Mango (Mangifera indica L.) is a climacteric tropical fruit consumed around the world. Although ethylene and abscisic acid (ABA) have been considered to be stimulators that trigger mango fruit ripening, their regulation mechanisms in modulating mango fruit ripening remain uncertain. In this study, we performed integrative analyses of metabolome and transcriptome data combined with a series of physiological and experimental analyses in the ‘Keitt’ mango, and we characterized changes in accumulation of specific metabolites at different stages during fruit development and ripening, which were strongly correlated with transcriptional changes and embodied physiological changes as well as taste formation. Specifically, we found that ABA, rather than ethylene, was highly associated with mango ripening, and exogenous ABA application promoted mango fruit ripening. Transcriptomic analysis identified diverse ripening-related genes involved in sugar and carotenoid biosynthesis and softening-related metabolic processes. Furthermore, networks of ABA- and ripening-related genes (such as MiHY5, MiGBF4, MiABI5, and MibZIP9) were constructed, and the direct regulation by the key ABA-responsive transcription factor MiHY5 of ripening-related genes was experimentally confirmed by a range of evidence. Taken together, our results indicate that ABA plays a key role in directly modulating mango fruit ripening through MiHY5, suggesting the need to reconsider how we understand ABA function in modulating climacteric fruit ripening.

Mango (Mangifera indica L.) is famous for its sweet flavor and aroma. China is one of the major mango-producing countries. Mango is known for variations in flowering intensity that impacts fruit yield and farmers' profitability. In the present study, transcriptome and metabolome analyses of three cultivars with different flowering intensities were performed to preliminarily elucidate their regulatory mechanisms. The transcriptome profiling identified 36,242 genes. The major observation was the differential expression patterns of 334 flowering-related genes among the three mango varieties. The metabolome profiling detected 1,023 metabolites that were grouped into 11 compound classes. Our results show that the interplay of the FLOWERING LOCUS T and CONSTANS together with their upstream/downstream regulators/repressors modulate flowering robustness. We found that both gibberellins and auxins are associated with the flowering intensities of studied mango varieties. Finally, we discuss the roles of sugar biosynthesis and ambient temperature pathways in mango flowering. Overall, this study presents multiple pathways that can be manipulated in mango trees regarding flowering robustness.

The WRKY family is one of the largest transcription factor (TF) families in plants and is involved in the regulation of plant physiological processes, such as anthocyanin accumulation. However, little information is known regarding the WRKY genes in the mango. In this study, a total of 87 mango WRKY genes were identified and named MiWRKY1 to MiWRKY87. Phylogenetic results showed that the 87 MiWRKYs could be divided into three groups (I, II, III) and five subgroups of group II (II-a, II-b, II-c, II-d, II-e), with high similarity in exon–intron structures and WRKY domain and motif compositions within the same group and subgroup. One tandem duplication (MiWRKY76 and MiWRKY82) and 97 pairs of segmental duplicates were identified in the mango genome. Syntenic analysis showed that mango MiWRKY genes had 52 and 69 orthologous pairs with Arabidopsis and citrus, respectively. Promoter cis-acting element analysis revealed that MiWRKYs contain a large number of elements associated with light signaling, hormonal response, environmental stress, and plant development. Tissue specific expression profiles showed that the expression of MiWRKY genes displayed tissue preference. Quantitative-PCR analysis showed that high expression levels of MiWRKY1, MiWRKY3, MiWRKY5, MiWRKY81, and MiWRKY84 were detected in the skin of red mango cultivar, and the expressions of MiWRKY1 and MiWRKY81 were up-regulated during light-induced anthocyanin accumulation in the mango, indicating these genes might regulate anthocyanin biosynthesis in the mango. This study provides comprehensive genetic information on the MiWRKYs in mango fruit.

Mango (Mangifera indica L.) has been widely cultivated as a culturally and economically significant fruit tree for roughly 4000 years. Despite its rich history, little is known about the crop’s domestication, genomic variation, and the genetic loci underlying agronomic traits. This study employs the whole-genome re-sequencing of 224 mango accessions sourced from 22 countries, with an average sequencing depth of 16.37×, to explore their genomic variation and diversity. Through phylogenomic analysis, M. himalis J.Y. Liang, a species grown in China, was reclassified into the cultivated mango group known as M. indica. Moreover, our investigation of mango population structure and differentiation revealed that Chinese accessions could be divided into two distinct gene pools, indicating the presence of independent genetic diversity ecotypes. By coupling genome-wide association studies with analyses of genotype variation patterns and expression patterns, we identified several candidate loci and dominant genotypes associated with mango flowering capability, fruit weight, and volatile compound production. In conclusion, our study offers valuable insights into the genetic differentiation of mango populations, paving the way for future agronomic improvements through genomic-assisted breeding.

Background: The dramatic temperature fluctuations spurred by global warming and the accompanying extreme weather events inhibit mango growth and threaten mango productivity. Particularly, mango flowering is highly sensitive to temperature changes. The mango fruit setting rate was significantly positively correlated with pollen activity, and pollen activity was regulated by different metabolites. Methods: In this study, the in vitro pollen of two mango varieties (‘Renong No.1’ and ‘Jinhuang’), in which sensitivity to temperature differed significantly, were subjected to different temperature stresses (15 °C, 25 °C and 35 °C), and their metabolomics were analyzed. Results: The present results showed that 775 differential metabolites were screened by liquid chromatography–mass spectrometry and divided into 12 categories. The two varieties had significant differences in metabolite expression under different temperature stresses and the effect of low temperature on ‘Renong No.1’ mainly focused on amino acid metabolism, while the effect on ‘Jinhuang’ was mainly related to glycolysis. However, under the 35 °C temperature stress, ‘Renong No.1’ responded by redistributing riboflavin and betaine in vivo and the most obvious metabolic pathway of ‘Jinhuang’ enrichment was pyrimidine metabolism, which had undergone complex main body formation and extensive regulatory processes. The changes of metabolites of different varieties under low temperature and high temperature stress were different. Among them, flavonoids or flavonoid derivatives were included in class A (216 metabolites), C (163 metabolites) and D (233 metabolites) metabolites, indicating that flavonoid metabolites had an obvious regulatory effect on mango pollen metabolism under different temperature stress. Conclusions: The present results provide valuable information for reproductive biology studies and breeding in mango, in particular, the selection and breeding of the most suitable varieties for different production areas.