Zhu Mingqiang, Jiang Shan, Huang Jinqiu, Li Zhihui, Xu Shuang, Liu Shaojia, He Yonggang, Zhang Zhihong
State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Institute of Food Crops, Hubei Academy of Agricultural Sciences, Wuhan 430070, China.
Int J Mol Sci. 2024 Jan 29;25(3):1648. doi: 10.3390/ijms25031648.
Moderate control of rice tillering and the development of rice varieties with large panicles are important topics for future high-yield rice breeding. Herein, we found that low-tillering rice varieties stopped tillering earlier and had a larger leaf area of the sixth leaf. Notably, at 28 days after sowing, the rice seedlings of the low-tillering group had an average single-culm above-ground biomass of 0.84 g, significantly higher than that of the multi-tillering group by 56.26%, and their NSC (non-structural carbohydrate) and starch contents in sheaths were increased by 43.34% and 97.75%, respectively. These results indicated that the low-tillering group of rice varieties had a stronger ability to store photosynthetic products in the form of starch in their sheaths, which was thus more beneficial for their large panicle development. The results of carbon and nitrogen metabolism analyses showed that the low-tillering group had a relatively strong carbon metabolism activity, which was more favorable for the accumulation of photosynthesis products and the following development of large panicles, while the multi-tillering group showed relatively strong nitrogen metabolism activity, which was more beneficial for the development and formation of new organs, such as tillers. Accordingly, in the low-tillering rice varieties, the up-regulated genes were enriched in the pathways mainly related to the synthesis of carbohydrates, while the down-regulated genes were mainly enriched in the nitrogen metabolism pathways. This study provides new insights into the mechanism of rice tillering regulation and promotes the development of new varieties with ideal plant types.
适度控制水稻分蘖以及培育大穗型水稻品种是未来高产水稻育种的重要课题。在此，我们发现低分蘖水稻品种分蘖停止较早，且倒6叶叶面积较大。值得注意的是，播种后28天，低分蘖组水稻秧苗单茎地上部生物量平均为0.84克，显著高于多蘖组56.26%，其叶鞘中NSC（非结构性碳水化合物）和淀粉含量分别增加了43.34%和97.75%。这些结果表明，低分蘖组水稻品种以淀粉形式在叶鞘中储存光合产物的能力较强，因此更有利于其大穗发育。碳氮代谢分析结果表明，低分蘖组碳代谢活性相对较强，更有利于光合产物的积累和后续大穗的发育，而多蘖组氮代谢活性相对较强，更有利于分蘖等新器官的发育和形成。相应地，在低分蘖水稻品种中，上调基因主要富集在与碳水化合物合成相关的途径中，而下调基因主要富集在氮代谢途径中。本研究为水稻分蘖调控机制提供了新的见解，促进了理想株型新品种的培育。
