Biology subjects

Kuriakose, B.

Publications and source records attributed to Kuriakose, B..

5 recordsLinked to original sources

bioRxiv2022

Near-chromosomal de novo assembly of Bengal tiger genome reveals genetic hallmarks of apex-predation

The tiger, a poster child for conservation, remains an endangered apex predator. Continued survival and recovery will require a comprehensive understanding of their genetic diversity and the use of such information for population management. A high-quality tiger genome assembly will be an important tool for conservation genetics, especially for the Indian tiger, the most abundant subspecies in the wild. Here, we present high-quality near-chromosomal genome assemblies of a female and a male wild Indian tiger (Panthera tigris tigris). Our assemblies had a scaffold N50 of >140{square}Mb, with 19{square}scaffolds, corresponding to the 19 numbered chromosomes, containing 95% of the genome. Our assemblies also enabled detection of longer stretches of runs of homozygosity compared to previous assemblies which will improve estimates of genomic inbreeding. Comprehensive genome annotation identified 26,068 protein-coding genes, including several gene families involved in key morphological features such as the teeth, claws, vision, olfaction, taste and body stripes. We also identified 301 microRNAs, 365 small nucleolar RNAs, 632 tRNAs and other noncoding RNA elements, several of which are predicted to regulate key biological pathways that likely contribute to tigers apex predatory traits. We identify signatures of positive selection in the tiger genome that are consistent with the Panthera lineage. Our high-quality genome will enable use of non-invasive samples for comprehensive assessment of genetic diversity, thus supporting effective conservation and management of wild tiger populations.

genomics↗

bioRxiv2020

Human ACE2 receptor polymorphisms predict SARS-CoV-2 susceptibility

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus disease (COVID-19) that has resulted in a global pandemic. It is a highly contagious positive strand RNA virus and its clinical presentation includes severe to critical respiratory disease that appears to be fatal in [~]3-5% of the cases. The viral spike (S) coat protein engages the human angiotensin-converting enzyme2 (ACE2) cell surface protein to invade the host cell. The SARS-CoV-2 S-protein has acquired mutations that increase its affinity to human ACE2 by [~]10-15-fold compared to SARS-CoV S-protein, making it highly infectious. In this study, we assessed if ACE2 polymorphisms might alter host susceptibility to SARS-CoV-2 by affecting the ACE2 S-protein interaction. Our comprehensive analysis of several large genomic datasets that included over 290,000 samples representing >400 population groups identified multiple ACE2 protein-altering variants, some of which mapped to the S-protein-interacting ACE2 surface. Using recently reported structural data and a recent S-protein-interacting synthetic mutant map of ACE2, we have identified natural ACE2 variants that are predicted to alter the virus-host interaction and thereby potentially alter host susceptibility. In particular, human ACE2 variants S19P, I21V, E23K, K26R, T27A, N64K, T92I, Q102P and H378R are predicted to increase susceptibility. The T92I variant, part of a consensus NxS/T N-glycosylation motif, confirmed the role of N90 glycosylation in immunity from non-human CoVs. Other ACE2 variants K31R, N33I, H34R, E35K, E37K, D38V, Y50F, N51S, M62V, K68E, F72V, Y83H, G326E, G352V, D355N, Q388L and D509Y are putative protective variants predicted to show decreased binding to SARS-CoV-2 S-protein. Overall, ACE2 variants are rare, consistent with the lack of selection pressure given the recent history of SARS-CoV epidemics, however, are likely to play an important role in altering susceptibility to CoVs.

genetics↗

bioRxiv2019

Deciphering the transcriptomic insight during organogenesis in castor (Ricinus communis L.), jatropha (Jatropha curcas L.) and sunflower (Helianthus annuus L.)

