title: The 35-amino acid C2 protein of Cotton leaf curl Kokhran virus, Burewala, implicated in resistance breaking in cotton, retains some activities of the full-length protein.
abstract: With one exception, all the begomoviruses characterized so far encode an ~134-amino acid (aa) (A)C2 protein. The exception is the "Burewala" strain of Cotton leaf curl Kokhran virus (CLCuKoV-Bu), associated with resistance breaking in cotton across Pakistan and northwestern India, that encodes a truncated 35-aa C2. The C2 protein encoded by begomoviruses performs multiple functions including suppression of post-transcriptional gene silencing (PTGS), modulating microRNA (miRNA) expression and may be a pathogenicity determinant. The study described here was designed to investigate whether the CLCuKoV-Bu 35-aa C2 retains the activities of the full-length C2 protein. The results showed the 35-aa C2 of CLCuKoV-Bu acts as a pathogenicity determinant, suppresses PTGS and upregulates miRNA expression when expressed from a Potato virus X vector in Nicotiana benthamiana. The symptoms induced by expression of full-length C2 were more severe than those induced by the 35-aa C2. The accumulation of most developmental miRNAs decreases with the full-length C2 protein and increases with the 35-aa peptide of CLCuKoV-Bu. The study also revealed that 35-aa peptide of CLCuKoV-Bu maintains suppressor of silencing activity at a level equal to that of full-length C2. The significance of the results with respect to virus fitness and resistance breaking is discussed.
authors.affiliation: Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Jhang Road, Faisalabad, Pakistan.|Botanical Institute of the University of Basel, Zürich-Basel Plant Science Center, Part of the Swiss Plant Science Web, Schnbeinstrasse 6, 4056, Basel, Switzerland.|Centre for Biotechnology and Microbiology, University of Swat, Swat, Pakistan.
authors.forename: Fazal
authors.initials: F
authors.lastname: Akbar
authors.affiliation: Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Jhang Road, Faisalabad, Pakistan.|Institute of Biochemistry and Biotechnology, University of the Punjab, Lahore, Pakistan.
authors.forename: Zafar
authors.initials: Z
authors.lastname: Iqbal
authors.affiliation: Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Jhang Road, Faisalabad, Pakistan.
authors.forename: Rob W
authors.initials: RW
authors.lastname: Briddon
authors.affiliation: Botanical Institute of the University of Basel, Zürich-Basel Plant Science Center, Part of the Swiss Plant Science Web, Schnbeinstrasse 6, 4056, Basel, Switzerland.|MDPI AG, Klybeckstrasse 64, 4057, Basel, Switzerland.
authors.forename: Franck
authors.initials: F
authors.lastname: Vazquez
authors.affiliation: Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Jhang Road, Faisalabad, Pakistan. saeed_hafeez@yahoo.com.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Saeed
mesh_terms: D000596:Amino Acids / Q000235:genetics*; D053839:Begomovirus / Q000235:genetics*; D005814:Genes, Viral / Q000235:genetics; D003368:Gossypium / Q000821:virology*; D007194:India; D035683:MicroRNAs / Q000235:genetics; D010154:Pakistan; D010935:Plant Diseases / Q000821:virology; D017863:Potexvirus / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D000596:Amino Acids; D035683:MicroRNAs; D014764:Viral Proteins
keywords: Begomovirus; Gene silencing; MicroRNA; Resistance breaking; Suppressor