Correlation Analysis between Well-cellar Early Transplanting of Robust Seedlings and Diseases in Shiyan Tobacco-growing Area

[Objectives]The paper was to investigate the relationship between the well-cellar early transplanting of robust seedlings and the prevalence of diseases in the Shiyan tobacco-growing area.[Methods]The relationship between disease occurrence and meteorological factors during the field growth period was examined by analyzing the prevalence of flue-cured tobacco virus diseases,brown spot,and total disease in the Shiyan tobacco-growing area before(2013-2017)and after(2018-2022)the well-cellar early transplanting of robust tobacco seedlings.[Results]The implementation of a well-cellar early transplanting technique of robust seedlings resulted in a reduction in the average incidence of tobacco virus disease,brown spot,and total disease by 0.83%,8.85%,and 7.91%,respectively,in comparison to the incidence observed prior to early transplanting.These findings suggest that early transplanting can significantly reduce the incidence of flue-cured tobacco diseases.Prior to the well-cellar early transplanting of robust tobacco seedlings,there was a significant(including highly significant)positive correlation between the incidence of brown spot and total disease and precipitation in August and September.The incidence of brown spot and total disease in tobacco plants was found to be significantly positively correlated with May precipitation and significantly negatively correlated with May sunshine hours following the well-cellar early transplanting of robust seedlings.The advancement of the transplanting period by 20 d resulted in a reduction in the growing period of tobacco plants in the field under autumn rains(late August to November)in western China.This effectively circumvented the suitable conditions for disease occurrence and can reduce the incidence of disease.[Conclusions]This study offers a framework for enhancing the quality and efficiency of flue-cured tobacco production in the northwest tobacco-growing area of Hubei.

Control Effects of Different Agents on Tobacco Mosaic Virus Disease

[Objectives] This study was conducted to screen out suitable agents for controlling tobacco mosaic virus disease and the best control period in Zhangzhou tobacco area, providing a theoretical basis for the control of virus diseases, thereby improving the quality of flue-cured tobacco and the income of tobacco farmers. [Methods] The effects on tobacco mosaic virus disease under the interaction between different agents and different application periods were investigated. The incidence of tobacco mosaic virus disease was investigated, and its control effect was analyzed. [Results] Different agents and different application periods had different control effects on tobacco mosaic virus disease. The incidence of tobacco mosaic virus disease: At 30 and 45 d after transplanting, the incidences of A2B1 treatment were the lowest, at 0.85%, 1.71%, respectively;and at 60 d after transplanting, the incidence of A3B1 treatment was the lowest, only 10.68%. The control effect: At 30 and 45 d after transplanting, A2B1 treatment had better control effects, reaching 79.39% and 73.06%, respectively. [Conclusions] 3% hypersensitive protein sprayed at 1 d before transplanting and 7 and 15 d after transplanting achieved the best effect, followed by 10% ningnanmycin sprayed at 1 d before transplanting and 7 and 15 d after transplanting. In tobacco production, it is recommended to apply 1 000 times dilution of 3% supersensitive protein microgranules for three times(at 1 d before transplanting and 7 and 15 d after transplanting), which can effectively prevent tobacco mosaic virus disease.

CONCERNING THE RELATION OF TOBACCOGLYCOPROTEIN TO BUERGER'S DISEASE

Objective To comprehend the reiation of tobacco glycoprotein (TGP) to Buerger,s disease.Metbods TGP was isolated from crude tobacco leaves by basic immunologic techniques. Serum anti- TGPantibodies were tested by Western blot analysis in 11 patients with Buerger,s disease, 15 healthy male smokers and11 nonsmoking healthy male subjects. Results 1. TGP is a dark brown protein of molecular weight 14000. It maybe a subunit of some high molecular weight protein, and exists in crude tobacco leaves. 2. Western blot analysisshowed that 81.81% of patients with Buerger’s disease (9/11), 33.33% of healthy smokers (5/15) and 27.27% ofhealthy nonsmokers (3/11) had serum anti- TGP antibodies. There was significant dtherence between patientswith Buerger,s disease and two control groups (P<0.05), and no signilicant dtherence between both control groups(P>0.05). Conclusion TGP does play an important role in the pathogenesis of Buerger’s disease. As anti - TGPantibodies are also found in some control subjects, it is speculated that other etiologic factors might coordinatelycontribute to the specifc vascular response to TGP in susceptible subjects.

