Complete sequence and diversity of a maize-associated Polerovirus in East Africa

Authors: MASSAWE, DEOGRACIOUS - The Ohio State University; Stewart, Lucy; KAMATENESI, JOVIA - Rwanda Agriculture Board (RAB); ASIIMWE, THEODORE - Rwanda Agriculture Board (RAB); Redinbaugh, Margaret

Submitted to: Virus Genes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2018
Publication Date: 4/23/2018
Citation: Massawe, D., Stewart, L.R., Kamatenesi, J., Asiimwe, T., Redinbaugh, M.G. 2018. Complete sequence and diversity of a maize-associated Polerovirus in East Africa. Virus Genes. 54(3):432-437. https://doi.org/10.1007/s11262-018-1560-5.
DOI: https://doi.org/10.1007/s11262-018-1560-5

Interpretive Summary: Corn is a staple crop in East African countries including Kenya, Uganda, Rwanda, and Tanzania. In recent years, corn production has been reduced and threatened by the emergence and spread of virus-cause Maize lethal necrosis (MLN) in East Africa. Utilizing next generation sequencing of surveyed corn in East Africa, we identified virus populations associated with virus symptoms. In addition to the known viruses causing MLN, we identified a virus that has not previously been described in East Africa, but is similar to viruses recently identified in Korea and China. It is more distantly related to a corn-infecting virus identified in the U.S., maize yellow dwarf virus (MYDV), thus we refer to it as "MYDV-like virus." We discovered this virus in high incidence throughout East Africa, often in co-infections with viruses known to cause MLN. Comparing coat protein-coding sequences of 20 East African isolates to each other and other reported sequences showed minor differences with the Asian viruses, but very little variability across the East African isolates. Discovery of this virus in East Africa adds key knowledge for detection and management of viruses that impact corn.

Technical Abstract: Since 2011-2012, Maize lethal necrosis (MLN) has emerged in East Africa, causing massive yield loss and propelling research to identify viruses and virus populations present in maize. As expected, next generation sequencing (NGS) has revealed diverse and abundant viruses from the family Potyviridae, primarily SCMV, and MCMV (Tombusviridae), which are known to cause MLN by synergistic co-infection. In addition to these expected viruses, we identified a virus in the genus Polerovirus (family Luteoviridae) in 104/172 samples selected for MLN or other potential virus symptoms from Kenya, Uganda, Rwanda, and Tanzania. This polerovirus has not previously been reported in East Africa, but is 97% identical to virus sequences recently reported from China (MaYMV; KU291101, KU291107) infecting maize, 83% identical to polerovirus infecting barley in Korea (BVG; KT962089), and 79% identical to the U.S. maize-infecting polerovirus maize yellow dwarf virus (MYDV-RMV; KT992824). Nucleotide sequences from P0 of 24 individual East African isolates shared 98% or higher identity, indicating limited diversity of this virus in East Africa. We refer to this virus as “MYDV-like polerovirus” until detailed symptom analyses for standard plant virus nomenclature are developed.