MUSTARD GENE IMPROVES HEALTH-PROMOTING COMPOUNDS IN TOMATO
The 3-Hydroxy-3-methylglutaryl-coenzyme A synthase (HMGS) of the mevalonate pathway produces phytosterols, which can lower blood cholesterol levels. In a previous study, the overexpression of the BjHMGS1 synthase from mustard (Brassica juncea) increased sterol content in Arabidopsis.
Using the same method, the team of Pan Liao from the University of Hong Kong aims to increase the production of antioxidants in tomato (Solanum lycopersicum). The team overexpressed the BjHMGS1 genes from both wildtype and the mustard mutant S359A in separate tomato lines.
Analysis of the tomato lines overexpressing the wildtype BjHMGS1 revealed that genes associated with production of the precursors of phytosterols, carotenoids and vitamin E were upregulated. This caused an accumulation of squalene and phytosterols, as well as α-tocopherol (vitamin E) and carotenoids in tomato fruits. Moreover, tomato lines overexpressing the S359A mutant BjHMGS1 bore fruits with even higher squalene and phytosterol contents than the lines overexpressing the wildtype BjHMGS.
The manipulation of BjHMGS1 could be a promising strategy to increase health-promoting squalene, phytosterols, α-tocopherol and carotenoids in tomato.