Differential regulation of grain sucrose accumulation and metabolism in Coffea arabica (Arabica) and Coffea canephora (Robusta) revealed through gene expression and enzyme activity analysis

Coffea arabica (Arabica) and Coffea canephora (Robusta) are the two main cultivated species used for coffee bean production. Arabica genotypes generally produce a higher coffee quality than Robusta genotypes. Understanding the genetic basis for sucrose accumulation during coffee grain maturation is an important goal because sucrose is an important coffee flavor precursor. Nine new Coffea genes encoding sucrose metabolism enzymes have been identified: sucrose phosphate synthase (CcSPS1, CcSPS2), sucrose phosphate phosphatase (CcSP1), cytoplasmic (CaInv3) and cell wall (CcInv4) invertases and four invertase inhibitors (CcInvI1, 2, 3, 4). Activities and mRNA abundance of the sucrose metabolism enzymes were compared at different developmental stages in Arabica and Robusta grains, characterized by different sucrose contents in mature grain. It is concluded that Robusta accumulates less sucrose than Arabica for two reasons: Robusta has higher sucrose synthase and acid invertase activities early in grain development – the expression of CcSS1 and CcInv2 appears to be crucial at this stage and Robusta has a lower SPS activity and low CcSPS1 expression at the final stages of grain development and hence has less capacity for sucrose re-synthesis. Regulation of vacuolar invertase CcInv2 activity by invertase inhibitors CcInvI2 and/or CcInvI3 during Arabica grain development is considered

Effects of Zn/B nanofertilizer on biophysical characteristics and growth of coffee seedlings in a greenhouse

[[abstract]]The effects of Zn/B nanofertilizer on the biophysical characteristics and growth of coffee seedlings in a greenhouse were investigated. Zn/B nanofertilizer was prepared by loading ZnSO4 and H3BO3 on a chitosan nanoparticles emulsion that was prepared by ionic gelation with tripolyphosphate. The nanofertilizer was characterized by TEM, SEM, zeta potential value and size distribution. The nanofertilizer was sprayed on the leaves of coffee seedlings in five different doses of 0, 10, 20, 30 and 40 ppm. Application of the nanofertilizer enhanced the uptake of zinc, nitrogen and phosphorus. The results were found to increase the chlorophyll content and photosynthesis of the coffee. Finally, the nanofertilizer promoted growth of the coffee plants in the leaf area, height of plant and stem diameter. The nanofertilizer seems to be a great potential foliar feed for the growth of coffee and other plants.[[sponsorship]]科技部[[notice]]補正完