Cassava brown streak virus has a rapidly evolving genome: implications for virus speciation, variability, diagnosis and host resistance.
Cassava is a major staple food for about 800 million people in the tropics and sub-tropical regions of the world. Production of cassava is significantly hampered by cassava brown streak disease (CBSD), caused by Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). The disease is suppressing cassava yields in eastern Africa at an alarming rate. Previous studies have documented that CBSV is more devastating than UCBSV because it more readily infects both susceptible and tolerant cassava cultivars, resulting in greater yield losses. Using whole genome sequences from NGS data, we produced the first coalescent-based species tree estimate for CBSV and UCBSV. This species framework led to the finding that CBSV has a faster rate of evolution when compared with UCBSV. Furthermore, we have discovered that in CBSV, nonsynonymous substitutions are more predominant than synonymous substitution and occur across the entire genome. All comparative analyses between CBSV and UCBSV presented here suggest that CBSV may be outsmarting the cassava immune system, thus making it more devastating and harder to control.
National Crops Resources Research Institute, P.O. Box 7084, Kampala, Uganda.
Titus
T
Alicai
Mikocheni Agricultural Research Institute, Coca cola Road, Box 6226, Dar es Salaam, Tanzania.
Joseph
J
Ndunguru
Mikocheni Agricultural Research Institute, Coca cola Road, Box 6226, Dar es Salaam, Tanzania.
Peter
P
Sseruwagi
Mikocheni Agricultural Research Institute, Coca cola Road, Box 6226, Dar es Salaam, Tanzania.
Fred
F
Tairo
National Crops Resources Research Institute, P.O. Box 7084, Kampala, Uganda.
Geoffrey
G
Okao-Okuja
National Crops Resources Research Institute, P.O. Box 7084, Kampala, Uganda.
Resty
R
Nanvubya
National Crops Resources Research Institute, P.O. Box 7084, Kampala, Uganda.
Lilliane
L
Kiiza
The Ohio State University, 154W 12th Avenue, Columbus, Ohio 43210, USA.
Laura
L
Kubatko
Crop Protection Branch, Department of Agriculture and Food, Western Australia, Bentley Delivery Centre, Perth, 6983, Western Australia, Australia.
Monica A
MA
Kehoe
The University of Western Australia, ARC Centre of Excellence in Plant Energy Biology and School of Chemistry and Biochemistry, Crawley, Perth 6009, Western Australia, Australia.
Laura M
LM
Boykin
D000596:Amino Acids / Q000235:genetics; D001483:Base Sequence; D060467:Disease Resistance / Q000235:genetics*; D019143:Evolution, Molecular; D049810:Genetic Speciation; D014644:Genetic Variation; D016679:Genome, Viral; D059014:High-Throughput Nucleotide Sequencing; D002365:Manihot / Q000821:virology*; D010802:Phylogeny; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000821:virology; D018547:Plant Stems / Q000821:virology; D019176:Potyviridae / Q000235:genetics* / Q000302:isolation & purification; D012641:Selection, Genetic; D014454:Uganda
D000596:Amino Acids