甘薯CLE多肽家族的全基因组鉴定和IbCLE12的克隆及抗旱性表达分析

Genome-Wide Identification of CLE Peptide Family in Sweet Potato and Cloning and Expressing Analysis of IbCLE12 under Drought Stress

CLAVATA3/Embryo surrounding region-related(CLE)多肽作为植物体内小分子信号激素,在植物的生长发育和抗逆性中发挥重要的调控作用。本研究从甘薯近缘野生种Ipomoea trifida的基因组数据库中筛选出12个ItfCLE基因,并对其结构、蛋白理化性质、进化关系以及转录水平的表达进行了分析。结果表明,12个ItfCLE蛋白的长度和分子量分别为81~154 aa和9.0~17.5 kDa;均具有C末端保守基序(VSKRKVPSGPBPJHN);除了ItfCLE2和ItfCLE6,均为不稳定蛋白;除了ItfCLE5,均为亲水性脂溶蛋白;亚细胞定位表明均为胞外分泌型小肽。进化分析表明这12个CLE多肽属于5个不同的亚组。表达模式分析表明,各ItfCLE基因在不同组织中的表达不同,ItfCLE9和ItfCLE10在花中表达较高,ItfCLE4和ItfCLE12在根中表达较高,ItfCLE2、ItfCLE6和ItfCLE8在茎中表达较高;ItfCLE12基因受干旱诱导表达最高,ItfCLE8受干旱和盐胁迫诱导上调表达。进一步从甘薯栽培种济薯25中克隆ItfCLE12的同源基因IbCLE12,实时荧光定量结果表明IbCLE12受PEG6000干旱和ABA处理诱导显著上调表达,推测IbCLE12在甘薯抗旱性中发挥重要的调控作用。本研究结果可为进一步解析甘薯CLE多肽家族功能及IbCLE12基因在甘薯抗旱性中的分子机制奠定基础。

CLAVATA3/Embryo surrounding region-related(CLE)peptides are signalling phytohormones in plants,which play important roles in plant growth,development and responses to stresses.In this study,we discovered 12 ItfCLE genes members in siploid sweetpotato,Ipomoea trifida.The results of bioinformatics analysis showed that the 12 ItfCLE genes were between 81-154 aa in length,with a predicted molecular weight of 9.0-17.5 kDa.All of them conteins a C-terminal conserved motif(VSKRKVPSGPBPJHN).Most of them were unstable proteins,except for ItfCLE2 and ItfCLE6.Except for ItfCLE5,other ItfCLE proteins were hydrophilic proteins.The subcellular location revealed that all ItfCLE were extracellular role of secretory small peptides.Phylogenetic analysis shows that 12 CLE proteins were divided into five subgroups.The expression analysis in different tissues showed that ItfCLE mainly expressed in flower(ItfCLE9 and ItfCLE10),root(ItfCLE4 and ItfCLE12)and stem(ItfCLE2,ItfCLE6and ItfCLE8),respectively.After treatments of drought,salt,cold,heat and disease stresses,ItfCLE12 was up-expressed most obviously under drought stress and ItfCLE8 was up-expressed under drought and salt stresses.We cloned the homologous gene of ItfCLE12 sweetpotato cultivar Jishu 25,and named IbCLE12.Quantitative real-time polymerase chain reaction(qRT-PCR)showed that IbCLE12 was up-expressed under PEG6000 and ABA treatment in Jishu 25.These results will provide molecular-level insights of IbCLE12 into drought tolerance in sweetpotao.