Main conclusionmiRNAs control leaf size of maize crop during chilling stress tolerance by regulating developmentally important transcriptional factors and sustaining redox homeostasis of cells.AbstractChilling 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.

中文翻译：

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阐明 microRNA 在玉米 (Zea mays L.) 叶片生长对低温胁迫的反应中的调节作用

主要结论miRNAs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冷胁迫耐受期间玉米作物的叶片大小。摘要冷却温度（0-15°C）是玉米（Zea mays）栽培的主要限制因素，它抑制了玉米过早生长导致叶片变小。生长和发育发生在沿叶基部到叶尖呈线性分布的分生组织、伸长区和成熟区。为防止受冷引起的叶片缩短，本研究旨在阐明 microRNA (miRNA) 基因在控制生长和发育阶段转换过程中的调节作用。在这方面，杂交玉米 ADA313 幼苗经过低温处理，导致最终叶长减少 26% 和 29%，第四叶细胞产量下降。流式细胞术数据结合细胞周期基因的表达分析表明下降的原因是从G2/M而不是G1/S开始的失败。通过对 321 种已知玉米 miRNA 的 miRNome 分析，24、6 和 20 种 miRNA 根据它们的低温反应分别被分配到假定的分生组织、伸长区和成熟区。为了更深入地了解细胞产量减少，在计算机上对分生组织特异性 miRNA 进行了目标预测分析。在 miRNA 中，miR160、miR319、miR395、miR396、miR408、miR528、和 miR1432 被选择用于通过 qRT-PCR 确认其预测目标的负调节潜力。这些发现表明玉米在低温胁迫下生长和产量提高的证据。