Quinclorac (QNC) is an effective but environmentally persistent herbicide commonly used in rice production. However, few studies have investigated its environmental behavior and degradation. In the present study, we carried out microbial cultures in the presence of QNC to observe changes in soil microbiota and to identify species capable of QNC degradation by using high-throughput sequencing of the 16S rRNA. Pseudomonas was the dominant genus, and Pseudomonas putida II-2 and other species were found to be capable of mineralizing QNC as a source of carbon and energy. However, this degradation rate was slow, only reaching 51.5 ± 1.6% for 7 days at 30 °C on QNC + minimal salt medium. Achromobacter sp. QC36 co-metabolized QNC when rice straw was added into the mineral salt medium containing QNC, and a mixed culture of both strains could mineralize approximately 92% of the 50 mg/L QNC after 5 days of cultivation in the presence of rice straw, at 25-35 °C and pH 6.0-8.0. Non-phytotoxicity of tobacco after degradation of QNC by mixed strains was evidenced in a pot experiment. These results suggest that this mixed culture may be useful in QNC bioremediation and can be used as a bio-formulation for agro-economical and industrial application.

The basic leucine zipper (bZIP) transcription factors play important regulatory roles, influencing plant growth and responses to environmental stresses. In the present study, 132 bZIP genes identified in the tobacco genome were classified into 11 groups with Arabidopsis and tomato bZIP members, based on the results of a phylogenetic analysis. An examination of gene structures and conserved motifs revealed relatively conserved exon/intron structures and motif organization within each group. The results of an investigation of whole-genome duplication events indicated that segmental duplications were crucial for the expansion of the bZIP gene family in tobacco. Expression profiles confirmed that the NtbZIP genes are differentially expressed in various tissues, and several genes are responsive to diverse stresses. Notably, NtbZIP62, which was identified as an AtbZIP37/ABF3 homolog, was highly expressed in response to salinity. Subcellular localization analyses proved that NtbZIP62 is a nuclear protein. Furthermore, the overexpression of NtbZIP62 in tobacco significantly enhanced the salt stress tolerance of the transgenic plants. The results of this study may be relevant for future functional analyses of the bZIP genes in tobacco.