As the world population increases to more than 9.5 billion by 2050, we will need to produce new varieties of rice with higher yield and stress tolerance. In nature, plants often encounter a combination of drought, salinity, or temperature stresses. Proteomic analysis can be employed for comparative analysis of plants unique and shared responses to stress.
After 4 weeks of plant growing in normal condition, IAC1131 and Nipponbare rice plants were exposed to multiple abiotic stress that was imposed for 2 and 4 days, including a combination of 50% field capacity watering (FC) as drought stress, 50mM NaCl as salt stress and 33/18°C as temperature stress. Leaf proteins were extracted with trichloroacetic acid- acetone method followed by methanol-chloroform precipitation, and digested in solution with trypsin. Peptides were labeled with Tandem Mass Tags (TMT), fractionated, separated, and analyzed on a Q Exactive Orbitrap mass spectrometer. Proteome Discoverer v2.1 was used for the peptide to spectrum matching, and TMTPrepPro was used for further analysis of quantitative proteomics. A total of 6215 non-redundant proteins were reproducibly identified and quantified across both genotypes treated with multiple abiotic stress. Approximately 16% of these (987) were differentially expressed proteins, with double the number of proteins changed in abundance in Nipponbare (689) in comparison with IAC1131 (298). The largest number of DEPs for a single time point (449) was identified in Nipponbare after 2 days stress, however, for IAC1131, the greater number of DEPs was measured at 4 day stress time point (220). More than 20% of the proteins commonly increased in abundance belonged to the heat shock protein (HSP) family, with similar expression patterns in both genotypes. The greater number of significantly changed proteins in Nipponbare in comparison to IAC1131 suggests that Nipponbare may be more sensitive to multiple abiotic stresses.