Phenotypic characterization of Atmsh7 deficient plants

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

Paraná

Congreso; LIV Reunión Anual de la Sociedad Argentina de Investigación Bioquímica (SAIB); 2018

The mismatch repair (MMR) system maintains genome integrity by correcting replication-associated errors and inhibiting recombination between divergent DNA sequences. In plants, MMR is initiated by the binding of heterodimeric MutS homologue (MSH) complexes, MSH2-MSH6, MSH2-MSH7 and MSH2-MSH3 to mismatches or unpaired nucleotides. MSH2-MSH7 is also involved in meiotic recombination. In order to study the effects of the absence of MSH7 in Arabidopsis thaliana (Col-0), a phenotypic characterization of the first generation of knockout msh7 mutant plants has been carried out in early stages of the development and in reproductive organs. We observed that the length of the siliques and the number of seeds per silique of mutant plants are lower than in wild type (WT). Additionally, a low percentage of mutant seeds (0.008-0.010%) show deformations and color changes. Seed morphology and color change were not observed in WT. STRING-DB analysis showed that MSH7 shows a predicted interaction with the DNA polymerase epsilon catalytic subunit (ESD7/POL2A/TIL1/ABO4), an enzyme that is essential for viability of the embryo and is involved in abscisic acid (ABA) signaling. One of the central regulators in ABA signaling is ABI3, a transcription factor that interacts genetically with other proteins and controls accumulation of chlorophyll and anthocyanins. Accordingly, we found that some of the mutant seeds show chlorophyll fluorescence. We conclude that msh7 mutants show decreased seed yield due to less siliques containing less seeds and altered seed morphology and color, suggesting that MSH7 is involved in establishment and seed production in Arabidopsis.