Cloning Of Chenopodium Amaranticolor NDR1and Characterization Of It’s Role In Virus Resistance

Functional analysis of resistance genes is a crucial step plant genetic engineering for diseasesresistance. Arabidopsis NDR1(non-race-specific disease resistance1) gene, encoding a plasmamembrane protein, plays an important role in the CC-NB-LRR (nucleic acid binding or coiled-coilleucine-rich repeat) class of R gene mediated disease resistance. NDR1gene mediates a broadspectrum of resistance for bacterial and fungal disease, but about NDR1gene resistance to plant viruseshas not been reported.In this study, two Arabidopsis NDR1homologous genes, named CaNDR1a and CaNDR1b, werecloned from Chenopodium amaranticolor which is a broad-spectrum anti-viral plant. On the basis oftheir expression level analysis and their subcellular localization, we tested the resistance of T1generation of transgenic tobacco plants to the virus by enzyme-linked immunosorbent assay, and triedto reveal CaNDR1a and CaNDR1b gene antiviral properties. The main results are as follows:1) According to the previous results of transcriptome sequencing, CaNDR1a and CaNDR1b werecloned by RT-PCR, bioinformatic analysis revealed CaNDR1a and CaNDR1b are share a highsimilarity with Arabidopsis NDR1.2) Through real-time PCR, we found that CaNDR1a and CaNDR1b are up-regulated remarkablyafter Chenopodium amaranticolor inoculated by TMV or CMV, the expression level ofCaNDR1a and CaNDR1b increased3～5fold. It is indicated CaNDR1genes play an importantrole in virys resistance.3) Plant transient expression vectors were constructed, and were introduced into Nicotianabenthamiana leaves by Agrobacterium infiltration. We have found CaNDR1a and CaNDR1blocated in the cell membrane, which was not altered by virus infection. This suggests thatCaNDR1a and CaNDR1b gene expressed mainly in response to virus infection process in thecell membrane and mediate signal transduction disease.4) Plant expression vectors are transformed to the N. tabacumcv. NC89by A. tumefaciens. Weobtained genetically modified tobaccos, some transgenic lines significantly delayedaccumulation of TMV and CMV on infection leaves by ELISA, indicating that the transgenicexpression of CaNDR1a and CaNDR1b render resistant to certain viruses.