Comparative proteomic analysis on fruit ripening processes in two varieties of tropical mango (Mangifera indica)

Mango (Mangifera indica L.) is an economically important fruit. However, the marketability of mango is affected by the perishable nature and short shelf-life of the fruit. Therefore, a better understanding of the mango ripening process is of great importance towards extending its postharvest shelf life. Proteomics is a powerful tool that can be used to elucidate the complex ripening process at the cellular and molecular levels. This study utilized 2-dimensional gel electrophoresis (2D-GE) coupled with MALDI-TOF/TOF to identify differentially abundant proteins during the ripening process of the two varieties of tropical mango, Mangifera indica cv. ‘Chokanan’ and Mangifera indica cv ‘Golden Phoenix’. The comparative analysis between the ripe and unripe stages of mango fruit mesocarp revealed that the differentially abundant proteins identified could be grouped into the three categories namely, ethylene synthesis and aromatic volatiles, cell wall degradation and stress-response proteins. There was an additional category for differential proteins identified from the ‘Chokanan’ variety namely, energy and carbohydrate metabolism. However, of all the differential proteins identified, only methionine gamma-lyase was found in both ‘Chokanan’ and ‘Golden Phoenix’ varieties. Six differential proteins were selected from each variety for validation by analysing their respective transcript expression using reverse transcription-quantitative PCR (RT-qPCR). The results revealed that two genes namely, glutathione S-transferase (GST) and alpha-1,4 glucan phosphorylase (AGP) were found to express in concordant with protein abundant. The findings will provide an insight into the fruit ripening process of different varieties of mango fruits, which is important for postharvest management

Plant odors as fruit fly attractants

Plant odors consist of a mixture of volatile compounds that are conveyed by diffusion through air and may disperse over a long distance. They play a major role in mediating insect-plant relationships, particularly food location and selection of suitable sites for mating or oviposition. This chapter presents state-of-the-art research on the response of fruit flies (Diptera, Tephritidae) to plant odors and their potential for the development of trapping systems. Main research results from Tephritids of economic importance (i.e., Rhagoletis, Ceratitis, Bactrocera/Dacus, and Anastrepha) show evidence of response to (i) general plant volatiles from host or non-host plants, the so-called 'green leaf volatiles', (ii) essential oils from host or non-host plants, and (iii) fruit odors (whole fruit, wounded or crushed fruit, extracts, etc.). Synergies between plant odors and food odors or sex pheromones are also addressed. Factors including insect physiology (age, mating status, egg load, etc.), experience (learning), and genetic background can substantially modify the response pattern to plant odors. One of the main challenges of using plant odors as fruit fly attractant is to improve the technology for identification (analysis), synthesis and emission (dispensers) of key compounds that may compete with natural volatile blends in the field. Further research should include the role of microorganisms in host location and recognition by fruit flies. Synthetic plant odors could be used either as kairomones for trapping systems, as allomones to push flies away from the crop or to disrupt host location, or as synomones to attract natural enemies to the crop. (Résumé d'auteur