Department of Forest Environmental Sciences, Faculty of Agriculture, Kyushu University, Motooka, Fukuoka, 819-0395, Japan.
Department of Agricultural Science and Technology, Faculty of Agriculture, Setsunan University, Hirakata, Osaka, 573-0101, Japan.
J Plant Res. 2020 Jul;133(4):525-535. doi: 10.1007/s10265-020-01189-w. Epub 2020 Apr 18.
Light-induced chloroplast movements control efficient light utilization in leaves, and thus, are essential for leaf photosynthesis and biomass production under fluctuating light conditions. Chloroplast movements have been intensively analyzed using wild-type and mutant plants of Arabidopsis thaliana. The molecular mechanism and the contribution to biomass production were elucidated. However, the knowledge of chloroplast movements is very scarce in other plant species, especially grass species including crop plants. Because chloroplast movements are efficient strategy to optimize light capture in leaves and thus promote leaf photosynthesis and biomass, analysis of chloroplast movements in crops is required for biomass production. Here, we analyzed chloroplast movements in a wide range of cultivated and wild species of genus Oryza. All examined Oryza species showed the blue-light-induced chloroplast movements. However, O. sativa and its ancestral species O. rufipogon, both of which are AA-genome species and usually grown in open condition where plants are exposed to full sunlight, showed the much weaker chloroplast movements than Oryza species that are usually grown under shade or semi-shade conditions, including O. officinalis, O. eichingeri, and O. granulata. Further detailed analyses of different O. officinalis accessions, including sun, semi-shade, and shade accessions, indicated that the difference in chloroplast movement strength between domesticated rice plants and wild species might result from the difference in habitat, and the shape of mesophyll chlorenchyma cells. The findings of this study provide useful information for optimizing Oryza growth conditions, and lay the groundwork for improving growth and yield in staple food crop Oryza sativa.
光诱导的叶绿体运动控制叶片中有效的光利用，因此对于在波动的光照条件下的叶片光合作用和生物量生产是必不可少的。使用拟南芥的野生型和突变体植物对叶绿体运动进行了深入分析。阐明了分子机制及其对生物量生产的贡献。然而，在其他植物物种中，特别是包括作物植物在内的禾本科植物，叶绿体运动的知识非常匮乏。由于叶绿体运动是优化叶片中光捕获的有效策略，从而促进叶片光合作用和生物量，因此需要对作物中的叶绿体运动进行分析以实现生物量生产。在这里，我们分析了广泛栽培和野生的稻属物种中的叶绿体运动。所有检查的稻属物种均表现出蓝光诱导的叶绿体运动。然而，O. sativa及其祖先种 O. rufipogon 都是 AA 基因组物种，通常在露天条件下生长，植物会暴露在全日照下，与通常在阴凉或半阴凉条件下生长的稻属物种相比，其叶绿体运动较弱，包括 O. officinalis、O. eichingeri 和 O. granulata。对不同的 O. officinalis 品种（包括阳光、半阴凉和阴凉品种）的进一步详细分析表明，驯化水稻植物和野生种之间叶绿体运动强度的差异可能是由于栖息地和叶肉栅状组织细胞的形状不同所致。这项研究的结果为优化稻属生长条件提供了有用的信息，并为提高主食作物 O. sativa 的生长和产量奠定了基础。
