基因改造ipt (isopentenyl transferase)青花菜葉表與土壤微生物相之研究

Abstract

有鑑於基因改造技術的快速發展，釐清基改植物對環境安全之影響殊有必要。本研究以基改異戊烯轉移酶(isopentenyl transferase; ipt) 基因之青花菜(Brassica oleracea var. italica)為對象，探討基改與非基改青花菜對環境微生物群落之影響，參試青花菜品種(系)包括基改ipt 青花菜「綠王」自交系(103 轉殖系)、作為對照組未轉殖的自交系(104 自交系)、以及商用一代雜交「綠王」品種。基改ipt 青花菜之土壤pH 為7.27.7，相較對照組土壤pH 值7.07.7，兩者無顯著差異；定植當天基改ipt 青花菜根圈土壤有機質含量較高，但定植後90 d 各品系間土壤有機質含量在1.521.96%間，差異不顯著。對照組104 自交系葉表面總真菌數在2010 年顯著較高，同一年度葉表面之總細菌雖高於其他品系，但差異未達顯著水準。利用選擇性培養基評估土壤指標性微生物族群數目之消長，大部分微生物族群含量在田間定植期有顯著差異，但花球採收及整地後，各品種(系)間已無差異且整體變動趨勢相似。在2010 年定植後第105 d 仍有顯著差異的微生物族群為格蘭氏陰性菌、尿素氧化菌與纖維分解菌。利用變性膠體梯度電泳法分析基改ipt與非基改青花菜至種植60 d，土壤微生物rDNA 的相似性以103 轉殖系與104 自交系(CK)相似性係數較相近，且高於商用品種「綠王」，此結果與根圈真菌群落分布一致；2009與2010 兩個年度之相似度分析試驗結果亦相一致。 The rapid development of transgenic technology has raised the concern of potential impact for genetically modified plant to the environment. In this study, isopentenyl transferase (ipt) transgenic broccoli (Brassica oleracea var. italica) inbred line 103, non-transgenic inbred line 104, and the commercial F1 hybrid variety ‘Green King’ were used for investigation on the influence of transgenic broccoli to environmental microbial communities. As results indicated, ipt transgenic broccoli showed no effect on soil pH, while higher content of rhizosphere organic matter examined in 103 transgenic line at the transplantation day. However, soil organic matter data showed no significant difference in all lines after ninety days. In 2010, total number of fungi and bacteria were estimated, and inbred line 104 displayed significantly higher counts than other lines. Besides, almost all kinds of microbial population showed significant difference between transgenic and non-transgenic lines during the planting season. There is no significant difference after harvest and tillage. Nevertheless, population differences in gram-negative bacteria, urea-oxidizing bacteria and cellulolytic bacteria existed in 105th day after transplantation in 2010. From examination of the similarity coefficient of soil microorganisms between transgenic and non-transgenic broccoli lines, it showed that commercial F1 hybrid variety ‘Green King’ displayed lower similarity coefficient score than the other two lines.