Contribution of the DNA glycosylase MBD4L to DNA repair during seed germination

LESCANO I; NOTA MF ; TORRES JR; CECCHINI NM; ALVAREZ ME

Salta

Congreso; LV Reunión Anual de SAIB y Congreso PABMB; 2019

SAIB

DNA repair is crucial to maintain genome integrity and ensure cell survival and accurate transmission of genetic information. Plants experience high levels of DNA damage at different stages of their life, which is often caused by stressful conditions. Cycles of dehydration and rehydration during seed development are associated with high levels of reactive oxygen species, resulting in oxidation of DNA bases and DNA strand breaks. Genome damage is exacerbated during seed aging, decreasing seed vigor and viability. Consequently, DNA must be repaired prior to germination to prevent genomic damage from being fixed after cell division. The base excision repair (BER) contributes to this end by using DNA glycosylases to excise damaged bases from the genome. Here, we studied the expression pattern of the Arabidopsis DNA glycosylase MBD4L (methyl-binding domain protein 4 like) during seed development, germination, and seedling establishment. We further analyzed germination phenotypes associated with the deficiency/overexpression of MBD4L. Interestingly, mbd4l mutants showed late germination under basal conditions. This phenotype was not caused by enhanced sensitivity to abscisic acid (ABA). Interestingly, late germination was exacerbated by exposure to genotoxic agents. Therefore, MBD4L may contribute to DNA repair, and consequently to proper plant development, by activating the BER system before seed germination. To test this hypothesis, the expression pattern of MBD4L and genes responding to DNA damaged (LIG1, RAD51, PARP2) has been analyzed along with germination.