无题项目

Barley yellow dwarf disease, caused by the Barley yellow dwarf virus (BYDVs), significantly impacts global wheat crop production. It has reached epidemic proportions in Qinghai Province of China. To explore the primary epidemic strains, genetic evolution, and molecular characteristics of the disease, our research team collected 90 samples from various locations in Qinghai Province between July and September 2019. Molecular identification and genetic analysis identified BYDV-GAV as the predominant strain in Qinghai Province, with a detection rate of 92%. We successfully cloned 44 BYDV-GAV isolates with a genome length of approximately 5.7 kb. Analysis of molecular population genetics indicated low genetic divergence (genetic distance <0.1) among geographical populations of BYDV-GAV in Qinghai Province. The low FST values (<0.33) and high Nm values (2.65-6.21) suggested significant gene flow and reduced genetic differentiation between isolates. Tajima's D value was negative, and the dN/dS value of the CP gene exceeded 1, indicating non-synonymous mutations and positive selection pressure or diversified selection in BYDV-GAV isolates from Qinghai Province. Phylogenetic analysis revealed nine distinct groups with a sequence similarity of 99% among the BYDV-GAV isolates, suggesting a common ancestral origin. These findings imply the relative stability of the disease in Qinghai Province.