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Cucumber mosaic virus (CMV) is the harm tobacco production a disease one, but has not been found in the production of effective prevention and treatment measures. Plant induced resistance is a resistance against pathogenic microorganisms plants under inducible factor. Cross-protection is a protective effect on plants caused by a weak virus. By salicylic acid (SA), methyl jasmonate (MeJA) chemical-induced factor-induced tobacco produce cross-protective effect of CMV disease resistance and weak virus (Fny-CMV-Δ2b) plants, in order to find a effective means of prevention and treatment of CMV. CMV 2b gene can promote CMV intercellular movement infested plants, the spread of long-distance movement and system, inhibition of post-transcriptional gene silencing and SA-mediated plant virus resistance. In this study, has been constructed missing 2b CMV (Fny-CMV-Δ2b) study of cross-protective effect of tobacco plants. The results show that, Fny-CMV-Δ2b performance slight mosaic symptoms on tobacco plants inoculated necrotic lesions the host of Chenopodium amaranticolor generated of necrotic lesions significantly reduced relative to the CMV Fny-CMV-Δ2b a weak virus. Fny-CMV-Δ2b can improve plant height and leaf area, increased by 15.49% and 18.26%, respectively, also significantly improve the whole plant, stems, leaves and roots of plants fresh and dry weight, indicating that Fny-CMV-Δ2b to promote the healthy growth of plants, can significantly improve the biological production of tobacco plants. Compared Fny-CMV significantly reduce the plant's total chlorophyll, chlorophyll a, chlorophyll b, Fny-CMV-Δ2b plants total chlorophyll, chlorophyll a, chlorophyll b content has no effect; net photosynthetic rate of the plants were inoculated with Fny-CMV ( P), transpiration rate (E) and stomatal conductance (Gs) decreased significantly, the intercellular CO 2 concentration (Ci) is slightly higher, but the vaccination Fny-CMV-Δ2b plants photosynthesis indicators did not change significantly; Fny-CMV-Δ2b of plants of photosystem Ⅱ (PS Ⅱ) also had no effect, indicating that Fny-CMV-Δ2b without destroying the plant's photosynthetic organs, does not affect the photosynthesis of plants. SA can induce a variety of plants resistant to viral, fungal and bacterial diseases, plays an important role in the resistance (SAR), is one of the signaling molecules that induce systemic acquired resistance in plant generation system; MeJA a important plant hormone with a wide range of physiological functions, can also induce plant SAR. In this study, two different periods of growth in the tobacco foliar application of SA and MeJA study induced tobacco resistance to CMV. The study results show that: the foliar application of SA and MeJA could induce tobacco resistance to CMV disease index was reduced from close to 60 to about 40, induced resistance to CMV were 31.69% and 33.89%; spraying SA and MeJA able to significantly increase the SOD activity in tobacco leaves, 273.56% and 349.16%, respectively, compared with the control; spraying SA and MeJA significantly increased POD activity in tobacco leaves increased by 40.71% and 42.17%, respectively, compared with the control, inoculated with CMV After two processing POD activity was increased by 12.99% and 35.70%; spraying SA and MeJA also be able to significantly increase the tobacco leaves H 2 O 2 content SAs, relative to the control increased by 147.62% and 220.00%, respectively inoculated with CMV, two processing H 2 O 2 content were increased by 155.98% and 170.55%; and the MeJA treatment can reduce the CAT activity in tobacco leaves, 43.94% and 49.76%, respectively, compared with the control. This means that the SA and MeJA lower CAT activity by raising plants in vivo activity of SOD and POD activity to improve the SAR a second messenger H 2 O 2 content to induction SAR generation plants, to improve resistance to CMV. In short, the lack of 2b of CMV can promote the healthy growth of tobacco does not affect the tobacco leaf photosynthesis and chlorophyll fluorescence characteristics; SA and MeJA able to increase tobacco SOD and POD activity and H 2 O content, lower CAT activity induced tobacco resistance to CMV.
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