A Novel L-Amino Acid Oxidase from Trichoderma harzianum ETS 323 Associated with Antagonism of Rhizoctonia solani

作者：Yang Chia Ann; Cheng Chi Hua; Lo Chaur Tsuen; Liu Shu Ying; Lee Jeng Woei^*; Peng Kou Cheng

来源：Journal of Agricultural and Food Chemistry, 2011, 59(9): 4519-4526.

DOI：10.1021/jf104603w

• L-amino acid oxidase
• flavoprotein
• Trichoderma harzianum
• Rhizoctonia solani
• biocontrol

Trichoderma spp. are used as biocontrol agents against phytopathogens such as Rhizoctonia solani, but their biocontrol mechanisms are poorly understood. A novel L-amino oxidase (Th-LAAO) was identified from the extracellular proteins of Trichoderma harzianum ETS 323. Here, we show a FAD-binding glycoprotein with the best substrate specificity constant for L-phenylalanine. Although the amino acid sequence of Th-LAAO revealed limited homology (16-24%) to other LAAO members, a highly conserved FAD-binding motif was identified in the N-terminus. Th-LAAO was shown to be a homodimeric protein, but the monomeric form was predominant when grown in the presence of deactivated Rhizoctonia solani. Furthermore, in vitro assays demonstrated that Th-LAAO had an antagonistic effect against Rhizoctonia solani and a stimulatory one on hyphal density and sporulation in T. harzianum ETS 323. These findings further our understanding of T. harzianum as a biocontrol agent and provide insight into the biological function of L-amino acid oxidase.

• 出版日期2011-5-11
• 单位东华大学; 河北医科大学