摘要：

为探究生防菌以不同方式处理油茶后的转录组变化,明确生防菌提高油茶抗性的分子调控机制。以2年生的油茶苗为试验材料,利用喷叶和灌根2种方式将生防菌特基拉芽孢杆菌接种到油茶苗上,以等量的无菌水作为对照,取处理15 d后的油茶叶片进行转录组分析。结果表明,转录组测序共获得167 118 913条序列,差异表达基因(DEGs)有19 164条,其中,样本CK-vs-DZY 6715的DEGs有4 722个,样本CKG-vs-DZY 6715G的DEGs有14 442个,两组样本共有的DEGs数量为2 573个,样本CKG-vs-DZY 6715G特有的DEGs数量最多(11 869个),最少的是样本CK-vs-DZY 6715(2 149个)。GO富集分析表明,两组样本的DEGs被注释到生物学过程、分子功能和细胞组分,主要涉及代谢过程、细胞过程、单一生物过程、细胞、细胞组分、膜、结合、催化活性、转运活性等。KEGG pathway分析显示,两组样本的DEGs被富集到代谢过程、次级代谢产物的生物合成过程的数量最多,而样本CK-vs-DZY 6715的DEGs还主要被富集到植物激素信号转导通路,样本CKG-vs-DZY 6715G中DEGs还主要被富集到植物与病原体互作通路,主要涉及的与抗病性相关的DEGs大量上调表达,包括pckA、PGAM、ACOX1、FATB、asnB、ansA、FLS、LAR、AUX1、GID1、ETR、FLS2、CDPK、pfkA,但基因表达量在喷叶和灌根方式间存在差异,喷叶中与次级代谢产物的生物合成和植物激素信号转导有关的基因表达量更高,而灌根的则是与代谢过程和植物病原互作有关的基因表达量更高。研究认为,生防菌特基拉芽孢杆菌以喷叶或灌根方式处理油茶均有助于油茶抗病性的增强,只是2种处理方式的主要作用机制略存在不同。

关键词: 油茶, 抗病性, 转录组分析, 生防菌

Abstract:

To explore the transcriptome changes after biocontrol bacteria treat Camellia oleifera in different ways,and understand the molecular regulatory mechanism of biocontrol bacteria enhancing C.oleifera resistance.The 2-year-old C.oleifera seedlings were selected as experimental materials,and the biocontrol bacterium Bacillus tequilensis was inoculated onto seedlings by leaf spraying and root irrigation,as well as an equal amount of sterile water was used as a control,and the C.oleifera leaves were taken after 15 days of treatment for transcriptome sequencing analysis.The results indicated that a total of 167 118 913 reads were obtained by transcriptome sequencing,with 19 164 differentially expressed genes(DEGs).Among which there were 4 722 DEGs in sample CK-vs-DZY 6715 and 14 442 DEGs in sample CKG-vs-DZY 6715G,and the number of DEGs common to the two groups of samples was 2 573,with the highest number of unique DEGs to sample CKG-vs-DZY 6715G(11 869),followed by sample CK-vs-DZY 6715(2 149).GO enrichment analysis showed that the DEGs of the two groups of samples were annotated into biological processes,molecular functions,and cellular components,mainly involving metabolic process,cellular process,single biological process,cell,cell part,membrane,binding,catalytic activity,transport activity,etc.KEGG pathway analysis showed that the DEGs of the two groups of samples were enriched into metabolic pathway and biosynthesis of secondary metabolites,while DEGs were also mainly enriched to plant hormone signaling transduction in sample CK-vs-DZY 6715,and the DEGs of sample CKG-vs-DZY 6715G were mainly enriched in the plant pathogen interaction.The main DEGs related to disease resistance were up-regulated expression,including pckA,PGAM,ACOX1,FATB,asnB,ansA,FLS,LAR,AUX1,GID1,ETR,STPK,CDPK,pfkA.However,there were differences in gene expression levels between spray and root irrigation methods,the expression levels of genes related to the biosynthesis of secondary metabolites and plant hormone signal transduction were higher in spray,while those related to metabolic pathway and plant pathogen interactions were higher in root irrigation.Thus,this paper concluded that the biocontrol bacteria Bacillus tequilensis could enhance disease resistance in C.oleifera after treatment with leaf spray or root irrigation,only that the main mechanism of action of the two treatment methods was slightly different.

Key words: Camellia oleifera, Disease resistance, Transcriptome analysis, Biocontrol bacteria