Chakraborty Chandrima, Das Arup, Basak Chandra, Roy Shuddhanjali, Agarwal Tanushree, Ray Sudipta
Plant Functional Genomics Laboratory, Department of Botany, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, West Bengal 700019 India.
Physiol Mol Biol Plants. 2022 Dec;28(11-12):2057-2067. doi: 10.1007/s12298-022-01264-7. Epub 2022 Dec 14.
Plants are unavoidably exposed to a range of environmental stress factors throughout their life. In addition to the external environmental factors, the production of reactive oxygen species as a product of the cellular metabolic process often causes DNA damage and thus affects genome stability. Homologous recombination (HR) is an essential mechanism used for DNA damage repair that helps to maintain genome integrity. Here we report that the recombinase, PpRecA2, a bacterial RecA homolog from moss can partially complement the function of RecA in the bacterial system. Transcript analysis showed induced expression of PpRecA2 upon experiencing DNA damaging stressors indicating its involvement in DNA damage sensing and repair mechanism. Over-expressing the chloroplast localizing PpRecA2 confers protection to the chloroplast genome against DNA damage by enhancing the chloroplastic HR frequency in transgenic tobacco plants. Although it fails to protect against nuclear DNA damage when engineered for nuclear localization due to the non-availability of interacting partners. Our results indicate that the chloroplastic HR repair mechanism differs from the nucleus, where chloroplastic HR involves RecA as a key player that resembles the bacterial system.
The online version contains supplementary material available at 10.1007/s12298-022-01264-7.
植物在其整个生命周期中不可避免地会受到一系列环境胁迫因素的影响。除了外部环境因素外，作为细胞代谢过程产物的活性氧的产生常常会导致DNA损伤，从而影响基因组稳定性。同源重组（HR）是一种用于DNA损伤修复的重要机制，有助于维持基因组完整性。在此我们报告，重组酶PpRecA2，一种来自苔藓的细菌RecA同源物，能够在细菌系统中部分补充RecA的功能。转录分析表明，在经历DNA损伤应激时PpRecA2的表达被诱导，这表明它参与了DNA损伤感应和修复机制。过表达定位于叶绿体的PpRecA2通过提高转基因烟草植物中的叶绿体HR频率，为叶绿体基因组提供了针对DNA损伤的保护。尽管由于缺乏相互作用的伙伴，当将其设计为核定位时，它无法保护核DNA免受损伤。我们的结果表明，叶绿体HR修复机制与细胞核不同，其中叶绿体HR涉及RecA作为类似于细菌系统的关键参与者。
在线版本包含可在10.1007/s12298-022-01264-7获取的补充材料。
