An Lu, Tao Yang, Chen Hao, He Mingjie, Xiao Feng, Li Ganghua, Ding Yanfeng, Liu Zhenghui
College of Agriculture, Nanjing Agricultural University, Nanjing, China.
Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, China.
Front Plant Sci. 2020 Nov 30;11:587641. doi: 10.3389/fpls.2020.587641. eCollection 2020.
Embryo-endosperm interaction is the dominant process controlling grain filling, thus being crucial for yield and quality formation of the three most important cereals worldwide, rice, wheat, and maize. Fundamental science of functional genomics has uncovered several key genetic programs for embryo and endosperm development, but the interaction or communication between the two tissues is largely elusive. Further, the significance of this interaction for grain filling remains open. This review starts with the morphological and developmental aspects of rice grain, providing a spatial and temporal context. Then, it offers a comprehensive and integrative view of this intercompartmental interaction, focusing on (i) apoplastic nutrient flow from endosperm to the developing embryo, (ii) dependence of embryo development on endosperm, (iii) regulation of endosperm development by embryo, and (iv) bidirectional dialogues between embryo and endosperm. From perspective of embryo-endosperm interaction, the mechanisms underlying the complex quality traits are explored, with grain chalkiness as an example. The review ends with three open questions with scientific and agronomic importance that should be addressed in the future. Notably, current knowledge and future prospects of this hot research topic are reviewed from a viewpoint of crop physiology, which should be helpful for bridging the knowledge gap between the fundamental plant sciences and the practical technologies.
胚乳与胚的相互作用是控制籽粒灌浆的主要过程，因此对于全球三种最重要的谷类作物——水稻、小麦和玉米的产量和品质形成至关重要。功能基因组学的基础科学已经揭示了一些控制胚和胚乳发育的关键遗传程序，但这两个组织之间的相互作用或交流在很大程度上仍不清楚。此外，这种相互作用对籽粒灌浆的重要性也尚不明确。本综述首先从水稻籽粒的形态和发育方面入手，提供一个时空背景。然后，对这种隔室间的相互作用进行全面综合的阐述，重点关注：（i）从胚乳到发育中胚的质外体营养物质流动；（ii）胚发育对胚乳的依赖性；（iii）胚对胚乳发育的调控；（iv）胚与胚乳之间的双向对话。从胚乳与胚相互作用的角度，以籽粒垩白为例，探讨复杂品质性状的潜在机制。综述最后提出了三个具有科学和农学重要性的开放性问题，有待未来加以解决。值得注意的是，本综述从作物生理学的角度对这一热门研究课题的现有知识和未来前景进行了回顾，这将有助于弥合基础植物科学与实用技术之间的知识差距。
