Bakker Peter A H M, Glandorf Debora C M, Viebahn Mareike, Ouwens Theodora W M, Smit Eric, Leeflang Paula, Wernars Karel, Thomashow Linda S, Thomas-Oates Jane E, van Loon Leendert C
Institute of Biology, Utrecht University, Section of Plant Pathology, The Netherlands.
Antonie Van Leeuwenhoek. 2002 Aug;81(1-4):617-24. doi: 10.1023/a:1020526126283.
Pseudomonas putida WCS358r, genetically modified to have improved activity against soil-borne pathogens, was released into the rhizosphere of wheat. Two genetically modified derivatives carried the phz or the phl biosynthetic gene loci and constitutively produced either the antifungal compound phenazine-1-carboxylic acid (PCA) or the antifungal and antibacterial compound 2,4-diacetylphloroglucinol (DAPG). In 1997 and 1998, effects of single introductions of PCA producing derivatives on the indigenous microflora were studied. A transient shift in the composition of the total fungal microflora, determined by amplified ribosomal DNA restiction analysis (ARDRA), was detected. Starting in 1999, effects of repeated introduction of genetically modified microorganisms (GMMs) were studied. Wheat seeds coated with the PCA producer, the DAPG producer, a mixture of the PCA and DAPG producers, or WCS358r, were sown and the densities, composition and activities of the rhizosphere microbial populations were measured. All introduced strains decreased from 10(7) CFU per gram of rhizosphere sample to below the detection limit after harvest of the wheat plants. The phz genes were stably maintained in the PCA producers, and PCA was detected in rhizosphere extracts of plants treated with this strain or with the mixture of the PCA and DAPG producers. The phl genes were also stably maintained in the DAPG producing derivative of WCS358r. Effects of the genetically modified bacteria on the rhizosphere fungi and bacteria were analyzed by using amplified ribosomal DNA restriction analysis. Introduction of the genetically modified bacterial strains caused a transient change in the composition of the rhizosphere microflora. However, introduction of the GMMs did not affect the several soil microbial activities that were investigated in this study.
恶臭假单胞菌WCS358r经过基因改造后对土壤传播病原体具有更强的活性，被释放到小麦根际。两种转基因衍生物携带了phz或phl生物合成基因位点，并组成型地产生抗真菌化合物吩嗪-1-羧酸（PCA）或抗真菌和抗菌化合物2,4-二乙酰基间苯三酚（DAPG）。在1997年和1998年，研究了单次引入产生PCA的衍生物对本地微生物区系的影响。通过扩增核糖体DNA限制性分析（ARDRA）确定，总真菌微生物区系的组成发生了短暂变化。从1999年开始，研究了重复引入转基因微生物（GMM）的影响。播种了用产生PCA的菌株、产生DAPG的菌株、PCA和DAPG产生菌的混合物或WCS358r包衣的小麦种子，并测量了根际微生物种群的密度、组成和活性。在小麦植株收获后，所有引入的菌株从每克根际样品10(7) CFU降至检测限以下。phz基因在产生PCA的菌株中稳定维持，在用该菌株或PCA和DAPG产生菌的混合物处理的植物根际提取物中检测到了PCA。phl基因也在WCS358r的产生DAPG的衍生物中稳定维持。通过扩增核糖体DNA限制性分析来分析转基因细菌对根际真菌和细菌的影响。引入转基因细菌菌株导致根际微生物区系的组成发生短暂变化。然而，引入GMMs并未影响本研究中所调查的几种土壤微生物活性。
