Characterization of DNAbeta associated with begomoviruses in China and evidence for co-evolution with their cognate viral DNA-A.
Eighteen samples of begomoviruses isolated from tobacco, tomato and weed species in Yunnan, China were found to be associated with DNAbeta molecules, for which the complete nucleotide sequences were found to contain 1333-1355 nt. The 18 DNAbeta molecules identified consist of three main types, each associated with a different begomovirus species: 72-99 % nucleotide identity was found within one type, but only 39-57 % identity was found between types. All the DNAbeta molecules reported here and elsewhere contain a 115 nt conserved region that has 93-100 % identity with a consensus sequence, and have a common ORF encoding 118 amino acids on the complementary strand (designated C1). Co-agroinoculation of the DNA-A component of Tomato yellow leaf curl China virus tobacco isolate Y10, with its associated DNAbeta (Y10beta), shows this DNAbeta to be involved in symptom induction in tobacco and tomato. The in-frame ATG mutation of C1 of Y10beta caused much milder symptoms as compared with wild Y10beta, indicating a functional role for this ORF. Pairwise nucleotide sequence identity comparisons of DNAbeta molecules and their cognate viral DNA-A molecules indicate that DNAbeta molecules have co-evolved with their cognate helper viruses. Recombination between DNAbeta molecules is documented and a DNAbeta species concept is proposed and discussed.
Zhou
Xueping
X
Institute of Biotechnology, Zhejiang University, Hangzhou 310029, P.R. China.
Xie
Yan
Y
Institute of Biotechnology, Zhejiang University, Hangzhou 310029, P.R. China.
Tao
Xiaorong
X
Institute of Biotechnology, Zhejiang University, Hangzhou 310029, P.R. China.
Zhang
Zhongkai
Z
Yunnan Biotechnology Research Institute, Yunnan Academy of Agricultural Sciences, Kunming 650223, P.R. China.
Li
Zhenghe
Z
Institute of Biotechnology, Zhejiang University, Hangzhou 310029, P.R. China.
Fauquet
Claude M
CM
International Laboratory for Tropical Agricultural Biotechnology, Danforth Plant Science Center, St Louis, MO 63132, USA.
D001483:Base Sequence; D002681:China; D004279:DNA, Viral / Q000032:analysis / Q000235:genetics*; D019143:Evolution, Molecular; D017791:Geminiviridae / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D018551:Solanum lycopersicum / Q000821:virology; D008969:Molecular Sequence Data; D010802:Phylogeny; D010935:Plant Diseases / Q000821:virology; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D014026:Nicotiana / Q000821:virology
D004279:DNA, Viral