VIEW ARTICLE

Physiology and Biochemistry

Influence of Heterodera glycines on Leghemoglobins of Soybean Nodules. Jeng- sheng Huang, Associate professor, Department of Plant Pathology, North Carolina State University, Raleigh 27650; Kenneth R. Barker, professor, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Phytopathology 73:1002-1004. Accepted for publication 8 February 1983. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-1002.

Four- to five-day-old soybean seedlings were dipped in a suspension containing 10⁹ colony-forming units of Rhizobium japonicum and transplanted, seven per 20-cm-diameter clay pot containing a soil:sand (1:1, v/v) mixture. Three days after transplanting, some pots were inoculated with 2,500 juveniles of race 1 of Heterodera glycines per plant; other uninoculated pots served as controls. Plants were harvested 5 wk after nematode inoculation. Nodules harvested from nematode-infected soybeans had lower fresh weights per plant and lower specific nitrogenase activity (micromoles of C₂H₄ formed per gram of nodules per hour) as assayed by the acetylene reduction procedure. Leghemoglobins (Lb) were extracted from soybean nodules, purified in a Sephadex G-15 column, and separated into four components, Lba, Lbb, Lbc, and Lbd by DEAE-cellulose column chromatography. Leghemoglobin content per gram of nodule was lower in nematode-infected soybeans than in the nodules of control plants. Lba from nematode-infected and control plants had similar ultraviolet and visible light spectra and gel electrophoresis profiles, as did the Lbb, Lbc, and Lbd. The ratio of Lbc/Lba, however, was higher from nematode-infected soybeans than from control plants. The significance of this difference is discussed.