Rice as a cereal crop species is a significant part of the staple diet for half of the world’s population and is grown in every continent apart from Antarctica. Reduced rice crop productivity is mostly attributed to various abiotic stresses, which are a major area of concern when we are faced with increasing food requirements. The major abiotic stresses include drought, oscillating temperature and high salinity, all of which negatively influence the yield of crops.
In nature it is unlikely that plants are exposed to abiotic stresses in isolation. Plants respond to multiple stresses differently from how they respond to individual stresses, activating a specific program of gene and protein regulation relating to the exact environmental stress. Rather than being additive, the presence of an abiotic stress can have the effect of reducing or enhancing the susceptibility to other abiotic stresses. In this project, we are examining the combined effects of drought, temperature and salt stress in different permutations.
As a baseline study, we have investigated the proteomic response to drought stress in eight different rice varieties; Nipponbare, Doongara, IAC1131, Mahsuri, Reiziq, N22, IR2006-P12 and IDSA77. Plants were grown in a temperature controlled greenhouse to late vegetative stage and then exposed to drought stress, with leaf samples collected at the point of severe stress, and also following recovery. For initial studies of combination of multiple abiotic stresses, Nipponbare plants were subjected to simultaneous salt, drought and temperature oscillation stresses. Proteins were extracted from leaf tissue, with in-gel and in-solution digested peptides separated and identified using nanoflow reversed-phase liquid chromatography – tandem orbitrap mass spectrometry on a Thermo Q-exactive. Peptides and proteins were identified using Proteome Discoverer and GPM software. Our results will be useful for the design of agronomically relevant strategies for the development of broad spectrum stress tolerant crops.