Bacterial Relationships in Aquaponics: New Research Directions

The growth rates and welfare of fish and the quality of plant production in aquaponics system rely on the composition and health of the system’s microbiota. The overall productivity depends on technical specifications for water quality and its movement amongst components of the system, including a wide range of parameters including factors such as pH and flow rates which ensure that microbial components can act effectively in nitrification and remineralization processes. In this chapter, we explore current research examining the role of microbial communities in three units of an aquaponics system: (1) the recirculating aquaculture system (RAS) for fish production which includes biofiltration systems for denitrification; (2) the hydroponics units for plant production; and (3) biofilters and bioreactors, including sludge digester systems (SDS) involved in microbial decomposition and recovery/remineralization of solid wastes. In the various sub-disciplines related to each of these components, there is existing literature about microbial communities and their importance within each system (e.g. recirculating aquaculture systems (RAS), hydroponics, biofilters and digesters), but there is currently limited work examining interactions between these components in aquaponics system, thus making it an important area for further research

Molecular cloning and expression analysis of a gene encoding KUP/HAK/KT-type potassium uptake transporter from Cryptomeria japonica

Potassium ion (K+) is an essential and the most abundant intracellular cation in plants. The roles of K+ in various aspects of plant life are closely linked to its transport across biological membranes such as the plasma membrane and the tonoplast, which is mediated by membrane-bound transport proteins known as transporters and channels. Information on the molecular basis of K+ membrane transport in trees, especially in conifers, is currently limited. In this study, we isolated one complementary DNA, CjKUP1, which is homologous to known plant K+ transporters, from Cryptomeria japonica. Complementation tests using an Escherichia coli mutant, which is deficient in K+ uptake activity, was conducted to examine the K+ uptake function of the protein encoded by CjKUP1. Transformation of the K+-uptake-deficient mutant with CjKUP1 complemented the deficiency of this mutant. This result indicates that CjKUP1 has a function of K+ uptake. The expression levels of CjKUP1 in male strobili were markedly higher from late September to early October than in other periods. The expression levels in male and female strobili were higher than those in other organs such as needles, inner bark, differentiating xylem, and roots. These results indicate that CjKUP1 is mainly involved in K+ membrane transport in the cells of reproductive organs of C. japonica trees, especially in male strobili during pollen differentiation.ArticleTrees-Struct. Funct. 28(5):1527-1537 (2014)journal articl