BackgroundCastor is a non-edible oilseed crop with a multitude of pharmaceutical and industrial uses. Profitable cultivation of the crop is hindered by various factors and one of the approaches for genetic improvement of the crop belonging to a monotypic genus is to exploit biotechnological tools. The major limitation for successful exploitation of biotechnological tools is the in vitro recalcitrance of castor tissues. Response of castor tissues to in vitro culture is poor which necessitated study on understanding the molecular basis of organogenesis in cultured tissues of castor, through de novo transcriptome analysis, by comparing with two other crops (jatropha and sunflower) with good regeneration ability.\n\nResultsRNA-seq analysis was carried out with hypocotyl explants from castor, jatropha and cotyledons from sunflower cultured on MS media supplemented with different concentrations of hormones. Genes that showed strong differential expression analysis during dedifferentiation and organogenic differentiation stages of callus included components of auxin and cytokinin signaling, secondary metabolite synthesis, genes encoding transcription factors, receptor kinases and protein kinases. In castor, many genes involved in auxin biosynthesis and homeostasis like WAT1 (Wall associated thinness), vacuolar transporter genes, transcription factors like short root like protein were down-regulated while genes like DELLA were upregulated accounting for regeneration recalcitrance. Validation of 62 differentially expressed genes through qRT-PCR showed a consensus of 77.4% with the RNA-Seq analysis.\n\nConclusionThis study provides information on the set of genes involved in the process of organogenesis in three oilseed crops which forms a basis for understanding and improving the efficiency of plant regeneration and genetic transformation in castor.

plant biology↗

bioRxiv2019

Deciphering the unique SNPs among leading Indian Tomato Cultivars using Double Digestion Restriction Associated DNA sequencing

World-wide grown and consumed tomato (Solanum lycopersicum) crop used as model system for new cultivar and fruit development. Genetic and genomic research of Indian tomato cultivars will provide an insight to develop new breeding strategies and crop improvement. The present study aimed to identify the high quality common and unique single nucleotide polymorphisms (SNPs), present in 9 different Indian tomato cultivars using double digestion restriction associated DNA sequencing (ddRAD-seq). Total of 36,847,092 raw reads (3.68 GB) were generated for all samples and 3,329,625 of high-quality reads were aligned uniquely to the reference tomato genome. Using stringent filtering, a total of 1,165 SNPs and 69 INDELs were found in genic regions, along with the unique variants to each cultivar was observed. Similarly, 7 and 33 variants were identified in chloroplast and mitochondrial genome of tomato. In addition, the population structure and genetic relationship among these cultivars suggested 4 well-differentiated sub-populations. Functional annotation of SNP/INDLEs associated with flanking sequences along with gene ontology and pathway analysis was performed. Identified SNPs/INDELs could be useful as markers for variety identification for genetic purity analysis. Findings from this work will be useful to plant breeders and research community to deepen their understanding and enhance tomato breeding programs.

genomics↗

bioRxiv2019

Whole genome sequencing and comparative genomic analysis reveal novel allelic variations unique to a purple colored rice landrace (Oryza sativa ssp. indica cv. Purpleputtu)

Purpleputtu (Oryza sativa ssp. indica cv. Purpleputtu) is a unique rice landrace from southern India that exhibits predominantly purple color. This study reports the underlying genetic complexity of the trait and associated domestication and de-domestication processes during its coevolution with present day cultivars. Along-with genome level allelic variations in the entire gene repertoire associated with purple, red coloration of grain and other plant parts. Comparative genomic analysis of the whole genome sequence of Purpleputtu (PP) revels total of 3,200,951 variants including 67,774 unique variations were observed in PP when compared with 108 rice genomes. Multiple sequence alignment uncovered a 14bp deletion in Rc (Red colored, a transcription factor of bHLH class) locus of PP, a key regulatory gene of anthocyanin biosynthetic pathway. Interestingly, this deletion in Rc gene is a characteristic feature of the present-day white pericarped rice cultivars. Phylogenetic analysis of Rc locus revealed a distinct clade showing proximity to the progenitor species rufipogon and nivara. In addition, PP genome exhibits a well conserved a 4.5Mbp region on chromosome 5 that harbors several loci associated with domestication of rice. Further, PP showed 1,387 unique SNPs compared to 3,024 lines of rice (SNP-Seek database). The results indicate that PP genome is rich in allelic diversity and can serve as an excellent resource for rice breeding for a variety of agronomically important traits such as disease resistance, enhanced nutritional values, stress tolerance and protection from harmful UV-B rays.

genomics↗