Tomato DCL2b is required for the biosynthesis of 22-nt small RNAs, the resulting secondary siRNAs, and the host defense against ToMV

Abstract

Short sequences provide pathogen protection A protein that processes gene-regulating RNA molecules helps defend tomato plants against viral infections. The various DCL proteins play a prominent role in processing tiny RNAs known as microRNA and short interfering RNA, which in turn modulate gene activity. Researchers led by Hongliang Zhu at China Agricultural University set out to study a DCL protein produced by tomatoes that remains poorly defined from a functional perspective. The researchers did not notice any prominent abnormalities when they genetically manipulated plants to eliminate expression of the DCL2b gene. However, these DLC2b-deficient plants proved disproportionately vulnerable to tomato mosaic virus, with infection producing striking developmental defects. Zhu and colleagues determined that loss of this gene disrupts processing of a subset of regulatory RNAs that may help mediate the plant antiviral response.