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Fish diseases are major challenges now-a-days which disrupt the stable supply of fishes around the world. Fish diseases are caused by bacterial and fungal infection and other environmental factors (poor water quality) are generally responsible for mass mortalities both in cultured as well as in wild fishes. Bacterial infection produces septicaemia, ulcerative and haemorrhagic diseases causing significant mortality in fishes of different habitats and affects the economy of the aquaculture sector. Polluted environs contains always disease spreading pathogens in addition to facultative microbes. The current review suggests that the incidences of bacterial infection in fishes have increased significantly, with new pathogens regularly recognized. Furthermore, the accounts of the whole genomes of various bacterial species over the years have allowed the identification of an important number of virulence genes that affect the pathogenic potential of these bacteria. The literature over review provides the most relevant information derived from the available bacterial genomes in relation to virulence and on the diverse virulence factors. Thus an attempt is made in the current review to portray the importance of profiling and evaluation of effect of the pathogenic bacteria in the fish fauna.

Toxic metals have disturbed the quality of freshwater ecosystems worldwide. The concentration of heavy metals was investigated in liver, gills and muscle tissues of Schizothorax niger and Cyprinus carpio captured from river Jhelum of Kashmir Himalaya. The heavy metals displayed a wide range of disparity in studied tissues, seasons, sites and species. Cu2+ exhibited the highest concentration (279.6 μg/kg) in the liver tissues of S. niger in autumn at site 2 and the lowest (53.1 μg/kg) in the gill tissues in winter at site 1. In C. carpio, the Cu2+ was recorded highest (309.4 μg/kg) in the liver tissues in autumn at site 2. The concentration of Zn2+ was found highest (575.7 μg/kg) in the liver tissues at site 2 and the lowest (65.8 μg/kg) was recorded in the muscle tissues in autumn at site 1. Zn2+ was recorded highest (416.6 μg/kg) in the liver tissues in autumn at site 3 and lowest (51.5 μg/kg) in the gills of C. carpio during winter at site 1 (control). The concentration of Pb2+ (14.42 μg/kg) and Fe2+ (323.9 μg/kg) was observed in the liver tissue and gills of S. niger at site 3. Similar levels of Pb2+ and Fe2+ were recorded in the tissues of C. carpio at different sites. Four-way ANOVA (four way) indicated a statistically significant variation (p ≤ 0.05) in heavy metals with the sites, seasons, species and organs. The study emphasises the utmost need to monitor the level of heavy metals in S. niger on a regular basis as this native fish species is showing a continuous decline in the freshwater ecosystems of Kashmir Valley.

The rhizosphere is an environment of plant roots in which most of the microbial activities of soil occur. The two vital components of soil rhizosphere are root exudates and soil microbes. Root exudates are the chemical compounds that are secreted by roots and act as a source of food for soil microbes especially for mycorrhizae. These chemical compounds plays significant role in soil microbe and plant interaction. The soil mycorrhizae are important for plant growth development and health. They are the main components that enrich the soil nutrients and maintain the soil health in sustainable manner. Furthermore, they enhance the plant growth regulators, provide defense mechanism to the plants, regulate enzymatic activities, increase rate of photosynthesis and supports in bioremediations, thus acting as eco-facilitator in sustainable agriculture both in terms of production and environmental protection.