Functional annotation and homology studies of Gossypium arboreum root cDNA Library under drought stress

Functional Genomics

poster

JAMAL, ADIL; SHAHID, MUHAMMAD NAVEED; AFTAB, BEENISH; RASHID, BUSHRA ; HUSNAIN, TAYYAB

JAMAL, ADIL

JAMAL, ADIL; SHAHID, MUHAMMAD NAVEED; AFTAB, BEENISH; RASHID, BUSHRA ; HUSNAIN, TAYYAB

Twenty first century is the era where modern genomic approaches like gene identification, their characterization and expression under environmental stresses explore the functional genomics in crop plants. In this regard cDNA library construction, functional annotation and homology studies is a powerful approach for studying a large number of genes (sequences) for those crops whose genome is not completely sequenced. No more information is available on Gossypium arboreum root genes and functions. Therefore study was aimed to develop drought stressed Gossypium arboreum (FDH-786) cDNA library to study the functions and homology of clones expressed in roots under dehydration Biochemical attributes were performed both in cotton (FDH-786) roots and leaf tissue it was found that proline, total soluble protein, total soluble sugars and total free amino acids are significantly higher in drought stressed roots and leaves as compared to irrigated plant tissues. Biochemical assays were performed in roots to confirm significant accumulation of biological molecules (Proteins, sugars and amino acids) that escort to search drought tolerant functional EST in roots of G. arboreum which are kinases, transcription factors and binding proteins playing an important role in drought induction mechanism in roots. A cDNA library from drought stressed roots has been constructed. Ten thousands clones were randomly picked and PCR amplified. The inserts size was found in a range of 200-1000bp. Seven hundred eleven (711) clones (submitted to NCBI GenBank JK757087-JK757798) were sequenced and annotated. Twenty four percent (24%) clones didn't show significant homology to GenBank non-redundant database. It showed the potential of cotton (G.arboreum) genome for the identification of new genes under abiotic stresses. Twenty seven percent (27%) clones sequences show similarity with Gossypium species, seven percent (7%) show significant homology with Populus trichochorpa sequences, six percent (6%) with Oryza, five percent (5%) with Zea mays, four percent (4%) with Glycine max, three percent (3%) with Medicago and Niocotiana species , two percent (2%) with Arabidopsis, Atriplex and Ricinus species, while forteen percent (14%) have significant homology with other plant species. 27% homology with cotton confirms the authenticity of the cotton cDNA library. It revealed a collection of valuable drought stress (response to water deprevation) tolerant EST that include stress proteins (late embryogenesis abundant, heat shock protein, dehydrin, ERD six like1) Transcription Factor (Cys2/His2-type zinc-finger proteins, WRKY, B-box type zinc finger family, NAC domain containing protein, MADS-box protein, Homeodomain leucine zipper, Basic Helix-Loop-Helix), Kinases (diacylglycerol kinase, Shaggy like kinases, Histidine kinase, leucine rich repeat receptor, RAN GTPase activating protein kinase, like auxin resistant), Binding protein (ATP-Binding Cassette, TGF-β receptor interacting protein, Acyl-COA binding protein, RAS-related GTP-binding nuclear protein) Transferases (glutathione transferase), flavin mononucleotide. All these dehydration responsive factors are involved in the regulation of abscisic acid pathway interaction either directly or indirectly. Ultimately these kinases, protein, transporters and osmo-regulators contribute toward the activation of late responsive genes in plants.