JAZ repressors of metabolic defense promote growth and reproductive fitness in Arabidopsis (Proc. Natl. Acad. Sci. USA)

Jasmonates promote defense reponses but at the expense of growth. JAZ proteins repress jasmonate responses. Guo et al. examined the consequences of knocking out 10 of the 13 JAZ genes in Arabidopsis, by producing a jaz decuple, or jazD mutant. They compared jazD mutant to previously described jazQ mutants that have five JAZ genes knocked out, and found that jazD is more severe in all responses than jazQ. As expected, jazD mutant show enhanced defense and severely reduced growth responses. The authors analyzed transcriptomic and proteomic data and found that jazD mutants exhibit symptoms of carbon starvation, even though rates of photosynthesis are comparable to wild-type plants. They suggest that this apparent carbon-starvation is because the plants use large amounts of energy in their production of defense compounds. The authors conclude: “We propose that JAZ proteins assist in balancing the growth–defense continuum not as a binary on–off switch but rather by matching the biotic stress level to available resources“. (Summary by Mary Williams) Proc. Natl. Acad. Sci. USA