Title : Plant systems biology: Application to rice for understanding drought stress response mechanism during vegetative, reproductive and grain-filling stages
Abstract:
Rice is one of the major global food crops. Although the overall yield of rice has been increasing, the growing population and adverse climatic changes pose huge challenges for their sustained production in the future. Drought stress severely affects rice production worldwide. It affects all stages of rice growth and development including vegetative, reproductive, and grain-filling stages. Therefore, systematic approaches are highly required to explore their effects on rice phenotypic and cellular responses. It could be achieved by combining the available multiple high throughput data such as genomics, metabolomics, proteomics and transcriptomics, thereby analysing the possible biochemical adaptations to several abiotic and biotic stresses, and subsequently improving the crop yield. We have employed similar systems biology approach and initially developed a core mathematical model of rice to characterize cellular behaviour and metabolic states under drought stress conditions. The core model was then further expanded to reconstruct a fully compartmentalized genome scale metabolic model. Subsequently, transcriptomics data were systematically integrated with the model to identify the potential candidate regulatory genes. Critical transcription factors (TFs) such as AP2/ERF, bZIP, MYB and NAC that control important gene regulatory pathways were identified through analysis of the patterns of spatio-temporal expression and cis-element enrichment for rice plants subjected to drought stress during tillering, booting and panicle elongation stages. Similarly, important TFs such AP2/ERF, bZIP, bHLH, CRF, MYB, NAC, WRKY and ZnF were identified for rice leaves moderately tolerant to drought during grain-filling stage. Moreover, identification of genes and cis-elements associated with brassinosteroid signaling pathway indicates a key role in drought tolerance during grain-filling stage. The information gathered from these analyses can guide the breeding of new rice varieties in response to drought tolerance during both vegetative and reproductive stages, leading to improved rice production.
