Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC, USA.
Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA.
Plant Biotechnol J. 2022 Jan;20(1):47-58. doi: 10.1111/pbi.13693. Epub 2021 Oct 22.
Crop plant partial resistance to plant pathogens controlled by quantitative trait loci (QTL) is desirable in cultivar development programmes because of its increased durability. Mechanisms underlying such resistance are difficult to study. We performed RNA-seq analyses for tobacco (Nicotiana tabacum) nearly isogenic lines (NILs) with and without favourable allele(s) at Phn7.1, a major QTL influencing partial resistance to the soil-borne pathogens Phytophthora nicotianae and Ralstonia solanacearum. Based upon combined analyses of transcriptome-based sequence variation and gene expression profiles, we concluded that allelic variability at the Phn7.1 locus was likely generated from homoeologous exchange, which led to deletion of low-expressing members of the SAR8.2 gene family and duplication of high-expressing SAR8.2 genes from a different subgenome of allotetraploid tobacco. The high expression of endogenous Phn7.1-associated SAR8.2 genes was correlated with observed resistance to P. nicotianae. Our findings suggest a role for genomic rearrangements in the generation of favourable genetic variability affecting resistance to pathogens in plants.
作物对植物病原体的部分抗性受数量性状位点 (QTL) 控制，在品种开发计划中因其耐久性增加而受到青睐。这种抗性的机制很难研究。我们对具有和不具有 Phn7.1 有利等位基因的烟草 (Nicotiana tabacum) 近等基因系 (NIL) 进行了 RNA-seq 分析，Phn7.1 是影响对土壤传播病原体 Phytophthora nicotianae 和 Ralstonia solanacearum 部分抗性的主要 QTL。基于基于转录组序列变异和基因表达谱的综合分析，我们得出结论，Phn7.1 基因座的等位基因变异可能是由同源交换产生的，这导致 SAR8.2 基因家族低表达成员缺失，并且来自异源四倍体烟草不同亚基因组的高表达 SAR8.2 基因重复。内源性 Phn7.1 相关 SAR8.2 基因的高表达与观察到的对 P. nicotianae 的抗性相关。我们的发现表明，基因组重排在产生影响植物病原体抗性的有利遗传变异性方面发挥作用。
