oh & Choi, 2022, Essays Biochem. 8 Oh et al., 2023, Plant Biotechnol. J. 9 Brabham et al., 2024, bioRxiv. 10 Fick et al., 2022, Front. Plant Sci.