Chatterjee Debamalya, Zhang Ziru, Lin Pei-Yu, Wang Po-Hao, Sidhu Gurpreet K, Yennawar Neela H, Hsieh Jo-Wei Allison, Chen Pao-Yang, Song Rentao, Meyers Blake C, Chopra Surinder
Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA.
National Center for Maize Improvement, China Agricultural University, Beijing 100083, China.
Plant Cell. 2024 Dec 23;37(1). doi: 10.1093/plcell/koae301.
The basal endosperm transfer layer (BETL) of the maize (Zea mays L.) kernel is composed of transfer cells for nutrient transport to nourish the developing kernel. To understand the spatiotemporal processes required for BETL development, we characterized 2 unstable factor for orange1 (Zmufo1) mutant alleles. The BETL defects in these mutants were associated with high levels of reactive oxygen species, oxidative DNA damage, and cell death. Interestingly, antioxidant supplementation in in vitro cultured kernels alleviated the cellular defects in mutants. Transcriptome analysis of the loss-of-function Zmufo1 allele showed differential expression of tricarboxylic acid cycle, redox homeostasis, and BETL-related genes. The basal endosperms of the mutant alleles had high levels of acetyl-CoA and elevated histone acetyltransferase activity. The BETL cell nuclei showed reduced electron-dense regions, indicating sparse heterochromatin distribution in the mutants compared with wild-type. Zmufo1 overexpression further reduced histone methylation marks in the enhancer and gene body regions of the pericarp color1 (Zmp1) reporter gene. Zmufo1 encodes an intrinsically disordered nuclear protein with very low sequence similarity to known proteins. Yeast two-hybrid and luciferase complementation assays established that ZmUFO1 interacts with proteins that play a role in chromatin remodeling, nuclear transport, and transcriptional regulation. This study establishes the critical function of Zmufo1 during basal endosperm development in maize kernels.
玉米（Zea mays L.）籽粒的基部胚乳转移层（BETL）由转移细胞组成，用于营养物质运输以滋养发育中的籽粒。为了解BETL发育所需的时空过程，我们对2个橙色1不稳定因子（Zmufo1）突变等位基因进行了表征。这些突变体中的BETL缺陷与高水平的活性氧、氧化性DNA损伤和细胞死亡有关。有趣的是，体外培养籽粒中添加抗氧化剂可减轻突变体中的细胞缺陷。对功能丧失的Zmufo1等位基因进行转录组分析，结果显示三羧酸循环、氧化还原稳态和BETL相关基因存在差异表达。突变等位基因的基部胚乳中乙酰辅酶A水平较高，组蛋白乙酰转移酶活性升高。BETL细胞核的电子致密区域减少，表明与野生型相比，突变体中的异染色质分布稀疏。Zmufo1过表达进一步降低了果皮颜色1（Zmp1）报告基因增强子和基因体区域的组蛋白甲基化标记。Zmufo1编码一种内在无序的核蛋白，与已知蛋白的序列相似性非常低。酵母双杂交和荧光素酶互补试验证实，ZmUFO1与在染色质重塑、核运输和转录调控中起作用的蛋白质相互作用。本研究确定了Zmufo1在玉米籽粒基部胚乳发育过程中的关键功能。
