猕猴桃AcSWEET基因家族的鉴定与表达分析

Identification and expression analysis of the AcSWEET gene family in Actinidia chinensis Planch.

SWEET(Sugars will eventually be exported transporters)是近年来在植物中发现的一组糖转运蛋白,在植物生长、发育和非生物及生物胁迫响应等多种生理过程中发挥着重要作用。本研究利用生物信息学方法对猕猴桃(Actinidia chinensis Planch.)AcSWEET基因家族进行了鉴定,共获得29个AcSWEET基因,并对其氨基酸数量、相对分子量、等电点、不稳定系数、亚细胞定位、亲水指数进行了分析。结果显示:29个基因编码的氨基酸数目为680~906个;分子量范围为7.531~101.266 kDa,等电点在6.95~9.90,多数蛋白为定位于细胞膜的疏水性蛋白,具有1~2个MtN3结构域或PQ-loop结构域。此外,AcSWEET基因的外显子数量在4~6个,系统进化分析结果表明猕猴桃AcSWEET基因家族被分为4个亚族,同一亚族基因具有相似的内含子、外显子以及保守基序。表达模式分析结果表明,这些基因在果实不同发育时期具有表达特异性。推测AcSWEET26、AcSWEET7、AcSWEET15和AcSWEET13可能参与猕猴桃的蔗糖转运和积累。

The sugar will eventually be exported transporters(SWEET)are a recently discovered group of sugar transporters in plants,which play important roles in various physiological processes,such as plant growth,development,and abiotic and biotic stress.This study aimed to characterize the Actinidia chinensis Planch.SWEET gene family and analyze its expression during fruit development using bioinformatics methods.A total of 29 AcSWEET genes were identified,and their amino acid quantity,relative molecular weights,isoelectric points,instability coefficients,subcellular localizations,and hydrophilicity indices were analyzed.Results showed that the 29 AcSWEET genes encoded proteins with amino acid lengths ranging from 680 to 906 residues,molecular weights between 7.531 kDa and 101.266 kDa,and isoelectric points between 6.95 and 9.9.Most proteins were relatively stable hydrophobic,and localized on the cell membrane,containing 1–2 MtN3 domains.Additionally,gene structure,conserved motifs,evolutionary relationships,cis-regulatory elements,and expression patterns at different developmental stages of fruit development were systematically analyzed.Results indicated that the AcSWEET genes had 4–6 exons.Phylogenetic analysis revealed that the kiwifruit SWEET gene family was divided into four subgroups,responsible for transporting glucose,fructose,and sucrose.Genes within the same subgroup shared similar intron-exon structures and conserved motifs.Expression pattern analysis during kiwifruit development indicated that the AcSWEET genes exhibited stage-specific expression.We speculated that AcSWEET26,AcSWEET7,AcSWEET15,and AcSWEET13 may be involved in sucrose transport and accumulation in kiwifruit.