Working group session:
Functional Genomics
Presentation type:
poster
Authors:
Husnain, Dr Tayyab; Jamal, Adil; Shahid, M. Naveed; Aftab, Beenish; Batool, Fatima; Rashid, Bushra
Presenter:
Husnain, Dr Tayyab
Correspondent:
Husnain, Dr Tayyab
Abstract:
Salinity and drought has adverse affects on the plant development and ultimately reduces the production. Very few reports are available for the genes induced by salt stress in Gossypium arboreum. Abiotic stress responsive genes were screened from cotton leaves by differential display and gene expression study was compared between control and salt stressed conditions in cotton variety FDH-171. By using 107 primers combination, 25 gene fragments were found to be up regulated in response to salt stress. Out of 25 induced fragments, 12 were rejected as false positive on reamplification and in quality control assay. The remaining fragments were selected for cloning and transformation. Sequence analysis on GenBank Databases(JG294129-JG294141) revealed that five fragments whose sizes ranging from 300-600bp have significant homology to well-known proteins (Protein kinase, proton gradient regulation, Yeast cadmium factor and expressed protein). Real-time PCR study confirmed the over expression of the identified transcripts in salt stressed samples as compared to control. Three transcripts showing good protein homology were further characterized as full length gene and submitted to NCBI GenBank database. Proton gradient regulator (JQ861978), Proteinase inhibitor (JX088126)and Yeast cadmium factor (JG294141) were characterized. Expression analysis using real time PCR reveled significant up regulation under salt stress using real time PCR.
Cotton variety FDH-786 was selected for expression profiling in root under drought stress condition. Physiological, water relations & biochemical assays were performed to analyze the preliminary evaluation for drought tolerance. In case of physiological and gas exchange parameters, relative water contents were significantly higher in control plants while cell membrane thermostability was found to be higher in drought stress plants which allows accumulation of ions, electrolytes and Osmolytes in drought stressed plants. Keeping an eye on gas exchange parameters it was found that transpiration rate, Stomatal conductance and instantaneous water use efficiency is significantly higher in drought stressed plants which shows their efficient utilization of carbon dioxide and water under drought stress. With regard to biochemical attributes both in 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 control plant tissues. 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 (20) clones were found to be differentially expressed on cDNA microarray platform. EST sequences of potential candidates for drought genes were BLAST to NCBI GenBank for their homology search against nucleotide, EST and protein data bases, using BLASTX and BLASTN. Out of twenty, ten (10) ESTs were novel (didn’t showed any homology) to NCBI GenBank nucleotide, EST and protein data bases. Seven (07) have shown homology in all the three databases. Ten (10) have shown homology to only EST database, seven (07) to EST and protein database and four (04) to nucleotide and protein database.
Functionally annotation differentially expressed drought stressed clones clustered, into novel (10), response to abiotic stress and stimulus (total 06 having 03 novel), signal transduction (total 02 having 01 novel), transport (total 02 having 01 novel), developmental processes (total 03 having 01 novel), cell organization & biogenesis (total 02 having 01 novel), electron transport (01), DNA or RNA binding (03), transcription factor activity (total 03 having 02 novel), hydrolase activity (total 03 having 02 novel), transporter activity (03 having 01 novel) and kinase activity (01). These novel 10 differentially expressed transcripts were found to be significantly up regulated using real time PCR studies.
These potential abiotic stress transcripts searched from cotton varieties can further characterized and used in molecular breeding to develop the plants with better architecture that can tolerate well under abiotic stresses.