Pollution

Tobacco (Nicotiana tabacum) is among the agricultural products with the highest added value in Turkey. Although frequently associated with its negative effects on human health, it also provides important contributions to the Turkish economy with the employment it creates in rural areas and continues to be a strategic product. Many postgraduate theses and studies related to the sociological and economic importance of the production of this plant, which is of great importance for our country, have been carried out. However, there are very limited studies on plant diseases in tobacco production areas in Turkey. Phytoplasma is one of the important plant pathogens that cause yield loss in tobacco. Since available data on phytoplasma diseases on tobacco was very scarce worldwide, field surveys to collect samples showing phytoplasma infection-like symptoms such as yellowish color changes, leaf blisters, proliferation, dwarfism, and other physical abnormalities were carried out in Çanakkale and Balıkesir provinces of Turkey from June to August 2021. The presence of phytoplasmas in six samples was confirmed by 16S ribosomal DNA amplification by nested-PCR using universal phytoplasma primer sets, which also suggested the pathogen associated with the symptoms on tobacco. According to phylogenetic study and virtual-RFLP analysis using AluI and MseI endonuclease enzymes, the six Turkish tobacco phytoplasma strains all belong to group 16SrXII and have more than 99% nucleotide sequence identity with some members of ‘Candidatus Phytoplasma solani’ of the taxonomic subgroup ‘stolbur’ (16SrXII-A). Genetic distances analysis indicated that group 16SrI was more closely related to 16SrXII than 16SrVI, in agreement with the groups clustering in the phylogenetic tree. Neutrality tests found that 16SrI and 16SrXII groups are experiencing expanding or bottleneck selections, probably due to new mutations in the 16S rRNA gene fragment. Meanwhile, 16SrVI populations are shown to be undergoing balancing selections, indicating that its isolates have evolved for a long time.

AbstractXylitol was first applied to enhance nitrogen removal from saline wastewater through “Candidatus Brocadia sinica”‐dominated anammox process under low temperature. The reactor was maintained at 15°C, and the salinity of wastewater was 35 g/L. Ammonium removal rate (ARR) and nitrite removal rate (NRR) were stable at around 0.27 kg/(m3 d) without xylitol addition. As an osmotic pressure regulator and cryoprotective agent, optimal ARR and NRR were 0.51 kg/(m3 d) and 0.63 kg/(m3 d) at 0.3 mM xylitol. At the addition of 1 mM high‐dosage xylitol, there existed dissimilatory reduction in nitrate to ammonium nitrogen and heterotrophic denitrification in the reactor. Remodified logistic model was suitable to simulate removal process with xylitol addition. As a result, xylitol dose should be controlled within 0.3 mM, which greatly promoted the nitrogen removal from saline wastewater under low temperature.Practitioner points Xylitol could be used as osmotic pressure regulator and cryoprotective agent to enhance nitrogen removal. The optimal dose was achieved at 0.3 mM xylitol for “Candidatus Brocadia sinica” in low‐temperature saline wastewater. High‐dosage xylitol could interfere with nitrogen removal efficiency due to the presence of DNAR and HB. Remodified logistic model was suitable for the analysis and prediction of nitrogen removal process with xylitol addition.