Castagnoli Marisa, Caccia Riccardo, Liguori Marialivia, Simoni Sauro, Marinari Sara, Soressi Gian Piero
Istituto Sperimentale per la Zoologia Agraria, Via Lanciola, 12/a, Cascine del Riccio, 1-50125 Firenze, Italy.
Exp Appl Acarol. 2003;31(3-4):177-89. doi: 10.1023/b:appa.0000010387.48323.ee.
A critical aspect dealing with the use of transgenic plants is the global evaluation of their environmental impact. The polyphagous mite Tetranychus urticae can be considered a suitable species to investigate unpredictable and undesirable effects on phytophagous arthropods. Three tomato near isogenic lines, that is, the cv. Riogrande (RIG), the transgenic lines RC332 (containing the Gox gene and showing high glucose oxidase activity), and MS498 (containing the KTI3 gene and exhibiting a high trypsin inhibition) were used in laboratory and greenhouse trials. Trichomes and contents of C and N of the leaves, differences in development and oviposition of T. urticae and damage caused were evaluated for each line. The laboratory trials evidenced that (1) the intrinsic rate of increase of two strains of T. urticae (T from tomato, B from bindweed), reared on the lower surface of tomato leaflets, was significantly lower in RIG than in transgenic lines and doubling time ranged between 6.9 and 11.6 days in the first and between 3.9 and 5.3 days in the latter; (2) the glandular four-lobed trichomes were always higher in RIG than in other genotypes; (3) the N leaf content was from 1.3 to 1.9 fold lower and the C/N ratio from 1.3 to 1.9 fold higher in RIG than in other lines. The greenhouse experiment, that lasted over a month and was performed by inducing an initially equal infestation of strain T, evidenced: (1) no significant difference between plant lines in the final mite infestation (motile stages per plant), nevertheless an almost double number of spider mites was counted in RC332; (2) a significantly higher percentage of damaged leaves and a significant higher average damage index on RC332 than on RIG (79% and 2.3 in the former, and 62% and 2.1 in the latter, respectively), even if in both transgenics a higher level of the most severe damages and a shorter time to approach them were observed; (4) a comparable number of mites causing the same damage level in all genotypes and a strong linear relation between the first four levels of damage and mite infestation. Although in the laboratory studies both transgenic lines enhanced the T. urticae population increase, the glasshouse studies were not as conclusive and they only suggest the possibility of any real difference between the transgenic and non-transgenic genotypes.
转基因植物应用中一个关键的方面是对其环境影响进行全面评估。多食性螨类二斑叶螨可被视为一个合适的物种，用于研究对植食性节肢动物不可预测的不良影响。使用了三个番茄近等基因系，即品种里奥格兰德（RIG）、转基因系RC332（含有Gox基因且具有高葡萄糖氧化酶活性）和MS498（含有KTI3基因且具有高胰蛋白酶抑制活性），进行了实验室和温室试验。对每个品系的叶片毛状体、碳和氮含量、二斑叶螨的发育和产卵差异以及造成的损害进行了评估。实验室试验表明：（1）在番茄小叶下表面饲养的二斑叶螨两个品系（来自番茄的T品系和来自旋花的B品系）的内禀增长率，在RIG中显著低于转基因系，第一代的倍增时间在6.9至11.6天之间，第二代在3.9至5.3天之间；（2）RIG中腺状四叶毛状体的数量始终高于其他基因型；（3）RIG中叶片氮含量比其他品系低1.3至1.9倍，碳氮比高1.3至1.9倍。持续一个多月的温室试验，通过对T品系进行初始等量侵染来进行，结果表明：（1）各植株系在最终螨类侵染（每株活动阶段）方面无显著差异，不过在RC332中统计到的红蜘蛛数量几乎是其两倍；（2）RC332上受损叶片的百分比显著高于RIG，平均损害指数也显著更高（前者分别为79%和2.3，后者分别为62%和2.1），即使在两个转基因品系中都观察到更严重损害的水平更高且达到该水平的时间更短；（4）所有基因型中造成相同损害水平的螨类数量相当，且前四个损害水平与螨类侵染之间存在很强的线性关系。尽管在实验室研究中两个转基因系都促进了二斑叶螨种群的增长，但温室研究的结论并不那么确凿，仅表明转基因和非转基因基因型之间可能存在实际差异。
