Anthocyanin accumulation is regulated by specific genes during fruit ripening. Currently, peel coloration of mango fruit in response to exogenous ethylene and the underlying molecular mechanism remain largely unknown. The role of MiMYB8 on suppressing peel coloration in postharvest ‘Guifei’ mango was investigated by physiology detection, RNA-seq, qRT-PCR, bioinformatics analysis, yeast one-hybrid, dual-luciferase reporter assay, and transient overexpression. Results showed that compared with the control, low concentration of exogenous ethylene (ETH, 500 mg·L⁻¹) significantly promoted peel coloration of mango fruit (cv. Guifei). However, a higher concentration of ETH (1000 mg·L⁻¹) suppressed color transformation, which is associated with higher chlorophyll content, lower a* value, anthocyanin content, and phenylalanine ammonia-lyase (PAL) activity of mango fruit. M. indica myeloblastosis8 MiMYB8 and MiPAL1 were differentially expressed during storage. MiMYB8 was highly similar to those found in other plant species related to anthocyanin biosynthesis and was located in the nucleus. MiMYB8 suppressed the transcription of MiPAL1 by binding directly to its promoter. Transient overexpression of MiMYB8 in tobacco leaves and mango fruit inhibited anthocyanin accumulation by decreasing PAL activity and down-regulating the gene expression. Our observations suggest that MiMYB8 may act as repressor of anthocyanin synthesis by negatively modulating the MiPAL gene during ripening of mango fruit, which provides us with a theoretical basis for the scientific use of exogenous ethylene in practice.

Improving fruit quality is one of the most critical core tasks in fruit tree breeding. However, the complexity of the constituent factors of fruit quality and their interrelationships, the significant influence of environmental factors on quality, and the diversity of consumer demands, among other factors, make quality breeding a more challenging endeavor than other breeding objectives. Essentially, fruit quality is defined by the delicate balance of sugar, acid, and aromas, which collectively influence the fruit’s flavor, consumer satisfaction, and economic value. While substantial progress has been made in the depiction of the metabolic pathways underlying these traits, the molecular mechanism coordinating carbon partitioning and competition between sugars, acids, and volatiles remains unknown. This review focuses on recent advances in understanding stone fruit metabolism and identifies key gaps in knowledge. We emphasize the need for integrated approaches combining spatial metabolomics, transcriptomics, genetics, and genomics to reveal the regulatory networks underlying metabolomic variation during fruit development and ripening. We also discuss the application of molecular tools, such as marker-assisted selection and metabolite-associated markers, to accelerate the breeding of flavor-balanced stone fruit cultivars. By adapting these advances in breeding practices, we can achieve coordinated improvement and precise regulation of various components of fruit quality, thereby developing elite stone fruit cultivars with improved flavor that meet prevailing consumer demands.

A pot study was performed under greenhouse condition to check the possibility that using Trichoderma harzianum could improve the growth, production and quality of watermelon genotype. Plant growth medium inoculated with T. harzianum at 1 × 104 cfu, 1.25 × 104 cfu and 1.50 × 104 cfu respectively, while un-inoculated with fungi used as control treatment. Plant growth medium inoculated with higher concentration (1.50 × 104 cfu) of T. harzianum significantly increased plant root and shoot length and brings early flowering. The higher values of plant fresh and dry weight, leaf area, stomatal conductance, transpiration rate, net photosynthesis rate and number of fruit per plant of watermelon was obtained with 1.50 × 104 cfu. However, T. harzianum levels of 1.50 × 104 cfu and 1.25 x 104 cfu produced statistically similar results for carbohydrate content, total soluble solids, vitamin A content and ?-carotene of watermelon. It was observed that plant grown in growth medium inoculated with T. harzianum has direct relation with growth and quality of watermelon. Compared to all tested levels, the higher level of T. harzianum 1.5 × 104 cfu is the most effective in improving growth, yield and quality of watermelon genotype (cv. Sugar baby).