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Cloning and Characterization of Pectate Lyases Expressed in the Esophageal Gland of the Pine Wood Nematode Bursaphelenchus xylophilus

March 2006 , Volume 19 , Number  3
Pages  280 - 287

Taisei Kikuchi , 1 Hajime Shibuya , 1 Takuya Aikawa , 1 and John T. Jones 2

1Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan; 2Plant-Pathogen Interactions Programme, Scottish Crop Research Institute, Invergowrie, Dundee, DD2 5DA, U.K.

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Accepted 3 November 2005.

Two pectate lyase genes (Bx-pel-1 and Bx-pel-2) were cloned from the pine wood nematode, Bursaphelenchus xy-lophilus. The deduced amino acid sequences of these pectate lyases are most similar to polysaccharide lyase family 3 proteins. Recombinant BxPEL1 showed highest activity on polygalacturonic acid and lower activity on more highly methylated pectin. Recombinant BxPEL1 demonstrated full dependency on Ca2+ for activity and optimal activity at 55°C and pH 8 to 10 like other pectate lyases of polysaccharide lyase family 3. The protein sequences have predicted signal peptides at their N-termini and the genes are expressed solely in the esophageal gland cells of the nematode, indicating that the pectate lyases could be secreted into plant tissues to help feeding and migration in the tree. This study suggests that pectate lyases are widely distributed in plant-parasitic nematodes and play an important role in plant-nematode interactions.

Additional keywords: horizontal gene transfer.

© 2006 The American Phytopathological Society