Proteomic analysis of rice leaves during drought stress and recovery.
Three-week old plants of rice (Oryza sativa L. cv CT9993 and cv IR62266) developed gradual water stress over 23 days of transpiration without watering, during which period the mid-day leaf water potential declined to approximately -2.4 MPa, compared with approximately -1.0 MPa in well-watered controls. More than 1000 protein spots that were detected in leaf extracts by proteomic analysis showed reproducible abundance within replications. Of these proteins, 42 spots showed a significant change in abundance under stress, with 27 of them exhibiting a different response pattern in the two cultivars. However, only one protein (chloroplast Cu-Zn superoxide dismutase) changed significantly in opposite directions in the two cultivars in response to drought. The most common difference was for proteins to be up-regulated by drought in CT9993 and unaffected in IR62266; or down-regulated by drought in IR62266 and unaffected in CT9993. By 10 days after rewatering, all proteins had returned completely or largely to the abundance of the well-watered control. Mass spectrometry helped to identify 16 of the drought-responsive proteins, including an actin depolymerizing factor, which was one of three proteins detectable under stress in both cultivars but undetectable in well-watered plants or in plants 10 days after rewatering. The most abundant protein up-regulated by drought in CT9993 and IR62266 was identified only after cloning of the corresponding cDNA. It was found to be an S-like RNase homologue but it lacked the two active site histidines required for RNase activity. Four novel drought-responsive mechanisms were revealed by this work: up-regulation of S-like RNase homologue, actin depolymerizing factor and rubisco activase, and down-regulation of isoflavone reductase-like protein.
D051339:Actin Depolymerizing Factors; D000595:Amino Acid Sequence; D001483:Base Sequence; D029773:Citrullus / Q000737:chemistry; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D019992:Databases as Topic; D051345:Destrin; D004190:Disasters; D015180:Electrophoresis, Gel, Two-Dimensional; D005838:Genotype; D007091:Image Processing, Computer-Assisted; D013058:Mass Spectrometry; D008840:Microfilament Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D012275:Oryza / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D010802:Phylogeny; D018515:Plant Leaves / Q000737:chemistry*; D010940:Plant Proteins; D020543:Proteome; D012260:Ribonucleases / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013997:Time Factors; D014867:Water / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry
D051339:Actin Depolymerizing Factors; D018076:DNA, Complementary; D051345:Destrin; D008840:Microfilament Proteins; D010455:Peptides; D010940:Plant Proteins; D020543:Proteome; C054765:rca protein, plant; D014867:Water; D012260:Ribonucleases; C489908:S-like RNase protein, plant