Publications of NIPGR Scientists
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Item Plant biotic stress: tools and techniques for crop protection(Springer Nature Publishing AG, 2026) Acharya, Krishna Ramakrishnan; Chilakala, Aswin Reddy; Senthil-Kumar, MuthappaAs climate change continues to impact crop yields, developing strategies to enhance plant tolerance to biotic stress has become increasingly important. This requires a thorough evaluation of the tools and methodologies used to manipulate and study biotic stress tolerance. It is crucial to comprehensively understand both conventional and modern techniques, as well as their effectiveness in addressing the specific needs of the crop under study. Detecting diseases at the early stages of plant development can prevent significant losses in large-scale cultivations. Two broad approaches commonly used to mitigate biotic stresses are eliminating causative agents such as fungi, bacteria, nematodes, viruses, or pests, and imparting resistance to the plant. Although there are similarities in the tools and techniques used to address different biotic stresses, each scenario requires dedicated case studies. It is also essential to stay up to date with the latest developments in plant biotechnology to incorporate a cross-disciplinary approach in conducting and validating experiments. This chapter provides an overview of methods covered in this book ranging from molecular breeding to nondestructive techniques that help achieve the goal of safeguarding plant health.Item Extracellular acidification assay to evaluate the effectiveness of antifungal agents on the pathogenicity of Macrophomina phaseolina(Springer Nature Publishing AG, 2026) Acharya, Krishna Ramakrishnan; Chilakala, Aswin Reddy; Senthil-Kumar, MuthappaMacrophomina phaseolina is a fungus that causes dry root rot disease and considerable yield loss worldwide. Fungi exhibit various ways of absorbing nutrients through their plasma membrane, such as free or facilitated diffusion, diffusion channels, or active transport. Glucose, as a preferred carbon source, activates the plasma membrane H+-ATPase, resulting in the release of protons. Consequently, the protons, along with the organic acid metabolites released into the extracellular environment, acidify the cell surroundings. This decrease in pH cues the fungus to shift from saprotrophic to necrotrophic growth, facilitating host invasion. Sustainable dry root rot disease management often relies on the employment of antifungal agents from various biological sources. Despite the discovery of numerous antifungal agents, only a limited number have been evaluated for their efficacy against this phytopathogenic fungus. This scarcity of testing is primarily due to the limitations of existing methods, which often lack standardisation and reproducibility. This chapter introduces a rapid and sensitive method to assess the antifungal activity of various agents against M. phaseolina. By measuring extracellular pH changes after treatment in the presence of a nutrient source, we can determine the inhibitory concentrations of these agents and evaluate their potential for controlling fungal pathogenicity in plants.Item Drought attenuates plant responses to multiple rhizospheric pathogens: A study on a dry root rot-associated disease complex in chickpea fields(Elsevier B.V., 2023) Chilakala, Aswin Reddy; Pandey, Prachi; Durgadevi, Athimoolam; Kandpal, Manu; Patil, Basavanagouda S.; Rangappa, Krishnappa; Reddy, Puli Chandra Obul; Ramegowda, Venkategowda; Senthil-Kumar, MuthappaContext or problem: Root rots, a major factor contributing to yield loss in chickpea, often occur in disease complexes. Objective or research question: Plant responses to disease complexes are not well elucidated. We sought a clear understanding of a newly identified disease complex in chickpea, dry root rot (DRR)–wilt disease complex, in the field and studied the effect of drought on the severity of the complex and its effect on yield. We compared plant responses to DRR alone and the disease complex under drought and determined the phytohormones involved in plant defense against the disease complex. Methods: We compared the effect of 14 environments (two soil moisture regimes at seven locations) on the incidence of the disease complex and yield loss in four chickpea genotypes. We also studied the effect of drought on rhizospheric and root endo-microbial communities by whole-genome and metagenomic sequencing and performed LC-MS-based phytohormonal profiling of chickpea roots. Results: Soil moisture and plant genetic variability were critical in modulating disease incidence in field conditions. DRR was the primary driver of the disease complex under drought stress. Drought aggravated the yield reductions caused by the disease complex from 35% to 60% in susceptible genotypes. Further, drought-tolerant genotypes performed better under combined disease complex infection and drought stress and exhibited lesser yield losses than susceptible genotypes. Pathogenic fungi such as Macrophomina phaseolina, Fusarium oxysporum, and Rhizoctonia solani were enriched in the chickpea rhizosphere, and M. phaseolina was predominant in infected chickpea roots under both well-watered and drought conditions. Symbiotic associations of chickpea with nitrogen-fixing bacteria were suppressed under drought stress. Abscisic acid, jasmonic acid, and salicylic acid were found to be involved in defense against the disease complex across various stages of plant growth. Implications or significance: We highlight the interaction between drought and soil pathogens affecting chickpea yield and suggest the utilization of drought-tolerant root traits as donor traits for improving combined stress resistance. We also demonstrate growth stage–dependent phytohormonal responses elicited by DRR and the DRR–wilt disease complex. The identification and management of root rots is essential, and our findings offer valuable new insights into a lesser-known but highly significant disease complex of chickpea. Data availability statement: Manuscript data is available at Supplementary File S1. The soil microbe whole-genome and metagenome and root-microbe 16 S and ITS sequencing data are available at NCBI PRJNA871091 and PRJNA895851.Item Dry root rot disease: Current status and future implications for chickpea production(Springer Nature Publishing AG, 2023) Mirchandani, Rishabh; Irulappan, Vadivelmurugan; Chilakala, Aswin Reddy; Senthil-Kumar, MuthappaChickpea is one of the most important food legumes in the world. Several abiotic and biotic factors limit chickpea yields, notably, heat, drought, and dry root rot (DRR) disease. The occurrence and severity of DRR are further magnified by abiotic stresses. This review highlights the current impact of DRR on chickpea production in India, the deepening of the economic losses caused by DRR owing to drought, and integrated management practices to curb DRR. Management strategies and research targeting this aspect are critical because the long-term consequences of this rapidly emerging disease could be severe owing to climate change.Item Combined drought and heat stress influences the root water relation and determine the dry root rot disease development under field conditions: A study using contrasting chickpea genotypes(Frontiers Media S.A., 2022) Chilakala, Aswin Reddy; Mali, Komal Vitthalrao; Irulappan, Vadivelmurugan; Patil, Basavanagouda S.; Pandey, Prachi; Rangappa, Krishnappa; Ramegowda, Venkategowda; Kumar, M. Nagaraj; Puli, Chandra Obul Reddy; Mohan-Raju, Basavaiah; Senthil-Kumar, MuthappaAbiotic stressors such as drought and heat predispose chickpea plants to pathogens of key importance leading to significant crop loss under field conditions. In this study, we have investigated the influence of drought and high temperature on the incidence and severity of dry root rot disease (caused by Macrophomina phaseolina) in chickpea, under extensive on- and off-season field trials and greenhouse conditions. We explored the association between drought tolerance and dry root rot resistance in two chickpea genotypes, ICC 4958 and JG 62, with contrasting resistance to dry root rot. In addition, we extensively analyzed various patho-morphological and root architecture traits altered by combined stresses under field and greenhouse conditions in these genotypes. We further observed the role of edaphic factors in dry root rot incidence under field conditions. Altogether, our results suggest a strong negative correlation between the plant water relations and dry root rot severity in chickpeas, indicating an association between drought tolerance and dry root rot resistance. Additionally, the significant role of heat stress in altering the dynamics of dry root rot and the importance of combinatorial screening of chickpea germplasm for dry root rot resistance, drought, and heat stress have been revealed.