Abstract: 【Objective】 Modern molecular biology and high-throughput sequencing technology were applied to screen different miRNAs and their target genes that respond to drought stress during the differentiation of tassel flower organs in different cultivars of corn, thus further excavating and identifying genes related to maize development and reveal signaling pathways and molecular regulatory networks for differences in traits.【Methods】 The drought-tolerant inbred line "PHBA6" and the drought-sensitive inbred line "Ji 63" were used as the research objects. The miRNA library was constructed using deep sequencing technology to identify the differentially expressed miRNAs. The target genes were subjected to functional annotation, cluster analysis and pathway enrichment.【Results】 A total of 337 precursor miRNAs were identified, including 289 known miRNAs and 48 new miRNAs. A total of 155 differentially expressed miRNAs were found in the three libraries in two groups. Target prediction, GO functional classification and genetic and genomic (KEGG) -based functional enrichment showed that these miRNAs might play a role in drought stress by targeting a range of stress-related genes. Analysis showed that at least 55 predicted target genes were further regulated by 60 miRNAs. Further analysis showed that the NAC, MYB and MAPK gene families scored highest under drought stress, indicating that they played an important role in drought resistance of plants. According to the target gene prediction, a series of cotton miRNAs were related to these top genes, including miR164, miR172, miR1520, miR6158, ghr-n24, ghr-n56, and so on.【Conclusion】 miRNAs may play an important role in drought tolerance during the differentiation of maize tassel flower organs. The screening of miRNAs provided new targets for molecular-assisted breeding and transgenic breeding.

Key words: corn; deep sequencing; drought; tassel; differentiation stage; miRNA

摘要： 【目的】 运用现代分子生物学及高通量测序技术,研究不同品种玉米雄穗花器官分化期响应干旱胁迫的差异miRNA和其靶基因,挖掘和鉴定与玉米发育相关的基因,分析其性状差异的信号通路及分子调控网络。【方法】 以耐旱自交系"PHBA6"和干旱敏感自交系“吉63”为研究对象,应用深度测序技术进行miRNA文库构建,鉴定其差异表达的 miRNA,对差异表达mi RNA及其靶基因进行功能注释、聚类分析及通路富集。【结果】 鉴定了总共337种前体miRNA,其中包含289种已知的miRNA和48种新的miRNA。在3个文库,两个分组中共有155种差异表达miRNA。基于GO功能分类及遗传和基因组(KEGG)的功能富集显示,这些miRNA可能通过靶向一系列与胁迫相关的基因而在干旱胁迫中发挥作用。至少55个预测的靶基因进一步被60个miRNA调控。NAC,MYB和MAPK基因家族在干旱胁迫下评分最高,在植物抗旱中重要作用。一系列miRNA与这些排名靠前的基因相关,包括miR164、miR172、miR1520、miR6158、ghr-n24、ghr-n56等。【结论】 miRNAs可能在玉米雄穗花器官分化期耐旱中发挥重要作用,miRNAs的筛选为分子辅助育种和转基因育种将提供新的靶标。

关键词: 玉米, 深度测序, 干旱, 雄穗, 分化期, miRNA