LAUSR

Pathogenesis-related proteins (PRs) are a great protein superfamily in plants and play important roles during plants respond to a variety of pathogens and environmental stress. In the present study, a PR10 gene, PnPR10–3, was isolated from Panax notoginseng which is a kind of transitional herb medicine in China. The expression pattern of PnPR10–3 gene after inoculation with Fusarium solani as well as treatment with several signal molecules including MeJA, ETH, H2O2, and SA was analyzed through quantitative reverse transcription-PCR (qRT-PCR), and up-regulated gene expression indicated that PnPR10–3 responded to F. solani infection and defense related signal molecules. The transient expression of the PnPR10–3 and GFP fusion gene was detected in the cytoplasm of onion (Allium cepa) epidermal cells which indicated that the PnPR10–3 was a cytoplasmic protein. In addition, the recombinant protein of PnPR10–3 was expressed in Escherichia coli and purified by affinity chromatography, and the PnPR10–3 protein showed evident antifungal and RNase activities. Moreover, the PnPR10–3 gene was transferred into tobacco (Nicotiana tabacum) in order to verify its function. The transgenic tobacco plants containing PnPR10–3 gene were analyzed through qRT-PCR, and the PnPR10–3 gene was stably expressed in T2 generation transgenic tobacco. The PnPR10–3 transgenic tobacco showed much higher level of resistance to F. solani infection than the wild-type (WT) tobacco, meanwhile, the RNase activities in the transgenic tobacco were much higher than the WT during F. solani infection. In conclusion, the cytoplasmic protein PnPR10–3 with RNase activity is involved in the defense response of P. notoginseng to F. solani infection.