MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-construction by Ministry and Province), College of Agriculture, Yangtze University, Jingzhou 434025, Hubei, China.
Key Laboratory of Integrated Pest Management of Crops in Central China, Ministry of Agriculture/Hubei Key Laboratory of Crop Diseases, Insect Pests and Weeds Control, Institute of Plant Protection and Soil Science, Hubei Academy of Agricultural Sciences, Wuhan 430064, Hubei, China.
Int J Biol Macromol. 2023 Dec 31;253(Pt 5):127215. doi: 10.1016/j.ijbiomac.2023.127215. Epub 2023 Oct 2.
Light-harvesting chlorophyll a/b binding proteins are encoded by nucleus genes and widely involve in capturing light energy, transferring energy, and responding to various stresses. However, their roles in wheat photosynthesis and stress tolerance are largely unknown. Here, Triticum aestivumlight-harvesting chlorophyll a/b binding protein TaLhc2 was identified. It showed subcellular localization in chloroplast, contained light responsive cis-elements, and highly expressed in green tissues and down-regulated by multiple stresses. TaLhc2 promoted the colonization of hemi-biotrophic pathogen; further analysis showed that TaLhc2 strengthened BAX-induced cell death, enhanced the ROS accumulation, and up-regulated pathogenesis-related genes; those results suggested that TaLhc2 has adverse influence on host immunity and function as a susceptible gene, thus host decreased its expression when faced with pathogen infection. RT-qPCR results showed that TaLhc2 was down-regulated by drought and salt stresses, while TaLhc2 improved the ROS accumulation under the two stresses, suggesting TaLhc2 may participate in wheat responding to abiotic stress. Additionally, TaLhc2 can increase the content of total chlorophyll and carotenoid by 1.3 % and 2.9 %, increase the net photosynthetic rate by 18 %, thus promote plant photosynthesis. Conclusively, we preliminarily deciphered the function of TaLhc2 in biotic/abiotic stresses and photosynthesis, which laid foundation for its usage in wheat breeding.
光能捕获叶绿素 a/b 结合蛋白由核基因编码，广泛参与光能捕获、能量传递以及对各种胁迫的响应。然而，它们在小麦光合作用和胁迫耐受中的作用在很大程度上是未知的。在这里，我们鉴定了小麦光能捕获叶绿素 a/b 结合蛋白 TaLhc2。它显示出定位于叶绿体的亚细胞定位，含有光响应顺式元件，在绿色组织中高度表达，并受到多种胁迫的下调。TaLhc2 促进了半生物营养性病原体的定殖；进一步的分析表明，TaLhc2 增强了 BAX 诱导的细胞死亡，增加了 ROS 积累，并上调了病程相关基因；这些结果表明 TaLhc2 对宿主免疫有不良影响，作为易感基因，因此当宿主面临病原体感染时，会降低其表达。RT-qPCR 结果表明，干旱和盐胁迫下调 TaLhc2 的表达，而 TaLhc2 增加了两种胁迫下的 ROS 积累，表明 TaLhc2 可能参与了小麦对非生物胁迫的响应。此外，TaLhc2 可以使总叶绿素和类胡萝卜素的含量分别增加 1.3%和 2.9%，使净光合速率增加 18%，从而促进植物光合作用。总之，我们初步解析了 TaLhc2 在生物/非生物胁迫和光合作用中的功能，为其在小麦育种中的应用奠定了基础。
