榴莲(DuriozibethinusL.),俗称“水果之王”,“在东南亚拥有重要的经济意义,包括泰国。在其成熟过程中,据报道,植物激素脱落酸(ABA)含量增加。然而,全面了解ABA在榴莲果实成熟中的具体作用仍然难以捉摸。此外,对这种标志性水果的类胡萝卜素裂解途径的分子方面知之甚少。因此,我们对榴莲中的类胡萝卜素裂解加氧酶(CCO)家族进行了全基因组鉴定。该家族包括负责ABA产生的九种顺式环氧类胡萝卜素双加氧酶(NCED)和表现出不同底物特异性的类胡萝卜素裂解双加氧酶。通过系统发育分析,我们将榴莲中的14个CCO分为8个不同的亚家族。值得注意的是,每个DzCCO亚家族都显示出保守的基序组成。顺式作用元件预测表明,与植物激素和环境胁迫响应相关的顺式元件分布在DzCCO启动子中。此外,进行转录组分析以检查果实发育和成熟阶段的表达模式。有趣的是,DzNCED5a,成熟相关基因,在成熟阶段表现出最高的表达水平,表现优于其他CCO。在“Monthong”品种和其他榴莲品种的成熟期,其表达与ABA含量的增加显着相关。在烟叶中瞬时表达的DzNCED5a证实了其在ABA生物合成中的功能。这些发现强调了DzNCED5a在ABA生产中的参与及其在榴莲果实成熟中的潜在重要性。总的来说,这项研究提供了对榴莲果实成熟过程中CCO的意义的见解。
Durian (Durio zibethinus L.), popularly known as the \"King of fruits,\" holds significant economic importance in Southeast Asia, including Thailand. During its ripening process, the phytohormone abscisic acid (ABA) content has been reported to increase. However, a comprehensive understanding of ABA\'s specific role in durian fruit ripening remains elusive. Furthermore, little is known about the molecular aspects of the carotenoid cleavage pathway in this iconic fruit. Therefore, we performed genome-wide identification of the carotenoid cleavage oxygenase (CCO) family in durian. This family includes the nine-cis-epoxycarotenoid dioxygenases (NCEDs) responsible for ABA production and the carotenoid cleavage dioxygenases exhibiting diverse substrate specificities. Through phylogenetic analysis, we classified 14 CCOs in durian into 8 distinct subfamilies. Notably, each DzCCO subfamily displayed a conserved motif composition. Cis-acting element prediction showed that cis-elements related to plant hormones and environmental stress responses were distributed in the DzCCO promoter. In addition, transcriptome analysis was performed to examine the expression pattern during the fruit development and ripening stages. Interestingly, DzNCED5a, a ripening-associated gene, exhibited the highest expression level at the ripe stage, outperforming other CCOs. Its expression markedly correlated with increased ABA contents during the ripening stages of both the \"Monthong\" variety and other durian cultivars. Transiently expressed DzNCED5a in Nicotiana benthamiana leaves confirmed its function in ABA biosynthesis. These findings highlight the involvement of DzNCED5a in ABA production and its potential importance in durian fruit ripening. Overall, this study provides insights into the significance of CCOs in durian fruit ripening.