Wang Qun, Feng Fan, Zhang Kechun, He Yonghui, Qi Weiwei, Ma Zeyang, Song Rentao
State Key Laboratory of Maize Bio-breeding, Frontiers Science Center for Molecular Design Breeding, Joint International Research Laboratory of Crop Molecular Breeding, National Maize Improvement Center, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China.
Sanya Institute of China Agricultural University, Sanya, China.
Nat Plants. 2024 Dec;10(12):1999-2013. doi: 10.1038/s41477-024-01845-2. Epub 2024 Nov 27.
The endosperm of cereal grains feeds the entire world as a major food supply; however, little is known about its defence response during endosperm development. The Inducer of CBF Expression 1 (ICE1) is a well-known regulator of cold tolerance in plants. ICE1 has a monocot-specific homologue that is preferentially expressed in cereal endosperms but with an unclear regulatory function. Here we characterized the function of monocot-specific ZmICE1a, which is expressed in the entire endosperm, with a predominant expression in its peripheral regions, including the aleurone layer, subaleurone layer and basal endosperm transfer layer in maize (Zea mays). Loss of function of ZmICE1a reduced starch content and kernel weight. RNA sequencing and CUT&Tag-seq analyses revealed that ZmICE1a positively regulates genes in starch synthesis while negatively regulating genes in aleurone layer-specific defence and the synthesis of indole-3-acetic acid and jasmonic acid (JA). Exogenous indole-3-acetic acid and JA both induce the expression of numerous defence genes, which show distinct spatial-specific expression in the basal endosperm transfer layer and subaleurone layer, respectively. Moreover, we dissected a JA-ZmJAZ9-ZmICE1a-MPI signalling axis involved in JA-mediated defence regulation. Overall, our study revealed ZmICE1a as a key regulator of endosperm defence response and a coordinator of the defence-storage trade-off in endosperm development.
谷物的胚乳作为主要食物来源养活了全世界；然而，人们对其在胚乳发育过程中的防御反应知之甚少。CBF表达诱导因子1（ICE1）是植物中一种著名的耐寒性调节因子。ICE1有一个单子叶植物特有的同源物，它在谷物胚乳中优先表达，但调节功能尚不清楚。在这里，我们对单子叶植物特有的ZmICE1a的功能进行了表征，它在整个胚乳中表达，在其外围区域（包括玉米（Zea mays）的糊粉层、亚糊粉层和胚乳基部转移层）中占主导地位。ZmICE1a功能丧失会降低淀粉含量和籽粒重量。RNA测序和CUT&Tag-seq分析表明，ZmICE1a正向调节淀粉合成相关基因，同时负向调节糊粉层特异性防御以及吲哚-3-乙酸和茉莉酸（JA）合成相关基因。外源吲哚-3-乙酸和JA均诱导大量防御基因的表达，这些基因分别在胚乳基部转移层和亚糊粉层表现出明显的空间特异性表达。此外，我们剖析了一条参与JA介导的防御调节的JA-ZmJAZ9-ZmICE1a-MPI信号轴。总体而言，我们的研究揭示了ZmICE1a是胚乳防御反应的关键调节因子，也是胚乳发育中防御-储存权衡的协调者。
