Edwardsiella ictaluri is a devastating intracellular bacterial pathogen, responsible for significant losses in the aquaculture sector. It affects over 40 fish species including striped catfish Pangasianodon hypophthalmus. In the present study, a case of large-scale mortalities ( 70–80

Edwardsiella ictaluri is a devastating intracellular bacterial pathogen, responsible for significant losses in the aquaculture sector. It affects over 40 fish species including striped catfish Pangasianodon hypophthalmus. In the present study, a case of large-scale mortalities (~ 70–80%) in farmed P. hypophthalmus from Uttar Pradesh, India was investigated. The affected fish exhibited erratic swimming, haemorrhagic vent, pinpoint ulcerations on skin, and white foci in the internal organs. Wet mount examination of gills and skin scrapings showed no parasites. Histopathological examination of the naturally diseased fish showed necrotic granulomas in kidneys, and multifocal necrotic areas in spleen and liver. Notably, bacterial isolates recovered from the diseased fish were presumptively identified as E. ictaluri based on phenotypic tests. The isolates were confirmed as E. ictaluri based on amplification of species-specific fimbrial gene, and amplification and sequencing of 16S rRNA and gyrB genes. The phylogenetic analysis revealed that sequences of gyrB gene of E. ictaluri provided higher species-level resolution compared to 16S rRNA sequences. Furthermore, following experimental infection with E. ictaluri, 100% mortality was observed in striped catfish. The clinical signs and histopathological lesions resembled those of naturally infected fish, and E. ictaluri was re-isolated from the experimentally infected fish. Based on these observations, it was confirmed that E. ictaluri was responsible for mortalities in the farmed striped catfish. Considering the rapid expansion of striped catfish culture in the country, and documented susceptibility of cyprinids and cichlids in other countries, the emergence of this pathogen is a significant concern in Indian aquaculture.

A cell line has been established from the heart tissue of three spot gourami Trichopodus trichopterus using explant method, and designated as three spot gourami heart (TSGH) cell line. The TSGH cells have been passaged over 70 times at 28 degrees C in L-15 medium supplemented with 10 % fetal bovine serum. The cells were cryopreserved in liquid nitrogen at regular passages and successfully revived with good cell viability. The cells have epithelial morphology which was confirmed by strong fluorescence for cytokeratin marker. Chromosomal analysis of TSGH cells revealed diploid chromosome number of 46. PCR amplification and sequencing of the partial fragments of the two mitochondrial genes, namely 16S rRNA and cytochrome c oxidase subunit I (COI) revealed that the cell line was derived from T. trichopterus. The cell line was found to be free of Mycoplasma contamination and exhibited good transfection efficiency. TSGH cells were susceptible to Infectious spleen and kidney necrosis virus, Cyprinid herpesvirus-2 and Tilapia Lake virus as evidenced by cytopathic effects and PCR/RT PCR. This novel cell line would be helpful for surveillance of viral diseases affecting gouramis.

The emergence and spread of transboundary aquatic animal diseases have been frequently associated with in-ternational trade of live aquatic animals. Tilapia is one of the most traded aquatic animals and the recent global spread of Tilapia tilapinevirus, also known as tilapia lake virus (TiLV), is speculated to be due to transboundary movement of infected fish. Further, extensive trade of ornamental cichlids can be a major threat to the spread of TiLV. However, there is little information about susceptibility of ornamental fishes, especially cichlids, to this virus. In this background, the present study evaluated the susceptibility of three ornamental cichlids (angelfish, firemouth cichlid and parrotfish) and two non-cichlids (three spot gourami and goldfish) vis-`a-vis Nile tilapia following experimental infection with TiLV through intraperitoneal injection. The study carried out quantifi-cation of viral load using real-time PCR, histopathology and isolation of the virus in permissive cell line developed previously from Oreochromis niloticus heart (OnH). Experimental infection resulted in the successful reproduction of the disease in tilapia with typical clinical signs. In angelfish, 40% mortality was observed and the TiLV copy number/100 ng RNA was determined to be 2.49 x 106, 1.52 x 106 and 2.64 x 104 in the target tissues, namely liver, spleen and brain, respectively at 4 days post-infection (dpi). In addition, TiLV could be detected in the target tissues till end of the experimental period of 24 days. Although no clinical signs or mortality were observed in firemouth cichlid, but TiLV copies were detected in the target organs with significant increase in the viral load up to 12 dpi. Histopathological examination of liver tissue of the experimentally infected fishes revealed typical syncytial cells only in tilapia whereas necrosis of hepatocytes was observed in tilapia, angelfish and firemouth cichlid. Besides, TiLV could be isolated from target tissues of both angelfish and firemouth cichlid at 8 dpi, using OnH cell line. On the other hand, in parrotfish, three spot gourami and goldfish, the virus copy number in the target tissues showed a decline from 1 dpi and no evidence of virus replication could be noticed in the cell line studies. Hence, these three ornamental fishes were considered resistant to experimental infection with TiLV. The findings of this study indicated the existence of wide host-range of TiLV in non-tilapine orna-mental fishes including angelfish and firemouth cichlid, and the potential role of these fishes in the epidemiology of TiLV disease.

