转Cry1Ac+Cry2Ab基因棉花主要生化物质含量变化及其对棉田昆虫的影响

【目的】新型转基因棉花在进入大规模商业化应用前,需对其生态环境安全性进行评价;同时,经基因改造的新型转基因抗虫棉花可能影响抗虫棉的次生代谢,进而导致一些综合的生态学效应,致使棉花生理上发生改变,这也是转基因植物安全性评价研究的重要内容。【方法】比较了不同关键时期新型转Cry1Ac+Cry2Ab基因棉花与转Cry1Ac基因棉花和非转基因棉花叶片的鲜重、干重和干鲜比、主要酶超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)]活性、营养物质(蛋白质、氨态氮、脯氨酸和可溶性糖)和次生代谢产物(棉酚和单宁)含量的差异及其对棉田不同昆虫营养层昆虫个体总数和物种数的影响。【结果】棉花生长的蕾期、花期和花铃期,转Cry1Ac+Cry2Ab基因棉花、转Cry1Ac基因棉花和非转基因棉花叶片的鲜重、干重和干鲜比呈先升高后降低的趋势;SOD和POD活性在花铃期明显升高,CAT、APX和GR活性无显著变化;蛋白质、氨态氮含量无明显变化,脯氨酸和可溶性糖含量均表现为先升高后下降的趋势;棉酚含量在3个时期无显著变化,而单宁含量呈逐渐升高的趋势。3种棉花叶片中干物质积累、主要酶活性、营养物质和次生代谢产物含量均无显著差异;单株大铃数表现为转Cry1Ac+Cry2Ab基因棉花转Cry1Ac基因棉花非转基因棉花,小铃数则表现为转Cry1Ac基因棉花Cry1Ac+Cry2Ab基因棉花非转基因棉花;昆虫群落和害虫亚群落的昆虫个体总数均表现为转Cry1Ac+Cry2Ab基因棉田转Cry1Ac基因棉田非转基因棉田,天敌亚群落昆虫个体总数无显著变化;3种棉田中昆虫群落、害虫亚群落和天敌亚群落的物种数均未发生显著变化。【结论】转Cry1Ac+Cry2Ab基因棉花叶片干物质积累、产量性状、生化物质含量、酶活性在不同生长期表现不同,但上述参数在3种棉花之间无显著差异;且转Cry1Ac+Cry2Ab基因棉花具有较好的抗虫性,能有效降低棉田害虫数量。

Effects of transgenic Cry1Ac+Cry2Ab cotton on biochemical substances and insects

Aim] A very important ecological task before introducing a new type of genetically modified cotton for large-scale commercial applications is to evaluate its biosafety. The secondary metabolism of cotton may be affected by the new gene introduced and even lead to a series of ecological effects. The physiological changes in the cotton cultivar are also an important part of safety evaluation of transgenic plants.Method] This paper compares the transgenic Cry1Ac+Cry2Ab cotton and Cry1Ac cotton with non-transgenic cotton in selected parameters during different critical developmental (seedling, budding and flowering and boll forming stages) periods. These parameters include the fresh and dry mass and ratio of dry mass to fresh mass of cotton leaf. Activities of important enzymes like SOD (super oxide dismutase), CAT (catalase), POD (peroxidase), APX (ascorbate peroxidase) and GR (glutathione reductase) were measured. We also measured the amounts of protein, ammonia nitrogen, soluble sugars, and secondary metabolites like gossypol and tannins. The number of individuals and species in different layers were investigated.Result] During the budding, flowering and boll forming, the cotton leaf fresh mass, dry mass, their ratio, protein content and soluble sugars all showed first an increasing, then a decreasing trend. Activities of SOD and POD enzyme significantly increased in the boll forming stage, however, the other enzymes, CAT, APX and GR did not change significantly during the three periods. Ammonia nitrogen had no obvious change. Tannin contents gradually increased, while the gossypol content did not change significantly. Accumulation of dry matter, enzyme activities, nutrient content, and the amounts of secondary metabolites had no significant difference between the three kinds of cotton leaves. The number of big bolls was highest in Cry1Ac+Cry2Ab cotton, followed by Cry1Ac cotton and non-transgenic cotton; the number of small bolls was lowest in Cry1Ac cotton, followed by Cry1Ac+Cry2Ab, then non-transgenic cotton. The total number of insect individuals in the insect community and pest sub-community showed that Cry1Ac+Cry2Ab cotton < Cry1Ac cotton < non-transgenic cotton fields. However, the total number of individuals in the natural enemy sub-community was not significantly different. The number of species in the pest and natural enemy sub-communities between the three kinds of cotton varieties had no obvious difference.Conclusion] Accumulation of dry matter, yield, the amount of biochemical substances and enzyme activities in the transgenic Cry1Ac+Cry2Ab cotton showed differences in the three different development stages. The same parameters between the transgenic and non-transgenic cotton had no obvious differences. We registered no difference in the abundance of the censused arthropod community.