摘要：

为了探究玉米抗寒过程中涉及的关键调控网络和基因,明确对低温胁迫响应的关键调控通路和基因,为后续深入研究鲜食玉米抗寒胁迫的分子机制奠定基础,以耐寒品种闽甜6855为研究材料,利用转录组技术对其受5 ℃低温胁迫24,48,72 h后的基因表达情况进行分析。PCA结果显示,重复间样本可以显著聚集在一起,且处理样本与CK样本显著分开。差异分析结果显示,闽甜6855在低温处理前后差异基因为4 000~7 000个,而不同时长低温处理样本间差异基因较少,为100~2 000个,表明低温是引起基因差异的主要因素,且对低温胁迫的响应主要在前期。KEGG注释分析结果显示,差异基因在植物激素信号转导和MAPK上存在显著富集,表明这2个信号通路积极响应抗寒胁迫。此外,在植物病原菌互作和植物昼夜节律调控通路差异基因也出现了显著富集,暗示着在生物和非生物胁迫的通路上也存在着重叠或共有调控途径,而调控昼夜节律的基因在植物适应低温环境的过程中起着关键的调节作用。

关键词: 鲜食玉米, 闽甜6855, 低温胁迫, 全长转录组, 育种

Abstract:

In order to preliminarily explore the key regulatory networks and genes involved in maize cold resistance,identify the key regulatory pathways and genes in response to low temperature stress,which laying a foundation for further research on the molecular mechanism of cold stress resistance.Here,a cold tolerance variety Mintian 6855 was employed to determine the gene expression pattern at 24,48 and 72 hours post low temperature of 5 ℃ stress by using transcriptome technique.The PCA analysis revealed that the repeated samples were well clustered together and significantly separated from CK samples.The results of difference analysis showed that about 4 000—7 000 difference genes expressed after cold stress treatments,while,only about 100—2 000 showed difference expressing among low temperature treated samples,indicating that low temperature was the main factor results in genes difference expressing,and the difference expression genes were mainly responded in the early stage.Meanwhile,KEGG annotation analysis results revealed that the differentially expressed genes were enriched in pathways of plant hormone signal transduction and MAPK,suggesting that these two signaling pathways actively respond to cold stress.In addition,different express genes were also enriched in plant-pathogen interaction as well as circadian rhythm plant,strongly implied that there were overlapping or common regulatory pathways in biological and abiotic stress pathways,while,genes that regulate circadian rhythms also playing a key role in plant adaptation to low temperatures.

Key words: Fresh-eating corn, Mintian 6855, Low temperature stress, Full-length transcriptome, Breeding