School of Biosciences, Faculty of Science, The University of Nottingham, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia.
Division of Plant and Crop Sciences, School of Biosciences, The University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.
Mol Biol Rep. 2020 Jun;47(6):4183-4197. doi: 10.1007/s11033-020-05519-y. Epub 2020 May 22.
The Rab GTPase family plays a vital role in several plant physiological processes including fruit ripening. Fruit softening during ripening involves trafficking of cell wall polymers and enzymes between cellular compartments. Mango, an economically important fruit crop, is known for its delicious taste, exotic flavour and nutritional value. So far, there is a paucity of information on the mango Rab GTPase family. In this study, 23 genes encoding Rab proteins were identified in mango by a comprehensive in silico approach. Sequence alignment and similarity tree analysis with the model plant Arabidopsis as a reference enabled the bona fide assignment of the deduced mango proteins to classify into eight subfamilies. Expression analysis by RNA-Sequencing (RNA-Seq) showed that the Rab genes were differentially expressed in ripe and unripe mangoes suggesting the involvement of vesicle trafficking during ripening. Interaction analysis showed that the proteins involved in vesicle trafficking and cell wall softening were interconnected providing further evidence of the involvement of the Rab GTPases in fruit softening. Correlation analyses showed a significant relationship between the expression level of the RabA3 and RabA4 genes and fruit firmness at the unripe stage of the mango varieties suggesting that the differences in gene expression level might be associated with the contrasting firmness of these varieties. This study will not only provide new insights into the complexity of the ripening-regulated molecular mechanism but also facilitate the identification of potential Rab GTPases to address excessive fruit softening.
Rab GTPase 家族在包括果实成熟在内的几种植物生理过程中起着至关重要的作用。果实成熟过程中的软化涉及细胞壁聚合物和酶在细胞区室之间的运输。芒果是一种经济上重要的水果作物，以其美味的口感、独特的风味和营养价值而闻名。到目前为止，关于芒果 Rab GTPase 家族的信息还很少。在这项研究中，通过全面的计算机方法在芒果中鉴定出了 23 个编码 Rab 蛋白的基因。与模式植物拟南芥的序列比对和相似性树分析，使推断出的芒果蛋白能够被归为八个亚家族。通过 RNA-Seq（RNA 测序）进行的表达分析表明，Rab 基因在成熟和未成熟的芒果中表达差异，表明在成熟过程中涉及囊泡运输。相互作用分析表明，参与囊泡运输和细胞壁软化的蛋白质相互连接，进一步证明 Rab GTPases 参与了果实软化。相关性分析表明，RabA3 和 RabA4 基因的表达水平与芒果品种未成熟阶段的果实硬度之间存在显著关系，表明基因表达水平的差异可能与这些品种硬度的差异有关。这项研究不仅将为成熟调控的分子机制的复杂性提供新的见解，还将有助于鉴定潜在的 Rab GTPases，以解决果实过度软化的问题。
