甘薯储藏期低温胁迫的转录组分析和关键基因挖掘

Transcriptome Analysis and Key Gene Mining of Sweetpotato under Low Temperature Stress during Storage

甘薯在储藏过程中受到低温冷害会大大降低甘薯的商品价值,因此研究甘薯耐低温储藏的分子机制,减少低温在甘薯储藏过程中的影响具有重要意义。本研究选取了较耐低温储藏、不耐低温储藏以及表现居中的3个甘薯品种商薯19(S19)、烟薯25(Y25)和苏薯16(S16),分别在9℃和6℃储藏35 d。提取上述处理的薯块总RNA进行转录组测序和比较分析,发现与对照相比,S19在低温储藏后的差异表达基因较少,而Y25则相反,S16居中。差异表达基因KEGG和GO分析发现,甘薯块根在低温胁迫下蛋白酶体相关基因的表达水平较高。最终,通过比较不同品种不同温度下的转录组数据,得到响应储藏期低温胁迫的候选基因Ibat.Brg.02F_G010830,该基因注释为冷胁迫响应类受体蛋白激酶。qRT-PCR验证该基因的表达与转录组数据相一致。进一步分析了该基因及其等位基因和同源基因的进化关系,并分析了该基因在不同品种中的变异。本研究将为甘薯低温储藏响应机制解析以及耐低温储藏品种的选育提供支撑。

Low temperature stress during storage will greatly reduce the commodity value of sweetpotato.It is of great significance to study the molecular mechanism of cryopreservation tolerance and reduce the influence of low temperature in the storage process of sweetpotato.In this study,‘Shangshu 19'(S19),‘Yanshu 25'(Y25)and‘Sushu 16'(S16),three sweetpotato varieties that showed tolerance,intolerance,and moderately tolerant to low temperature storage,were stored at 9℃and 6℃for 35 days,respectively.The total RNA of above tuberous roots were exacted for transcriptome sequencing and comparative analyis,and the results showed that S19 had fewer differentially expressed genes after low temperature storage,while the opposite was observed for Y25,and S16 was intermediate.KEGG and GO analysis of differentially expressed genes showed that the expression level of proteasome related genes was higher in tuberous roots under low temperature stress.Finally,by comparing the transcriptome data of tuberous root of different varieties under different storage temperatures,a candidate gene Ibat.Brg.02F_G010830 that responds to low temperature stress during storage was obtained and it was annotated as cold-responsive protein kinase 1-like.qRT-PCR verified that the expression of this gene was consistent with the transcriptome data.The phylogenetic analysis of this gene and its alleles and orthologs was conducted,as well as the variation of this gene in different varieties.This study will provide support for the resolution of response mechanism under low temperature storage and the selection of varieties with low temperature storage tolerance.