In Planta Localization of a B-1,4-Endoglucanase Secreted by Heterodera glycines

Xiaohong Wang, Diane Meyers, Yitang Yan, Thomas Baum, Geert Smant, Richard Hussey, and Eric Davis

ABSTRACT

Polyclonal sera specific to ß-1,4-endoglucanases (cellulases) synthesized in the subventral esophageal glands of the soybean cyst nematode, Heterodera glycines, were used to provide the first identification of a nematode esophageal gland protein that is secreted into host plant tissue. Sera generated to proteins encoded by HG-eng-1 and Hg-eng-2 (endoglucanase) genes did not cross-react with soybean root proteins on Western blots (immunoblots) or in immunofluorescence microscopy of noninoculated (control) soybean root sections.. In cross sections of soybean roots at 24 h after inoculation of roots with second-stage juveniles of H. glycines, HG-ENG-1 was localized within the nematode's subventral gland cells and was not detected in root tissue. HG-ENG-2 was localized within the subventral gland cells and was secreted from the juvenile's stylet into root cortical tissue at 24 h after inoculation of roots with second-stage juveniles of H. glycines.  HG-ENG-2 was localized along the juvenile's migratory path through the root cortex.