Two homologous, chloroplast located CAAX proteases were identified to be functional redundancy in determining soybean leaf color, and they probably play essential roles in regulating light harvesting and absorption during photosynthesis process. Leaf color mutants are ideal materials for studying photosynthesis and chlorophyll metabolism. The soybean [Glycine max (L.) Merr.] yellowing leaf (yl) variation is a recombinant mutant characterized by yellow foliage, which derived from the specific cross between green seed-coated and yellow seed-coated soybean varieties. Molecular cloning and subsequent gene silencing revealed that the yellow leaf trait of yl was controlled by two recessive nuclear genes, glyma11g04660 and glyma01g40650, named as YL1 and YL2 respectively, and the latter was confirmed to be same as the earlier reported green seed-coat gene G. Both YL1 and YL2 belonged to chloroplast-located proteases possessing Abi domain, and these genes were expressed in various tissues, especially in young leaves. In yl, the expression of YL1 and YL2 were suppressed in most tissues, and the young leaf of yl presented an increased maximal photochemical efficiency (Fv/Fm) as well as enhanced net photosynthesis activity (Pn), indicating that YL1 and YL2 are involved in light absorption regulation during photosynthesis process. Collectively, the identification and description of YL1 and YL2 in our study provides insights for the regulatory mechanism of photosynthesis process, and these findings will further assist to clarify the close relationship between photosynthesis and chlorophyll metabolism.

中文翻译：

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两个同源基因 YL1 和 YL2 的双重突变导致大豆 [Glycine max (L.) Merr] 出现叶片黄化表型。


两种同源的、位于叶绿体的 CAAX 蛋白酶被认为在确定大豆叶色方面具有功能冗余，并且它们可能在调节光合作用过程中的光捕获和吸收中发挥重要作用。叶色突变体是研究光合作用和叶绿素代谢的理想材料。大豆[Glycine max (L.) Merr.]黄叶(yl)变种是一种以黄色叶子为特征的重组突变体，它源自绿色种衣大豆品种和黄色种衣大豆品种的特异性杂交。分子克隆和随后的基因沉默表明yl的黄叶性状由两个隐性核基因glyma11g04660和glyma01g40650控制，分别命名为YL1和YL2，并证实后者与早期报道的绿色种皮基因相同G. YL1和YL2均属于具有Abi结构域的叶绿体蛋白酶，这些基因在多种组织中表达，特别是在幼叶中。在yl中，YL1和YL2的表达在大多数组织中受到抑制，yl的幼叶表现出最大光化学效率（Fv/Fm）增加以及净光合作用活性（Pn）增强，表明YL1和YL2参与其中光合作用过程中的光吸收调节。总的来说，我们研究中YL1和YL2的识别和描述为光合作用过程的调控机制提供了见解，这些发现将进一步有助于阐明光合作用与叶绿素代谢之间的密切关系。