新疆野苹果PYL基因家族的全基因组鉴定与表达分析

[Objective]Abscisic acid(ABA),a key phytohormone that controls plant growth and stress responses,and plays a key role in the regulation of seed dormancy and germination and growth and development,and the ABA receptor(Pyrabactin resistance-like,PYL)functions as one of the core components of the ABA signaling pathway.[Method]Genome-wide identification of PYL family members in Malus sieversii was carried out using bioinformatics methods and transcriptome sequencing,and the chromosomal locations,evolutionary relationships,gene structures,protein motifs,collinearity,cis-regulatory elements,as well as expression patterns in different tissues and expression profiles of PYL members in the process of low-temperature seed stratification were analyzed.[Result]14 PYL genes were identified in the whole genome of Malus sieversii,and distributed on seven chromosomes,and the gene distribution had a clustering phenomenon.Phylogenetic analyses classified them into three subgroups,with MsiPYL3-5,MsiPYL10-12 and MsiPYL14 in group I,MsiPYL1-2 in group II,and MsiPYL6-9 and MsiPYL13 in group III.Family members contained 0-4 introns and 1-5 exons,and PYR-PYL-RCAR-like conserved structures were present in all subfamilies.5 fragment duplication events were identified,involving 9 MsiPYL genes.5 pairs of genes MsiPYL1-MsiPYL2,MsiPYL4-MsiPYL11,MsiPYL5-MsiPYL10,MsiPYL9-MsiPYL13 and MsiPYL10-MsiPYL14 were colinear genes in the colinear region.Cis-acting element analyzes showed that cis-acting elements involved in hormone response,growth and developmental response,abiotic and biotic stress response were prevalent in varying numbers and types in the 2000 bp upstream sequence of PYL gene in Malus sieversii.Gene ontology enrichment demonstrated that the MsiPYL gene was mainly involved in the abscisic acid activation signaling pathway,regulation of phosphatase activity and phosphoprotein phosphatase activity.KEGG pathway analysis showed that it was mainly involved in mitogen-activated protein kinase(MAPK)signaling pathway-plant and phytohormone signaling.MsiPYL gene was constitutively expressed in six different tissues,and the expression level was significantly higher in reproductive organs(flowers and fruits)than in nutrient organs(roots and stems).In MsiPYL3,MsiPYL9 and MsiPYL13,the expression levels were higher in reproductive organs(flowers,fruits and seeds)and nutrient organs(roots,stems and leaves).MsiPYL12 was expressed at significantly higher levels in flowers,fruits,seeds and leaves than in seeds and stems.In other MsiPYL,the expression levels were significantly higher in flowers,fruits and leaves than in seeds,roots and stems.There were some differences in expression patterns among gene family members during the four periods of low-temperature stratification(30,60,90,and 120 d).The expression pattern of MsiPYL8(MsiPYR1)was analyzed by real-time fluorescence quantitative PCR under different low-temperature stratification treatments in seeds,and its overall expression showed a significant down-regulation trend.[Conclusion]The identification and characterization of the PYL gene family in Malus sieversii at the genome level provides a basis for revealing the role of the MsiPYL8(MsiPYR1)gene in seed dormancy lifting in Malus sieversii,and contributes to the future study of the biological function and abiotic stress response of MsiPYL genes.