Essential role of the gene in somatic homologous recombination in .

Constant exposure to various environmental and endogenous stresses can cause structural DNA damage, resulting in genome instability. Higher eukaryotic cells deploy conserved DNA repair systems, which include various DNA repair pathways, to maintain genome stability. Homologous recombination (HR), one of these repair pathways, involves multiple proteins. BRCA2, one of the proteins in the HR pathway, is of substantial research interest in humans because it is an oncogene. However, the study of this gene is limited due to the lack of availability of homozygous -knockout mutants in mammals, which results in embryonic lethality. has two copies of the homologs: and . Therefore, the single mutants remain nonlethal and fertile in . The homolog, which plays a significant role in the HR pathway of germline cells and during the defense response, is well-studied in . Our study focuses on the functional characterization of the homolog in the somatic cells of , using the homozygous mutant line. The phenotypic differences of mutants were characterized and compared with wild plants. The role of in spontaneous somatic HR (SHR) was studied using the -gus detector line. plants have a 6.3-fold lower SHR frequency than the control detector plants. Expression of four other HR pathway genes, including , , , and , was significantly reduced in mutants. Thus, our findings convey that the homolog plays an important role in maintaining spontaneous SHR rates and has a direct or indirect regulatory effect on the expression of other HR-related genes.