|Coyne, Clarice - Clare|
Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2014
Publication Date: 3/7/2014
Citation: Konecná, E., Šafárová, D., Navrátil, M., Hanácek, P., Coyne, C.J., Flavell, A., Vishyakova, M., Ambrose, M., Redden, R., Smykal, P. 2014. Geographical gradient of the eIF4E alleles conferring resistance to potyviruses in pea (Pisum sp.) germplasm. PLoS One. 9(3):e90394. DOI: 10.1371/journal.pone.0090394. Interpretive Summary: After fungi, viruses cause the most devastating diseases worldwide causing economically significant losses of crop yield and quality. Moreover, on-going climate change could accelerate temporal and spatial diseases spread and their severity. Detailed knowledge about natural and cultural pathosystems is necessary to avoid and/or limit negative impact on crop production by development of resistant/tolerant cultivars and application of appropriate agro-technical measurement and agricultural zoning. Among the biggest and the most important viral genera are the Begomovirus and Potyvirus. Pea seed borne mosaic virus (PSbMV) is a member of Potyvirus genus. Its natural host range is connected with legumes. The economically important host plants are pea, lentil, faba bean, and chickpe. The virus causes various symptoms depends on the host and virus isolate/pathotype, such as downward rolling of leaflets, the transient clearing and swelling of leaf veins, chlorotic mosaics, stunting, and delayed flowering. PSbMV is transmitted between plants in a non-persistent manner by the aphids and then infect seeds. Discovered in Czechoslovakia it has been recently reported worldwide, causing serious yield losses. Due to its seed borne transmission PSbMV represents serious phytosanitary risk both for germplasm maintenance and seed production. In this study we have combined our knowledge of pea germplasm diversity with that of the eIF4E resistance gene and systematically screened 2803 accessions with known geographical origin and 149 wild Pisum sp. for the resistance or susceptible gene.
Technical Abstract: The eukaryotic translation initiation factor 4E was shown to be involved in natural resistance against several potyviruses in plants. In this study we have combined our knowledge of pea germplasm diversity with that of the eIF4E gene for virus resistance and screened 2803 accessions with known geographical origin complemented with 149 accessions of wild Pisum sp. Using length polymorphism of eIF4E intron 3 we detected four alleles (eIF4EA-B-C and eIF4ES). Sequencing resulted in the detection of 31 haplotypes with 156 polymorphic sites. Original eIF4EA allele conferring resistance to P1 PSbMV was found in 53 accessions (1.9%), of which 28 were modern varieties with single source of resistance, while 15 were landraces from India, Afghanistan and Nepal and 7 were from Ethiopia or Eastern Africa. A newly discovered allele eIF4EB was present in 328 accessions (11.7%) originating from Ethiopia (29%), Afghanistan (23%), India (20%), Israel (25%) and China (39%). The deduced amino acid sequence of eIF4EB allele was identical to susceptible eIF4ES allele except of two amino acid exchanges. The eIF4EC allele was detected in 91 accessions (3.2%) from India (20%), Afghanistan (33%), Iberian Peninsula (22%) and Balkan (9.3%). Haplotype network analysis indicated different evolution of eIF4E alleles. Wild Pisum elatius JI261 from Turkey had a sensitive allele at the amino acid level, but at the nucleotide level showed a transitory stage to the eIF4EB allele, while other wild Pisum sp. were more distant. These data highlight the importance of Ethiopian, Central Asia and Chinese regions as the secondary centres of diversity for pea, corresponding with the diversity of the pathogen.