Institute of Biotechnology, National Dong-Hwa University, Hualien 97401, Taiwan, R.O.C.
Phytopathology. 2012 Nov;102(11):1054-63. doi: 10.1094/PHYTO-11-11-0315.
ABSTRACT Previous studies have shown that the extracellular proteins of Trichoderma harzianum ETS 323 grown in the presence of deactivated Botrytis cinerea in culture include a putative l-amino acid oxidase and have suggested the involvement of this enzyme in the antagonistic mechanism. Here, we hypothesized that the mycoparasitic process of Trichoderma spp. against B. cinerea involves two steps; that is, an initial hyphal coiling stage and a subsequent hyphal coiling stage, with different coiling rates. The two-step antagonism of T. harzianum ETS 323 against B. cinerea during the mycoparasitic process in culture was evaluated using a biexponential equation. In addition, an l-amino acid oxidase (Th-l-AAO) was identified from T. harzianum ETS 323. The secretion of Th-l-AAO was increased when T. harzianum ETS 323 was grown with deactivated hyphae of B. cinerea. Moreover, in vitro assays indicated that Th-l-AAO effectively inhibited B. cinerea hyphal growth, caused cytosolic vacuolization in the hyphae, and led to hyphal lysis. Th-l-AAO also showed disease control against the development of B. cinerea on postharvest apple fruit and tobacco leaves. Furthermore, an apoptosis-like response, including the generation of reactive oxygen species, was observed in B. cinerea after treatment with Th-l-AAO, suggesting that Th-l-AAO triggers programmed cell death in B. cinerea. This may be associated with the two-step antagonism of T. harzianum ETS 323 against B. cinerea.
摘要 先前的研究表明，在含有失活的 Botrytis cinerea 的培养物中生长的 Trichoderma harzianum ETS 323 的细胞外蛋白包括一种假定的 l-氨基酸氧化酶，并表明该酶参与了拮抗机制。在这里，我们假设 Trichoderma spp. 对 B. cinerea 的菌寄生过程涉及两个步骤，即初始菌丝卷曲阶段和随后的菌丝卷曲阶段，具有不同的卷曲速率。使用双指数方程评估了 T. harzianum ETS 323 在培养物中的菌寄生过程中对 B. cinerea 的两步拮抗作用。此外，从 T. harzianum ETS 323 中鉴定出一种 l-氨基酸氧化酶（Th-l-AAO）。当 T. harzianum ETS 323 与失活的 B. cinerea 菌丝一起生长时，Th-l-AAO 的分泌增加。此外，体外测定表明 Th-l-AAO 可有效抑制 B. cinerea 菌丝生长，导致菌丝细胞质空泡化，并导致菌丝裂解。Th-l-AAO 还表现出对采后苹果果实和烟草叶片上 B. cinerea 发育的疾病控制作用。此外，在用 Th-l-AAO 处理后，B. cinerea 中观察到类似凋亡的反应，包括活性氧的产生，表明 Th-l-AAO 触发了 B. cinerea 中的程序性细胞死亡。这可能与 T. harzianum ETS 323 对 B. cinerea 的两步拮抗作用有关。
