Li Xia, Wang Peng, Li Jing, Wei Shaobo, Yan Yanyan, Yang Jun, Zhao Ming, Langdale Jane A, Zhou Wenbin
Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK.
Commun Biol. 2020 Apr 1;3(1):151. doi: 10.1038/s42003-020-0887-3.
Photosynthetic efficiency is a major target for improvement of crop yield potential under agricultural field conditions. Inefficiencies can occur in many steps of the photosynthetic process, from chloroplast biogenesis to functioning of the light harvesting and carbon fixation reactions. Nuclear-encoded GOLDEN2-LIKE (GLK) transcription factors regulate some of the earliest steps by activating target genes encoding chloroplast-localized and photosynthesis-related proteins. Here we show that constitutive expression of maize GLK genes in rice leads to enhanced levels of chlorophylls and pigment-protein antenna complexes, and that these increases lead to improved light harvesting efficiency via photosystem II in field-grown plants. Increased levels of xanthophylls further buffer the negative effects of photoinhibition under high or fluctuating light conditions by facilitating greater dissipation of excess absorbed energy as heat. Significantly, the enhanced photosynthetic capacity of field-grown transgenic plants resulted in increased carbohydrate levels and a 30-40% increase in both vegetative biomass and grain yield.
光合效率是提高农田条件下作物产量潜力的主要目标。从叶绿体生物发生到光捕获和碳固定反应的运作，光合作用过程的许多步骤都可能出现效率低下的情况。核编码的类GOLDEN2（GLK）转录因子通过激活编码叶绿体定位和光合作用相关蛋白的靶基因来调节一些最早的步骤。我们在此表明，水稻中玉米GLK基因的组成型表达导致叶绿素和色素 - 蛋白天线复合物水平提高，并且这些增加导致田间种植植物中通过光系统II提高了光捕获效率。叶黄素水平的增加通过促进将多余吸收的能量以热的形式更大程度地耗散，进一步缓冲了高光或波动光条件下光抑制的负面影响。值得注意的是，田间种植的转基因植物增强的光合能力导致碳水化合物水平增加，营养生物量和谷物产量均增加30 - 40％。
