Mol Biol Evol:美国科学家等发表植物抗病基因调控研究论文
2016年8月10日，国际分子生物学和进化领域的权威期刊《molecular Biology and Evolution》杂志上在线发表了华中农业大学园艺林学学院基因组学实验室匡汉晖教授研究组和美国圣路易斯唐纳德植物科学中心的Blake C. Meyers教授题为“The Diversification of Plant NBS-LRR Defense Genes Directs the Evolution of micrornAs that Target Them”论文，研究揭示了植物抗病基因调控方面研究进展。匡汉晖教授及张雨博士为论文共同第一作者，Blake C. Meyers教授为论文通讯作者。
植物依靠多种机制抵抗微生物病原体，其中NBS-LRR类抗病基因尤为重要。但该基因家族过高表达也会对植物产生毒害作用。近年来，研究发现抗病基因的表达受小rna的控制。
在调查了70种陆生植物的抗病基因，并与大量的miRNA数据进行耦合分析后，研究者发现miRNA与抗病基因的多样性高度相关。进一步的分析发现抗病基因的复制是产生新miRNA的重要途径，不同的miRNA通过靶向抗病基因的保守结构域，对抗病基因的表达进行调控，表现出趋同进化模型。通过对miRNA和抗病基因靶标序列的分析，发现密码子上摇摆位点的碱基差异是导致miRNA多样性的原因。该研究提出的植物miRNA和抗病基因共演化模型，不仅揭示了miRNA对保持植物抗病基因平衡的机制，同时对植物基因家族和基因组进化提供了新的观点。
原文链接：
The Diversification of Plant NBS-LRR Defense Genes Directs the evolution of MicroRNAs that Target Them
原文摘要：
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.
作者：Blake C. Meyers
