Grain size, a crucial trait that determines rice yield and quality, is typically regulated by multiple genes. Although numerous genes controlling grain size have been identified, the precise and dynamic regulatory network governing grain size is still not fully understood. In this study, we unveiled a novel regulatory module composed of OsHB5, OsAPL and /, which plays a crucial role in modulating grain size in rice. As a positive regulator of grain size, OsAPL has been found to interact with OsHB5 both in vitro and in vivo. Through chromatin immunoprecipitation-sequencing, we successfully mapped two potential targets of OsAPL, namely , a positive regulator in grain size and , a negative regulator in lignification that is also associated with grain size control. Further evidence from EMSA and chromatin immunoprecipitation-quantitative PCR experiments has shown that OsAPL acts as an upstream transcription factor that directly binds to the promoters of and . Moreover, EMSA and dual-luciferase reporter assays have indicated that the interaction between OsAPL and OsHB5 enhances the repressive effect of OsAPL on and . Collectively, our findings discovered a novel regulatory module, OsHB5-OsAPL-OsMADS27/OsWRKY102, which plays a significant role in controlling grain size in rice. These discoveries provide potential targets for breeding high-yield and high-quality rice varieties.

中文翻译：

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一种新型 OsHB5-OsAPL-OsMADS27/OsWRKY102 调节模块调节水稻的颗粒大小

籽粒大小是决定水稻产量和品质的关键性状，通常受到多个基因的调控。尽管已经鉴定出许多控制晶粒大小的基因，但控制晶粒大小的精确且动态的调控网络仍不完全清楚。在这项研究中，我们推出了一种由 OsHB5、OsAPL 和 / 组成的新型调控模块，它在调节水稻籽粒大小方面发挥着至关重要的作用。作为晶粒尺寸的正调节因子，OsAPL 在体外和体内均被发现与 OsHB5 相互作用。通过染色质免疫沉淀测序，我们成功定位了 OsAPL 的两个潜在靶标，即晶粒尺寸的正调节因子和木质化的负调节因子，木质化也与晶粒尺寸控制相关。来自 EMSA 和染色质免疫沉淀定量 PCR 实验的进一步证据表明，OsAPL 作为上游转录因子，直接与 和 的启动子结合。此外，EMSA 和双荧光素酶报告基因检测表明 OsAPL 和 OsHB5 之间的相互作用增强了 OsAPL 对 和 的抑制作用。总的来说，我们的研究发现了一种新的调控模块 OsHB5-OsAPL-OsMADS27/OsWRKY102，它在控制水稻籽粒大小方面发挥着重要作用。这些发现为选育高产优质水稻品种提供了潜在目标。