Purification and characterization of alkaline pectin lyase from a newly isolated Bacillus clausii and its application in elicitation of plant disease resistance.
Alkaline pectin lyase (PNL) shows potential as a biological control agent against several plant diseases. We isolated and characterized a new Bacillus clausii strain that can produce 4,180 U/g of PNL using sugar beet pulp as a carbon source and inducer. The PNL was purified to apparent homogeneity using ultrafiltration, ammonium sulfate fractionation, DEAE Sepharose Fast Flow, and Sephadex G-75 gel filtration. The purified PNL was found to be a monomeric protein with a molecular weight of 35 kDa, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). It demonstrated optimal activity with K(m) of 0.87 mg/ml at pH 10.0 and 60 °C. The enzyme is stable in the pH range of 8.0-10.0 and temperature ≤40 °C. Ca(2+) was found to stimulate the enzymatic activity of the PNL by up to 410 %. Mass spectrometric results gave 38 % match coverage with pectate lyase from B. clausii KSM-K16 (gi|56961845). The PNL was found to elicit disease resistance in cucumber seedlings, suggesting that it may have applications in biocontrol and sustainable agriculture.
College of Arts and Sciences of Beijing Union University, Beijing 100191, China.
Zuming
Z
Li
Zhihui
Z
Bai
Baoguo
B
Zhang
Baojv
B
Li
Bo
B
Jin
Michael
M
Zhang
Francis
F
Lin
Hongxun
H
Zhang
D000595:Amino Acid Sequence; D001407:Bacillus / Q000737:chemistry / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000494:pharmacology; D001681:Biological Assay; D018553:Cucumis sativus / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology; D060467:Disease Resistance; D004795:Enzyme Stability; D008969:Molecular Sequence Data; D010802:Phylogeny; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D011133:Polysaccharide-Lyases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000494:pharmacology
D001426:Bacterial Proteins; D011133:Polysaccharide-Lyases; C027349:pectin lyase