Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
Mol Biol Rep. 2010 Oct;37(7):3583-91. doi: 10.1007/s11033-010-0007-4. Epub 2010 Mar 4.
Previous studies have shown the role of melanized appressoria in the pathogenicity of various fungi. Diplocarpon rosae is a worldwide outdoor fungal pathogen of rose plants causing black spot disease of rose leaves. To fully understand how this fungus colonizes its host, which is critical for the development of an efficient and sustainable disease management program, we studied the fungal (especially the appressoria) structures of D. rosae in detail at an early stage of infection. Using both microscopic and biochemical analyses, we observed strong melanized appressoria formation localized at the point of D. rosae penetration, which forms the pathogen-plant interface. Treatment of infected plants with melanin biosynthesis inhibitors (MBIs) prevented melanization of D. rosae appressoria and positively correlated with significant reductions in black spot disease symptoms, suggesting that melanization of appressoria might be a critical factor for the pathogenicity of D. rosae. Our findings were confirmed and validated by the lack of melanized appressorial ring formation on an artificial surface and on a D. rosae-non host plant system, Arabidopsis thaliana. Our findings suggest that localized melanization of appressoria is a crucial factor for the pathogenicity of D. rosae and treatment of the fungus with MBIs seems to be a promising disease management alternative for black spot disease of roses.
先前的研究表明，黑化的附着胞在各种真菌的致病性中起着重要作用。玫瑰球腔菌是一种世界性的户外真菌病原体，可引起玫瑰叶片的黑斑病。为了充分了解这种真菌如何定殖其宿主，这对于开发高效和可持续的疾病管理计划至关重要，我们在感染的早期阶段详细研究了 D.rosae 的真菌（特别是附着胞）结构。通过微观和生化分析，我们观察到强烈的黑化附着胞形成，定位于 D.rosae 穿透的点，这形成了病原体与植物的界面。用黑色素生物合成抑制剂 (MBI) 处理感染的植物可以阻止 D.rosae 附着胞的黑化，并与黑斑病症状的显著减少呈正相关，这表明黑化的附着胞可能是 D.rosae 致病性的关键因素。我们的发现通过在人工表面和 D.rosae-非宿主植物系统拟南芥上缺乏黑化附着胞环的形成得到了证实和验证。我们的研究结果表明，附着胞的局部黑化是 D.rosae 致病性的关键因素，用 MBI 处理真菌似乎是一种有前途的玫瑰黑斑病的疾病管理替代方法。
