Abstract
The maintenance of genome integrity is crucial in seeds, due to the constant challenge of several endogenous and exogenous factors. The knowledge concerning DNA damage response and chromatin remodeling during seed development is still scarce, especially in Phaseolus vulgaris L. A transcriptomic profiling of the expression of genes related to DNA damage response/chromatin remodeling mechanisms was performed in P. vulgaris seeds at four distinct developmental stages, spanning from late embryogenesis to seed desiccation. Of the 14,001 expressed genes identified using massive analysis of cDNA ends, 301 belong to the DNA MapMan category. In late embryogenesis, a high expression of genes related to DNA damage sensing and repair suggests there is a tight control of DNA integrity. At the end of filling and the onset of seed dehydration, the upregulation of genes implicated in sensing of DNA double-strand breaks suggests that genome integrity is challenged. The expression of chromatin remodelers seems to imply a concomitant action of chromatin remodeling with DNA repair machinery, maintaining genome stability. The expression of genes related to nucleotide excision repair and chromatin structure is evidenced during the desiccation stage. An overview of the genes involved in DNA damage response and chromatin remodeling during P. vulgaris seed development is presented, providing insights into the mechanisms used by developing seeds to cope with DNA damage.
Highlights
Maintenance of genome integrity is important to the seed phase of the plant lifecycle [1].Chromatin integrity is constantly being challenged by environmental factors like drought and ionizing radiation or free radicals and alkylating agents generated by endogenous processes [2,3]
Seed samples harvested at 10 days after anthesis (DAA) represent the late embryogenic stage, in which evidence of a high rate of cell division associated with embryo differentiation and morphogenesis has been described by us in a previous study [21]
Among the different DNA Damage Response (DDR) components found expressed during seed development, we focused our attention on those acting upstream DNA repair, like the double-strand breaks (DSBs) sensing and signal transduction components (Figure S2)
Summary
Chromatin integrity is constantly being challenged by environmental factors like drought and ionizing radiation or free radicals and alkylating agents generated by endogenous processes [2,3]. These agents cause a variety of DNA damage, including DNA base oxidation and alkylation, the formation of pyrimidine dimers and abasic sites, single- and double-strand breaks (SSBs and DSBs), and DNA inter-strand crosslinks, and seriously threaten the integrity of the plant genome [2]. While ATR seems to be critical in the response to disturbances during the progression of DNA replication, the ATM kinase is activated in response to double-strand breaks (DSBs) [6].
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