Browsing by Author "Sinha, Ranjita"

Now showing 1 - 6 of 6

Concurrent drought stress and vascular pathogen infection induce common and distinct transcriptomic responses in chickpea
(Frontiers Media S.A., 2017) Sinha, Ranjita; Gupta, Aarti; Senthil-Kumar, Muthappa
Chickpea (Cicer arietinum); the second largest legume grown worldwide is prone to drought and various pathogen infections. These drought and pathogen stresses often occur concurrently in the field conditions. However, the molecular events in response to that are largely unknown. The present study examines the transcriptome dynamics in chickpea plants exposed to a combination of water-deficit stress and Ralstonia solanacearum infection. R. solanacearum is a potential wilt disease causing pathogen in chickpea. Drought stressed chickpea plants were infected with this pathogen and the plants were allowed to experience progressive drought with 2 and 4 days of R. solanacearum infection called short duration stress (SD stresses) and long duration stress (LD stresses), respectively. Our study showed that R. solanacearum multiplication decreased under SD-combined stress compared to SD-pathogen but there was no significant change in LD-combined stress compared to LD-pathogen. The microarray analysis during these conditions showed that 821 and 1039 differentially expressed genes (DEGs) were unique to SD- and LD-combined stresses, respectively, when compared with individual stress conditions. Three and fifteen genes were common among all the SD-stress treatments and LD-stress treatments, respectively. Genes involved in secondary cell wall biosynthesis, alkaloid biosynthesis, defense related proteins, and osmo-protectants were up-regulated during combined stress. The expression of genes involved in lignin and cellulose biosynthesis were specifically up-regulated in SD-combined, LD-combined, and LD-pathogen stress. A close transcriptomic association of LD-pathogen stress with SD-combined stress was observed in this study which indicates that R. solanacearum infection also exerts drought stress along with pathogen stress thus mimics combined stress effect. Furthermore the expression profiling of candidate genes using real-time quantitative PCR validated the microarray data. The study showed that down-regulation of defense-related genes during LD-combined stress resulted in an increased bacterial multiplication as compared to SD-combined stress. Overall, our study highlights a sub-set of DEGs uniquely expressed in response to combined stress, which serve as potential candidates for further functional characterization to delineate the molecular response of the plant to concurrent drought-pathogen stress.
Impact of concurrent drought stress and pathogen infection on plants
(Springer, 2015) Pandey, Prachi; Sinha, Ranjita; Mysore, Kirankumar S.; Senthil-Kumar, Muthappa
Concurrent abiotic and biotic stress situations greatly limit the crop productivity. The global climate change is predicted to bring forth the frequent incidences of concurrent stresses, predominantly drought and pathogen infections. Thus, understanding the impact of drought on plant–pathogen interaction is important. In this chapter, we review the recent studies that focus on the effect of concurrent drought and pathogen infection on plants. These studies indicate that concurrent stress conditions lead to the activation of unique combat pathways that are otherwise not elicited under independent stresses. Plant responses, thus, seem to be adaptively tailored for combating the combined stresses. Here, we focus on the impact of drought stress on plant–pathogen relations and highlight the different ways by which plant–pathogen interactions are modulated at physiological and molecular level. Various studies reviewed in this chapter show that the stress combinations should be considered as a “unique stress” and a better understanding of plant responses to these conditions is needed. Therefore, we propose that further efforts should be directed to identify the potential pathways conferring concurrent stress tolerance.
Impact of drought stress on simultaneously occurring pathogen infection in field-grown chickpea
(Springer Nature, 2019) Sinha, Ranjita; Irulappan, Vadivelmurugan; Mohan-Raju, Basavaiah; Suganthi, Angappan; Senthil-Kumar, Muthappa
Drought stress and pathogen infection simultaneously occur in the field. In this study, the interaction of these two stresses with chickpea, their individual and combined effect and the net impact on plant growth and yield traits were systematically assessed under field and confined pot experiments. The field experiments were conducted for four consecutive years from 2014–15 to 2017–18 at different locations of India. Different irrigation regimes were maintained to impose mild to severe drought stress, and natural incidence of the pathogen was considered as pathogen stress. We observed an increased incidence of fungal diseases namely, dry root rot (DRR) caused by Rhizoctonia bataticola, black root rot (BRR) caused by Fusarium solani under severe drought stress compared to well-irrigated field condition. Similar to field experiments, pot experiments also showed severe disease symptoms of DRR and BRR in the presence of drought compared to pathogen only stress. Overall, the results from this study not only showed the importance of combined drought and DRR stress but also provided systematic data, first of its kind, for the use of researchers.
