RESUMEN
Soybean mosaic virus (SMV) is a critical pathogen that reduces the soybean yield and seed quality worldwide, and SMV has a restricted natural host range. In this study, we used sequence-independent amplification (SIA) methods to identify the viruses that may cause the Atractylodes macrocephala Koidz disease. Results revealed that there is SMV in diseased Atractylodes macrocephala leaves, and we named this isolate as SMV-Am. To further characterize the genomic structural and phylogenetic relationships of SMV-Am, genomic dsRNA was extracted, and the genomic sequence was amplified by RT-PCR and RACE. The results of bioinformatics analysis showed that the genomic RNA of SMV-Am is 9587 nucleotides in length, which conforms to the typical characteristics of Potyvirus. According to the sequence alignment of complete nucleotide sequences, SMV-Am showed the highest level of nucleotide homology and amino acid sequences to SMV-Liaoning, 96. 57% and 98. 86%, respectively. In addition, phylogenetic analysis based on the nucleotide sequences of other SMV isolates of SMV-Am revealed that SMV-Am was most closely related to SMV-Liaoning. Then, the SMV-Am protein was further analyzed by I-TASSER and PyMOL software, revealing that the key amino acid mutations led to the structural changes of P1, HC-Pro, P3, 6K2, NIa-pro and NIb proteins, with P1 the most obvious. Finally, recombination has been detected at the position of 6560-8950 nucleotides, the main parent is the isolate SMV-XFQ012 (accession number KP710875. 1), and the secondary parent is isolate SMV-pCB301-SC15 (accession number MH919386. 1). This study is the first report of SMV in Atractylodes macrocephala Koidz, and these results are expected to provide a scientific basis for the prevention and control of SMV infection on Atractylodes macrocephala Koidz.
RESUMEN
Soybean mosaic virus (SMV), one of the major viral diseases of Pinellia ternata (Thunb.) Breit., has had a serious impact on its yield and quality. The construction of viral infectious clones is a powerful tool for reverse genetics research on viral gene function and interaction between virus and host. To clarify the molecular mechanism of SMV infection in Pinellia ternata, it is particularly important to construct the SMV full-length cDNA infectious clone. Therefore, the infectious clone of Soybean mosaic virus Shanxi Pinellia ternata isolate (SMV-SXBX) was constructed in this study by Gibson in vitro recombination system, and the healthy Pinellia ternata leaves were inoculated by Agrobacterium infiltration, further through mechanical passage and RT-PCR, confirming that the 3' end of the SMV-SXBX infectious clone had a stable infectivity when it contained 56-nt of poly(A) tail. This method is not only convenient and efficient, but also avoids the instability of SMV infectious clones in Escherichia coli. The construction of SMV full-length infectious cDNA clones laid the foundation for further study on the molecular mechanism of SMV replication and pathogenesis.