The mango (Mangifer indica L.) is an important species of the family Anacardiaceae and is one of the most important crops cultivated commercially in many parts of the world. Hence, a better understanding of the phylogeny in this species is crucial as it is the basis knowledge of improving its genetic resources which is beneficial for breeding programs. Phylogenetic relationships among 13 mango cultivars from Indonesia, Malaysia and Taiwan were carried out by comparing DNA sequence data sets derived from the Internal Transcribed Spacer (ITS) region pfnuclear ribosomal DNA (nrDNA). Analysis using parsimony method showed that the cultivars were classified into three major groups. The first group composed almost Malaysian cultivars although with low bootstrap value, the second group consisted of mainly Taiwan cultivars and the last group included mostly Indonesia one. The results indicated that some cultivars have a close relationships with each other even it is originated from different countries. With regards to the relationship among these cultivars, this gives better insight for generating new cultivar.
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.