Isolation and characteristics of the CN gene, a tobacco mosaic virus resistance N gene homolog, from tobacco.
Nicotiana rustica L. HZNH, a native Chinese tobacco germplasm, displays a hypersensitive response (HR) and systemic acquired resistance following infection with tobacco mosaic virus (TMV). A resistance gene, CN, cloned from HZNH plants, was homologous to the N and NH genes identified in other Nicotiana species. The CN coding region (3423 bp) shares 93.63% and 86.50% nucleotide identity with N and NH, respectively. Whereas the five CN exon sequences are highly homologous with those of N and NH, the four introns differ significantly in length and sequence. Sequence analysis revealed that CN belongs to the TIR/NBS/LRR gene class. Expression of CN was up-regulated after TMV infection and was temperature sensitive. Organ-specific expression analysis suggested that CN transcripts accumulated at high levels in leaves, low levels in stems, and minimal levels in roots. When CN was inserted into TMV-susceptible N. tabacum cv. K326 plants by Agrobacterium-mediated transformation, the transgenic plants displayed HR and systemic HR due to uninhibited movement of the virus.
Zhang
Gai-Yun
GY
Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, People's Republic of China.
Chen
Ming
M
Guo
Jia-Ming
JM
Xu
Tong-Wen
TW
Li
Lian-Cheng
LC
Xu
Zhao-Shi
ZS
Ma
You-Zhi
YZ
Chen
Xue-Ping
XP
D000595:Amino Acid Sequence; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000502:physiology*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000235:genetics*; D014027:Tobacco Mosaic Virus / Q000235:genetics* / Q000472:pathogenicity
C089425:N protein, Nicotiana glutinosa; D010940:Plant Proteins