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, 100193, China.
State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
New Phytol. 2024 Sep;243(5):1855-1869. doi: 10.1111/nph.19949. Epub 2024 Jul 4.
Grain filling in maize (Zea mays) is intricately linked to cell development, involving the regulation of genes responsible for the biosynthesis of storage reserves (starch, proteins, and lipids) and phytohormones. However, the regulatory network coordinating these biological functions remains unclear. In this study, we identified 1744 high-confidence target genes co-regulated by the transcription factors (TFs) ZmNAC128 and ZmNAC130 (ZmNAC128/130) through chromatin immunoprecipitation sequencing coupled with RNA-seq analysis in the zmnac128/130 loss-of-function mutants. We further constructed a hierarchical regulatory network using DNA affinity purification sequencing analysis of downstream TFs regulated by ZmNAC128/130. In addition to target genes involved in the biosynthesis of starch and zeins, we discovered novel target genes of ZmNAC128/130 involved in the biosynthesis of lipids and indole-3-acetic acid (IAA). Consistently, the number of oil bodies, as well as the contents of triacylglycerol, and IAA were significantly reduced in zmnac128/130. The hierarchical regulatory network centered by ZmNAC128/130 revealed a significant overlap between the direct target genes of ZmNAC128/130 and their downstream TFs, particularly in regulating the biosynthesis of storage reserves and IAA. Our results indicated that the biosynthesis of storage reserves and IAA is coordinated by a multi-TFs hierarchical regulatory network in maize endosperm.
玉米（Zea mays）的灌浆过程与细胞发育密切相关，涉及到负责储存物质（淀粉、蛋白质和脂质）和植物激素生物合成的基因的调控。然而，协调这些生物学功能的调控网络仍然不清楚。在这项研究中，我们通过在 zmnac128/130 功能丧失突变体中进行染色质免疫沉淀测序结合 RNA-seq 分析，鉴定了 1744 个受转录因子（TFs）ZmNAC128 和 ZmNAC130 共同调控的高可信度靶基因（ZmNAC128/130）。我们进一步通过 ZmNAC128/130 调控的下游 TF 的 DNA 亲和纯化测序分析构建了一个层次调控网络。除了参与淀粉和 zein 生物合成的靶基因外，我们还发现了 ZmNAC128/130 参与脂质和吲哚-3-乙酸（IAA）生物合成的新靶基因。一致地，在 zmnac128/130 中油体的数量以及三酰甘油和 IAA 的含量显著减少。以 ZmNAC128/130 为中心的层次调控网络揭示了 ZmNAC128/130 的直接靶基因与其下游 TF 之间存在显著重叠，特别是在调节储存物质和 IAA 的生物合成方面。我们的结果表明，在玉米胚乳中，储存物质和 IAA 的生物合成是由一个多 TF 层次调控网络协调的。
