MECHANISMS OF BIOCONTROL OF SOIL-BORNE PLANT-PATHOGENS BY RHIZOBACTERIA
MECHANISMS OF BIOCONTROL OF SOIL-BORNE PLANT-PATHOGENS BY RHIZOBACTERIA
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DOI：
10.1007/bf00011694
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发表时间：
1990-12-01
期刊：
影响因子：
4.9
通讯作者：
OPPENHEIM, A
中科院分区：
文献类型：
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作者：
CHET, I;ORDENTLICH, A;OPPENHEIM, A
细菌拮抗负责生物防治，可通过抗生、竞争或寄生等方式起作用。寄生依赖于裂解酶降解病原真菌的细胞壁。在温室条件下，粘质沙雷氏菌是罗氏菌核和立枯丝核菌的有效生防剂。10(5)或10(6)个菌落形成单位g~(-1)土壤的种群效果最好。粘质链霉菌悬浮液的淋洗和滴施对罗氏链霉菌的防治效果优于喷雾、混入土壤或种衣剂。根际细菌在根际的种群密度最高的部位是根的近端，在根尖处细菌密度显著下降，之后又增加。分离的沙雷氏菌具有降解几丁质的活性，能够从罗氏葡萄球菌的细胞壁中释放N-乙酰-D-氨基葡萄糖。将编码几丁质酶的基因克隆到大肠杆菌中，并将该酶唯一地从细菌中分泌到其生长培养基中。用克隆基因产生的部分纯化的几丁质酶喷洒罗氏链霉菌时，菌丝顶端迅速而广泛地破裂。该几丁质酶制剂在温室条件下能有效降低大豆上的罗氏链球菌病和棉花上的立枯丝核菌的发病率。当使用含有几丁质酶基因(PLCHIA)的质粒(PLCHIA)的活大肠杆菌细胞时，也获得了类似的效果。对几丁质酶等在植物病害防治中发挥重要作用的裂解酶进行基因工程，似乎可以提高生防剂的效果。
Bacterial antagonism, responsible for biological control, may operate by antiobiosis, competition or parasitism. Parasitism relies on lytic enzymes for the degradation of cell walls of pathogenic fungi. Serratia marcescens was found to be an efficient biocontrol agent of Sclerotium rolfsii and Rhizoctonia solani under greenhouse conditions. Populations of 10(5) or 10(6) colony forming units g-1 soil were the most effective. Drench and drip application of S. marcescens suspension were more effective in controlling S. rolfsii than spraying, mixing in soil or seed coating. The highest population density of the bacteria in the rhizosphere was found on the proximal portion of the root, decreasing significantly until the tips, where it increased again. The isolated Serratia, found to possess chitinolytic activity, was able to release N-acetyl D-glucosamine from cell walls of S. rolfsii. The gene coding for chitinase was cloned into Escherichia coli and the enzyme was uniquely excreted from the bacterium into its growth medium. When S. rolfsii was sprayed by partially purified chitinase produced by the cloned gene, rapid and extensive bursting of the hyphal tips was observed. This chitinase preparation was effective in reducing disease incidence caused by S. rolfsii in beans and R. solani in cotton, under greenhouse conditions. A similar effect was obtained when a viable E. coli cell, containing the plasmid with the chitinase gene (pLCHIA), was applied. It appears that genetic engineering of the lytic enzymes; such as chitinase, which play an important role in plant disease control, may improve the efficacy of biocontrol agents.