Author: Maryam Aldammas
Aldammas, Maryam, 2019 Expression analysis of HvSAP genes encoding Stress-Associated Proteins in response to salinity and drought stresses in barley (Hordeum vulgare L.), Flinders University, College of Medicine and Public Health
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Abiotic stresses, such as drought and salt, affect the growth and productivity of crop plants and are serious threats to agriculture. Members of the Stress Associated Protein (SAP) family contain A20, AN1, or both A20/AN1 zinc finger domains at the N- or C-terminus and have been shown to be strongly stress-responsive in many plants, however little is known about this gene family in barley. In this study, 17 HvSAP genes were identified with strong homology to known OsSAP genes in rice. Five novel genes, HvSAP5, HvSAP6, HvSAP11, HvSAP12 and HvSAP15, were described and functionally characterized in this study. The regulation of gene expression is a key factor in plant adaptation to stress. The aim of this study was to identify all HvSAP genes in barley (Hordeum vulgare L.), and to analyse the expression of selected genes in response to salinity, drought and to combined salt and drought stress in barley plants. The five studied HvSAP genes showed a great diversity in response to abiotic stresses in barley cultivars from Kazakhstan. Under salt stress, HvSAP5, HvSAP6, HvSAP12 and HvSAP15 genes were highly expressed in leaves of all studied barley cultivars. The HvSAP11 gene was mostly non-responsive to salinity. In contrast, exposure to drought caused significant up-regulation of HvSAP6 and HvSAP11 genes in all studied barley cultivars, while expression of the remaining genes, HvSAP5, HvSAP12 and HvSAP15, were genotype-dependent. The combination of both salinity and drought stress did not show a simple additive effect, or sum of responses to the two stresses, but rather quite different responses. Only the HvSAP6 gene was highly expressed in all barley accessions and across the three categories of stress applied. Most, but not all, genotypes had significant up-regulation of HvSAP5, HvSAP11 and HvSAP15 gene expression in response to combined stress, while the expression of HvSAP12 was so variable that it was not possible to make any conclusions about the response of this gene,
Keywords: Barley-HvSAP genes
Subject: Biotechnology thesis
Thesis type: Masters
Completed: 2019
School: College of Medicine and Public Health
Supervisor: Kathleen Soole