Biologists Identify Six Genes in Maize Responsible for Production of Plant Antibiotics
Yezhang Ding, Alisa Huffaker, and Eric Schmelz of the University of
California San Diego and their colleagues have developed a systematic and
combined approach to identify genes in maize that will produce surprisingly
diverse antibiotic cocktails that can be produced as defensive blends
against numerous disease agents.
In the study, the UC San Diego biologists describe how they combined an
array of scientific approaches to clearly identify six genes that encode
enzymes responsible for the production of key maize antibiotics known to
control disease resistance.
Maize plants without small molecule antibiotic defenses commonly suffer
dramatic increases in fungal disease susceptibility. An evolutionary step
was a comparatively recent gene duplication three million years ago from the
hormone pathway responsible for plant growth called gibberellins. Two highly
promiscuous oxidative enzymes termed cytochrome P450s were characterized to
produce unique reactions different from known conifer pathways. The effort
has leveraged more than 2,000 plant samples, each with 36,861 transcripts,
spanning 300 different maize lines to systematically narrow candidates and
define a maize pathway for antibiotics effective against fungal pathogens.