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.

The sensory quality of coffee begins in the plant tree, where the characteristics of the fruits define the composition of the chemical precursors, which can be preserved or transformed in stages such as mucilage fermentation, and are the basis for the beverage attributes. This study evaluated three degrees of maturity and their comportment in fermentation under two temperatures and two-time extensions, establishing their sensory and chemical characteristics through analytical techniques such as liquid and gas chromatography. The effect of the prolongation time was evidenced for oxalic, quinic, citric acids, glucose, and fructose in two of the three degrees of maturity evaluated. The interaction of the process conditions increased the content of fructose and glucose in one of the states, being more evident at 20 °C. The treatments associated with the most advanced stage of maturity and with higher temperature decreased the scores of five sensory attributes and the fructose content increased by 48.50% and the glucose content increased by 47.31%. Advanced stages of maturity preserve quality standards, but their performance can be differential in postharvest processes, especially in those that are beyond the standards, such as those involving prolongations in different processes such as fermentation.

Background: The study of coffee polysaccharides-degrading enzymes from the coffee berry borerHypothenemus hampei,has become an important alternative in the identification for enzymatic inhibitors that can be used as an alternative control of this dangerous insect. We report the cloning, expression and biochemical characterization of a mannanase gene that was identified in the midgut of the coffee berry borer and is responsible for the degradation of the most abundant polysaccharide in the coffee bean.Methods: The amino acid sequence of HhMan was analyzed by multiple sequence alignment comparisons with BLAST (Basic Local Alignment Search Tool) and CLUSTALW. APichia pastorisexpression system was used to express the recombinant form of the enzyme. The mannanase activity was quantified by the 3,5-dinitrosalicylic (DNS) and the hydrolitic properties were detected by TLC.Results: An endo-1,4-β-mannanase from the digestive tract of the insectHypothenemus hampeiwas cloned and expressed as a recombinant protein in thePichia pastorissystem. This enzyme is 56% identical to the sequence of an endo-β-mannanase fromBacillus circulansthat belongs to the glycosyl hydrolase 5 (GH5) family. The purified recombinant protein (rHhMan) exhibited a single band (35.5 kDa) by SDS-PAGE, and its activity was confirmed by zymography. rHhMan displays optimal activity levels at pH 5.5 and 30°C and can hydrolyze galactomannans of varying mannose:galactose ratios, suggesting that the enzymatic activity is independent of the presence of side chains such as galactose residues. The enzyme cannot hydrolyze manno-oligosaccharides such as mannobiose and mannotriose; however, it can degrade mannotetraose, likely through a transglycosylation reaction. The K_mand k_catvalues of this enzyme on guar gum were 2.074 mg ml^-1and 50.87 s^-1, respectively, which is similar to other mannanases.Conclusion: This work is the first study of an endo-1,4-β-mannanase from an insect using this expression system. Due to this enzyme’s importance in the digestive processes of the coffee berry borer, this study may enable the design of inhibitors against endo-1,4-β-mannanase to decrease the economic losses stemming from this insect.

Coffee production between the first and second harvest presents a difference in the fruit load with the plant age that could affect the leaf gas exchange. This research aimed to evaluate the effect of the increase in fruit load that occurs between the first and second harvest of the Coffea arabica L. production cycle on the measured gas exchange, at the two phenological stages of the fruit. The accessions E057, E318, E338 and E554 were used, as well as a completely randomized design, with three replications, using the accessions as treatments and the harvest measurements during the production cycle as the repeated measures. The variables yield per tree, number of fruits, absolute growth rates for height and stem, leaf area, leaf-to-fruit ratio and leaf gas exchange were measured across the phenological stages of fruit filling and ripening. The increase in the fruit load that occurs with age in the second harvest, if compared to the first harvest, showed a positive and significant effect on the net assimilation rate that was not expected for the obtained leaf-to-fruit ratios. Likewise, the differences in the assimilation rates were higher during the fruit-filling stage. This result suggests that the source-sink relationship may vary with the crop age and fruit phenological stage, and is not entirely depend on the leaf-to-fruit ratio.

World production of coffee (Coffea spp.) has increased in recent decades due to its growing demand. Nitrogen (N) is one of the most required nutrients by coffee crops and in many cases, the most yield-limiting; nevertheless, a high percentage of supplied N is lost, generating pollution, greenhouse gases, and economic losses. Given this scenario, it is a priority to adopt practices that increase nitrogen use efficiency related to the capacity of plants to absorb and use N to produce biomass. This article provides context about NUE and determining factors in coffee: plant, soil, climate, and management. On the plant side, despite advances in genetics and the results of genotype evaluation, it may be a decade or more before improved coffee varieties with high EUN become available or used in world coffee farming. Both the physical, chemical, and biological properties of the soil and the elements of the climate, mainly temperature, precipitation, and solar radiation, have an influence on coffee growth and many of the processes that intervene in the N cycle and NUE; however, some components of these two factors are not fully controllable. Management of the factors that determine NUE should focus on reducing N losses in the system, increasing its uptake and utilization by plants, and maintaining or increasing productivity.