玉米愈伤组织形成的转录组分析

Transcriptome Analysis of Maize Embryonic Calli

玉米遗传转化受体主要是未成熟幼胚,经过组织培养形成胚性愈伤组织,进而分化成苗。目前,对玉米胚性愈伤组织形成的分子机理的了解还不深入。为了挖掘调控玉米胚性愈伤组织形成的基因,本研究选取玉米自交系CAL28×郑58的F3群体中不同表型的愈伤组织进行RNA-seq分析。与愈伤发生差的Ⅱ型愈伤相比,愈伤发生好的Ⅰ型愈伤中共检测到4419个差异表达基因,其中1571个基因上调,2848个基因下调。GO富集分析结果表明,差异表达基因主要富集在细胞过程、催化活性、细胞组分等通路中。KEGG富集分析表明,差异表达基因主要富集在苯丙烷生物合成途径和植物激素信号转导途径。在生长素早期响应基因中,8个AUX/IAA家族基因,如IAA23、IAA33、IAA41,和4个GH3家族基因在Ⅰ型愈伤中上调表达。差异显著基因中共有隶属56个转录因子家族的2968个转录因子,其中与愈伤形成相关的AP2、WOX和LBD转录因子家族基因中的ZmEREB53、ZmEREB206、ZmEREB184、ZmLBD10、ZmLBD24、ZmLBD31、ZmLBD32、ZmWOX5b、ZmWOX9b等在Ⅰ型愈伤中的表达量显著上调,对这些靶标基因进行遗传操作有可能促进玉米愈伤组织形成。本研究发现的靶标基因具有较大的应用潜力,研究结果也为解析玉米愈伤组织形成的分子机理提供了理论参考。

The immature embryos of maize are able to form embryogenic calli through tissue culture,and are usually used as explants in genetic transformation.The molecular mechanism in the process of maize embryonic callus formation remains fully illustrated.To reveal the candidate genes that are involved in the callus formation of maize,two types of calli(type I,well growth;type II,poor growth)from F3 embryos of maize inbred line CAL28×Zheng58 were harvested for the RNA-seq analysis.4419 differentially expressed genes(DEGs)were revealed between two types,including 1571 up regulated genes and 2848 down regulated genes.GO enrichment analysis showed that DEGs were mainly enriched in the pathways such as cellular process,catalytic activity,and cell component.KEGG enrichment analysis showed that the enrichment of DEGs were mainly involved in phenylpropanoid biosynthesis and the plant hormone signal transduction pathway.Among the early auxin responses genes,eight AUX/IAA genes including IAA23,IAA33,IAA41,and four GH3 genes were upregulated in type I callus.A total of 2968 transcription factors belonging to 56 transcription factor families in DEGs were significantly enriched.The expression levels of ZmEREB53,ZmEREB206,ZmEREB184,ZmLBD10,ZmLBD24,ZmLBD31,ZmLBD32,ZmWOX5b and ZmWOX9b,which are from AP2,WOX and LBD transcription factor families,were significantly up-regulated in type I callus.Genetic manipulation of these target genes may possibly promote the formation of maize callus.Collectively,this study identified candidate DEGs with great application potential,which provide theoretical reference for deciphering the molecular mechanism of maize callus formation.