EVALUATION OF MICROBIOME DIVERSITY OF AQUAPONIC SYSTEM AND THEIR EFFECT ON PHYTOPATHOGENS AND PLANT GROWTH

Abstract

Aquaponic can be a sustainable agricultural production system. Most plant nutrients can be derived from fish feed through fish digestion or extraction and biofilter nitrification. Plant can act as biofilters and take up system effluent that would otherwise be discharged to the environment. One of the key problems in conventional aquaponic systems is that the nutrients in the effluent produced by fish are different than the optimal nutrient solution for plants. The present work was carried out for isolation, purification and selection of efficient bacterial isolates associated with some plants which grown under aquaponic system and desert areas due to their plant growth promoting activities and production of bioactive secondary metabolite. As well as, verify their effects, on sludge mineralization, growth and leaf spot disease severity of basil plants (Ocimum basillicum) in presence of Xanthomonas campestris and Pseudomonas cichorii. Results of this study can be summarized as follows: 1. Survey and isolation of bacterial leaf spot disease of plants grown under aquaponics systems in Egypt Six aquaponic farms in Egypt, cultivated with lettuce butterhead, oakleaf lettuce, pock choi, rocket, basil, hot pepper, spring onion, watercress, cherry tomato, calendula, red baby leaf and purple kale plants, were surveyed for leaf spot disease incidence of those plants during 2016. The disease incidence percent ranged from 1- 17.6 % on tested plants. The infected basil recorded the highest values with all tested farms. Cell densities (log10 cfu /g) of Xanthomonas and Pseudomonas bacteria in three different habitats i.e., cultivated water tank, infected plants and grow bed of six aquaponic farms were determined using selective media. The percentage of infected plants by Pseudomonas ranged between 10-30% whereas, hot pepper, purple kale and spring onion plants didn’t have Pseudomonas as a causal agent. In Al-Manashy