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Mechanisms involved in the cold tolerant Trichoderma atroviride biocontrol.

机译：耐冷木霉阿特罗韦德生物防治的机制。

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摘要

Trichoderma atroviride is a cold tolerant fungus that parasitizes a wide range of plant pathogenic fungi. The mechanisms involved in biocontrol by T. atroviride are only partially understood. This research evaluated the effect of four different groups of plant pathogenic fungi (Botrytis cinerea, Phytophthora capsici, Rhizoctonia solani and Sclerotinia sclerotiorum) on enzyme expression at 22°C and 7°C. The enzymes expressed (proteinase and endo-beta-1,3-glucanase) were purified and characterized, and three 73 kDa N-acetyl-beta- D-glucosaminidase genes from three different T. atroviride biotypes were sequenced. The R-1,6-glucanase profiles and the regulation of N-acetyl-beta-D-glucosaminidases by plant pathogenic fungi were also studied. I document the production of N-acetyl-beta-D-glucosaminidase, exochitinase, endochitinase, beta-1,3-glucanase, beta-1,6-glucanase and proteinase by T. atroviride at room temperature. The timing of enzyme expression was pathogen dependent. A high concentration of glucose repressed the expression of glucanases, but had no effect on the expression of N-acetyl-beta-D-glucosaminidase. At 7°C, T. atroviride produced the same enzymes as at room temperature except beta-1,6-glucanase. The total activities of the chitinases increased over a 30 day incubation period while the expression of glucanases and proteinase depended on the inducer. A new 18.8 kDa serine proteinase and a new 77 kDa endo-beta-1,3-glucanase were purified to electrophoretical homogeneity. These two purified enzymes showed strong antifungal activity by inhibiting conidial germination of Botrytis cinerea. Three 73 kDa N-acetyl-beta-D-glucosaminidase genes were sequenced from T. atroviride biotypes 861, 453 and 603. Gene sequences of the enzyme from the T. atroviride biotypes are different from the published gene sequence of T. harzianum . This indicates that the N-acetyl-beta-D-glucosaminidase sequence can be used to differentiate the species and isolates of Trichoderma. The expression of beta-1,6-glucanase is complex and at least three different sizes of beta-1,6-glucanase were detected from T. atroviride. The expression of beta-1,6-glucanase varied with carbon source and pH. Mycelia of plant pathogen regulated the expression of N-acetyl-beta-D-glucosaminidase. Two different sizes of N-acetyl-beta-D-glucosaminidase were detected when T. atroviride was grown with S. sclerotiorum and its filtrates. Only one N-acetyl-beta- D-glucosaminidase was detected with other pathogens, autoclaved mycelia or glucose. The expression of a 73 kDa N-acetyl-beta-D-glucosaminidase was contact-dependent and regulated by an extracellular factor.
机译：木霉Atroviride是一种耐寒真菌，可寄生多种植物致病真菌。仅通过部分理解就了解了阿托韦德衣原体生物防治中涉及的机制。这项研究评估了四种不同的植物病原真菌（灰葡萄孢菌，疫霉菌，茄子枯萎病菌和核盘菌菌核菌）在22°C和7°C下对酶表达的影响。纯化和鉴定了表达的酶（蛋白酶和内切β-1,3-葡聚糖酶），并对来自三种不同阿奇韦德生物型的三种73 kDa N-乙酰基-β-D-葡糖胺酶基因进行了测序。还研究了R-1,6-葡聚糖酶的概况以及植物病原真菌对N-乙酰基-β-D-氨基葡萄糖苷酶的调控。我记录了在室温下由阿魏韦球菌产生的N-乙酰基-β-D-氨基葡萄糖苷酶，外切酶，内切几丁质酶，β-1,3-葡聚糖酶，β-1,6-葡聚糖酶和蛋白酶。酶表达的时间取决于病原体。高浓度的葡萄糖抑制了葡聚糖酶的表达，但对N-乙酰基-β-D-葡萄糖苷酶的表达没有影响。在7°C时，除β-1,6-葡聚糖酶外，阿托韦韦特罗德菌产生的酶与室温相同。几丁质酶的总活性在30天的孵育期内增加，而葡聚糖酶和蛋白酶的表达取决于诱导物。一个新的18.8 kDa丝氨酸蛋白酶和一个新的77 kDa内-beta-1,3-葡聚糖酶被纯化到电泳均质。这两种纯化的酶通过抑制灰葡萄孢菌的分生孢子萌发而显示出强大的抗真菌活性。从A.trotroide生物型861、453和603测序了3个73 kDa N-乙酰基-β-D-氨基葡萄糖苷酶基因。来自A.trotroide生物型的酶基因序列与已发表的T. harzianum基因序列不同。这表明N-乙酰基-β-D-氨基葡萄糖苷酶序列可用于区分木霉属的种和分离株。 β-1,6-葡聚糖酶的表达很复杂，并且从阿育韦德杆菌中检测到至少三种不同大小的β-1,6-葡聚糖酶。 β-1,6-葡聚糖酶的表达随碳源和pH的变化而变化。植物病原体的菌丝体调节了N-乙酰基-β-D-氨基葡萄糖苷酶的表达。当用硬核假单胞菌及其滤液培养A.troviride时，检测到两种不同大小的N-乙酰基-β-D-氨基葡萄糖苷酶。在其他病原体，高压灭菌的菌丝体或葡萄糖中，仅检测到一种N-乙酰基-β-D-氨基葡萄糖苷酶。 73 kDa N-乙酰基-β-D-氨基葡萄糖苷酶的表达是接触依赖性的，并受细胞外因子的调控。

著录项

  • 作者

    Cheng, Mingyuan.;

  • 作者单位

    University of Alaska Fairbanks.;

  • 授予单位 University of Alaska Fairbanks.;
  • 学科 Biology Microbiology.; Agriculture Plant Pathology.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 153 p.
  • 总页数 153
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 微生物学;植物病理学;
  • 关键词

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