Molecular Biology and Genetics Department, Gebze Technical University, Kocaeli, Turkey.
Planta. 2020 Jan 6;251(2):38. doi: 10.1007/s00425-019-03331-y.
miRNAs control leaf size of maize crop during chilling stress tolerance by regulating developmentally important transcriptional factors and sustaining redox homeostasis of cells. Chilling temperature (0-15 °C) is a major constraint for the cultivation of maize (Zea mays) which inhibits the early growth of maize leading to reduction in leaf size. Growth and development take place in meristem, elongation, and mature zones that are linearly located along the leaf base to tip. To prevent shortening of leaf caused by chilling, this study aims to elucidate the regulatory roles of microRNA (miRNA) genes in the controlling process switching between growth and developmental stages. In this respect, hybrid maize ADA313 seedlings were treated to the chilling temperature which caused 26% and 29% reduction in the final leaf length and a decline in cell production of the fourth leaf. The flow cytometry data integrated with the expression analysis of cell cycle genes indicated that the reason for the decline was a failure proceeding from G2/M rather than G1/S. Through an miRNome analysis of 321 known maize miRNAs, 24, 6, and 20 miRNAs were assigned to putative meristem, elongation, and mature zones, respectively according to their chilling response. To gain deeper insight into decreased cell production, in silico, target prediction analysis was performed for meristem specific miRNAs. Among the miRNAs, miR160, miR319, miR395, miR396, miR408, miR528, and miR1432 were selected for confirming the potential of negative regulation with their predicted targets by qRT-PCR. These findings indicated evidence for improvement of growth and yield under chilling stress of the maize.
miRNA 通过调节发育重要的转录因子和维持细胞的氧化还原稳态来控制玉米作物在冷胁迫耐受性下的叶片大小。冷却温度（0-15°C）是玉米（Zea mays）种植的主要限制因素，它抑制了玉米的早期生长，导致叶片面积减少。生长和发育发生在沿着叶片基部到顶端线性排列的分生组织、伸长和成熟区。为了防止叶片因冷却而缩短，本研究旨在阐明 microRNA (miRNA) 基因在控制生长和发育阶段之间转换的调控作用。在这方面，杂种玉米 ADA313 幼苗被处理到冷却温度下，导致最终叶片长度减少 26%和 29%，第四叶片的细胞产生减少。流式细胞术数据与细胞周期基因的表达分析相结合表明，下降的原因是 G2/M 而不是 G1/S 失败。通过对 321 个已知玉米 miRNA 的 miRNome 分析，根据它们的冷响应，将 24、6 和 20 个 miRNA 分别分配到假定的分生组织、伸长和成熟区。为了更深入地了解细胞产生减少的原因，对分生组织特异性 miRNA 进行了计算机模拟的靶标预测分析。在这些 miRNA 中，miR160、miR319、miR395、miR396、miR408、miR528 和 miR1432 被选择用于通过 qRT-PCR 确认其与预测靶标负调控的潜力。这些发现为提高玉米在冷胁迫下的生长和产量提供了证据。
