Bt水稻Cry1Ab杀虫蛋白表达的时间动态及其在水稻土中的降解  

Temporal expression patterns of Cry1Ab insecticidal protein in Bt rice plants and its degradation in paddy soils

作　　者：白耀宇[1] 蒋明星[1] 程家安[1] 

机构地区：[1]浙江大学应用昆虫学研究所

出　　处：《生态学报》2005年第7期1583-1590,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30070500)~~

摘　　要：采用ELISA技术检测了Bt水稻克螟稻1号(KMD1)和克螟稻2号(KMD2)不同生育期茎和叶片中cry1Ab基因的表达水平,以及植株组织(茎和叶片)室内埋于不同稻田土壤中其Cry1Ab杀虫蛋白的降解动态。结果表明,不论是KMD1还是KMD2,茎和叶片中cry1Ab基因的表达量为3.7～9.1μg/g鲜重,均以拔节期和孕穗期相对较低,灌浆初期显著升高,黄熟期又明显下降(但仍然维持在较高的表达量)。KMD1茎和叶片中Cry1Ab蛋白在3种水稻土即青紫泥田、黄松田和黄筋泥田中的降解,均以前期(处理后12d内)较快,但中后期明显较慢;处理后42d,这两种组织中的Cry1Ab残留量均稳定在μg级水平,分别仅有0.20～0.85μg/g干重和0.35～1.81μg/g干重。KMD1茎和叶片中Cry1Ab蛋白降解动态与土壤类型密切相关,青紫泥田中降解最快,黄筋泥田中次之,黄松田中最慢。淹水可加快土壤中茎和叶的腐解,从而促进其中Cry1Ab蛋白的降解。KMD2粉碎叶中Cry1Ab蛋白在有菌水稻土中的降解快于无菌土中,表明土壤微生物存在可加快Cry1Ab蛋白的降解。在各种土壤淹水与非淹水、灭菌与非灭菌处理条件下的Cry1Ab蛋白降解过程均可用指数方程进行拟合,算得其消减半衰期为2.2～11.6d不等。讨论了土壤类型、淹水等影响Cry1Ab蛋白降解的可能机制,认为土壤微生物是其中起关键作用的一个因子。Bt （Bacillus thuringiensis） toxins produced in insect resistant transgenic Bt crops can enter soils in the forms of plant residues, root exudates and pollens, posing potential risks to beneficial organisms in the soil. Active Bt toxins may be bound to certain types of soil and persist there for a long period of time. In the present study, seasonal expression patterns of gt cry1Ab in plant tissues of Bt rice were observed, and then by burying the plant tissues highly expressing Cry1Ab into soils, degradation patterns of Cry1Ab in different types of soils, as well as the effects of flooding and microorganisms on its degradation, were determined. Thirty day-old plants of transgenic rice lines, KMD1 and KMD2, and their parent nontransgenic cv. Xiushui 11 （japonica rice）, were transplanted in a greenhouse of Huajiachi campus of Zhejiang University in midMay. At jointing, booting, early milking and maturing stages, stems and leaf blades of KMD1 and KMD2 were sampled separately and concentrations of Cry1Ab within them were determined using enzyme-linked immunosorbent assay （ELISA） technique. It was found that, during the jointing and maturing stages, Cry1Ab in the stems and leaf blades of KMD1 ranged 3.74-7.50 and 3.78-9. 13μg/g fresh weight （FW）, respectively, and in those of KMD2 ranged 3.97-8.29 and 4.32-8.84μg/g FW, respectively. For each KMD, the Cry1Ab concentration was low in both stems and leaf blades at the iointing as well as booting stage （3.7-4.9μ/g FW）, but it significantly increased at early milking stage, reaching 7.5 -9.1μ/g FW. The toxins decreased obviously during maturing stage, while it still reached a level as high as 5.7-7.8μ/g FW. Three types of paddy soils, marine-fluvigenic yellow loamy paddy soil, pale paddy soil on quaternary red clay and blue clayey paddy soil, which were obviously different in organic matter content, total humic carbon and clay content, were collected from Hangzhou, Jinhua and Jiaxin of China, respectively. In the laboratory, each type of soils recei

关 键 词：BT水稻 CRY1AB杀虫蛋白 表达 水稻土 降解 

分 类 号：X592[环境科学与工程—环境工程]