Coexpression of Two Transgenes Alters Metabolite Accumulation in Tomato Fruits

Targeted manipulation of phenylalanine (Phe) synthesis is a potential strategy to boost biologically and economically important metabolites. South China Agricultural University's Qingjun Xie led a team of researchers from various institutions in increasing the levels of aromatic amino acids, tomato flavour-associated volatiles and antioxidant phenylpropanoids in tomato.

Overexpression of the petunia MYB transcript factor, ODORANT1 (ODO1), combined with expression of a feedback-insensitive E. coli 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (AroG), altered the levels of multiple primary and secondary metabolites in tomato fruit, boosting levels of multiple secondary metabolites.

The results indicate that coexpression of AroG and ODO1 has a dual effect on Phe and related biosynthetic pathways. It positively impacted tyrosine (Tyr) and antioxidant related metabolites, however, it negatively affected other downstream secondary metabolites of the Phe pathway as well as aromatic volatiles.

The metabolite profiles were also distinct from those obtained with either single transgene. Coexpression of the two genes also provided insights into regulation of phenylpropanoid metabolic pathways.

For more on this promising study, read the article in Plant Biotechnology Journal.