Abstract
MicroProteins are small, often single-domain proteins that are sequence-related to larger, often multidomain proteins. Here, we used a combination of comparative genomics and heterologous synthetic misexpression to isolate functional cereal microProtein regulators. Our approach identified LITTLE NINJA (LNJ), a microProtein that acts as a modulator of jasmonic acid (JA) signaling. Ectopic expression of LNJ in Arabidopsis resulted in stunted plants that resembled the decuple JAZ (jazD) mutant. In fact, comparing the transcriptomes of transgenic LNJ overexpressor plants and jazD revealed a large overlap of deregulated genes, suggesting that ectopic LNJ expression altered JA signaling. Transgenic Brachypodium plants with elevated LNJ expression levels showed deregulation of JA signaling as well and displayed reduced growth and enhanced production of side shoots (tiller). This tillering effect was transferable between grass species, and overexpression of LNJ in barley and rice caused similar traits. We used a clustered regularly interspaced short palindromic repeats (CRISPR) approach and created a LNJ-like protein in Arabidopsis by deleting parts of the coding sentence of the AFP2 gene that encodes a NINJA-domain protein. These afp2-crispr mutants were also stunted in size and resembled jazD Thus, similar genome-engineering approaches can be exploited as a future tool to create LNJ proteins and produce cereals with altered architectures.
Highlights
MicroProteins are small, often single-domain proteins that are sequence-related to larger, often multidomain proteins
Sequence analysis of LITTLE NINJA (LNJ) revealed that it is closely related to the Arabidopsis ABI5-BINDING PROTEIN2 (AFP2) gene that encodes a protein containing a NINJA domain
Our analysis discovered 183 genes to be significantly up-regulated by methyl jasmonate (MeJA) treatment in wild-type plants and 127 genes to be up-regulated in transgenic Brachypodium LNJ (BdLNJ)-OX plants (Fig. 4 A and B and Dataset S2)
Summary
MicroProteins are small, often single-domain proteins that are sequence-related to larger, often multidomain proteins. Our approach identified LITTLE NINJA (LNJ), a microProtein that acts as a modulator of jasmonic acid (JA) signaling. We used a clustered regularly interspaced short palindromic repeats (CRISPR) approach and created a LNJ-like protein in Arabidopsis by deleting parts of the coding sentence of the AFP2 gene that encodes a NINJA-domain protein. These afp2crispr mutants were stunted in size and resembled jazD. When JA is produced or ectopically applied, the CORONATINE INSENSITIVE 1 (COI1) JA-receptor recruits an ubiquitin-SCF-complex to degrade the JAZ-repressor This degradation alleviates the repressive activity on the transcription factors that can in turn induce JA-responsive gene expression [8]. Modulating LITTLE NINJA activity may provide strategies for future crop improvement and contribute to finding sustainable solutions for future agricultural production
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have