Szekeres A, Hatvani L, Leitgeb B
Department of Microbiology, Faculty of Sciences, University of Szeged, Hungary.
Acta Microbiol Immunol Hung. 2007 Mar;54(1):23-34. doi: 10.1556/AMicr.54.2007.1.3.
A total of 36 UV-induced mutants with altered colony morphology were isolated from strain Trichoderma harzianum T334, a potential biocontrol agent against plant pathogenic fungi with the ability to produce constitutively low levels of chitinases. The level of constitutive beta-1,4-N-acetyl-glucosaminidase production in standing and shaken cultures under non-inductive conditions was tested in mutants and compared to that of the parental strain. About 30% of the mutants showed significantly increased levels of enzyme production, with strain T334 col26a being the best producer. This mutant and the parental strain were subjected to in vitro confrontation assays with plant pathogenic Fusarium culmorum, Pythium debaryanum and Rhizoctonia solani strains. The mutant derivative could be characterized by significantly higher biocontrol index values than the parental strain in each experiment, suggesting, that mutants with improved constitutive extracellular chitinase secretion could be applied for biocontrol purposes against fungal plant pathogens.
从哈茨木霉T334菌株中总共分离出36个紫外线诱导的菌落形态发生改变的突变体，该菌株是一种潜在的植物病原真菌生物防治剂，能够组成性地产生低水平的几丁质酶。在突变体中测试了非诱导条件下静置培养和振荡培养时组成性β-1,4-N-乙酰葡糖胺酶的产生水平，并与亲本菌株进行了比较。约30%的突变体显示酶产生水平显著提高，其中菌株T334 col26a是最佳生产者。将该突变体和亲本菌株与植物病原性禾谷镰刀菌、德巴利腐霉和立枯丝核菌菌株进行体外对峙试验。在每个实验中，突变体衍生物的生物防治指数值显著高于亲本菌株，这表明具有改善的组成性细胞外几丁质酶分泌的突变体可用于防治真菌性植物病原体。
