A single transcription factor promotes both yield and immunity in rice ($) (Science)

Plants regularly prioritize either growth or defense, leading to reduced growth rate when the plant is under attack. Wang et al. have identified a simple switch  in rice that demonstrates this principle beautifully. The Ideal Plant Architecture 1 (IPA1) transcription factor is involved in controlling grain yield by reducing the number of unproductive tillers. The authors found that the ipa1-1D allele that confers higher grain yield also confers protection against the rice blast fungus.  Fungal infection induces IPA1 phosphorylation, and the phosphorylated form of IPA1 activates a different subset of genes than unphosphorylated IPA1. This reversible phosphorylation thus directly shifts the expressed genes from those promoting growth to those promoting defense. As the authors summarize, “Changing DNA binding specificity via phosphorylation of an amino acid to nimbly control different outcomes may prove to be a widespread phenomenon.” (Summary by Mary Williams) Science 10.1126/science.aat7675