Open Access Research article

Cloning and expression of an endo-1,4-β-xylanase from the coffee berry borer, Hypothenemus hampei

Beatriz Padilla-Hurtado1, Claudia Flórez-Ramos2, Carolina Aguilera-Gálvez1, Jefferson Medina-Olaya1, Andrés Ramírez-Sanjuan1, José Rubio-Gómez1 and Ricardo Acuña-Zornosa1*

Author Affiliations

1 Disciplina de Mejoramiento Genético, Centro Nacional de Investigaciones de Café (CENICAFE), Planalto, Km 4 vía antigua Chinchiná-Manizales, Chinchiná, Colombia

2 Disciplina de Fisiología Vegetal; Centro Nacional de Investigaciones de Café (CENICAFE), Planalto, Km 4 vía antigua Chinchiná-Manizales, Chinchiná, Colombia

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BMC Research Notes 2012, 5:23  doi:10.1186/1756-0500-5-23

Published: 10 January 2012

Abstract

Background

The coffee berry borer, Hypothenemus hampei, reproduces and feeds exclusively on the mature endosperm of the coffee seed, which has a cell wall composed mainly of a heterogeneous mixture of hemicellulose polysaccharides, including arabinoxylans. Xylanases are digestive enzymes responsible for the degradation of xylan based polymers, hydrolyzing them into smaller molecules that are easier to assimilate by insects. We report the cloning, expression and enzymatic characterization of a xylanase gene that was identified in the digestive tract of the coffee berry borer.

Methods

The complete DNA sequence encoding a H. hampei xylanase (HhXyl) was obtained using a genome walking technique in a cDNA library derived from the borer digestive tract. The XIP-I gene was amplified from wheat (Triticum aestivum variety Soisson). A Pichia pastoris expression system was used to express the recombinant form of these enzymes. The xylanase activity and XIP-I inhibitory activity was quantified by the 3,5-dinitrosalicylic (DNS). The biological effects of XIP-I on borer individuals were evaluated by providing an artificial diet enriched with the recombinant XIP-I protein to the insects.

Results

The borer xylanase sequence contains a 951 bp open reading frame that is predicted to encode a 317-amino acid protein, with an estimated molecular weight of 34.92 kDa and a pI of 4.84. Bioinformatic analysis revealed that HhXyl exhibits high sequence homology with endo-β-D-xylanases of Streptomyces bingchenggensis from glycosyl hydrolase 10 (GH10). The recombinant xylanase showed maximal activity at pH 5.5 and 37°C. XIP-I expressed as a recombinant protein inhibited HhXyl activity in vitro and caused individual H. hampei mortality in bioassays when included as a supplement in artificial diets.

Conclusion

A xylanase from the digestive tract of the coffee berry borer was identified and functionally characterized. A xylanase inhibitor protein, XIP-I, from wheat was shown to be a potent inhibitor of this xylanase, suggesting that its deployment has potential as a strategy to control coffee berry borer colonization of coffee plants.