lncRNA-miRNA-mRNA network in kidney transcriptome of Labeo rohita under hypersaline environment.

The present study describes the kidney transcriptome of Labeo rohita, a freshwater fish, exposed to gradually increased salinity concentrations (2, 4, 6 and 8ppt). A total of 10.25 Gbps data was generated, and a suite of bioinformatics tools, including FEELnc, CPC2 and BLASTn were employed for identification of long non-coding RNAs (lncRNAs) and micro RNAs (miRNAs). Our analysis revealed a total of 170, 118, 99, and 269 differentially expressed lncRNA and 120, 118, 99, and 124 differentially expressed miRNAs in 2, 4, 6 and 8 ppt treatment groups respectively. Two competing endogenous RNA (ceRNA) networks were constructed i.e. A* ceRNA network with up-regulated lncRNAs and mRNAs, down-regulated miRNAs; and B* ceRNA network vice versa. 2ppt group had 131 and 83 lncRNA-miRNA-mRNA pairs in A* and B* networks, respectively. 4ppt group featured 163 pairs in A* network and 191 in B* network, while the 6ppt had 103 and 105 pairs. 8ppt group included 192 and 174 pairs. These networks illuminate the intricate RNA interactions in freshwater fish to varying salinity conditions.

Interplay of gene expression and regulators under salinity stress in gill of Labeo rohita.

BACKGROUND: Labeo rohita is the most preferred freshwater carp species in India. The concern of increasing salinity concentration in freshwater bodies due to climate change may greatly impact the aquatic environment. Gills are one of the important osmoregulatory organs and have direct contact with external environment. Hence, the current study is conducted to understand the gill transcriptomic response of L. rohita under hypersalinity environment. RESULTS: Comprehensive analysis of differentially expressed long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and mRNAs was performed in gills of L. rohita treated with 2, 4, 6 and 8ppt salinity concentrations. Networks of lncRNA-miRNA-mRNA revealed involvement of 20, 33, 52 and 61 differentially expressed lncRNAs, 11, 13, 26 and 21 differentially expressed miRNAs in 2, 4, 6 and 8ppt groups between control and treatment respectively. These lncRNA-miRNA pairs were regulating 87, 214, 499 and 435 differentially expressed mRNAs (DE mRNAs) in 2, 4, 6 and 8ppt treatments respectively. Functional analysis of these genes showed enrichment in pathways related to ion transportation and osmolyte production to cope with induced osmotic pressure due to high salt concentration. Pathways related to signal transduction (MAPK, FOXO and phosphatidylinositol signaling), and environmental information processing were also upregulated under hypersalinity. Energy metabolism and innate immune response pathways also appear to be regulated. Protein turnover was high at 8ppt as evidenced by enrichment of the proteasome and aminoacyl tRNA synthesis pathways, along with other enriched KEGG terms such as apoptosis, cellular senescence and cell cycle. CONCLUSION: Altogether, the RNA-seq analysis provided valuable insights into competitive endogenous (lncRNA-miRNA-mRNA) regulatory network of L. rohita under salinity stress. L. rohita is adapting to the salinity stress by means of upregulating protein turnover, osmolyte production and removing the damaged cells using apoptotic pathway and regulating the cell growth and hence diverting the essential energy for coping with salinity stress.

Kidney transcriptome response to salinity adaptation in Labeo rohita.

The increasing salinization of freshwater resources, owing to global warming, has caused concern to freshwater aquaculturists. In this regard, the present study is aimed at economically important freshwater fish, L. rohita (rohu) adapting to varying degrees of salinity concentrations. The RNA-seq analysis of kidney tissue samples of L. rohita maintained at 2, 4, 6, and 8 ppt salinity was performed, and differentially expressed genes involved in various pathways were studied. A total of 755, 834, 738, and 716 transcripts were downregulated and 660, 926, 576, and 908 transcripts were up-regulated in 2, 4, 6, and 8 ppt salinity treatment groups, respectively, with reference to the control. Gene ontology enrichment analysis categorized the differentially expressed genes into 69, 154, 92, and 157 numbers of biological processes with the p value < 0.05 for 2, 4, 6, and 8 ppt salinity groups, respectively, based on gene functions. The present study found 26 differentially expressed solute carrier family genes involved in ion transportation and glucose transportation which play a significant role in osmoregulation. In addition, the upregulation of inositol-3-phosphate synthase 1A (INO1) enzyme indicated the role of osmolytes in salinity acclimatization of L. rohita. Apart from this, the study has also found a significant number of genes involved in the pathways related to salinity adaptation including energy metabolism, calcium ion regulation, immune response, structural reorganization, and apoptosis. The kidney transcriptome analysis elucidates a step forward in understanding the osmoregulatory process in L. rohita and their adaptation to salinity changes.

A rare chromosomal polymorphism in a Kangayam bull (Bosindicus) of south India.

A chromosomal polymorphism was detected on karyological screening of Kangayam breeding sires prior to subjecting them for frozen semen collection. One bull possessed the chromosomal complement 2n = 60, consisting of 58 acrocentric autosomes, one large sub-metacentric X-chromosome, and one small acrocentric Y-chromosome with a small visible p-arm, which was further confirmed using CBG- and GTG-banding. This polymorphism was attributed to a heterochromatin variation of the acrocentric Y-chromosome routine in the Bosindicus Linnaeus, 1758 cattle.