H9N2 avian influenza virus (AIV) infection is a major problem in poultry industry worldwide. In this study, molecular characterizations and phylogenetic relationships of hemagglutinin (HA) gene sequences of H9N2 AIV of 5 Chinese isolates in 2014 recently available in GenBank, 3 widely used vaccine strains, and 52 novel isolates in China from 2013 to 2015 were analyzed. The homology analysis showed that the nucleotide sequences of HA gene of these recent Chinese H9N2 AIV isolates shared homologies from 94.1 to 99.9%. Phylogenetic analysis showed that all isolates belonged to AIV lineage h9.4.2.5. Fifty-six out of the 57 recent Chinese H9N2 AIV isolates had the motifs PSRSSR↓GLF at the cleavage sites within the HA protein, while one isolate PWH01 harbored LSRSSR↓GLF. Remarkably, all of the recent Chinese H9N2 AIV strains had the Q216L substitution in the receptor binding site, which indicated that they had potential to infect humans. Most of recent Chinese H9N2 AIV isolates lost the potential N-linked glycosylation site at residues 200–202 compared with vaccine strains. This present study demonstrated that AIV lineage h9.4.2.5 was more predominant in China than other lineages as it harbored all the H9N2 AIV isolated between 2013 and 2015. Also we showed the importance of continuous surveillance of emerging H9N2 AIV in China and update of vaccine formulation accordingly in order to prevent and control H9N2 AIV.

Bulk-SSR method was used to analyze the genetic diversity of 44 open-pollinated varieties collected from Henan, Shandong, Shanxi, and Jilin provinces and Guangxi Zhuang Autonomous Region, China using 70 pairs of SSR primers. The purposes of this study were to (1) compare the genetic diversity among 44 Chinese maize open-pollinated varieties; (2) estimate the minimum number of alleles for construction of a stable dendrogram; and (3) trace the genetic relationships among local germplasm from different regions of China. In total, these 70 SSR primers yielded 292 alleles in 176 samples (4×44) analyzed. The number of alleles per locus was 4.17 on average and ranged from 2 to 8. The highest number of alleles per open-pollinated variety (55.25) was detected in Shanxi germplasm, which indicated that open-pollinated varieties from Shanxi possessed the largest genetic diversity among those from the five locations. The correlation coefficients between different genetic similarity matrices suggested that 200 alleles were sufficient for analysis of the genetic diversity of these 44 open-pollinated varieties. The cluster analysis showed that 44 open-pollinated varieties collected from three growing regions in China were accurately classified into three groups that were highly consistent with their geographic origins, and there is no correlation between GS and geographic distance in this study.