Soil microbial community responses to altered lignin biosynthesis in Populus tremuloides vary among three distinct soils
Soil microbial community responses to altered lignin biosynthesis in Populus tremuloides vary among three distinct soils
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DOI：
10.1007/s11104-007-9246-0
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发表时间：
2007-05-01
期刊：
影响因子：
4.9
通讯作者：
Pregitzer, Kurt S.
中科院分区：
文献类型：
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作者：
Bradley, Kate L.;Hancock, Jessica E.;Pregitzer, Kurt S.
转基因植物的开发和使用稳步增加，但关于土壤微生物对这些基因改造的反应的数据仍然很少。本研究采用温室试验方法，研究了杨树树干木质素改变对三种土壤微生物群落的影响，这三种土壤分别是沙壤土(科罗拉多州)、粉壤土(堪萨斯州)和粘壤土(德克萨斯州)。三个转基因杨树系是从北美五大湖地区常见的自然克隆培育而来的。茎木质素浓度分别降低了35%(23号线)、40%(141号线)和50%(72号线)。品系72和品系141的丁香型茎木质素含量分别增加了40%和20%。间接地，这些改良导致不同品系和土壤类型的根产量水平增加(5-13%)和降低(-5-57%)。采用磷脂脂肪酸(PLFA)、中性脂脂肪酸(NLFA)和胞外酶分析法研究了土壤微生物群落的响应。PLFA分析表明，三种土壤微生物群落组成存在较大差异。同样，不同土壤的NLFA总量也有很大差异，其中KS土壤的NLFA总量最高，CO的含量最低。除CO土壤中纤维素酶活性最高外，不同土壤的酶活性差异不大。在所有三种土壤中，对四个遗传系的反应并不一致。土壤类型和遗传系之间的相互作用使得很难评估转基因杨树对土壤微生物群落及其相关功能的潜在生态影响。考虑到这些相互作用，转基因杨树的田间试验应该涵盖商业种植的广泛土壤，以确定它们对常驻土壤微生物群落的影响(S)。
The development and use of transgenic plants has steadily increased, but there are still little data about the responses of soil microorganisms to these genetic modifications. We utilized a greenhouse trial approach to evaluate the effects of altered stem lignin in trembling aspen (Populus tremuloides) on soil microbial communities in three soils which differed in their chemical and physical properties; they included a sandy loam (CO-Colorado), a silt loam (KS-Kansas), and a clay loam (TX-Texas). Three transgenic aspen lines were developed from a natural clone common to the Great Lakes region of North America. The concentrations of stem lignin concentrations were reduced by 35% (Line 23), 40% (Line 141) and 50% (Line 72). Line 72 and Line 141 also had a 40 and 20% increase in syringyl-type stem lignin, respectively. Indirectly, these modifications resulted in increased (5-13%) and decreased (-5 to -57%) levels of root production across the lines and soil types. Responses of the soil microbial communities were investigated using: phospholipid fatty acids (PLFA), neutral lipid fatty acids (NLFA), and 3) extracellular enzyme assays. PLFA analyses indicated that there were large differences in microbial community composition between the three soils. Similarly, there were large differences in total NLFA between soils, with the KS soils having the highest amount and CO the lowest. Enzyme activities did not differ between soils, except for cellubiohydrolase, which was highest in CO soil. Across all three soils, responses to the four genetic lines were not consistent. Interactions between soil type and genetic line make it difficult to assess the potential ecological impacts of transgenic aspen on soil microbial communities and their associated functions. Given these interactions, field trials with transgenic aspen should encompass the wide range of soils targeted for commercial planting in order to determine their effect(s) on the resident soil microbial community.