Tilapia parvovirus (TiPV) has been associated with heavy mortalities in tilapia as a single infection or in co-infection with Tilapia lake virus (TiLV). In this study, TiPV was detected in farmed Nile tilapia, Oreochromis niloticus, from two geographical regions of India, Maharashtra and Uttar Pradesh. TiPV-specific polymerase chain reaction (PCR) reported earlier was used in the screening. Tilapia collected from Maharashtra showed characteristic clinical signs, and TiPV was detected along with TiLV and/or Aeromonas spp. However, fish from Uttar Pradesh were apparently healthy and only TiPV could be detected in these samples. A high prevalence of TiPV was recorded from both the geographical locations, Maharashtra and Uttar Pradesh (59.6% and 95.0% respectively). The virus could be detected in tissues such as the spleen, liver, kidney, brain and mucus. The spleen appeared to be the best tissue for detecting TiPV in apparently healthy tilapia. The presence of TiPV was further confirmed through sequencing the PCR products, isolation of the virus in the cell line and electron microscopy. Sequences of the NS1 gene of the two TiPV isolates showed similarity to the earlier reported TiPV isolates. The virus could be successfully propagated in O. niloticus Liver (OnL) cell line, and cytopathic effect was observed as early as 3 days post-infection. Furthermore, the presence of non-enveloped icosahedral to round virus particles measuring about 26-35 nm could be demonstrated in the cytoplasm and nucleus of infected OnL cells in transmission electron microscopy. With this confirmation of the presence of the virus, India is the third country to report TiPV after China and Thailand. The detection of TiPV in co-infection cases with TiLV and in apparently healthy Nile tilapia suggests its wide distribution and potential synergistic effect in co-infection cases. Therefore, this emerging virus needs holistic attention to understand its virulence, host-specificity and epidemiological risk factors.

The end product of germ cell maturation is the spermatozoa that are produced through a definite pattern in nature that requires a special environment. During proliferation of diploid germ cells, the spermatogonia repopulate the testis lobules by mitotic cell division. The natural germ cell proliferation and maturation has been modulated and manipulated by various factors to get maximum viable sperms for aquaculture practice. Environment and chemicals of natural and synthetic origin can interact with the endocrine system and alter the male germ cell generation and proliferation/inhibition in fish. In the present investigative review, an attempt has been made to ascertain various factors that influence the spermatogonial proliferation and maturation of fish with a special reference to Indian major carps, viz. catla, Catla catla, rohu, Labeo rohita and, mrigal, Cirrhinus mrigala. It was observed that physical factors such as temperature and photoperiod, and the chemical stimulants such as clomephene citrate, hormones and other chemicals stimulate the process. However, if not applied in optimal conditions/doses it may retract the germ cell proliferation and the entire spermatogenesis.

Abstract Climate change and temperature variations are of paramount importance to aquaculture. Here, we investigated the thermal stress response of five life stages of tilapia viz. spawn, fry, fingerling, juveniles and adults exposed to different temperatures (28°C to 40°C). Stress response was assessed in terms of survival/mortality, thermal shock, changes in hematology, histopathology of liver and gonad. The spawn, fry and fingerlings died within 1 to 39 min at 40°C due to thermal shock. Thermal acclimation was observed in these stages till 34°C. Beyond 34°C, low feed intake and susceptibility were marked. Significant increments in the hematological parameters were noticed when the water temperature elevated from 28°C to 32°C and thereafter deteriorated. Hematological parameters, gonadosomatic index (GSI), digestive somatic index (DSI) and hepatosomatic index (HSI) showed ideal conditions at temperatures between 28°C to 30°C. However, a marked change in the liver and gonad histoarchitecture and decreased organ somatic indices of adult tilapia were also noticed in response to elevated temperatures. This study suggests that the developmental stages of tilapia are highly susceptible to thermal shock and a gradual temperature rise helped them acclimate to 34°C. Further temperature rise may adversely affect tilapia aquaculture.

