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Residual antibiotics can enter soil and water bodies through organic fertilizers with food safety risk via plants absorption, while how do plant growth and quinolone accumulation respond to residual antibiotics levels in soil or water is not clear. Hydroponic experiment in greenhouse was conducted with floating seedlings of tobacco as model plant to investigate the responses of quinolone antibiotics accumulation and plant growth to different levels of ciprofloxacin (CIP) and norfloxacin (NOR). Results showed that CIP and NOR inhibited the growth of tobacco seedlings. The plant height, stem circumference, maximum leaf width, and maximum leaf area of tobacco seedlings were significantly decreased. So as to the plant biomass of leaves, stems, and roots. Accumulation of CIP in the tobacco seedlings in the T3 was 1.1 times that of the tobacco seedlings in the T1, NOR in the T4 was 1.2 times that of the tobacco seedlings in the T1. And the higher the concentration, the more significant the inhibitory effect. Both antibiotics can be absorbed and accumulated by tobacco seedlings. Additionally, the inhibitory effect of CIP was greater than that of NOR.

Cadmium (Cd) of tobacco is a pollutant that is extremely toxic to the health of humans. Protein plant cadmium resistance 8 gene has been characterized to increase the plant Cd resistance. In present experiment, the complete mRNA sequence of tobacco protein plant cadmium resistance 8 gene was amplified using the rapid amplification of cDNA ends methods. The full-length tobacco protein plant cadmium resistance 8 gene mRNA was 887bp containing an 555 bp open reading frame, which encodes a protein of 184 amino acids. BLAST analysis revealed that tobacco protein plant cadmium resistance 8 protein shares high homology with the protein plant cadmium resistance 8 of potato (81%), Lycopersicon esculentum (80%), Eutrema salsugineum (60%), Capsella rubella (58%) and thale cress (57%). Results also showed that tobacco protein plant cadmium resistance 8 gene has a closer genetic relationship with the protein plant cadmium resistance 8 gene of Lycopersicon esculentum. The expression profile was studied and the results indicated that tobacco protein plant cadmium resistance 8 gene was highly expressed in root, moderately expressed in stem, and hardly expressed in flower and leaf. These results established the primary foundation of utilizing tobacco protein plant cadmium resistance 8 gene to decrease the cadmium content of tobacco and benefit the health of humans in the future.

The complete mRNA sequence of one tobacco (Nicotiana tabacum) gene- apoplastic invertase, was amplified using the rapid amplification of cDNA ends methods based on some tobacco ESTs. The full-length tobacco apoplastic invertase gene mRNA was 1,985bp containing an 1,740 bp open reading frame, which encodes a protein of 579 amino acids. Sequence analysis revealed that the apoplastic invertase of tobacco shares high homology with the apoplastic invertase of potato (82%), Lycopersicon esculentum (81%) and Lycopersicon pennellii (78%). Results also showed that tobacco apoplastic invertase gene has a closer genetic relationship with the apoplastic invertase gene of Lycopersicon esculentum. The prediction of transmembrane helices showed that tobacco apoplastic invertase might be a transmembrane protein. The expression profile was studied and the results indicated that tobacco apoplastic invertase gene was differentially expressed in detected tobacco tissues including leaf, stem, root and flower. Our experiment established the foundation for further research on this tobacco gene.

Introduction: Changes in the rhizosphere microbiome and metabolites resulting from crop intercropping can significantly enhance crop growth. While there has been an increasing number of studies on various crop combinations, research on the intercropping of tobacco and maize at seedling stage remains limited., Methods: This study is the first to explore rhizosphere effects of intercropping between tobacco and maize seedling stages, we analyzed the nitrogen, phosphorus and potassium nutrients in the soil, and revealed the important effects on soil microbial community composition and metabolite profiles, thereby regulating crop growth and improving soil balance., Results and Discussion: Compared with mono-cropping, intercropping increased the biomass of the two crops and promoted the nutrient absorption of nitrogen, phosphorus and potassium. Under intercropping conditions, the activities of sucrase, catalase and nitrate reductase in tobacco rhizosphere soil and the content of available potassium, the activities of nitrate reductase and acid phosphatase in maize rhizosphere soil were significantly increasing. Rhizosphere soil bacterial and fungal communities such as Sphingomonas, Massilia, Humicola and Penicillium respond differently to crop planting patterns, and soil dominant microbial communities are regulated by environmental factors such as pH, Organic Matter, Available Potassium, Nitrate Reductase, and Urease Enzyme. Network analysis showed that soil microbial communities were more complex after intercropping, and the reciprocal relationship between bacteria and fungi was enhanced. The difference of metabolites in soil between intercropping and monocropping system was mainly concentrated in galactose metabolism, starch and sucrose metabolism pathway, and the content of carbohydrate metabolites was significantly higher than that of monocropping soil. Key metabolites such as D-Sucrose, D-Fructose-6-Phosphate, D-Glucose-1-Phosphatel significantly influence the composition of dominant microbial communities such as Sphingomonas and Penicillium. This study explained the effects of intercropping between flue-cured tobacco and maize on the content of soil metabolites and soil microbial composition in rhizosphere soil, and deepened the understanding that intercropping system can improve the growth of flue-cured crops seedlings through rhizosphere effects., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ma, Liu, Zhao, Dou, Yang, Liu, Nian, Tong, Li, Xu, Zhang, Zhang, Li, Deng and Liu.)