割手密SsPYL基因家族的全基因组鉴定及干旱胁迫下的表达模式分析OA

The PYR/PYL/RCAR(PYL)gene family(Pyrabactin Resistance 1/PYR1-Like/Regulatory Component of ABA Receptor),as core receptors of abscisic acid(ABA),play a pivotal regulatory role in the signaling pathways of plant responses to abiotic stresses such as drought.Saccharum spontaneum L.(wild sugarcane),an important wild rela-tive for sugarcane stress-resistant breeding,harbors abundant drought-tolerant genetic resources.However,systematic identification and functional analysis of its PYL gene family remain unreported to date.Based on the S.spontaneum genome data(Saccharum spontaneum Np-X2021),the study identified members of the SsPYL gene family using bioin-formatics approaches,and systematically analyzed the physicochemical properties,chromosomal localization,phyloge-netic relationships,gene structures,conserved motifs,and cis-acting elements in promoters.Additionally,quantitative real-time PCR(qRT-PCR)was employed to investigate the expression patterns of core members under drought stress.The results showed that 32 SsPYL genes,designated as SsPYL1 to SsPYL32,were identified in the S.spontaneum ge-nome.The encoded proteins ranged in length from 149 to 385 amino acids,with most being acidic and hydrophilic pro-teins primarily localized in the cytoplasm.The secondary structure was dominated by α-helices and random coils.Fur-thermore,SsPYLs exhibited uneven distribution across chromosomes,and segmental duplication was the dominant mechanism driving family expansion.A total of 54 pairs of syntenic genes were identified between SsPYLs and rice OsPYL genes,reflecting the evolutionary conservation of this family among monocotyledonous plants.Phylogenetic analysis clustered the 32 SsPYLs into three subfamilies,with members of the same subfamily sharing similar conserved motif compositions and gene structures.All SsPYL proteins contained the signature PYR_PYL_RCAR_like domain.The promoter regions of SsPYL genes were enriched in hormone-responsive and abiotic stress-related cis-acting ele-ments,such as ABRE(ABA-responsive element),ARE(anaerobic responsive element),and LTR(low-temperature re-sponsive element).Under drought stress,the expression levels of eight SsPYL genes(SsPYL1,SsPYL3,SsPYL4,SsPYL6,SsPYL8,SsPYL14,SsPYL19 and SsPYL24)were extremely significantly upregulated(P<0.01),among which SsPYL8,SsPYL14 and SsPYL19 showed more than 5-fold upregulation.The genes are thus speculated to be key candidate genes regulating drought tolerance in S.spontaneum.The study represents the first systematic characterization of the molecu-lar features and drought-responsive patterns of the SsPYL gene family in S.spontaneum.It would provide a theoretical basis for further exploring the functional mechanisms in ABA-mediated drought stress signaling pathways and offer important gene targets for the genetic improvement of drought tolerance in sugarcane.