Labeo calbasu is an important food fish and candidate species for diversification of carp aquaculture. In the present study, we have established a continuous cell line, designated as L. calbasu fin (LCF), from caudal fin of L. calbasu using explant method. The cell line has been subcultured for over 73 passages and the LCF cells show optimal growth in Leibovitz's L-15 medium supplemented with 20% fetal bovine serum at a temperature of 28°C. In karyotype analysis, the modal chromosome number of LCF cells at 35th passage was found to be 50. The amplification and sequencing of partial fragments of mitochondrial genes, namely 16S rRNA and COI from LCF cells confirmed the origin of cell line from L. calbasu. The LCF cells could be successfully transfected with GFP reporter gene, indicating suitability of these cells for expression of foreign genes. Further, following inoculation with supernatant from Tilapia lake virus (TiLV) infected cell line, no cytopathic effects were observed in the LCF cells and cell pellet was negative for TiLV in RT-PCR, indicating that LCF cells were not susceptible to TiLV. The developed cell line has been submitted to National Repository of Fish Cell Lines being maintained at ICAR-National Bureau of Fish Genetic Resources, Lucknow (accession no. NRFC063). The newly developed LCF cell line would be helpful in investigating diseases affecting this candidate species particularly the ones suspected to be of viral etiology, and for cytotoxicity and transgenic studies.

The tilapia lake virus (TiLV), a highly infectious negative-sense single-stranded segmented RNA virus, has caused several outbreaks worldwide since its first report from Israel in 2014, and continues to pose a major threat to the global tilapia industry. Despite its economic importance, little is known about the underlying mechanisms in the genomic evolution of this highly infectious viral pathogen. Using phylogenomic approaches to the genome sequences of TiLV isolates from various geographic regions, we report on the pervasive role of reassortment, selection, and mutation in TiLV evolution. Our findings provided the evidence of genome-wide reassortment in this newly discovered RNA virus. The rate of non-synonymous (dN) to synonymous (dS) substitutions was less than one (dN/dS = 0.076 to 0.692), indicating that each genomic segment has been subjected to purifying selection. Concurrently, the rate of nucleotide substitution for each genomic segment was in the order of 1-3 x 10-3 nucleotide substitutions per site per year, which is comparable to the rate of other RNA viruses. Collectively, in line with the results of the previous studies, our results demonstrated that reassortment is the dominant force in the evolution and emergence of this highly infectious segmented RNA virus.

Mortalities were observed in several Pangasianodon hypophthalmus farms (n = 52) of Uttar Pradesh, North India during December 2020–January 2021. The affected fish were lethargic, swimming near the water surface and had white or grayish cotton-like patches over the body surface. Wet mount examination of the patches revealed presence of non-septate hyphae suggestive of oomycete infection. However, no parasites were observed in skin and gill scrapings. Histopathological examination of the affected skin tissue indicated severe destruction of the epidermis, degenerative changes and penetration of the oomycete hyphae in the dermis and underlying musculature. From the affected skin lesions, oomycete could be isolated which was identified as Saprolegnia parasitica based on morphological characteristics, and amplification and sequencing of the internal transcribed spacer region. Importantly, from the diseased P. hypophthalmus, no bacteria and viruses could be isolated from kidney, and pooled kidney and spleen tissues, respectively. Further, following experimental infection with S. parasitica zoospores by immersion method, 100% mortality was observed in P. hypophthalmus, indicating that the isolate was virulent. From the experimentally-infected striped catfish, S. parasitica could be reisolated and the histopathological lesions were similar to those observed in naturally infected fish, thereby fulfilling Koch's postulates. Based on the gross and histopathological lesions, isolation of oomycete, molecular identification and bioassay, it was concluded that S. parasitica was responsible for mortalities in P. hypophthalmus farms. This forms the first report of mortalities of striped catfish due to oomycete S. parasitica infection and the findings will pave way for developing control measures for reducing losses in striped catfish farms due to saprolegniasis.

