| Summary: | 博士 === 國立臺灣大學 === 植物科學研究所 === 106 === To date, soil salinity is getting worse in the arable land because of drought stress and over application of fertilizer. High salinity is a major environmental factor, which hinders plant growth and productivity. To better understand the regulatory mechanisms by which plants cope with salt stress, we took genetic approaches to identify salt hypersensitive mutant 9 (sahy9), a new allele of apum23, in Arabidopsis thaliana. The seedlings of sahy9/apum23 mutant displayed postgermination developmental arrest and then became bleached after prolonged culture under various salt stressors. Transcriptomic and proteomic analyses of salt-treated sahy9/apum23 and wild-type seedlings revealed differential expression of genes/proteins that have similar functional categories of biological processes, primarily those involved in cellular and metabolic processes as well as abiotic and biotic stress responses. However, the consistency of differential gene expression at both the transcript and protein levels was low (~12%), which suggests the involvement of posttranscriptional processing during the salt response. Furthermore, the altered expression of genes and proteins mediated by SAHY9/APUM23 regarding salt sensitivity involves abscisic acid (ABA) biosynthesis and signaling, abiotic stress responses, and ribosome biogenesis-related genes. Importantly, NCED3, ABI2, PP2CA, and major ABA-responsive marker genes, such as RD20 and RD29B, were down-regulated at both the transcript and protein levels in conjunction with lower contents of ABA and changes in the expression of a subset of LEA proteins in sahy9/apum23 mutants under salt stress. Moreover, the salt hypersensitivity of sahy9/apum23 mutant was largely rescued by the exogenous application of ABA during salt stress. Collectively, these data suggest that the SAHY9/APUM23-mediated salt response is associated with the ABA signaling pathway and its downstream stress responsive network.
|
|---|
