Characterization of rate limiting genes of provitamin A biosynthesis pathway in Indian banana Musaspp

Abstract

Vitamin A deficiency (VAD) is a severe health problem worldwide. Biofortification of staple crops is a feasible and cost-effective means of delivering micronutrients to populations having limited access to diverse diets. Banana is a staple fruit crop, providing food-security in several developing countries, where VAD is a major problem. The commercially grown banana cultivar Grand Naine belongs to the Cavendish group (AAA genome). The introduction of new traits into banana remains difficult through conventional-breeding due to triploid genome, parthenocarpy and long life-cycle. However, the use of modern biotechnology tools holds a promise towards improving provitamin A carotenoids (pVACs) in banana. newlineIn the present study, we enhanced pVACs content in Grand Naine through gain-of-function (overexpression), and loss-of-function (CRISPR/Cas9) approaches. The embryogenic cell suspension (ECS) culture of Grand Naine was used for genetic-transformation. The study showed 1-deoxy-d-xylulose-5-phosphate synthase (DXS2), and phytoene synthase (PSY1) derived from Nendran are promising candidates for overexpression. Genome-editing (GE) was established in banana by targeting phytoene desaturase (PDS) through CRISPR/Cas9, and subsequently, implemented for lycopene epsilon-cyclase (LCYand#949;) editing. The DXS2 overexpressing lines showed upto ~20-fold enhanced and#946;-carotene equivalents (and#946;-CE) than in control. While lines over expressing PSY1 accumulated high lutein (upto ~4.2 fold). The LCYand#949; edited lines showed upto ~6-fold enhanced and#946;-carotene content, while reduced and#945;-carotene and lutein content than in control. newlineIn conclusion, the present study reports a significant step towards the development of the nutritionally enriched banana using overexpression and CRISPR/Cas9 approach for South Asian countries like India, where the prevalence of VAD is very high. newline newline