Genetic Variability and Molecular Evolution of Maize Yellow Mosaic Virus Populations from Different Geographic Origins

• Published in: Plant disease Vol. 105; no. 4; p. 896
• Main Authors: Sun, Sheng-Ren, Chen, Jian-Sheng, He, Er-Qi, Huang, Mei-Ting, Fu, Hua-Ying, Lu, Jia-Ju, Gao, San-Ji
• Format: Journal Article
• Language: English
• Published: United States 01.04.2021
• Subjects: China; Evolution, Molecular; Genome, Viral - genetics; Luteoviridae - genetics; Mosaic Viruses - genetics; Phylogeny; Plant Diseases; South America; Zea mays; South America; China; evolutionary forces; phylogenetic analysis; population genetic structure; viruses and viroids; field crops; pathogen diversity; geographic isolation; maize yellow mosaic virus
• DOI: 10.1094/PDIS-05-20-1013-RE
• ISSN: 0191-2917

Maize yellow mosaic virus (MaYMV) hosted in various gramineous plants was assigned to the genus (family ) in 2018. However, little is known about its genetic diversity and population structure. In this study, 509 sugarcane leaf samples with mosaic symptoms were collected in 2017 to 2019 from eight sugarcane-growing provinces in China. Reverse-transcription PCR results revealed that four positive-sense RNA viruses were found to infect sugarcane, and the incidence of MaYMV among samples from Fujian, Sichuan, and Guangxi Provinces was 52.1, 9.8, and 2.5%, respectively. Based on 82 partial MaYMV sequences and 46 whole-genome sequences from different host plants, phylogenetic analysis revealed that MaYMV populations are very closely associated with their source geographical regions (China, Africa, and South America). Pairwise identity analysis showed significant variability in genome sequences among MaYMV isolates with genomic nucleotide identities of 91.1 to 99.9%. In addition to codon mutations, insertions or deletions also contributed to genetic variability in individual coding regions, especially in the readthrough protein (P3-P5 fusion protein). Low gene flow and significant genetic differentiation of MaYMV were observed among the three geographical populations, suggesting that environmental adaptation is an important evolutionary force that shapes the genetic structure of MaYMV. Genes in the MaYMV genome were subject to strong negative or purification selection during evolution, except for the movement protein (MP), which was under positive selection pressure. This finding suggests that the MP may play an important role in MaYMV evolution. Taken together, our findings provide basic information for the development of an integrated disease management strategy against MaYMV.