Rowe Heather C, Kliebenstein Daniel J
Department of Plant Sciences, University of California, Davis, California 95616, USA.
Genetics. 2008 Dec;180(4):2237-50. doi: 10.1534/genetics.108.091439. Epub 2008 Oct 9.
The genetic architecture of plant defense against microbial pathogens may be influenced by pathogen lifestyle. While plant interactions with biotrophic pathogens are frequently controlled by the action of large-effect resistance genes that follow classic Mendelian inheritance, our study suggests that plant defense against the necrotrophic pathogen Botrytis cinerea is primarily quantitative and genetically complex. Few studies of quantitative resistance to necrotrophic pathogens have used large plant mapping populations to dissect the genetic structure of resistance. Using a large structured mapping population of Arabidopsis thaliana, we identified quantitative trait loci influencing plant response to B. cinerea, measured as expansion of necrotic lesions on leaves and accumulation of the antimicrobial compound camalexin. Testing multiple B. cinerea isolates, we identified 23 separate QTL in this population, ranging in isolate-specificity from being identified with a single isolate to controlling resistance against all isolates tested. We identified a set of QTL controlling accumulation of camalexin in response to pathogen infection that largely colocalized with lesion QTL. The identified resistance QTL appear to function in epistatic networks involving three or more loci. Detection of multilocus connections suggests that natural variation in specific signaling or response networks may control A. thaliana-B. cinerea interaction in this population.
植物对微生物病原体防御的遗传结构可能受病原体生活方式的影响。虽然植物与活体营养型病原体的相互作用通常由遵循经典孟德尔遗传的大效应抗性基因的作用控制，但我们的研究表明，植物对坏死营养型病原体灰葡萄孢的防御主要是数量性状且遗传复杂。很少有对坏死营养型病原体的数量抗性研究使用大型植物作图群体来剖析抗性的遗传结构。利用一个大型结构化的拟南芥作图群体，我们鉴定了影响植物对灰葡萄孢反应的数量性状位点，以叶片上坏死病斑的扩展和抗菌化合物camalexin的积累来衡量。通过测试多个灰葡萄孢分离株，我们在该群体中鉴定出23个独立的数量性状位点，其分离株特异性从仅与单个分离株相关到控制对所有测试分离株的抗性不等。我们鉴定出一组响应病原体感染控制camalexin积累的数量性状位点，它们在很大程度上与病斑数量性状位点共定位。所鉴定的抗性数量性状位点似乎在涉及三个或更多位点的上位性网络中起作用。多位点连接的检测表明，特定信号传导或反应网络中的自然变异可能控制该群体中拟南芥与灰葡萄孢的相互作用。
