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Characteristics and Function of the Chitin Binding Protein from Xenorhabdus nematophila

[ Vol. 26 , Issue. 6 ]

Author(s):

Jia Liu, Ping Song, Jie Zhang, Ziyan Nangong, Xiaobei Liu, Yue Gao and Qinying Wang*   Pages 414 - 422 ( 9 )

Abstract:


Background: Genome sequence analysis (GenBank access No.: FN667742.1) shows that Xenorhabdus nematophila ATCC19061 contains one gene (Xn-cbp) encoding chitin binding protein (Xn-CBP).

Objective: The present work aims to clarify the characteristics and function of Xn-CBP from X. nematophila HB310.

Methods: In this study, the Xn-cbp gene was cloned and expressed in Escherichia coli BL21 (DE3). Substrate binding assays were performed to explain the ability of Xn-CBP combined with the polysaccharide. The insecticidal toxicity of Xn-CBP against the second-instar larvae of Helicoverpa armigera was determined by feeding method. Besides, the antifungal activity of Xn-CBP against Coniothyrium diplodiella, Verticillium dahlia, and Fusarium oxysporum was tested by spore germination assay and hyphal extension assay.

Results: Xn-CBP encoded 199 amino acids with a calculated mass of 28 kDa, which contained a signal peptide and a chitin binding domain. The Bmax and Kd values of Xn-CBP to colloidal chitin were 2.46 and 4.08, respectively. Xn-CBP had insecticidal activity against the H. armigera with a growth inhibition rate of 84.08%. Xn-CBP had the highest spore germination inhibitory effect on C. diplodiella with the inhibition rate of 83.11%. The hyphal growth inhibition rate of Xn-CBP to F. oxysporum, 41.52%, was higher than the other two fungi.

Conclusion: The Xn-CBP had the highest binding ability to colloidal chitin and it showed insecticidal activity and antifungal activity. The present study laid a foundation for further exploitation and utilization of X. nematophila.

Keywords:

Antifungal activity, chitin binding protein, insecticidal activity, substrate binding, Xenorhabdus nematophila, spore germination.

Affiliation:

College of Plant Protection, Agricultural University of Hebei, Baoding, 071001, College of Plant Protection, Agricultural University of Hebei, Baoding, 071001, Luanping, State-owned Forestry Farm Management of Chengde City, Chengde 068250, College of Plant Protection, Agricultural University of Hebei, Baoding, 071001, College of Plant Protection, Agricultural University of Hebei, Baoding, 071001, College of Plant Protection, Agricultural University of Hebei, Baoding, 071001, College of Plant Protection, Agricultural University of Hebei, Baoding, 071001

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