摘要：科研人员证明了在不同的环境下培育的在遗传上相同的林木品种暴露在干旱环境下的响应有差别。这项发现呼应了科学家发现的在不同地点抚养的在遗传上相同的人类双胞胎的表现：尽管遗传物质相同，同卵双胞胎的健康因为接触的环境的不同而可能有很大的差异。Malcolm M. Campbell及其同事发现了植物的地理来源和个体历史可能对它对各种环境条件的响应产生持久的影响。这组科研人员研究了成对的三种具有经济重要性的杨树品种——杂交杨树DN34、Walker和Okanese。每个品种的在遗传上相同的两个成员来自加拿大不同地区的苗圃。当这些植株在同样的条件下在实验室一起生长然后接触干旱环境的时候，在不同地区培养的相同品种展现出了基因活动的惊人差异。Campbell的研究组还观察到了在不同苗圃培育的同一品种的成员之间的化学改变（称为甲基化）的不同。改变甲基化的模式可能显著影响哪些基因被打开和关闭。这作者推测说，这些环境诱导的植物基因组的变化可能改变对风等其他气候条件和对土壤营养水平的响应以及对病虫害的抗性。这组作者说，这种所谓的“苗圃效应”可能为棉白杨、杂交杨树、以及山杨等许多品种提供多样性。这些树是通过根或枝条的扦插繁殖产生在遗传上相同的植株。
生物探索推荐英文论文摘要：
Clone history shapes Populus drought responses
Abstract
Just as animal monozygotic twins can experience different environmental conditions by being reared apart, individual genetically identical trees of the genus Populus can also be exposed to contrasting environmental conditions by being grown in different locations. As such, clonally propagated Populus trees provide an opportunity to interrogate the impact of individual environmental history on current response to environmental stimuli. To test the hypothesis that current responses to an environmental stimulus, drought, are contingent on environmental history, the transcriptome- level drought responses of three economically important hybrid genotypes—DN34 (Populus deltoides × Populus nigra), Walker [P. deltoides var. occidentalis × (Populus laurifolia × P. nigra)], and Okanese [Walker × (P. laurifolia × P. nigra)]—derived from two different locations were compared. Strikingly, differences in transcript abundance patterns in response to drought were based on differences in geographic origin of clones for two of the three genotypes. This observation was most pronounced for the genotypes with the longest time since establishment and last common propagation. Differences in genome-wide DNA methylation paralleled the transcriptome level trends, whereby the clones with the most divergent transcriptomes and clone history had the most marked differences in the extent of total DNA methylation, suggesting an epigenomic basis for the clone history-dependent transcriptome divergence. The data provide insights into the interplay between genotype and environment in the ecologically and economically important Populus genus, with implications for the industrial application of Populus trees and the evolution and persistence of these important tree species and their associated hybrids.
