杜梨PbKRP2序列特征与表达特性分析OA

The Kip-related protein(KRP)gene family acts as a key regulator of the cell cycle,modulating cell division and endoreduplication by inhibiting cyclin-dependent kinase(CDK)activity,and participates in plant abiot-ic stress responses.To investigate the structural characteristics and environmental stress response profile of PbKRP2 in Pyrus betulifolia,the gene was cloned using reverse transcription PCR(RT-PCR).Bioinformatic analysis was con-ducted to elucidate its sequence features,predicted protein interactions,and phylogenetic relationships.Quantitative Real-time PCR(qRT-PCR)was employed to assess the tissue-specific expression characteristics of PbKRP2 and its expression patterns under various stress conditions.Results showed that PbKRP2 was 585 bp in length,contained 4 exons and 3 introns,and encoded a 194-amino acid protein.The predicted protein had 25 potential phosphorylation sites,a O-glycosylation site,and a conserved C-terminal cyclin-dependent kinase inhibitor(CDI)domain.Phyloge-netic analysis indicated that PbKRP2 was closely related to PyKRP2 in Prunus yedoensis var.nudiflora,PpKRP2 in Prunus persica,and MdKRP2 in Malus domestica.Protein interaction network screening identified potential interac-tions between PbKRP2 and 10 proteins.Analysis of the static structure of potential interacting proteins suggested that PbKRP2 formed spatial interaction conformations with its target proteins PbCDKB1;1 and PbCYCD7;1,respec-tively.The promoter region of PbKRP2 contained multiple cis-acting regulatory elements responsive to environmental factors and hormonal signals.qRT-PCR analysis demonstrated that PbKRP2 transcript levels were significantly high-er in stems and leaves compared to roots,petals,and fruits.Furthermore,PbKRP2 transcription levels were consist-ently upregulated under low-temperature stress and abscisic acid(ABA)treatment,but significantly downregulated under dehydration and salt stress.In summary,these findings provide a candidate gene for stress-resistant breeding of pear and genetic improvement of fruit trees by elucidating the sequence characteristics of PbKRP2 and its differ-ential response patterns to abiotic stresses.