Heterologous microProtein expression identifies LITTLE NINJA, a dominant regulator of jasmonic acid signaling

Abstract

Significance In plants, hormone signaling is, to some extent, controlled by transcriptional repressors that are degraded in a hormone-dependent manner. These repressor complexes consist of multiple proteins that assemble. MicroProteins are small single-domain proteins that are sequence-related to larger, multidomain proteins and act by disrupting protein complex formation. By forming protein complexes, or by sequestering signaling proteins, microProteins can act as effective modulators of protein activity. Our studies have discovered LITTLE NINJA, a NINJA-related microProtein that modulates JA signaling by attenuating the repression of JA-signaling. Transgenic plants ectopically expressing LITTLE NINJA are shorter and bushier than wild-type plants. Modulating LITTLE NINJA activity may provide strategies for future crop improvement and contribute to finding sustainable solutions for future agricultural production.