高羊茅光合作用与激素信号对低氮胁迫的转录组响应

Transcriptome Responses of Photosynthesis and Hormone Signals in Tall Fescue to Low Nitrogen Stress

养分胁迫直接影响高羊茅的生长发育,为研究高羊茅对低氮胁迫响应的分子机制,利用Illumina技术从高羊茅幼苗中获得了超过6000万个序列信息,拼接得到72666个unigenes并进行了分析。差异性分析显示,共检测到13112个响应低氮胁迫的基因,其中2346个上调基因,10766个下调基因。GO注释和KEGG显著性富集分析发现,差异基因主要富集在代谢过程、RNA转运、mRNA监测、次生代谢物的合成及胞吞作用通路中。在低氮胁迫下,光合作用相关基因被显著抑制,特别是捕光叶绿素a/b结合蛋白基因,这些基因的下调导致光合活性下降,有机质积累减少;植物激素相关基因大规模上调,表明氮信号与植物激素之间存在反馈调节。qRT-PCR分析表明,选出的差异表达基因与高通量测序结果基本一致。

Tall fescue(Festuca arundinacea)is one of the most important pasture grasses in the world,nutrient stress directly affects the growth and development of tall fescue.In order to study the molecular mechanism of tall fescue response to low nitrogen stress,more than 60 million sequencing reads was obtained from tall fescue seedlings under low nitrogen using Illumina sequencing technology,and 72666 unigenes were spliced and analyzed.The differential analysis showed that a total of 13112 genes responding to low nitrogen stress were detected,including 2346 up-regulated genes and 10766 down-regulated genes.GO annotation and KEGG pathway mapping showed that the differential genes were mainly enriched in metabolic process,RNA transport,mRNA surveillance pathway,biosynthesis of secondary metabolites and endocytosis pathways.Under low nitrogen stress,the photosynthetic related genes were significantly inhibited,especially the light harvesting chlorophyll a/b binding protein.The down-regulation of these genes led to the decline of photosynthesis activities and decrease of organic matter accumulation.The large-scale up-regulation of plant hormone related genes indicated that there might be feedback regulation between nitrogen signal and phytohormones.The qRT-PCR analysis showed that the selected differentially expressed genes were basically consistent with the results of high-throughput sequencing.