Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Plant Sciences, Banana, fruit ripening, metabolite flux analysis, Musa species, proteomics, starch, STARCH DEGRADATION, PROTEOMIC ANALYSIS, STATISTICAL-MODEL, MUSA SPP., BANANA, METABOLISM, IDENTIFICATION, PROTEINS, ETHYLENE, EXPRESSION, Fructose, Fruit, Musa, Plant Breeding, Plantago, Starch, banana, 0604 Genetics, 0607 Plant Biology, 0703 Crop and Pasture Production, Plant Biology & Botany, 3004 Crop and pasture production, 3101 Biochemistry and cell biology, 3108 Plant biology

Abstract:

In this study, we aimed to investigate for the first time different fruit development stages in plantain banana in order gain insights into the order of appearance and dominance of specific enzymes and fluxes. We examined fruit development in two plantain banana cultivars during the period between 2-12 weeks after bunch emergence using high-throughput proteomics, quantification of major metabolites, and analyses of metabolic fluxes. Starch synthesis and breakdown are processes that take place simultaneously. During the first 10 weeks fruits accumulated up to 48% of their dry weight as starch, and glucose 6-phosphate and fructose were important precursors. We found a unique amyloplast transporter and hypothesize that it facilitates the import of fructose. We identified an invertase originating from the Musa balbisiana genome that would enable carbon flow back to growth and starch synthesis and maintain a high starch content even during ripening. Enzymes associated with the initiation of ripening were involved in ethylene and auxin metabolism, starch breakdown, pulp softening, and ascorbate biosynthesis. The initiation of ripening was cultivar specific, with faster initiation being particularly linked to the 1-aminocyclopropane-1-carboxylate oxidase and 4-alpha glucanotransferase disproportionating enzymes. Information of this kind is fundamental to determining the optimal time for picking the fruit in order to reduce post-harvest losses, and has potential applications for breeding to improve fruit quality.