Department of Environmental and Forest Biology, College of Environmental Science and Forestry, State University of New York, Syracuse, NY, 13210, USA.
Insect Sci. 2020 Oct;27(5):1067-1078. doi: 10.1111/1744-7917.12713. Epub 2019 Aug 19.
American chestnut (Castanea dentata [Marsh.] Borkh.) was once the dominant hardwood species in Eastern North America before an exotic fungal pathogen, Cryphonectria parasitica (Murrill) Barr, functionally eliminated it across its range. One promising approach toward restoring American chestnut to natural forests is development of blight-tolerant trees using genetic transformation. However, transformation and related processes can result in unexpected and unintended phenotypic changes, potentially altering ecological interactions. To assess unintended tritrophic impacts of transgenic American chestnut on plant-herbivore interactions, gypsy moth (Lymantria dispar L.) caterpillars were fed leaf disks excised from two transgenic events, Darling 54 and Darling 58, and four control American chestnut lines. Leaf disks were previously treated with an LD dose of either the species-specific Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) or the generalist pathogen Bacillus thuringiensis subsp. kurstaki (Btk). Mortality was quantified and compared to water blank controls. Tree genotype had a strong effect on the efficacies of both pathogens. Larval mortality from Btk-treated foliage from only one transgenic event, Darling 54, differed from its isogenic progenitor, Ellis 1, but was similar to an unrelated wild-type American chestnut control. LdMNPV efficacy was unaffected by genetic transformation. Results suggest that although genetic modification of trees may affect interactions with other nontarget organisms, this may be due to insertion effects, and variation among different genotypes (whether transgenic or wild-type) imparts a greater change in response than transgene presence.
美国山核桃（Castanea dentata [Marsh.] Borkh.）曾是北美东部的主要硬木树种，但一种外来真菌病原体Cryphonectria parasitica（Murrill）Barr 使其在整个分布范围内功能性灭绝。利用遗传转化培育耐枯萎病的树木是恢复美国山核桃自然林的一种有前途的方法。然而，转化和相关过程可能导致意想不到的和意外的表型变化，从而潜在地改变生态相互作用。为了评估转基因美国山核桃对植物-食草动物相互作用的三重非预期影响，吉普赛蛾（Lymantria dispar L.）毛毛虫被喂食从两个转基因事件 Darling 54 和 Darling 58 以及四个对照美国山核桃品系中切下的叶片圆盘。叶片圆盘事先用特定物种的 Lymantria dispar 多角体病毒（LdMNPV）或广谱病原体苏云金芽孢杆菌亚种 kurstaki（Btk）的 LD 剂量处理。死亡率被量化并与水空白对照进行比较。树种基因型对两种病原体的功效都有很强的影响。只有一个转基因事件 Darling 54 的 Btk 处理叶片中的幼虫死亡率与其同基因亲本 Ellis 1 不同，但与不相关的野生型美国山核桃对照相似。LdMNPV 的功效不受遗传转化的影响。结果表明，尽管对树木进行遗传修饰可能会影响与其他非目标生物的相互作用，但这可能是由于插入效应，并且不同基因型（无论是转基因还是野生型）之间的变异比转基因的存在更能引起反应的变化。
