Molecular Crop Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.
Omics Sciences and Bioinformatics Center, Chulalongkorn University, Bangkok, Thailand.
PLoS One. 2021 Aug 10;16(8):e0252367. doi: 10.1371/journal.pone.0252367. eCollection 2021.
The involvement of the phytohormone ethylene as the main trigger of climacteric fruit ripening is well documented. However, our knowledge regarding the role of ethylene response factor (ERF) transcription factor in the transcriptional regulation of ethylene biosynthesis during fruit ripening remains limited. Here, comprehensive transcriptome analysis and expression profiling revealed 63 ERFs in durian pulps, termed DzERF1-DzERF63, of which 34 exhibited ripening-associated expression patterns at three stages (unripe, midripe, and ripe) during fruit ripening. Hierarchical clustering analysis classified 34 ripening-associated DzERFs into three distinct clades, among which, clade I consisted of downregulated DzERFs and clade III included those upregulated during ripening. Phylogenetic analysis predicted the functions of some DzERFs based on orthologs of previously characterized ERFs. Among downregulated DzERFs, DzERF6 functional prediction revealed its role as a negative regulator of ripening via ethylene biosynthetic gene repression, whereas among upregulated genes, DzERF9 was predicted to positively regulate ethylene biosynthesis. Correlation network analysis of 34 ripening-associated DzERFs with potential target genes revealed a strong negative correlation between DzERF6 and ethylene biosynthetic genes and a strong positive correlation between DzERF9 and ethylene biosynthesis. DzERF6 and DzERF9 showed differential expression patterns in association with different ripening treatments (natural, ethylene-induced, and 1-methylcyclopropene-delayed ripening). DzERF6 was downregulated, whereas DzERF9 was upregulated, during ripening and after ethylene treatment. The auxin-repressed and auxin-induced expression of DzERF6 and DzERF9, respectively, confirmed its dose-dependent responsiveness to exogenous auxin. We suggest ethylene- and auxin-mediated roles of DzERF6 and DzERF9 during fruit ripening, possibly through transcriptional regulation of ethylene biosynthetic genes.
植物激素乙烯作为果实成熟的主要触发因素的参与已得到充分证实。然而，我们对于乙烯反应因子（ERF）转录因子在果实成熟过程中乙烯生物合成的转录调控中的作用的了解仍然有限。在这里，全面的转录组分析和表达谱分析揭示了榴莲果肉中的 63 个 ERF，称为 DzERF1-DzERF63，其中 34 个在果实成熟过程中的三个阶段（未成熟、中熟和成熟）表现出与成熟相关的表达模式。层次聚类分析将 34 个与成熟相关的 DzERF 分为三个不同的分支，其中分支 I 由下调的 DzERF 组成，分支 III 包括在成熟过程中上调的那些。系统发育分析根据先前表征的 ERF 的同源物预测了一些 DzERF 的功能。在下调的 DzERF 中，DzERF6 的功能预测表明其通过抑制乙烯生物合成基因的表达作为成熟的负调节剂，而在上调的基因中，DzERF9 被预测为正向调节乙烯生物合成。34 个与成熟相关的 DzERF 与潜在靶基因的相关网络分析显示，DzERF6 与乙烯生物合成基因之间存在强烈的负相关，DzERF9 与乙烯生物合成之间存在强烈的正相关。DzERF6 和 DzERF9 与不同的成熟处理（自然、乙烯诱导和 1-甲基环丙烯延迟成熟）相关的表达模式不同。DzERF6 在成熟和乙烯处理后下调，而 DzERF9 上调。DzERF6 和 DzERF9 分别对生长素的抑制和诱导表达证实了其对外源生长素的剂量依赖性反应。我们建议 DzERF6 和 DzERF9 在果实成熟过程中发挥乙烯和生长素介导的作用，可能通过对乙烯生物合成基因的转录调控。