Blood parrot cichlid, a hybrid of Amphilophus citrinellus (male) and Paraneetroplus synspilus (female), is among the most popular ornamental fishes globally. In this study, three cell lines were established from brain, spleen, and heart tissues of the blood parrot cichlid using explant method and these were designated as parrot fish brain (PFB), parrot fish spleen (PFS) and parrot fish heart (PFH), respectively. All the cell lines have been subcultured for over 120 passages and these grow optimally at 28-32 degrees C in Leibovitz's L-15 medium containing 20% fetal bovine serum. PFB and PFH cells depict epithelial morphology whereas PFS cells consist of fibroblast-like cells. Although the chromosome number of blood parrot cichlid was 2n = 48, the cell lines exhibited heteroploidy and aneu-ploidy, suggesting transformation. The sequencing of amplified fragments of two mitochondrial genes, namely COI and 16S rRNA confirmed that the cell lines originated from blood parrot cichlid. The three cell lines were free of Mycoplasma contamination. Besides, their successful transfection with a GFP reporter gene suggested potential application in transient gene expression studies. All the three cell lines were susceptible to Tilapia tilapinevirus, also known as Tilapia lake virus (TiLV), which was indicated by appearance of cytopathic effects and RT-PCR. Of the three cell lines, PFS was found to be the most permissive with maximum TiLV copy number of 2.5 x 108 per 100 ng of total RNA, as determined by qRT-PCR. Importantly, the TiLV disease was successfully reproduced in naive tilapia after injection of cell culture supernatant from TiLV-infected PFS cell line, and this was evidenced by clinical signs, histopathological alterations, reisolation of virus and specific amplification in RT-PCR. The three newly established cell lines were submitted to National Repository on Fish Cell Lines at ICAR-NBFGR. This forms the first report of development of cell lines from blood parrot cichlid, and these would be useful for surveillance of diseases suspected to be of viral origin in this candidate species and also other orna-mental cichlids.

Tilapia tilapinevirus, also known as tilapia lake virus (TiLV), is an emerging fish virus that primarily affects tilapines. However, the virus has also been detected in a few non-tilapines. As tilapia is generally farmed in polyculture systems along with carps in South Asian countries, there is a likelihood that TiLV-infected tilapia can transmit the virus to the co-cultured species. In view of the above, the susceptibility of three carp species, namely catla (Catla catla), mrigal (Cirrhinus mrigala) and silver carp (Hypophthalmichthys molitrix) was evaluated vis-à-vis tilapia, following experimental infection with TiLV. No clinical signs and histopathological alterations could be observed in carps. RT-qPCR revealed that TiLV copy numbers in liver and brain of all the three carps were almost negligible and did not show any increase with time, suggesting that the virus did not replicate in liver and brain, the target organs of TiLV. Further, TiLV could not be isolated from pooled liver and brain tissues of carps using permissive CFF cell line. On the contrary, in tilapia, typical clinical signs and histopathological lesions were observed and there was significant increase in TiLV copy number up to 6 days post-injection. Furthermore, the virus was successfully isolated from pooled liver and brain tissue of infected tilapia. From the above findings, it could be concluded that C. catla, C. mrigala and H. molitrix are resistant to TiLV infection and unlikely to be carriers for this virus.

Aim: Goldfish (Carassius auratus L.), a freshwater fish belonging to the family Cyprinidae, is an important ornamental fish species in the world. Herewith, we report a case of systemic mycobacteriosis along with concurrent fibroma in goldfish. Methodology: The protruding mass and internal organs exhibiting lesions were collected for histopathology and molecular diagnosis. The sections of cutaneous mass were stained with haematoxylin and eosin (H&E) and Masson trichrome, whereas sections from spleen as well as kidney were stained with H&E and Ziehl-Neelsen. For identifying the etiological agent, 16S rRNA gene fragment was amplified and sequenced, using genus-specific primers for Mycobacterium sp. Results: In histopathology, multiple granulomas could be observed in kidney and spleen sections. Importantly, typical acid-fast bacilli were demonstrated in granulomas in spleen. The sequence of 16S rRNA gene fragment amplified from spleen and kidney showed maximum similarity to Mycobacterium stomatepiae. Besides, the histopathological characteristics of the protruding mass were consistent with cutaneous fibroma. Interpretation: These findings assume significance as several Mycobacterium species, including the current one from ornamental fish are reported to be of zoonotic significance.

