State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Key Laboratory for Enhancing Resource Use Efficiency of Crops in South China, Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of Plant Molecular Breeding, College of Agriculture, South China Agricultural University, Guangzhou, 510642, China.
Guangdong Academy of Agricultural Sciences, Rice Research Institute, Guangzhou, 510640, China.
New Phytol. 2023 Dec;240(6):2419-2435. doi: 10.1111/nph.19271. Epub 2023 Sep 24.
Crop yield must increase to achieve food security in the face of a growing population and environmental deterioration. Grain size is a prime breeding target for improving grain yield and quality in crop. Here, we report that autophagy emerges as an important regulatory pathway contributing to grain size and quality in rice. Mutations of rice Autophagy-related 9b (OsATG9b) or OsATG13a causes smaller grains and increase of chalkiness, whereas overexpression of either promotes grain size and quality. We also demonstrate that THOUSAND-GRAIN WEIGHT 6 (TGW6), a superior allele that regulates grain size and quality in the rice variety Kasalath, interacts with OsATG8 via the canonical Atg8-interacting motif (AIM), and then is recruited to the autophagosome for selective degradation. In consistent, alteration of either OsATG9b or OsATG13a expression results in reciprocal modulation of TGW6 abundance during grain growth. Genetic analyses confirmed that knockout of TGW6 in either osatg9b or osatg13a mutants can partially rescue their grain size defects, indicating that TGW6 is one of the substrates for autophagy to regulate grain development. We therefore propose a potential framework for autophagy in contributing to grain size and quality in crops.
面对不断增长的人口和环境恶化，作物产量必须提高以确保粮食安全。粒型是提高作物产量和品质的主要选育目标。在这里，我们报告自噬作为一个重要的调控途径，有助于水稻粒型和品质的形成。水稻自噬相关蛋白 9b（OsATG9b）或 OsATG13a 的突变导致粒型变小和垩白度增加，而过量表达则促进粒型和品质的提高。我们还证明，THOUSAND-GRAIN WEIGHT 6（TGW6）是一个调节水稻品种 Kasalath 粒型和品质的优良等位基因，通过典型的 Atg8 相互作用基序（AIM）与 OsATG8 相互作用，然后被招募到自噬体进行选择性降解。同样，在粒重生长过程中，OsATG9b 或 OsATG13a 的表达变化导致 TGW6 丰度的相互调节。遗传分析证实，在 osatg9b 或 osatg13a 突变体中敲除 TGW6 可以部分挽救其粒型缺陷，表明 TGW6 是自噬调节谷物发育的底物之一。因此，我们提出了一个自噬参与作物粒型和品质形成的潜在框架。
