In field trials three years ago, biotechnologists showed that they could
increase maize productivity by introducing a rice gene into the plant that
regulated the accumulation of sucrose in kernels, which also led to more
kernels per maize plant. This promising technique is set to do the same for
other crops, including wheat and rice.
The rice gene affected the performance of a natural chemical in maize,
trehalose 6-phosphate (T6P), which influences sucrose distribution in the
plant. But they were keen to discover more intimate details of the
relationships governing the increased productivity.
The transgenic maize depressed levels of T6P in the phloem, a major
component of the plant's transportation network. This allows more sucrose to
move to developing kernels and, serendipitously, increasing rates of
photosynthesis, thereby producing even more sucrose for more kernels. The
team also looked at the phloem within the plant's reproductive structures
which are sensitive to drought. Female kernels abort, but keeping sucrose
flowing within the structures prevents this abortion.