Title: Co-infection and disease severity of Maize dwarf mosaic virus and Maize chlorotic dwarf virus strains Authors
|Morales-Cruz, Katia -|
|Zambrano, Jose Luis -|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 22, 2014
Publication Date: N/A
Interpretive Summary: Co-infections by multiple plant viruses are common in field settings, and are likely for the two major U. S. corn viruses: Maize dwarf mosaic virus (MDMV) and Maize chlorotic dwarf virus (MCDV). In some cases, virus co-infections can lead to much more severe disease than either virus alone. To examine whether this was the case for MDMV and MCDV, we tested co-inoculated plants for virus accumulation of each virus, disease symptoms, and traits such as leaf length and node height for four weeks after inoculation under greenhouse conditions. Based on our results, we conclude that co-infection of MDMV and the severe strain of MCDV (MCDV-S) results in stronger and more persistent disease symptoms than infection with either virus alone. We did not observe symptom enhancement when MDMV was coinfected with a mild strain of MCDV (MCDV-M1) or when two different strains of MCDV were co-infected (MCDV-M1 and MCDV-S).
Technical Abstract: Two major maize viruses have been reported in the United States: Maize dwarf mosaic virus (MDMV) and Maize chlorotic dwarf virus (MCDV). These viruses co-occur in regions where maize is grown such that co-infections are likely. Co-infection of different strains of MCDV is also observed frequently, and a synergistic enhancement of symptoms in co-infected plants was previously reported. Here we examined the impact of co-infections of two strains of MCDV (MCDV-S and MCDV-M1, severe and mild), and co-infections of MCDV and MDMV in ‘Spirit’ maize in greenhouse experiments. Quantitative plant growth and development parameters were measured and virus accumulation was measured by RT-qPCR. Based on our results, we conclude that virus symptoms are enhanced and plants show less recovery over time in co-infections of MDMV and MCDV-S compared to single infections with either virus. In contrast, MDMV co-infections with MCDV-M1 did not show symptom enhancement for either virus, and co-infection of MCDV-M1 and MCDV-S results in symptoms intermediate between the two single infections.