title: The Diversification of Plant NBS-LRR Defense Genes Directs the Evolution of MicroRNAs That Target Them.
abstract: High expression of plant nucleotide binding site leucine-rich repeat (NBS-LRR) defense genes is often lethal to plant cells, a phenotype perhaps associated with fitness costs. Plants implement several mechanisms to control the transcript level of NBS-LRR defense genes. As negative transcriptional regulators, diverse miRNAs target NBS-LRRs in eudicots and gymnosperms. To understand the evolutionary benefits of this miRNA-NBS-LRR regulatory system, we investigated the NBS-LRRs of 70 land plants, coupling this analysis with extensive small RNA data. A tight association between the diversity of NBS-LRRs and miRNAs was found. The miRNAs typically target highly duplicated NBS-LRRs In comparison, families of heterogeneous NBS-LRRs were rarely targeted by miRNAs in Poaceae and Brassicaceae genomes. We observed that duplicated NBS-LRRs from different gene families periodically gave birth to new miRNAs. Most of these newly emerged miRNAs target the same conserved, encoded protein motif of NBS-LRRs, consistent with a model of convergent evolution for these miRNAs. By assessing the interactions between miRNAs and NBS-LRRs, we found nucleotide diversity in the wobble position of the codons in the target site drives the diversification of miRNAs. Taken together, we propose a co-evolutionary model of plant NBS-LRRs and miRNAs hypothesizing how plants balance the benefits and costs of NBS-LRR defense genes.
authors: Key Laboratory of Horticulture Biology, Ministry of Education, and Department of Vegetable Crops, College of Horticulture and Forestry, Huazhong Agricultural University, Wuhan, People's Republic of China Donald Danforth Plant Science Center, St. Louis.
authors: Yu
authors: Y
authors: Zhang
authors: Donald Danforth Plant Science Center, St. Louis.
authors: Rui
authors: R
authors: Xia
authors: Key Laboratory of Horticulture Biology, Ministry of Education, and Department of Vegetable Crops, College of Horticulture and Forestry, Huazhong Agricultural University, Wuhan, People's Republic of China.
authors: Hanhui
authors: H
authors: Kuang
authors: Donald Danforth Plant Science Center, St. Louis Division of Plant Sciences, University of Missouri - Columbia bmeyers@danforthcenter.org.
authors: Blake C
authors: BC
authors: Meyers
mesh_terms: D001665:Binding Sites; D005075:Biological Evolution; D019607:Brassicaceae / Q000235:genetics; D030561:Databases, Nucleic Acid; D060467:Disease Resistance / Q000235:genetics; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D014644:Genetic Variation; D035683:MicroRNAs / Q000235:genetics*; D000070576:NLR Proteins / Q000235:genetics*; D009711:Nucleotides / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics; D010944:Plants / Q000235:genetics*
chemical_list: D035683:MicroRNAs; D000070576:NLR Proteins; D009711:Nucleotides; D010940:Plant Proteins
keywords: NBS-LRR; disease resistance gene; microRNA.; plant