Molecular characterization of a divergent genetic variant of wheat Eqlid mosaic virus from a Texas wheat field.

Investigations conducted during the spring 2020 season to diagnose the associated viral agent of a severe mosaic disease of wheat in a Texas Panhandle field revealed the presence of wheat Eqlid mosaic virus (WEqMV; genus Tritimovirus, family Potyviridae) in the analyzed samples. The complete genome sequences of two WEqMV isolates were determined, and each was found to be 9,634 nucleotides (nt) in length (excluding the polyA tail) and to contain 5' and 3' untranslated regions of 135 nt and 169 nt, respectively, based on rapid amplification of cDNA ends (RACE) assays. Both sequences contained an open reading frame (ORF) of 9,330 nt encoding a polyprotein of 3,109 amino acids (aa). The ORF sequences of the two isolates were 100% identical to each other, but only 74.7% identical to that of the exemplar WEqMV-Iran isolate, with 85.7% aa sequence identity in the encoded polyprotein. The Texas WEqMV isolates also diverged significantly from WEqMV-Iran in the individual proteins at the nt and aa levels. This is the first report of WEqMV in the United States and the first report of this virus outside of Iran, indicating an expansion of its geographical range.

Rapid detection of Potato leafroll virus and Potato virus Y by reverse transcription loop-mediated isothermal amplification method in north-east India.

Potato leafroll virus (PLRV) and Potato virus Y (PVY) are two important viruses causing serious potato yield losses in the North-east region and other planting areas in India. As a consequence, it is urgent to develop an efficient and quick method for the identification and diagnosis in the field. The results presented here showed that the reverse transcription loop-mediated isothermal amplification (RT-LAMP) method was efficient and sensitive than reverse transcription-polymerase chain reaction (RT-PCR) for the detection of PLRV and PVY. The RT-LAMP primers specifically targeted PLRV and PVY (including PVYO, PVYN, and PVYNTN strains) and resulted in typical sigmoidal amplification curves. Ten-fold serial dilutions of PLRV and PVY total RNA indicated that RT-LAMP is faster and at least a hundred times more sensitive than RT-PCR in detecting both the viruses. Additionally, samples that RT-PCR could not detect at a diluted concentration of 10-3 and 10-4 ng/µl were identified by RT-LAMP. Thus, RT-LAMP offers many advantages over RT-PCR such as low cost and high accuracy, sensitivity, and specificity for the rapid diagnosis of plant virus diseases. In conclusion, the results highlighted the efficacy of the RT-LAMP method in quickly detecting PLRV and PVY in infected plants.