油菜素甾醇信号调控粒形的分子机制与育种应用研究进展

Molecular mechanisms of brassinosteroid signaling in regulating grain size and its breeding applications

摘要

油菜素甾醇(brassinosteroids,BR)信号在作物籽粒发育中扮演着双重角色:调控颖壳细胞的伸长与分裂;激活糖分转运和淀粉合成相关基因，其作为一类重要的甾醇类植物激素，在植物的生长发育调控中发挥着重要作用。近 20 年来，BR 信号通路的核心组分从细胞表面受体到细胞核内转录因子的传导网络已被系统解析，建立了以受体激酶 BRI1(BR insensitive1)、共受体 BAK1(BRI1-associated receptor kinase1)、负调控激酶 GSK3/SHAGGY-like 家族以及转录因子 BZR1/BES1(brassinazole resistant1/bri1-EMS-suppressor1)为核心骨架的信号通路。本文系统综述了 BR 信号调控籽粒发育的分子机制，系统阐述了 BR 的合成、感知与传导，BR 调控籽粒发育的细胞学和分子机制，BR 与生长素、赤霉素等其他信号通路的交叉机制，以及不同作物中 BR 调控籽粒发育的保守性与特异性。最后，指出该领域面临的主要问题与挑战，并对利用 BR 相关基因实现作物产量与品质协同改良的分子设计育种前景进行展望。

Abstract

Brassinosteroids (BR) signaling plays a dual role in crop grain development: regulating cell elongation and division in the spikelet hull, and activating genes involved in sugar transport and starch biosynthesis. BR is a class of essential steroidal phytohormones, and plays indispensable roles in regulating plant growth and development. Over the past two decades, the core components of the BR signaling pathway, which span the transduction network from cell-surface receptors to nuclear transcription factors, have been systematically elucidated. A canonical signaling model centered on the receptor kinase BRI1 (BR insensitive1), the co-receptor BAK1 (BRI1-associated receptor kinase1), the negative regulatory GSK3/SHAGGY-like kinase family, and the transcription factors BZR1/BES1 (brassinazole resistant1/bri1-EMS-suppressor1) have been established. This review systematically summarizes the molecular mechanisms by which BR signaling regulates grain development, covering BR biosynthesis, perception, and transduction, the cytological and molecular mechanisms underlying BR-mediated grain development, the crosstalk between BR and other phytohormones such as auxin and gibberellin, and the conservation and divergence of BR-regulated grain development across different crop species. Finally, we provide a comprehensive evaluation of the current research status, highlight the key issues and challenges facing the field, and discuss the prospects of molecular design breeding for achieving synergistic improvement of crop yield and grain quality by leveraging BR-related genes.

关键词

油菜素甾醇 / 粒形 / 信号转导 / BR 合成 / 分子设计育种

Key words

brassinosteroids / grain size / signal transduction / BR biosynthesis / molecular design breeding

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基金资助

国家自然科学基金项目(32470337)

中央高校基本科研业务费专项资金(KJYQ2025013)