The Key Laboratory for Poplar Breeding and Germplasm Improvement, The Southern Modern Forestry Collaborative Innovation Center, College of Forestry, Nanjing Forestry University, Nanjing 210037, China.
College of Information Science and Technology, Nanjing Forestry University, Nanjing 210037, China.
Plant Dis. 2020 Apr;104(4):1133-1143. doi: 10.1094/PDIS-08-19-1699-RE. Epub 2020 Feb 12.
Identification of the particular genes in an genes supercluster underlying resistance to the rust fungus in poplar genome remains challenging. Based on the de novo assembly of the genome, all of the detected major genetic loci conferring resistance to were confined to a 3.5-Mb region on chromosome 19. The transcriptomes of the resistant and susceptible genotypes were sequenced for a timespan from 0 to 168 hours postinoculation. By mapping the differentially expressed genes to the target genomic region, we identified two constitutive expression genes and one inducible expression gene that might confer resistance to . Nucleotide variations were predicted based on the reconstructed haplotypes for each allele of the candidate genes. We also confirmed that salicylic acid was the phytohormone mediating signal transduction pathways, and was identified as a key gene inhibiting rust reproduction. Finally, quantitative reverse transcription PCR assay revealed consistent expressions with the RNA-sequencing data for the detected key genes. This study presents an efficient approach for the identification of particular genes underlying phenotype of interest by the combination of genetic mapping, transcriptome profiling, and candidate gene sequences dissection. The identified key genes would be useful for host resistance diagnosis and for molecular breeding of elite poplar cultivars exhibiting resistance to infection. The detected genes are also valuable for testing whether the combination of individual genes can induce durable quantitative resistance.
鉴定杨树基因组中抗锈菌基因超级簇中的特定基因仍然具有挑战性。基于 的从头组装，所有检测到的赋予对锈病抗性的主要遗传基因座都局限于 19 号染色体上的 3.5Mb 区域。在接种后 0 至 168 小时的时间段内，对抗性和敏感性基因型的转录组进行了测序。通过将差异表达基因映射到目标基因组区域，我们鉴定出两个组成型表达的 基因和一个诱导型表达的 基因，它们可能赋予对锈病的抗性。基于候选基因每个等位基因的重建单倍型，预测了核苷酸变异。我们还证实水杨酸是介导信号转导途径的植物激素， 被鉴定为抑制锈菌繁殖的关键基因。最后，定量逆转录 PCR 检测证实了检测到的关键基因与 RNA-seq 数据的一致表达。本研究通过遗传图谱、转录组图谱和候选基因序列剖析相结合，提出了一种鉴定与感兴趣表型相关的特定基因的有效方法。鉴定出的关键基因可用于宿主抗性诊断和对表现出抗 感染的优良杨树品种进行分子育种。检测到的 基因对于测试单个 基因的组合是否可以诱导持久的数量抗性也很有价值。
