College of Animal Science, Southwest University, Rongchang Campus, Chongqing, 402460, China.
Department of Grassland Science, Faculty of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
Biochem Genet. 2020 Dec;58(6):824-847. doi: 10.1007/s10528-020-09977-8. Epub 2020 Jun 6.
Orchardgrass (Dactylis glomerata L.) is drought resistant and tolerant to barren landscapes, making it one of the most important forages for animal husbandry, as well as ecological restoration of rocky landscapes that are undergoing desertification. However, orchardgrass is susceptible to rust, which can significantly reduce its yield and quality. Therefore, understanding the genes that underlie resistance against rust in orchardgrass is critical. The evolution, cloning of plant disease resistance genes, and the analysis of pathogenic bacteria induced expression patterns are important contents in the study of interaction between microorganisms and plants. Genes with nucleotide binding site (NBS) structure are disease-resistant genes ubiquitous in plants and play an important role in plant attacks against various pathogens. Using sequence analysis and re-annotation, we identified 413 NBS resistance genes in orchardgrass. Similar to previous studies, NBS resistance genes containing TIR (toll/interleukin-1 receptor) domain were not found in orchardgrass. The NBS resistance genes can be divided into four types: NBS (up to 264 homologous genes, accounting for 64% of the total number of NBS genes in orchardgrass), NBS-LRR, CC-NBS, and CC-NBS-LRR (minimum of 26 homologous genes, only 6% of the total number of NBS genes in orchardgrass). These 413 NBS resistance genes were unevenly distributed across seven chromosomes where chromosome 5 had up to 99 NBS resistance genes. There were 224 (54%) NBS resistance genes expressed in different tissues (roots, stems, leaves, flowers, and spikes), and we did not detect expression for 45 genes (11%). The remaining 145 (35%) were expressed in some tissues. And we found that 11 NBS resistance genes were differentially expressed under waterlogging stress, 5 NBS resistance genes were differentially expressed under waterlogging and drought stress, and 1 NBS resistance was is differentially expressed under waterlogging and heat stress. Most importantly, we found that 65 NBS resistance genes were significantly expressed in different control groups. On the 7th day of inoculation, 23 NBS resistance genes were differentially expressed in high resistance materials alone, of which 7 NBS resistance genes regulate the "plant-pathogen interaction" pathway by encoding RPM1. At the same time, 2 NBS resistance genes that were differentially expressed in the high resistance material after inoculation were also differentially expressed in abiotic stress. In summary, the NBS resistance gene plays a crucial role in the resistance of orchardgrass to rust.
鸭茅（Dactylis glomerata L.）耐旱，能耐受贫瘠的景观，是畜牧业最重要的饲料之一，也是遭受荒漠化的石质景观生态恢复的重要饲料。然而，鸭茅易患锈病，这会显著降低其产量和质量。因此，了解鸭茅中锈病抗性的基因基础至关重要。植物抗病基因的进化、克隆和病原菌诱导表达模式的分析是微生物与植物相互作用研究的重要内容。含有核苷酸结合位点（NBS）结构的基因是植物中普遍存在的抗病基因，在植物抵御各种病原体的侵害中发挥着重要作用。通过序列分析和重新注释，我们在鸭茅中鉴定出了 413 个 NBS 抗病基因。与之前的研究相似，鸭茅中没有发现含有 TIR（ toll/interleukin-1 receptor ）结构域的 NBS 抗病基因。NBS 抗病基因可分为四类：NBS（多达 264 个同源基因，占鸭茅 NBS 基因总数的 64%）、NBS-LRR、CC-NBS 和 CC-NBS-LRR（至少 26 个同源基因，仅占鸭茅 NBS 基因总数的 6%）。这 413 个 NBS 抗病基因在 7 条染色体上不均匀分布，其中 5 号染色体上多达 99 个 NBS 抗病基因。在不同组织（根、茎、叶、花和穗）中表达了 224 个（54%）NBS 抗病基因，未检测到 45 个基因（11%）的表达。其余 145 个（35%）在某些组织中表达。我们发现，在淹水胁迫下，有 11 个 NBS 抗病基因的表达存在差异，在淹水和干旱胁迫下，有 5 个 NBS 抗病基因的表达存在差异，在淹水和热胁迫下，有 1 个 NBS 抗病基因的表达存在差异。最重要的是，我们发现 65 个 NBS 抗病基因在不同的对照组中差异表达。在接种后的第 7 天，在高抗材料中单独检测到 23 个 NBS 抗病基因的表达存在差异，其中 7 个 NBS 抗病基因通过编码 RPM1 调节“植物-病原体相互作用”途径。同时，在接种后高抗材料中差异表达的 2 个 NBS 抗病基因也在非生物胁迫下差异表达。综上所述，NBS 抗病基因在鸭茅锈病抗性中起着至关重要的作用。
