The Quest for Golden Bananas: Investigating Carotenoid Regulation in a Fe’i Group Musa Cultivar

Abstract

The regulation of carotenoid biosynthesis in a high-carotenoid-accumulating Fe'i group Musa cultivar, "Asupina", has been examined and compared to that of a low-carotenoid-accumulating cultivar, "Cavendish", to understand the molecular basis underlying carotenogenesis during banana fruit development. Comparisons in the accumulation of carotenoid species, expression of isoprenoid genes, and product sequestration are reported. Key differences between the cultivars include greater carotenoid cleavage dioxygenase 4 (CCD4) expression in "Cavendish" and the conversion of amyloplasts to chromoplasts during fruit ripening in "Asupina". Chromoplast development coincided with a reduction in dry matter content and fruit firmness. Chromoplasts were not observed in "Cavendish" fruits. Such information should provide important insights for future developments in the biofortification and breeding of banana.

Pro‐vitamin A carotenoids in East African highland banana and other Musa cultivars grown in Uganda

“…There remains, however, persistently high levels of VAD particularly in remote hard-to-reach areas that will only be addressed through more innovative strategies. As such, where bananas are a major component of the daily carbohydrate intake, their biofortification with pVACs has the potential to help address VAD and therefore has become a key focus of local and international research and collaboration (Buah, Mlalazi, Khanna, Dale, & Mortimer, 2016;Paul et al, 2017). By increasing the amount of essential nutrients in staple food crops, biofortification aims to target malnourished populations in a more economically viable and sustainable way.…”

Pathogenic potential and virulence genotypes of intestinal and faecal isolates of porcine post-weaning enteropathogenic Escherichia coli

“…Of these, the low-cost intervention of periodically given high-dose vitamin A supplementation, the use of 'fortified rice' (the kernels are coated to include several critical micronutrients, including vitamin A; Kuong et al, 2016), and golden bananas containing naturally high concentrations of carotenoids (Buah et al, 2016) are the most promising.…”

Transgenic Pro-Vitamin A Biofortified Crops for Improving Vitamin A Deficiency and Their Challenges

“…Chromoplasts play critical roles in β-carotene storage under the Orange gene (Or) control, which a later section discusses. Therefore, both greater CCD4 expression and little presence of chromoplasts in Cavendish attribute to its low β-carotene [59].…”

“…are perennial monocots that are vegetatively propagated [59]. Natural variations in banana pVA contents contribute to the fruit color variation from white to dark orange.…”

“…Thus, utilization of Asupina PSY gene could increase β-carotene in widely consumed banana cultivars, facilitate GMO regulatory approval, and improve consumer acceptance of pVA bananas [60]. Buah et al (2016) further identified key differences between the two bananas; expression of CCD4 in Cavendish which decreased β-carotene in Cavendish, and conversion of amyloplasts to chromoplasts in Asupina which increased β-carotene in Auspina [59]. As in wheat CCD enzymes, expression of CCD4 gene cleaved more Cavendish β-carotenes to form apocarotenoids.…”