Carlsson-Granér U, Burdon J J, Thrall P H
Department of Ecology and Environmental Science Umeå University, S-901 87 Umeå, Sweden e-mail:
Centre for Plant Biodiversity Research, CSIRO-Plant Industry, GPO Box 1600, Canberra, A.C.T, 2601, Australia, , , , , , AU.
Oecologia. 1999 Nov;121(3):339-347. doi: 10.1007/s004420050937.
Hybridization between locally adapted plant populations has been postulated to have significant evolutionary consequences, and, in particular, may influence host-pathogen interactions with respect to resistance and virulence structure. This study investigated patterns of resistance and virulence in a hybrid zone between "bog" and "hill" ecotypes of the native Australian flax, Linum marginale, where the host is subject to attack by the rust pathogen, Melampsora lini. Analysis of the resistance structure of adjoining bog, hill and hybrid populations found that bog plants were generally susceptible to pathogen isolates taken from all these sites, but that hybrids exhibited resistance levels similar to the more resistant hill plants. Similarly, the virulence structure of rust isolates collected from the hybrid population was more similar to that of the hill isolates than the bog. Controlled crosses between bog and hill plants showed that crosses in one direction (bog females×hill males) were much more successful than the other. A multi-year reciprocal transplant study further indicated that bog plants had significantly higher survivorship than hill plants, regardless of site. It is suggested that likelihood of differential gene flow and survivorship for bog and hill plants may at least partially explain the maintenance of a relatively narrow hybrid zone.
本地适应的植物种群之间的杂交被认为具有重大的进化后果，特别是可能会在抗性和毒力结构方面影响宿主与病原体的相互作用。本研究调查了澳大利亚本土亚麻（Linum marginale）“沼泽”和“山地”生态型之间杂交区域的抗性和毒力模式，该宿主受到锈病病原体亚麻栅锈菌（Melampsora lini）的攻击。对相邻的沼泽、山地和杂交种群的抗性结构分析发现，沼泽植物通常对从所有这些地点分离出的病原体敏感，但杂交种表现出与抗性更强的山地植物相似的抗性水平。同样，从杂交种群中收集的锈菌分离株的毒力结构与山地分离株的更相似，而与沼泽分离株的不同。沼泽和山地植物之间的受控杂交表明，一个方向（沼泽雌株×山地雄株）的杂交比另一个方向更成功。一项多年的 reciprocal 移植研究进一步表明，无论在哪个地点，沼泽植物的存活率都显著高于山地植物。有人认为，沼泽和山地植物基因流动差异和存活率的可能性可能至少部分解释了相对狭窄杂交区域的维持。
