title: Population structure and diversity of citrus tristeza virus (CTV) isolates in Hunan province, China.
abstract: Stem-pitting (SP) is the main type of citrus tristeza virus (CTV) that causes severe damage to citrus trees, especially those of sweet orange, in Hunan province, China. Understanding the local CTV population structure should provide clues for effective mild strain cross-protection (MSCP) of the SP strain of CTV. In this study, markers for the p23 gene, multiple molecular markers (MMMs), and sequence analysis of the three silencing suppressor genes (p20, p23 and p25) were employed to analyze the genetic diversity and genotype composition of the CTV population based on 51 CTV-positive samples collected from 14 citrus orchards scattered around six major citrus-growing areas of Hunan. The results indicated that the CTV population structure was extremely complex and that infection was highly mixed. In total, p23 gene markers resulted in six profiles, and MMMs demonstrated 25 profiles. The severe VT and T3 types appeared to be predominantly associated with SP, while the mild T30 and RB types were related to asymptomatic samples. Based on phylogenetic analysis of the amino acid sequences of p20, p23 and p25, 19 representative CTV samples were classified into seven recently established CTV groups and a potentially novel one. A high level of genetic diversity, as well as potential recombination, was revealed among different CTV isolates. Five pure SP severe and two pure mild strains were identified by genotype composition analysis. Taken together, the results update the genetic diversity of CTV in Hunan with the detection of one possible novel strain, and this information might be applicable for the selection of appropriate mild CTV strains for controlling citrus SP disease through cross-protection.
authors: Horticulture and Landscape College, Hunan Agricultural University, Changsha, 410128, China.
authors: Cui
authors: C
authors: Xiao
authors: Horticulture and Landscape College, Hunan Agricultural University, Changsha, 410128, China.
authors: Run-Xian
authors: RX
authors: Yao
authors: Horticulture and Landscape College, Hunan Agricultural University, Changsha, 410128, China.
authors: Fang
authors: F
authors: Li
authors: Horticulture and Landscape College, Hunan Agricultural University, Changsha, 410128, China.|Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128, China.
authors: Su-Ming
authors: SM
authors: Dai
authors: Parco Scientifico e Tecnologico della Sicilia, z.i., Stradale Lancia 57, 95121, Catania, Italy.
authors: Grazia
authors: G
authors: Licciardello
authors: Parco Scientifico e Tecnologico della Sicilia, z.i., Stradale Lancia 57, 95121, Catania, Italy.
authors: Antonino
authors: A
authors: Catara
authors: Dipartimento di Agricoltura, Alimentazione e Ambiente, Università degli Studi di Catania, Piazza Università 2, 95131, Catania, Italy. gentilea@unict.it.
authors: Alessandra
authors: A
authors: Gentile
authors: Horticulture and Landscape College, Hunan Agricultural University, Changsha, 410128, China. deng7009@163.com.|Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128, China. deng7009@163.com.
authors: Zi-Niu
authors: ZN
authors: Deng
mesh_terms: D002681:China; D002957:Citrus / Q000821:virology*; D003001:Cloning, Molecular; D017790:Closterovirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D015870:Gene Expression; D005819:Genetic Markers; D014644:Genetic Variation; D016679:Genome, Viral; D005838:Genotype; D054884:Host-Pathogen Interactions; D010802:Phylogeny; D058974:Phylogeography; D010935:Plant Diseases / Q000821:virology; D011995:Recombination, Genetic; D014197:Trees / Q000821:virology; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D005819:Genetic Markers; D014764:Viral Proteins