Leaf color is directly associated with plant photosynthesis. Here, we have isolated and identified a spontaneous rice mutant named yd1 that has yellowish leaves and dwarf stature. Map-based cloning reveals that YD1 encodes a previously reported kinesin protein from the kinesin-4 subfamily, BC12/GDD1. Arginine-328 is replaced by leucine in yd1, BC12328Leu. YD1 is mainly expressed in leaves and is involved in chlorophyll (Chl) synthesis. The yd1 mutant had less Chl and a reduced and disordered thylakoid ultrastructure. In yd1 plants, Chl biosynthesis and photosynthesis associated gene expression was decreased and Chl degradation gene expression was increased, thereby leading to a reduced photosynthesis rate and grain yield. In this study we reveal that the novel BC12328Leu allele of BC12 modulated plant leaf color in yd1 plants, which has not been previously reported in studies of BC12/GDD1/MTD1/SRG1. Gene knockout results indicated that YD1 regulates leaf color in the indica rice background, but not in the japonica rice background. Our study provides new insights into molecular regulation of rice growth by BC12/GDD1 in different genetic backgrounds.

中文翻译：

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bc12/gdd1 新等位基因的表征表明籼稻和粳稻背景中 BC12/GDD1 的叶色功能差异

叶子颜色与植物光合作用直接相关。在这里，我们已经分离并鉴定了一种名为 yd1 的自发水稻突变体，它具有淡黄色的叶子和矮小的身材。基于图谱的克隆显示 YD1 编码先前报道的来自驱动蛋白 4 亚家族 BC12/GDD1 的驱动蛋白。yd1, BC12328Leu 中的精氨酸 328 被亮氨酸取代。YD1 主要在叶片中表达，参与叶绿素 (Chl) 的合成。yd1 突变体具有较少的 Chl 和减少和无序的类囊体超微结构。在 yd1 植物中，Chl 生物合成和光合作用相关基因表达减少，Chl 降解基因表达增加，从而导致光合作用速率和谷物产量降低。在这项研究中，我们揭示了 BC12 的新型 BC12328Leu 等位基因调节了 yd1 植物的植物叶色，以前在 BC12/GDD1/MTD1/SRG1 的研究中没有报道过。基因敲除结果表明，YD1 在籼稻背景中调节叶色，但在粳稻背景中没有调节作用。我们的研究为不同遗传背景下 BC12/GDD1 对水稻生长的分子调控提供了新的见解。