马铃薯PAL基因家族的全基因组鉴定及其在非生物胁迫下和块茎花色素苷合成中的表达分析

Genome-wide identification of potato(Solanum tuberosum L.)PAL gene family and its expression analysis in abiotic stress and tuber anthocyanin synthesis

苯丙氨酸解氨酶(phenylalanin ammonia-lyase,PAL)是苯丙烷代谢途径的限速酶和关键酶,在植物生长发育过程中发挥着重要作用。本研究在马铃薯(Solanum tuberosum L.)全基因组水平下,利用BlastP和HMM 3.1鉴定到8个PAL基因家族成员,利用ExPASy、CELLO、PlantCARE等在线工具,对PAL基因家族成员的进行生物信息学分析。利用PGSC数据库下载的RNA-seq数据,分析了StPALs在双单倍体(DM)马铃薯不同组织部位和非生物胁迫下的表达模式。对3个不同颜色马铃薯块茎组织(皮和肉)进行RNA-seq,以及利用3个不同颜色块茎杂交子代的薯肉进行qPCR分析。结果表明,8个StPALs分布在3、5、9和10号染色体上,它们与烟草(Nicotiana tabacum)PAL的亲缘关系较近。StPAL基因成员的启动子区域内含有多个顺式元件,包括光响应、逆境胁迫响应、激素响应、生长发育相关和转录因子调控的多种顺式元件。StPAL2在匍匐茎中特异表达,StPAL3/5/8在块茎和匍匐茎中特异表达,StPAL3在甘露醇处理下下调表达,StPAL3和StPAL8在热胁迫中上调表达。它们可能参与了马铃薯块茎的发育和非生物胁迫响应。5个StPALs(StPAL3/4/5/6/8)基因在彩色薯肉中均上调表达,可能参与马铃薯薯肉中花色素苷的生物合成。这些结果为进一步了解StPAL基因家族特征,深入分析StPALs基因在马铃薯中的功能提供了理论依据。

The phenylalanine ammonia-lyase(PAL)is the rate limiting enzyme and key enzyme in phenylpropane metabolism pathway,which plays an important role in plant growth.In this study,a total of 8 gene family members(StPALs)in potato(Solanum tuberosum L.)were identified by BlastP and Hmmer 3.1 software,and their bioinformation were analyzed by the ExPASy,CELLO,PlantCARE,and other online tool.We analyzed the relative expression pattern of StPAL genes in different tissues of double monoploid(DM)potato,as well as under abiotic stresses by RNA-seq in Potato Genome Sequencing Consortium(PGSC)database.We performed RNA-seq on white,red,and purple tuber skin and flesh of three potato cultivars,and the relative expression levels of StPALs genes in different colors tubers(flesh)of three hybrid progeny potatoes were detected by qPCR.StPAL genes were distributed on chromosomes 3,5,9,and 10,and eight StPALs were closely related to tobacco(Nicotiana tabacum)PAL.The cis-acting elements revealed that the promoter regions of StPAL genes contained many elements,including light response,stress response to adversity,hormone response,growth and development,and transcription factor binding elements.The results showed that StPAL2 was specifically expressed in stolons,and StPAL3/5/8 were mainly expressed in tubers and stolons.The relative expression level of StPAL3 gene were down-regulated under mannitol treatment,and the relative expression levels of StPAL3 and StPAL8 genes were up-regulated under heat stress.The above results suggested that StPALs might be involved in the tuber growth and abiotic stress response.By transcriptomic and qPCR analysis,the relative expression levels of 5 StPAL genes(StPAL3/4/5/6/8)were up-regulated in the flesh of color potato,suggesting that they may participate in the biosynthesis of anthocyanins in flesh.These results provide a theoretical basis for further understanding the StPAL gene family and analyzing the function of StPALs in potato.