title: Isolation and characterization of agar-degrading Paenibacillus spp. associated with the rhizosphere of spinach.
abstract: Agar-degrading bacteria in spinach plant roots cultivated in five soils were screened, and four strains of Paenibacillus sp. were isolated from roots cultivated in three soils. The agar-degrading bacteria accounted for 1.3% to 2.5% of the total bacteria on the roots. In contrast, no agar-degrading colony was detected in any soil (non-rhizosphere soil samples) by the plate dilution method, and thus these agar-degrading bacteria may specifically inhabit plant roots. All isolates produced extracellular agarase, and could grow using agar in the culture medium as the sole carbon source. Zymogram analyses of agarase showed that all four isolates extracellularly secreted multiple agarases (75-160 kDa). In addition, the isolates degraded not only agar but also various plant polysaccharides, i.e., cellulose, pectin, starch, and xylan.
authors.affiliation: Laboratory of Soil Microbiology, Department of Plant Resources, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Akifumi
authors.initials: A
authors.lastname: Hosoda
authors.forename: Masao
authors.initials: M
authors.lastname: Sakai
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Kanazawa
mesh_terms: D000362:Agar / Q000378:metabolism*; D001419:Bacteria / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000378:metabolism; D010802:Phylogeny; D011134:Polysaccharides / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics / Q000302:isolation & purification; D012988:Soil Microbiology; D018724:Spinacia oleracea / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D011134:Polysaccharides; D012335:RNA, Ribosomal; D000362:Agar; D006026:Glycoside Hydrolases; C019624:agarase