Significant and unique changes in phosphorylation levels of nine phosphoproteins of leaves of two apple rootstock genotypes under drought stress
Ontology highlight
ABSTRACT: Drought stress is a major problem around the world and although progress in understanding how vegetable crops and model plants adapt to drought have been made, there is still little information about how fruit crops deal with moderate drought stress. In this study, we investigated the response of two apple genotypes: a drought-sensitive genotype (M26) and a drought-tolerant genotype (MBB). Our results of the morphology, physiology and biochemistry under moderate drought stress, indicated that relative water content (RWC) and leaf area (LA) were not significant changes in two genotypes. However, it had larger leaf mass per area (LMA), and accumulated higher free proline (CFP), soluble sugars (CSS) and malonaldehyde (MDA) in the leaves. Thus, it appears that the MBB genotype could produce more osmosis-regulating substances. Phosphoproteomic was analyzed from leaves of both genotypes under moderate drought stress using the isobaric tags for relative and absolute quantification (iTRAQ) technology. A total of 595 unique phosphopeptides, 682 phosphorylated sites and 446 phosphoproteins were quantitatively analyzed in the two genotypes. Motif analyses of the phosphorylation sites showed that six motifs including [PxsP], [sP], [sD], [Rxxs], [sxP] and [sxs] were enriched. We identified 12 and 48 PLSC phosphoproteins in M26 and MBB, respectively. Among these, 9 PLSC phosphoproteins were common to both genotypes, perhaps indicating a partial overlaps of the mechanisms to moderate drought stress. Gene ontology analyses revealed that the PLSC phosphoproteins present a unique combination of metabolism, transcription, translation and protein processing, suggesting that the response in apple to moderate drought stress encompasses a new homeostasis of major cellular processes. The basic trend was an increase in protein abundance related to drought and organic substance upon moderate drought stress between two genotypes. These increases were higher in the drought-tolerant genotype (MBB) than in the drought-sensitive genotype (M26). The 23 differentially expressed mRNA encoding phosphoproteins were analysis by quantitative real-time PCR (qRT-PCR). Our study is the first to address the phosphoproteome of a major fruit crop, apple rootstocks, in response to moderate drought stress, and provide insights into the molecular regulation mechanisms of apple rootstock under moderate drought stress.
INSTRUMENT(S): Q Exactive
ORGANISM(S): Malus Baccata
TISSUE(S): Plant Cell, Leaf
DISEASE(S): Disease Free
SUBMITTER: Jing Ren
LAB HEAD: College of Horticulture,
PROVIDER: PXD005238 | Pride | 2016-11-08
REPOSITORIES: Pride
ACCESS DATA