Low soil moisture predisposes field-grown chickpea plants to dry root rot disease: evidence from simulation modeling and correlation analysis
(Springer Nature Publishing AG, 2021) Sinha, Ranjita; Irulappan, Vadivelmurugan; Patil, Basavanagouda S.; Reddy, Puli Chandra Obul; Ramegowda, Venkategowda; Mohan‑Raju, Basavaiah; Rangappa, Krishnappa; Singh, Harvinder Kumar; Bhartiya, Sharad; Senthil-Kumar, Muthappa
Rhizoctonia bataticola causes dry root rot (DRR), a devastating disease in chickpea (Cicer arietinum). DRR incidence increases under water defcit stress and high temperature. However, the roles of other edaphic and environmental factors remain unclear. Here, we performed an artifcial neural network (ANN)-based prediction of DRR incidence considering DRR incidence data from previous reports and weather factors. ANN-based prediction using the backpropagation algorithm showed that the combination of total rainfall from November to January of the chickpea-growing season and average maximum temperature of the months October and November is crucial in determining DRR occurrence in chickpea felds. The prediction accuracy of DRR incidence was 84.6% with the validation dataset. Field trials at seven diferent locations in India with combination of low soil moisture and pathogen stress treatments confrmed the impact of low soil moisture on DRR incidence under diferent agroclimatic zones and helped in determining the correlation of soil factors with DRR incidence. Soil phosphorus, potassium, organic carbon, and clay content were positively correlated with DRR incidence, while soil silt content was negatively correlated. Our results establish the role of edaphic and other weather factors in chickpea DRR disease incidence. Our ANN-based model will allow the location-specifc prediction of DRR incidence, enabling efcient decision-making in chickpea cultivation to minimize yield loss.
Possible strategies for the establishment of VIGS protocol in chickpea
(Caister Academic Press, 2018) Sinha, Ranjita; Senthil-Kumar, Muthappa
Chickpea is the second largest legume in the world. The worldwide production of chickpea is far below its potential because of the factors like nitrogen deficiency, low nutrient absorption, flower or seed abortion and its vulnerability to the abiotic and biotic stresses. Consequently, it is important to understand the key molecular factors involved in stress tolerance, growth, flowering and seed development for the genetic improvement of the existing varieties. Currently the whole genome sequencing data and transcriptome information are widely facilitating functional genomic studies in chickpea. Further, marker based trait association mapping information is available for assistance in breeding program. However, information about exact function of genes is still lacking because of the absence of genetic mutants and difficult genetic transformation in this crop. Hence, the current scenario demands the establishment of virus-induced gene silencing (VIGS) technique in chickpea. VIGS would serve as an important tool for the functional characterization of large number of genes. Despite attempts by several research teams, the VIGS protocol is not yet available till date, though VIGS has been successfully applied for the gene characterization in other legumes. In this chapter we propose some strategies that can be attempted for development of successful VIGS protocol. We also describe our experience from present and past research projects aimed to study VIGS in chickpea.
Understanding the impact of drought on foliar and xylem invading bacterial pathogen stress in chickpea
(Frontiers Media S.A., 2016) Sinha, Ranjita; Gupta, Aarti; Senthil-Kumar, Muthappa
In field conditions, plants are concurrently exposed to multiple stresses, where one stressor impacts the plants’ response to another stressor, and the resultant net effect of these stresses differs from individual stress response. The present study investigated the effect of drought stress on interaction of chickpea with Pseudomonas syringae pv. phaseolicola (Psp; foliar pathogen) and Ralstonia solanacearum (Rs; xylem inhabiting wilt causing pathogen), respectively, and the net-effect of combined stress on chlorophyll content and cell death. Two type of stress treatments were used to study the influence of each stress factor during combined stress, viz., imposition of drought stress followed by pathogen challenge (DP), and pathogen inoculated plants imposed with drought in course of pathogen infection (PD). Drought stress was imposed at different levels with pathogen inoculum to understand the influence of different stress intensities on stress interaction and their net impact. Drought stressed chickpea plants challenged with Psp infection (DPsp) showed reduced in planta bacterial number compared to Psp infection alone. Similarly, Rs infection of chickpea plants showed reduced in planta bacterial number under severe drought stress. Combined drought and Psp (DPsp) infected plants showed decreased cell death compared to plants infected only with Psp but the extent of cell death was similar to drought stressed plants. Similarly, chlorophyll content in plants under combined stress was similar to the individual drought stressed plants; however, the chlorophyll content was more compared to pathogen only infected plants. Under combined drought and Rs infection (DRs), cell death was similar to individual drought stress but significantly less compared to only Rs infected plants. Altogether, the study proposes that both stress interaction and net effect of combined stress could be majorly influenced by first occurring stress, for example, drought stress in DP treatment. In addition, our results indicate that the outcome of the two stress interaction in plant depends on timing of stress occurrence and nature of infecting pathogen.