Publications of NIPGR Scientists
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Item Induced post-invasive defenses in the nonhost plant Parthenium hysterophorus L. prevent root cortical colonization by Macrophomina phaseolina and impart resistance to dry root rot(Elsevier B.V., 2025) Mirchandani, Rishabh; Kandpal, Manu; Ranjan, Aashish; Sinharoy, Senjuti; Senthil-Kumar, MuthappaDry root rot (DRR) of chickpea is caused by the broad-range necrotrophic fungus Macrophomina phaseolina. Chickpea germplasm does not provide durable resistance to DRR, which is particularly devastating under drought. Even moderately resistant chickpea varieties become susceptible under combined stress. We hypothesized that nonhost resistance (NHR) is durable even under combined stress. Using the blotter paper assay and stereomicroscopic observations, we identified the asterid weed Parthenium hysterophorus as a potential nonhost of M. phaseolina among 82 potential nonhosts. Epidermal necrotic lesions were prevented in P. hysterophorus. In planta fungal load was 0.195 and 0.007 ng/ng total DNA in chickpea and P. hysterophorus, respectively. M. phaseolina could not colonize the P. hysterophorus root while up to 6 cortical cell layers were colonized in chickpea. Further, NHR was durable under combined stress. Dual RNA sequencing revealed that M. phaseolina actively attempted to infect the nonhost and activated specific genes in the xenobiotics degradation pathway. P. hysterophorus also showed an active defense response with1958 and 2294 differentially expressed genes at 2 and 4 DAI, respectively, with 363 upregulated at both time points. Differential expression of cell wall synthesis, phytohormone signaling, and other defense response pathways likely contributes to NHR. Few genes in the phenylpropanoid biosynthesis pathways in P. hysterophorus were also upregulated, possibly because these metabolites are linked to the distinct changes in the fungus during nonhost infection. We therefore conclude that P. hysterophorus exhibits post-invasive NHR to M. phaseolina and that general defense, phytohormone signaling and secondary metabolic pathways contribute to NHR.Item Navigating towards dry root rot resistance in mungbean: impacts, mechanisms, and management strategies(Springer Nature Publishing AG, 2024) Sadhana, Nithyananth Hemanth; Geethanjali, Subramaniam; Mirchandani, Rishabh; Natesan, Senthil; Senthil-Kumar, MuthappaVigna radiata L., commonly referred to as mungbean or green gram, holds significant importance as a pulse crop in India. However, its productivity is severely impacted by the combined incidence of dry root rot disease and drought stress. Dry root rot, caused by Macrophomina phaseolina, manifests as reduced yield and compromised produce quality. M. phaseolina is a necrotrophic fungus with a broad host range. Screening studies in several crops’ germplasms have shown a skewness towards susceptibility. Further, the fungus has augmented virulence and survivability in soil under low moisture and high heat. Thus, concurrent drought and dry root rot leads to significantly higher yield losses. This review highlights the status of the disease in mungbean and its future implications owing to the changing climate scenario. We also highlight the molecular and genomic studies conducted in mungbean and several other crops to elucidate the mechanisms involved in M. phaseolina resistance. The review also suggests management practices which can alleviate yield losses in dry root rot affected fields. Understanding the physiological and molecular mechanisms of dry root rot, drought, and their interaction on disease proliferation can help mitigate the challenges associated with dry root rot management and aid future research.Item Abiotic stress impact on the interaction between Macrophomina phaseolina and crop plants(Springer Nature Publishing AG, 2024) Ranjan, Shubhashish; Mirchandani, Rishabh; Senthil-Kumar, MuthappaMacrophomina phaseolina (Tassi.) Goid is an emerging pathogen that causes diseases like dry root rot and charcoal rot in more than 100 plant families. Abiotic stresses such as drought, salinity, and heat exacerbate this fungal effect and predispose crops to pathogen attacks. Importantly, these combined stresses lead to significant crop yield losses under field conditions. In this, we review the interaction between the devastating pathogen M. phaseolina and several abiotic stresses that are more likely to occur in scenarios of climate change. Drought, heat, and salinity are the major stresses that interact with M. phaseolina in the field. We discuss several field studies, unique physiological and molecular responses, and their mechanisms of control in response to combined stress. The net effect of these interactions depends on a multitude of factors; thus, these interactions modify the impact of biotic stresses on plants by altering their susceptibility. The aim of this review is to provide an overview of what is currently known about M. phaseolina and abiotic stress interactions, as well as several other edaphic factors that interact with plants. We briefly discuss the role of drought, salinity, heat stress, and edaphic factors (such as pH, N, P, K, etc.) that influence pathogen infection in plants. Furthermore, we discuss possible management strategies to combat crop loss due to combined stress. Thus, we suggest the future aspect of combined stress breeding, along with the use of multi-omics techniques and genome editing approaches, to develop cultivars that exhibit stability in a combined stress environment.
