Zhang Qi, Bai Gang, Yang Wenbo, Li Haiyan, Xiong Huilong
Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China.
Biosci Biotechnol Biochem. 2006 Nov;70(11):2727-32. doi: 10.1271/bbb.60330. Epub 2006 Nov 7.
The pine wilt disease caused by Bursaphelenchus xylophilus (BX), also known as the pine wood nematode (PWN), is the most devastating disease of pine trees. In this work, a high molecular weight B. xylophilus cellulase antigen (BXCa) was purified from total homogenates of nematodes. BXCa was found to be able to hydrolyze carboxymethyl cellulose (CMC) efficiently (155.65 U/mg) and to have an approximate molecular mass of 58.9 kDa. We harvested anti-BXCa antibodies and performed immunocytochemical assays, which revealed the localization of cellulase pools in the esophageal gland cells of the PWN. It was also discovered that cellulase was secreted from the stylet and was used to hydrolyze cellulose to facilitate the PWN entering host cells. These results are consistent with other plant parasitical nematodes. Interestingly, strong fluorescence signals from cellulase staining were observed in tracheid cells in naturally infected pine wood, in addition to ray cells and the resin canal zone. These results strongly suggest that the cellulase released by the PWN is one of the pathogenic substances of pine wilt disease and is responsible for the development of the early symptoms of the disease.
由松材线虫（Bursaphelenchus xylophilus，BX）引起的松树萎蔫病，又称松材线虫病，是松树最具毁灭性的病害。在这项研究中，从线虫的总匀浆中纯化出一种高分子量的松材线虫纤维素酶抗原（BXCa）。发现BXCa能够高效水解羧甲基纤维素（CMC）（155.65 U/mg），其近似分子量为58.9 kDa。我们收获了抗BXCa抗体并进行了免疫细胞化学分析，结果揭示了纤维素酶池在松材线虫食道腺细胞中的定位。还发现纤维素酶从口针分泌出来，用于水解纤维素以促进松材线虫进入宿主细胞。这些结果与其他植物寄生线虫一致。有趣的是，除了射线细胞和树脂道区域外，在自然感染的松木中的管胞细胞中也观察到了纤维素酶染色产生的强烈荧光信号。这些结果有力地表明，松材线虫释放的纤维素酶是松树萎蔫病的致病物质之一，并且与该病早期症状的发展有关。
