線蟲捕捉菌Arthrobotrys musiformis之幾丁質分解酵素蛋白生化特性分析；小花蔓澤蘭Mikania micrantha之本土真菌性病原生物防治潛力評估

Abstract

Purification and characterization of chitinase from nematode-trapping fungi Arthrobotrys musiformis Chitin, an essential component of exoskelton, cuticular layer, or cell wall of crustacean, insect, nematode or fungi, is a linear polymer of amino sugar N-acetyl glucosamine, linked by β-1,4-glycosidic linkage. Some reported nematode egg endoparasites with the aid of chitinase are able to penetrate the nematode egg shell. In a comparative study, we attempt to investigate the chitinase and encoding gene of Arthrobotry musiformis , a nematode trapping fungi. The chitinase in conducive culture medium was partially purified by anionic, hydrophobic and gel filtration high performance chromatography. The chitinase pI is around pH 3.4- pH 3.8, composed by three monomer, 29kDa, 33kDa and 38kDa in end purification step its activity, was proved both in gel or by spectrophotometry. Due to the low quantity of chitinase in the last purified fractionation, try to decode the N-terminal amino acid residue sequence fail, which further hinders the possibility for primer design to clone the encoding gene. Fungal pathogens of invaded Mikania micrantha biocontrol appraisal Investigation of the domestic fungal enemies against the invaded Mikania micrantha were carried out from May 2003 to June 2004 in more than 20 counties islandwide. Of totally 297 fungal strains have been isolated, 13 genera represent Acremonium , Alternaria , Colletotrichum , Curcularia , Cyllindrocladium , Fusarium , Leptosphaeria , Macrophomina , Nigrospora , Pestalotiopsis . Phoma . Phomopsis . Phyllostica genera were recovered. Of them, several Colletotrichum spices which invaded the leaf and stem of M. micrantha resulted in leaf spot and canker were mostly often encountered, and less than by Phomopsis, Phoma and Macrophomina. Some of these fungal pathogens can simultaneously infected M. micrantha and cause endemic. Inoculation of the invaded weed with the spore suspension in greenhouse, some Colletotrichum, Phomopsis, Phoma or Macrophomina spices can cause spot, necrosis, canker or blight of varied degree severity in leaves or stems. But the spraying culture filtrates cannot cause any symptoms, which preliminarily exclude the involvement of toxin in disease development.