Plant Physiology, University of Extremadura, Avda de Elvas s/n, 06006 Badajoz, Spain.
Plant Physiology, University of Vigo, Campus Lagoas-Marcosende, s/n, 36310 Vigo, Spain.
Int J Mol Sci. 2020 Jul 8;21(14):4819. doi: 10.3390/ijms21144819.
Fruit ripening and abscission are the results of the cell wall modification concerning different components of the signaling network. However, molecular-genetic information on the cross-talk between ripe fruit and their abscission zone (AZ) remains limited. In this study, we investigated transcriptional and hormonal changes in olive ( L. cv Picual) pericarp and AZ tissues of fruit at the last stage of ripening, when fruit abscission occurs, to establish distinct tissue-specific expression patterns related to cell-wall modification, plant-hormone, and vesicle trafficking in combination with data on hormonal content. In this case, transcriptome profiling reveals that gene encoding members of the α-galactosidase and β-hexosaminidase families associated with up-regulation of RabB, RabD, and RabH classes of Rab-GTPases were exclusively transcribed in ripe fruit enriched in ABA, whereas genes of the arabinogalactan protein, laccase, lyase, endo-β-mannanase, ramnose synthase, and xyloglucan endotransglucosylase/hydrolase families associated with up-regulation of RabC, RabE, and RabG classes of Rab-GTPases were exclusively transcribed in AZ-enriched mainly in JA, which provide the first insights into the functional divergences among these protein families. The enrichment of these protein families in different tissues in combination with data on transcript abundance offer a tenable set of key genes of the regulatory network between olive fruit tissues in late development.
果实成熟和脱落是细胞壁修饰的结果，涉及信号网络的不同成分。然而，关于成熟果实与其离区（AZ）之间的串扰的分子遗传信息仍然有限。在这项研究中，我们研究了橄榄（L. cv Picual）果皮和 AZ 组织在果实成熟最后阶段（即果实脱落时）的转录和激素变化，以建立与细胞壁修饰、植物激素和囊泡运输相关的组织特异性表达模式，同时结合激素含量数据。在这种情况下，转录组分析表明，编码与 RabB、RabD 和 RabH 类 Rab-GTPase 上调相关的 α-半乳糖苷酶和β-己糖胺酶家族成员的基因在富含 ABA 的成熟果实中特异性转录，而阿拉伯半乳聚糖蛋白、漆酶、裂合酶、内-β-甘露聚糖酶、鼠李糖合酶和木葡聚糖内切糖基转移酶/水解酶家族的基因在富含 JA 的 AZ 中特异性转录，这为 RabC、RabE 和 RabG 类 Rab-GTPase 的上调提供了第一个功能差异的见解。这些蛋白质家族在不同组织中的富集，结合转录丰度数据，为橄榄果实组织在后期发育过程中的调控网络的关键基因提供了一个可行的集合。
