关键词: 枇杷, 三倍体, EjSPL5, 亚细胞定位, 基因表达

Abstract: In this study，SQUMOSA PROMOTER BINDING PROTEIN LIKE5（EjSPL5）was isolated by homologous cloning and rapid amplification of cDNA ends（RACE）techniques from the triploid loquat‘Q27’. Full length cDNA sequence of EjSPL5 was 778 base pairs（bp），including a 24 bp 5′UTR and a 214 bp 3′UTR. Open reading frame（ORF）of EjSPL5 was 549 bp and encodes 182 amino acids. Sequence alignment analysis showed that EjSPL5 is highly similar to SPL proteins of Malus × domestica（Md），Arabidopsis thaliana（At）and Antirrhinum majus（Am），and has a conserved SBP domain and nuclear localization signal（NLS）. There were high homology of amino acid sequences in EjSPL5 and MdSPL5 of Malus × domestica. Subcellular localization of EjSPL5 was detected to be localized to nucleus. Real-time quantitative PCR analysis suggested that EjSPL5 was highly expressed in sepal and young fruit. There was a significant difference in the expression levels of EjSPL5 in the early and late flowering cultivars of diploid and triploid loquat. The expression of EjSPL5 was mainly concentrated in the first six stages of flower development，while the expression level of EjSPL5 was lower in the stages of white corollas and full bloom. However，the expression level of EjSPL5 was the highest in the morphological differentiation of flower bud in triploid loquat and the rapid elongation of lateral inflorescence branches in diploid loquat. Furthermore，the expression level of EjSPL5 in early-flowering cultivars was higher than that in lateflowering ones.

Key words: loquat, triploid, EjSPL5, subcellular localization, gene expression