Barley Mutant in HVSNAC1 (Stress-Responsive NAC 1) Generated through Tilling Strategy Shows Increased Tolerance to Drought and Oxidative Stress

Full text: SNAC1 is a member of NAC transcription factor family involved in the response to abiotic stresses, including drought and hydrogen peroxide homeostasis. TILLING (Targeting Induced Local Lesion IN Genomes) strategy is an efficient reverse genetics tool for generating new alleles in genes of interest. In the presented study the TILLING approach was used for functional analysis of HvSNAC1 gene in response to drought and oxidative stress in barley. We used the HorTILLUS platform developed at the University of Silesia in Katowice, Poland, for identification of mutations in the HvSNAC1 gene. One of the mutants, hvsnac1.c, carrying a missense change, was back-crossed to the wild type (WT) parent cultivar 'Sebastian' and used for physiological and molecular studies. The response of hvsnac1.c to drought, salinity and oxidative stress treatment was evaluated at seedling stage. The expression of HvSNAC1 target genes was analysed in mutant and WT under control and stress conditions. The hvsnac1.c mutant carries a C90G substitution that led to change of a highly conserved amino-acid residue aspartic acid-30 to glutamic acid. The mutant exhibited a higher relative water content (RWC) than the WT, after severe drought stress as well as after a period of re-watering. the hvsnac1.c showed also the lower sensitivity to oxidative stress induced by methyl viologen. The expression pattern of the HvSNAC1 gene and its two potential targets during drought using RT-qPCR technique lead to the conclusion that HvSRO1c (Similar to RDC One) and HvERD1 (Early Responsive to Drought 1) belong to the HvSNAC1 regulon in barley and may be involved in the drought stress response. Using TILLING mutant, we demonstrated an involvement of HvSNAC1 gene in response to drought and oxidative stress in barley. The hvsnac1.c mutant can be a valuable material for breeding purposes. (author)