Coordinated regulation of photosynthesis in rice increases yield and tolerance to environmental stress.

Madana M R Ambavaram,Utlwang Batlang,Andy Pereira,Niranjan Baisakh,Lutfor Rahman,Arjun Krishnan,Supratim Basu,Venkategowda Ramegowda

doi:10.1038/ncomms6302

Abstract

Plants capture solar energy and atmospheric carbon dioxide (CO2) through photosynthesis, which is the primary component of crop yield, and needs to be increased considerably to meet the growing global demand for food. Environmental stresses, which are increasing with climate change, adversely affect photosynthetic carbon metabolism (PCM) and limit yield of cereals such as rice (Oryza sativa) that feeds half the world. To study the regulation of photosynthesis, we developed a rice gene regulatory network and identified a transcription factor HYR (HIGHER YIELD RICE) associated with PCM, which on expression in rice enhances photosynthesis under multiple environmental conditions, determining a morpho-physiological programme leading to higher grain yield under normal, drought and high-temperature stress conditions. We show HYR is a master regulator, directly activating photosynthesis genes, cascades of transcription factors and other downstream genes involved in PCM and yield stability under drought and high-temperature environmental stress conditions.

Highlights

Plants capture solar energy and atmospheric carbon dioxide (CO2) through photosynthesis, which is the primary component of crop yield, and needs to be increased considerably to meet the growing global demand for food
Rice regulatory association network analysis. Since environmental stresses such as drought perturb many essential biological processes (BPs) important for growth and development[12], we reasoned that a global analysis of the regulation of stress responses would reveal the underlying transcription network regulating photosynthesis, photosynthetic carbon metabolism (PCM) and growth
To characterize the network of genes and BPs involved in stress response and tolerance, we developed separate ‘regulatory association networks’ in rice using genome-wide expression profiles of rice genes under ‘control’ and ‘stress’ conditions

Summary

Introduction

Plants capture solar energy and atmospheric carbon dioxide (CO2) through photosynthesis, which is the primary component of crop yield, and needs to be increased considerably to meet the growing global demand for food. The AP2 TF CBF4, known as DREB1, was shown by overexpression analysis to lead to drought adaptation in Arabidopsis[14]; the Arabidopsis AP2 TF called HARDY was reported to provide enhanced drought tolerance and water-use efficiency (WUE) in Arabidopsis and rice[4] Ectopic expression of these genes confer drought tolerance and/or adaptation by modifying cellular structures of leaves and roots, CO2 exchange and parameters such as WUE, which correlate with the transformed plants’ ability to withstand drought. Taken together, these and other findings indicate that AP2 TFs offer the potential to engineer plants in a way that makes them more productive under stress conditions

Methods

Results

Conclusion