Maize Yields Influenced by Unexpected Gene 'Moonlighting'

Researchers at Cold Spring Harbor Laboratory (CSHL) have identified a relationship between maize crop yield and the specific genetic activity associated with one of the plant's metabolic pathways.

Maize ears are normally not branched, and form one straight cob. However, maize mutants that don't have the RAMOSA3 gene end up with gnarly-looking branched ears. Professor David Jackson and his team at CSHL have connected the RAMOSA3 gene to branching, which can affect maize yields. When a maize plant has too many branches, it expends more energy towards making those branches, and less towards making seeds. More branches often means lower yields.

Professor Jackson and his team initially hypothesized that the enzyme that RAMOSA3 encodes, called TPP, and a sugar phosphate called T6P which TPP acts on, are likely responsible for the ear-branching. In a surprising twist, they found that a related gene, TPP4, also helps to control branching, but that gene's effect was unrelated to its enzymatic activity. To follow up on this, they blocked only the enzyme activity associated with RAMOSA3, and not the gene itself, and got normal-looking ears of maize. This indicates that although RAMOSA3 controls the activity of the enzyme, the enzyme activity is not responsible for branching. Thus, the gene may be "moonlighting" with a hidden activity, explains Jackson.

For more details, read the CSHL news article.