Partial Resistance of Medicago truncatula to Aphanomyces euteiches Is Associated with Protection of the Root Stele and Is Controlled by a Major QTL Rich in Proteasome-Related Genes
Partial Resistance of Medicago truncatula to Aphanomyces euteiches Is Associated with Protection of the Root Stele and Is Controlled by a Major QTL Rich in Proteasome-Related Genes
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DOI：
10.1094/mpmi-22-9-1043
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发表时间：
2009-09-01
影响因子：
3.5
通讯作者：
Jacquet, Christophe
中科院分区：
文献类型：
--
作者：
Djebali, Naceur;Jauneau, Alain;Jacquet, Christophe
为了深入研究豌豆根腐病病原菌Aphanomyceseuteiches与模式豆科植物蒺藜苜蓿之间的致病系统，建立了豌豆根腐病病原菌Aphanomyceseuteiches与模式豆科植物蒺藜苜蓿之间的致病系统。F83005.5法国材料和A17-Jemalong参考系分别对A. euteiches进行进一步的细胞学和遗传学分析。薄根切片的显微镜分析显示，两个接种线之间的主要差异发生在根中柱，这仍然是病原体在A17免费。仅在A17根中观察到显著特征，包括i）频繁的周皮层细胞分裂，ii）周皮层周围的木质素沉积，和iii）可溶性酚类化合物的积累。对139个重组自交系的F7群体进行了抗性遗传分析，并在第3染色体顶部附近确定了一个主效数量性状位点（QTL）。第二项研究，近等基因系对A。euteiches证实了该QTL在抗性表达中的作用。精细定位允许鉴定富含蛋白酶体相关基因的135-kb测序基因组DNA区域。这些基因中的大多数仅在接种的A17中被诱导。新的机制可能参与所观察到的部分电阻的建议。
A pathosystem between Aphanomyces euteiches, the causal agent of pea root rot disease, and the model legume Medicago truncatula was developed to gain insights into mechanisms involved in resistance to this oomycete. The F83005.5 French accession and the A17-Jemalong reference line, susceptible and partially resistant, respectively, to A. euteiches, were selected for further cytological and genetic analyses. Microscopy analyses of thin root sections revealed that a major difference between the two inoculated lines occurred in the root stele, which remained pathogen free in A17. Striking features were observed in A17 roots only, including i) frequent pericycle cell divisions, ii) lignin deposition around the pericycle, and iii) accumulation of soluble phenolic compounds. Genetic analysis of resistance was performed on an F7 population of 139 recombinant inbred lines and identified a major quantitative trait locus (QTL) near the top of chromosome 3. A second study, with near-isogenic line responses to A. euteiches confirmed the role of this QTL in expression of resistance. Fine-mapping allowed the identification of a 135-kb sequenced genomic DNA region rich in proteasome-related genes. Most of these genes were shown to be induced only in inoculated A17. Novel mechanisms possibly involved in the observed partial resistance are proposed.