Proteomics analysis of the photo-oxidation mutant 812HS rice (Oryza sativa L.) exposed to high light intensity

Abstract

The 812HS rice line, a mutant of two-line sterile rice, exhibits leaf photo-oxidation during the tillering-jointing stage since its chloroplasts are susceptible to damage induced by strong sunlight. To determine the proteomic response to light intensity, the 812HS rice line was exposed to natural light and shade (about one fourth natural light), and two-dimensional electrophoresis in combination with matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry was used to compare the proteomic expressions in the rice leaves. Although over 1000 reproducible proteins were detected, only 9.61 % of them displayed differential expression with 1.5-fold abundance. A search of the National Center for Biotechnology Information database revealed 53 proteins, 34 down-regulated and 19 up-regulated under highlight. Among these identified proteins, six ones were related to disease and defense, implying the defense and protection mechanism was built under strong light stress. The increase in S-adenosylmethionine synthetase involved in the biosynthesis of the phytohormone ethylene might contribute to the phenotypic modulation from green to etiolation in photo-oxidation-sensitive leaves. These results suggest the existence of a complex regulatory mechanism of the proteomes in photo-oxidation-sensitive 812HS rice under light stress.