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期 刊 ：植物保护学报 2007年

关键词：菌株AAEC05-3；毒素；致病力；稗草；除草活性；

Keywords:Strain AAEC05-3, phytotoxin, pathogenicity, Echinochloa crus-galli, herbicide activity,

摘 要 ：为了确定稗草生防菌狭卵链格孢Alternaria augustiovoidea菌株AAEC05-3防除稗草的潜力,研究了其孢子接种浓度和喷液量对该菌株致病力的影响及菌株的寄主专化性。结果表明,接种浓度和喷液量显著影响菌株的致病力,接种浓度达到1×10⁶个孢子/mL时,菌株对稗草生长抑制率达到85.32%。150mL/m²的喷液量对稗草的防除效果达到91.84%。进一步增加喷液量,菌株对稗草的生长抑制率降低。水稻、大豆、向日葵和绿豆对菌株不敏感,而小麦、玉米和谷子等作物对菌株较敏感,表明菌株寄主相对专一。通过柱层析法和高效液相色谱法分离到一除草活性化合物,化合物的最大紫外吸收峰在243nm和281.5nm。试验结果表明,采用C18柱并以甲醇∶ 水(v/v) ＝60∶ 40为流动相能较好地分离纯化该毒素。在100mg/L浓度下,毒素可完全抑制稗草种子的萌发。盆栽试验结果表明,在100mg/L浓度下,该毒素对稗草幼苗生长抑制率达76%。表明菌株AAEC05-3可有效防除稗草,具有微生物除草剂开发潜力。

Abstract:Barnyard grass, Echinochloa crus-galli, is one of the notorious weeds worldwide. To explore the potential of Alternaria augustiovoidea strain AAEC05-3 as mycoherbicide to control barnyard grass, the effect of inoculum potential and spray volume on the pathogenicity of strain AAEC05-3 to barnyard grass and host specificity of strain were studied using pot experiment. The inoculum potential and spray volume significantly affected the pathogenic efficiency. When the barnyard grass was inoculated with 1×10⁶ spore/mL, the strain inhibited the growth of barnyard grass at 85.32%. At the spray volume up to 150mL/m², the inhibition of strain against growth of barnyard grass arrived at 91.84%. At spray volumes over 150mL/m², the inhibition of strain AAEC05-3 to growth of barnyard grass show a decreasing utility. The strain did not infect rice, soybean, sunflower and mung bean,then wheat, maize and yellow corn were susceptible to the strain. The strain has the characteristic of host selective-specificity. One herbicide activity compound was isolated from the crude toxin by column chromatography and high performance liquid chromatography (HPLC). The compound has an ultraviolet absorbent peak at 243nm and 281.5nm. The phytotoxin could be isolated by using C18 column and gradient elution of methanol/H₂O (60∶ 40). The phytotoxin could completely inhibit seed germination of barnyard grass at concentration of 100mg/L. At concentration of 100mg/L, the growth of barnyard grass was strongly inhibited by the phytotoxin and the inhibition achieved at 76%. It was indicated that the strain AAEC05-3 could be used as potential mycoherbicide against barnyard grass.

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