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
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.