A coffee berry borer (Hypothenemus hampei) genome assembly reveals a reduced chemosensory receptor gene repertoire and male-specific genome sequences.

Coffee berry borer-CBB (Hypothenemus hampei) is a globally important economic pest of coffee (Coffea spp.). Despite current insect control methods for managing CBB, development of future control strategies requires a better understanding of its biology and interaction with its host plant. Towards this objective, we performed de novo CBB genome and transcriptome sequencing, improved CBB genome assembly and predicted 18,765 protein-encoding genes. Using genome and transcriptome data, we annotated the genes associated with chemosensation and found a reduced gene repertoire composed by 67 odorant receptors (ORs), 62 gustatory receptors (GRs), 33 ionotropic receptors (IRs) and 29 odorant-binding proteins (OBPs). In silico transcript abundance analysis of these chemosensory genes revealed expression enrichment in CBB adults compared with larva. Detection of differentially expressed chemosensory genes between males and females is likely associated with differences in host-finding behavior between sexes. Additionally, we discovered male-specific genome content and identified candidate male-specific expressed genes on these scaffolds, suggesting that a Y-like chromosome may be involved in the CBB's functional haplodiploid mechanism of sex determination.

Antagonism of plant growth promoting rhizobacteria against the causal agent of the vascular wilting of tomato / Antagonismo de rizobacterias promotoras del crecimiento vegetal contra el agente causal de la marchitez vascular del tomate

ABSTRACT Use of biotechnological potential of native microorganisms as bio-inputs is having a great impact on agricultural systems. Plant Growth Promoting Rhizobacteria (PGPR), in addition to their beneficial effect on plant growth and on the availability of soil elements, also have an antagonistic effect against different pathogens. In this study, growth promotion mechanisms with emphasis on the antagonism of PGPR isolated from sugarcane and tomato crops were evaluated. Antagonism against Fusarium oxysporum f.sp lycopersici (Fol) was determined by dual tests, inhibition of germination and production of chitinases and endoglucanases. 52 isolates were evaluated and according to their results in dual tests 10 were selected for further analysis. Isolate GIBI127 showed the best percentage of Inhibition Germination (IG) of Fol (59.29%). Then, a selection index was calculated using results from gi, dual tests and growth promotion mechanisms to select five best isolates. Finally, these bacteria were evaluated for chitinases and endoglucanases production using Miller's method. As a result, strain GIBI419 (Burkholderia cepacia) showed a higher production of these enzymes. Selected isolates have antagonistic potential along with plant growth promotion characteristics, which can be used for the development of microbial inoculants which allow the establishment of agricultural systems for tomato cultivation that are sustainable, efficient, and environmentally friendly.

RESUMEN El uso del potencial biotecnológico de microorganismos nativos como bioinsumos está teniendo un gran impacto en los sistemas agrícolas. Las rizobacterias promotoras del crecimiento vegetal (PGPR), además de su efecto benéfico en el crecimiento de las plantas y de facilitar la disponibilidad de elementos del suelo, también tienen un efecto antagónico frente a diferentes patógenos. En este estudio se evaluaron mecanismos de promoción del crecimiento con énfasis en el antagonismo de bacterias PGPR aisladas de cultivos de caña de azúcar y tomate. El antagonismo contra Fusarium oxysporum f.sp lycopersici (Fol) se determinó mediante pruebas duales, inhibición de la germinación y producción de quitinasas y endoglucanasas. Se evaluaron 52 aislamientos y según sus resultados en pruebas duales se seleccionaron 10 para su posterior análisis. El aislado GIBI127 mostró el mejor porcentaje de Inhibición de la Germinación (IG) de Fol (59,29%). Luego, se calculó un índice de selección utilizando los resultados de IG, pruebas duales y mecanismos de promoción del crecimiento para seleccionar los cinco mejores aislamientos. Finalmente, estas bacterias fueron evaluadas en la producción de quitinasas y endoglucanasas utilizando el método de Miller. Como resultado, se evidenció la cepa GIBI419 (Burkholderia cepacia) como la de mayor producción de estas enzimas. Los aislados seleccionados tienen un potencial antagónico junto con características de promoción del crecimiento de las plantas, que pueden usarse para el desarrollo de inoculantes microbianos que permitan el establecimiento de sistemas agrícolas para el cultivo de tomate que sean sostenibles, eficientes y amigables con el medio ambiente.

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

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-ß-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.