Abstract：
Calcium acts as a secondary messenger in plants and is essential for plant growth and development. However, studies on the pathway of aroma synthesis in \'Nanguo\' pear (Pyrus ussriensis Maxim.) are scarce. In this study, a bioinformatics analysis of transcriptomic data from calcium-treated \'Nanguo\' pear was performed, which identified two fatty acid desaturases, PuFAD2 and PuFAD3, and eight AP2/ERF transcription factors, all exhibiting the same expression patterns. Transient expression experiments showed overexpression of PuFAD2 and PuFAD3 significantly increased the levels of aromatic substrates linoleic acid, hexanal, linolenic acid, and (E)-2-hexenal, but RNAi (RNA interference) had the opposite expression. Promoter sequences analysis revealed that PuFAD2 and PuFAD3 have ERE (estrogen response element) motifs on their promoters. The strongest activation of PuFAD2 by PuERF008 was verified using a dual-luciferase reporting system. Additionally, yeast one-hybrid and electrophoretic mobility shift assays revealed PuERF008 could active PuFAD2. Transient overexpression and RNAi analyses of PuERF008 showed a strong correlation with the expression of PuFAD2. This study provides insights into the process of aroma biosynthesis in \'Nanguo\' pear and offers a theoretical basis for elucidating the role of calcium signaling in aroma synthesis.
摘要：
钙在植物中起第二信使的作用，对植物的生长和发育至关重要。然而,南国梨香气合成途径的研究（PyrusussriensisMaxim。)是稀缺的。在这项研究中,对钙处理的“南国”梨的转录组数据进行了生物信息学分析，鉴定出两种脂肪酸去饱和酶，PuFAD2和PuFAD3，以及八个AP2/ERF转录因子，都表现出相同的表达模式。瞬时表达实验显示PuFAD2和PuFAD3的过表达显著增加了芳香底物亚油酸的水平,己醛,亚麻酸,和（E）-2-己烯醛，但RNAi(RNA干扰)却有相反的表达。启动子序列分析表明，PuFAD2和PuFAD3在其启动子上具有ERE（雌激素反应元件）基序。使用双荧光素酶报告系统验证了PuERF008对PuFAD2的最强激活。此外,酵母单杂交和电泳迁移率变化分析显示，PuERF008可以激活PuFAD2。PuERF008的瞬时过表达和RNAi分析显示与PuFAD2的表达有很强的相关性。本研究为“南果梨”香气生物合成过程提供了见解，并为阐明钙信号在香气合成中的作用提供了理论基础。
