Effect of salt stress in Atmsh7 deficient plants

CHIRINOS ARIAS, M.C.; SPAMPINATO, C.

Salta

Congreso; LV Reunión Anual de la Sociedad Argentina de Investigación Bioquímica (SAIB); 2019

DNA mismatch repair (MMR) is a highly conserved biological pathway that improves the fidelity of DNA replication and recombination. MMR is initiated when MutS proteins recognize mismatches and small loops of unpaired nucleotides. Arabidopsis and other plants encode MutS protein homologs (MSH) conserved among other eukaryotic organisms, but also contain an extra MSH polypeptide (MSH7). In order to better understand the role of MSH7 in plant salt stress response, we conducted phenotypic and biochemical studies using an msh7 T-DNA insertional mutant. Seeds were sown on agar plates containing 0.5X Murashige and Skoog medium (MS) and grown for 10 days at 22°C under a 16/8 light/dark photoperiod. Seedlings were then transferred to agar plates containing MS medium or MS supplemented with 100 mM NaCl and grown for 48 hours. Alternatively, after the treatment seedlings were transplanted to soil. Results indicate that msh7 mutants under salt stress showed i) a lower decrease in chlorophyll and flavonoid levels, ii) a higher stomatic density and electrolyte leakage, iii) a higher 8-oxoG accumulation in DNA, iv) a higher rosette area and leaf area and a lower cell number, v) a decreased G0/G1 and an increased G2/M phase compared to those observed in WT plants under salt stress. In addition, nitroblue tetrazolium staining revealed that msh7 mutant control plants show a higher oxidative stress than WT control plants, consistent with its higher level of peroxidase activity. Taken together, our results suggest that MSH7 is involved in salt stress induced DNA damage response.