PDF(Pubmed)
Abstract：
Nucleotide-binding domain and leucine-rich repeat (NLR) immune receptor genes form a major line of defense in plants, acting in both pathogen recognition and resistance machinery activation. NLRs are reported to form large gene clusters in limber pine (Pinus flexilis), but it is unknown how widespread this genomic architecture may be among the extant species of conifers (Pinophyta). We used comparative genomic analyses to assess patterns in the abundance, diversity, and genomic distribution of NLR genes. Chromosome-level whole genome assemblies and high-density linkage maps in the Pinaceae, Cupressaceae, Taxaceae, and other gymnosperms were scanned for NLR genes using existing and customized pipelines. The discovered genes were mapped across chromosomes and linkage groups and analyzed phylogenetically for evolutionary history. Conifer genomes are characterized by dense clusters of NLR genes, highly localized on one chromosome. These clusters are rich in TNL-encoding genes, which seem to have formed through multiple tandem duplication events. In contrast to angiosperms and nonconiferous gymnosperms, genomic clustering of NLR genes is ubiquitous in conifers. NLR-dense genomic regions are likely to influence a large part of the plant\'s resistance, informing our understanding of adaptation to biotic stress and the development of genetic resources through breeding.
摘要：
核苷酸结合域和富含亮氨酸的重复序列（NLR）免疫受体基因构成了植物的主要防线，同时作用于病原体识别和抗性机制激活。据报道，NLR在松木松树（Pinusflexilis）中形成大的基因簇，但尚不清楚这种基因组结构在针叶树（Pinophyta）的现存物种中的广泛分布。我们使用比较基因组分析来评估丰度的模式，NLR基因的多样性和基因组分布。松科的染色体水平全基因组组装和高密度连锁图谱，柏科，使用现有和定制的管道扫描紫杉科和其他裸子植物的NLR基因。将发现的基因跨染色体和连锁群定位，并对进化史进行系统发育分析。针叶树基因组的特征是NLR基因的密集簇，高度定位在一条染色体上。这些簇富含TNL编码基因，这似乎是通过多个串联复制事件形成的。与被子植物和非针叶裸子植物相比，NLR基因的基因组聚类在针叶树中普遍存在。NLR密集的基因组区域可能会影响植物的大部分抗性，通过育种告知我们对适应生物胁迫和遗传资源开发的理解。
