Extensins (EXTs) are major protein components in plant cell walls that play crucial roles in higher plants. The function of EXTs has been reported in several plants but is limited in tomato, especially in fruit ripening. In this study, we identified 83 EXTs in tomato, and divided them into seven groups. The gene intron-exon structure and protein-motif composition of SlEXTs were similar within each group but different among groups. SlEXT genes showed different expression patterns in roots, leaves, flowers and fruits, and some SlEXT gene expressions in flowers could be regulated by treatments of auxin, gibberellic acid and jasmonic acid. In particular, SlSEXT8 had higher and increased expression during tomato fruit ripening, and its expression could be induced by ethylene, suggesting SlSEXT8 may be involved in tomato fruit softening. The result provides insights into the function of EXTs, and will facilitate to further study EXT roles in tomato fruit ripening.

延伸蛋白 (EXT) 是植物细胞壁中的主要蛋白质成分，在高等植物中起着至关重要的作用。EXTs 的功能在几种植物中已有报道，但在番茄中有限，尤其是在果实成熟中。在这项研究中，我们在番茄中鉴定了 83 个 EXT，并将它们分为七组。SlEXTs的基因内含子-外显子结构和蛋白质-基序组成在各组内相似，但组间不同。SlEXT基因在根、叶、花和果实中表现出不同的表达模式，花中部分SlEXT基因的表达受生长素、赤霉酸和茉莉酸处理的调控。特别是，SlSEXT8在番茄果实成熟过程中，SlSEXT8表达量较高且增加，其表达可能受乙烯诱导，表明SlSEXT8可能参与番茄果实软化。该结果提供了对 EXT 功能的深入了解，并将有助于进一步研究 EXT 在番茄果实成熟中的作用。