Wheat yellow mosaic virus (WYMV) is one of the most serious viral pathogens causing reductions in wheat yield in East Asia. We investigated the phylodynamics of WYMV by analysing the CP, VPg and P1 genes to understand the origin and dispersal of the virus. A Bayesian phylogenetic analysis revealed that the most recent common WYMV ancestor occurred in approximately 1742 (95% credibility interval, 1439–1916) CE (Common Era), and the evolutionary rates of the VPg, CP and P1 genes were 6.669 × 10−4 (95% credibility interval: 4.575 × 10−4–8.927 × 10−4), 2.468 × 10−4 (95% credibility interval: 1.667 × 10−4–3.338 × 10−4) and 5.765 × 10−5 (95% credibility interval: 3.285 × 10−6–1.252 × 10−4), respectively. Our phylogeographic analysis indicated that the WYMV population may have originated in Henan Province, China, first spreading to Japan in the mid-19th century and stopping after the Japanese surrender in World War II. The second wave spread to Japan from Shandong Province, China, in approximately 1977, a few years after the establishment of diplomatic relations between China and Japan. Before the founding of the People's Republic of China, Henan Province was the emigration centre of WYMV in East Asia, and after the late 20th century, Jiangsu and Shandong Provinces were also the virus emigration centres in East Asia. In addition, there were two migration pathways from Japan to Jiangsu and Shandong Provinces, China, in approximately 1918 and approximately 1999 respectively. Our results suggest that the wide spread of WYMV in East Asia is strongly related to human factors.
Read full abstract