Nile tilapia (Oreochromis niloticus) is one of the most important aquaculture species farmed worldwide. However, the recent emergence of tilapia lake virus (TiLV) disease, also known as syncytial hepatitis of tilapia, has threatened the global tilapia industry. To gain more insight regarding the host response against the disease, the transcriptional profiles of liver in experimentally-infected and control tilapia were compared. Analysis of RNASeq data identified 4640 differentially expressed genes (DEGs), which were involved among others in antigen processing and presentation, MAPK, apoptosis, necroptosis, chemokine signaling, interferon, NF-kB, acute phase response and JAK-STAT pathways. Enhanced expression of most of the DEGs in the above pathways suggests an attempt by tilapia to resist TiLV infection. However, upregulation of some of the key genes such as BCL2L1 in apoptosis pathway; NFKBIA in NF-kB pathway; TRFC in acute phase response; and SOCS, EPOR, PI3K and AKT in JAK-STAT pathway and downregulation of the genes, namely MAP3K7 in MAPK pathway; IFIT1 in interferon; and TRIM25 in NF-kB pathway suggested that TiLV was able to subvert the host immune response to successfully establish the infection. The study offers novel insights into the cellular functions that are affected following TiLV infection and will serve as a valuable genomic resource towards our understanding of susceptibility of tilapia to TiLV infection.

Aphanomyces invadans, the causative agent of epizootic ulcerative syndrome, is one of the most destructive pathogens of freshwater fishes. To date, the disease has been reported from over 160 fish species in 20 countries and notably, this is the first non-salmonid disease that has resulted in major impacts globally. In particular, Indian major carps (IMCs) are highly susceptible to this disease. To increase our knowledge particularly with regards to host immune response against A. invadans infection in a susceptible host, the gene expression profile in head kidney of A. invadans-infected and control rohu, Labeo rohita was investigated using RNA sequencing. Time course analysis of RNA-Seq data revealed 5608 differentially expressed genes, involved among others in Antigen processing and presentation, Leukocyte transendothelial migration, IL-17 signaling, Chemokine signaling, C-type lectin receptor signaling and Toll-like receptor signaling pathways. In the affected pathways, a number of immune genes were found to be downregulated, suggesting an immune evasion strategy of A. invadans in establishing the infection. The information generated in this study offers first systematic mechanistic understanding of the host–pathogen interaction that might underpin the development of new management strategies for this economically devastating fish-pathogenic oomycete A. invadans.

In recent years, infection with Shewanella putrefaciens has emerged as a serious problem in freshwater aquaculture. In the present study, we report large‐scale mortality in farmed tilapia Oreochromis niloticus from Hisar, North India. The diseased tilapia exhibited lethargy, swimming near the water surface, fin rot, hemorrhages on the operculum, and approximately 40% mortality. Gram‐negative, motile, catalase, and oxidase‐positive bacilli were isolated from the kidney of affected tilapia and confirmed as S. putrefaciens on the basis of biochemical tests and 16S rRNA gene sequencing. The antimicrobial sensitivity test revealed that S. putrefaciens strains were sensitive to quinolone, nitrofuran, tetracycline, aminoglycoside, cephalosporin, aminocyclitol, sulphonamide, and macrolide antibiotics, but resistant to beta‐lactam and glycopeptide antibiotics. The histopathological examination revealed degenerative changes in the kidney, liver, spleen, and intestine suggesting systemic infection. In experimental infection studies, the disease was reproduced in naive tilapia, and the clinical signs resembled those observed in natural cases. Further more, S. putrefaciens was re‐isolated from the kidney of challenged tilapia, fulfilling Koch's postulates. Therefore, the mortality in tilapia was attributed to S. putrefaciens infection.

In the present study, we have developed a continuous cell line from the heart tissue of the Oreochromis niloticus and used for studying susceptibility to tilapia lake virus (TiLV). The cell line, designated as OnH, has been subcultured up to 82 passages. The optimal growth of OnH cells was observed at 28-32 degrees C in iL-15 medium supplemented with 20 % fetal bovine serum. Karyotype analysis revealed that the modal chromosome number of OnH cells was 44. Partial amplification and sequencing of 16S rRNA gene confirmed the origin of OnH cell line from O. niloticus. Immunophenotyping revealed that OnH cells were of epithelial origin. These cells were successfully transfected with pAcGFP1-N1 mammalian expression vector. OnH cells showed cytopathic effects following inoculation with TiLV. The virus titration study indicated that the cells were highly susceptible to TiLV with TCID50 value of 10(5.3)/mL. The qRT-PCR studies revealed that the optimal temperature for TiLV replication in OnH cells was 28 degrees C. Further, transmission electron microscopy of TiLV-infected OnH cells showed a number of electron-dense virus particles measuring 60-90 nm diameter, which were enclosed in the vesicles in the cytoplasm. Therefore, the newly established OnH cell line provides a valuable tool for isolation of viruses from disease cases suspected to be of viral etiology in this candidate species' and also for transgenic and genetic manipulation studies.

