A MicroRNA Superfamily Regulates Nucleotide Binding Site–Leucine-Rich Repeats and Other mRNAs[W][OA]

By P. Shivaprasad, Ho-Ming Chen, K. Patel, Donna M Bond, B. Santos, David C. Baulcombe. The Plant Cell, 2012

685 citations recorded by the source corpus.

A large and diverse miRNA superfamily targets mRNAs of disease resistance proteins and initiates phased secondary siRNA that target other mRNAs. Pathogen-encoded suppressor proteins interfere with this process; consequently, infection increases the level of mRNAs for disease resistance and other proteins. Analysis of tomato (Solanum lycopersicum) small RNA data sets revealed the presence of a regulatory cascade affecting disease resistance. The initiators of the cascade are microRNA members of an unusually diverse superfamily in which miR482 and miR2118 are prominent members. Members of this superfamily are variable in sequence and abundance in different species, but all variants target the coding sequence for the P-loop motif in the mRNA sequences for disease resistance proteins with nucleotide binding site (NBS) and leucine-rich repeat (LRR) motifs. We confirm, using transient expression in Nicotiana benthamiana, that miR482 targets mRNAs for NBS-LRR disease resistance proteins with coiled-coil domains at their N terminus. The targeting causes mRNA decay and production of secondary siRNAs in a manner that depends on RNA-dependent RNA polymerase 6. At least one of these secondary siRNAs targets other mRNAs of a defense-related protein. The miR482-mediated silencing cascade is suppressed in plants infected with viruses or bacteria so that expression of mRNAs with miR482 or secondary siRNA target sequences is increased. We propose that this process allows pathogen-inducible expression of NBS-LRR proteins and that it contributes to a novel layer of defense against pathogen attack.

Subfields: Plant Science

View Paper: https://www.semanticscholar.org/paper/2d5c9e8484aee4f2333212aae4eef14c62b1d681

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In Plant Science

1. Michael J. Axtell
2. Olivier Voinnet

Citations in the corpus

• ShortStack: comprehensive annotation and quantification of small RNA genes. (2013, methodology): “For tomato, a list of 19 loci previously described as producing phased small RNAs was also curated from Shivaprasad et al. (2012).”