Nonphytotoxic copper oxide nanoparticles are powerful“nanoweapons”that trigger resistance in tobacco against the soil-borne fungal pathogen Phytophthora nicotianae

Investigations into the potential application of nanoparticles acting as nanofungicides in sustainable agriculture are rapidly expanding due to the high antimicrobial properties of these compounds,which do not risk inducing pathogen resistance to fungicides.A detailed understanding of the impact of copper oxide nanoparticles(CuO NPs)on soil-borne phytopathogenic fungi is yet to be obtained.This study aimed to explore the in vitro antifungal activity and control efficacy of CuO NPs applied via irrigation with respect to tobacco black shank(TBS)disease caused by Phytophthora nicotianae.The results revealed that CuO NPs greatly interfered with the reproductive growth process of this fungus,repressing hyphal growth,spore germination and sporangium production.Additionally,morphological damage,intracellular ROS accumulation and increased SOD enzyme activity in hyphae were the antifungicidal mechanisms of these NPs.In pot experiments,treatment with CuO NPs at 100 mg L^(–1)significantly suppressed TBS development,compared with the effect on control plants,and the control efficacy reached 33.69%without inducing phytotoxicity.Exposure to CuO NPs significantly activated a series of defense enzymes,and resistance genes in tobacco can further explain the mechanisms by which CuO NPs suppressed fungal infection.The Cu content in both the leaves and roots of P.nicotianae-infested plants increased by 50.03 and 27.25%,respectively,after treatment with 100 mg L^(–1)CuO NPs,compared with that of healthy plants.In particular,a higher Cu content was observed in infected roots than in leaves.Therefore,this study showed the potential of CuO NPs applied as nanofungicides and as nanoinducers of fungus resistance genes for the management of TBS through inhibition of pathogen infection and stimulation of plant defenses.

A LFD-RAA-Based Rapid Detection Method for Pseudomonas syringae pv. tabaci

This study aimed to achieve rapid detection of Pseudomonas syringae pv.tabaci,the pathogen of tobacco wildfire disease.The specific primers and probes for recombinase-aided amplification(RAA)were designed with HrpZ as the target gene.RAA was then combined with the lateral flow dipstick(LFD)to establish a LFD-RAA-based rapid detection system for the pathogen.Furthermore,the detection performance of the established method was tested.The results showed that the LFDRAA method had high specificity.The amplification could be completed after 25 min of reaction at 39℃.The sensitivity of the established method reached 0.0001 ng/μL,which was superior to that of PCR detection.Moreover,the LFD-RAA method could quickly detect P.syringae pv.tabaci from tobacco leaves,demonstrating field applicability.To sum up,the LFD-RAA method established in this study can be applied in the rapid detection and early diagnosis of tobacco wildfire disease.

Tabtoxin Tolerance in Transgenic Tobacco Plant Expressing a Tabtoxin Resistant Gene

Using genetic recombinant techniques, the tabtoxin resistant gene (trc gene) was to ligated a pBI121 vector under the CaMV 35S promoter to form the binary vector pBITR. Then the vector was introduced into Agrobacterium tumefaciens by triparental mating. After transforming the tobacco, many transgenic plants were obtained. PCR tests indicated that the trc gene was inserted in the genome DNA of tobacco. Biological activity analysis also demonstrated that the transgenic plant alleviated the symptom caused by the pathogen of tobacco wildfire disease.