Infection with Aphanomyces invadans is a serious fish disease with major global impacts. Despite affecting over 160 fish species, some of the species like the common carp Cyprinus carpio are resistant to A. invadans infection. In the present study, we investigated the transcriptomes of head kidney of common carp experimentally infected with A. invadans. In time course analysis, 5288 genes were found to be differentially expressed (DEGs), of which 731 were involved in 21 immune pathways. The analysis of immune-related DEGs suggested that efficient processing and presentation of A. invadans antigens, enhanced phagocytosis, recognition of pathogen-associated molecular patterns, and increased recruitment of leukocytes to the sites of infection contribute to resistance of common carp against A. invadans. Herein, we provide a systematic understanding of the disease resistance mechanisms in common carp at molecular level as a valuable resource for developing disease management strategies for this devastating fish-pathogenic oomycete.

Infection with tilapia lake virus (TiLV) has been reported to cause large-scale mortalities in tilapines, the second most cultured species in the world. Interestingly, in polyculture system, although tilapia is reported to suffer high mortalities due to infection with TiLV, the disease has not been reported in co-cultured species. Nevertheless, natural host switch is a frequent phenomenon among viruses of lower vertebrates, especially fish viruses. To analyse the risk of spread of virus to new host species, it is essential to study the susceptibility of other fish species to the virus. In India, tilapia is generally cultured along with Indian major carps (IMC) in polyculture systems. Keeping this in consideration, in the present study, the susceptibility of rohu Labeo rohita, an important major carp, to TiLV was evaluated following experimental infection and it was compared with a susceptible host, i.e. Nile tilapia Oreochromis niloticus. The results revealed that the experimentally-infected rohu did not exhibit any clinical signs and mortality. On the other hand, in tilapia, a cumulative mortality of 80% was observed during the experimental period of 12 days with clinical signs typical of TiLV disease. In histopathological examination of liver, one of the main target organ of TiLV, typical syncytial cells were observed in tilapia whereas, no alterations were observed in rohu. Importantly, in rohu, the virus copy numbers in liver and intestine were almost negligible (<3 virus copies) and did not increase with time course, and the virus was not detected in brain at any time point by qRT-PCR. However, in tilapia, there was significant increase in virus copy numbers in liver, brain as well as intestine up to 6 days post-infection (dpi), and thereafter, a marginal decrease was observed up to 12 dpi. Therefore, based on lack of clinical signs and mortality pattern, histopathological findings and results of qRT-PCR, it can be concluded that TiLV did not replicate in rohu, and it is not susceptible to infection with TiLV.

In the present study, arsenic tolerant bacteria were isolated and characterized from rhizospheric soil of rice plant growing in the arsenic contaminated area of West Bengal, India. Among 31 bacterial isolates, nine isolates were showed tolerance at higher concentration of arsenate (As V; 20000 mg mL-1). Selected arsenic tolerance bacterial isolates were characterized based on biochemical analysis, partial 16S rDNA gene sequencing and phylogenetic analysis. Results revealed that selected arsenic tolerant bacterial strains were lavished at 370C and neutral pH 7 and showed a positive response for catalase and oxidase enzymes. Using partial 16S rDNA based identification and phylogenetic analysis, selected bacterial isolates were identified as Jeotgalicoccus nanhaiensis, Alcaligenes faecalis, Paenalcaligenes sp., Providencia sp., Kocuria sp. and Pseudomonas stutzeri. Further, the isolated As tolerant bacterial strains may be tested for their possible utilization in arsenic mobilization in the rhizosphere for enhancing phytoremediation potential to remediate arsenic from contaminated sites. However, efficient arsenic accumulator strain like Pseudomonas stutzeri can be employed as bioresource to develop low-cost bioremediation technology for arsenic removal.