The WRKY Transcription Factor OsWRKY54 Is Involved in Salt Tolerance in Rice.

Salt stress is a critical limiting factor for rice growth and production. Although numerous salt-tolerant genes have been identified, the mechanism underlying salt stress tolerance in rice remains unclear. This study reports the need for an uncharacterized WRKY transcription factor OsWRKY54 for rice salt-tolerance. Salt stress resulted in a rapid induction of OsWRKY54 expression in roots. Immunostaining analysis showed that it was mainly expressed in the stele. The loss of OsWRKY54 resulted in greater Na accumulation in shoots and enhanced sensitivity of rice plants to salt stress. The real-time quantitative PCR (qRT-PCR) and transcriptome analysis revealed that OsWRKY54 regulated the expression of some essential genes related to salt tolerance, such as OsNHX4 and OsHKT1;5. Furthermore, OsWRKY54 was found to regulate OsHKT1;5 expression by directly binding to the W-box motif in its promoter. Thus, these results indicated that OsWRKY54 was a critical regulatory factor in salt tolerance in rice.

A NAC transcription factor OsNAC3 positively regulates ABA response and salt tolerance in rice.

BACKGROUND: NAC (NAM, ATAF and CUC) transcription factors (TFs) play vital roles in plant development and abiotic stress tolerance. Salt stress is one of the most limiting factors for rice growth and production. However, the mechanism underlying salt tolerance in rice is still poorly understood. RESULTS: In this study, we functionally characterized a rice NAC TF OsNAC3 for its involvement in ABA response and salt tolerance. ABA and NaCl treatment induced OsNAC3 expression in roots. Immunostaining showed that OsNAC3 was localized in all root cells. OsNAC3 knockout decreased rice plants' sensitivity to ABA but increased salt stress sensitivity, while OsNAC3 overexpression showed an opposite effect. Loss of OsNAC3 also induced Na+ accumulation in the shoots. Furthermore, qRT-PCR and transcriptomic analysis were performed to identify the key OsNAC3 regulated genes related to ABA response and salt tolerance, such as OsHKT1;4, OsHKT1;5, OsLEA3-1, OsPM-1, OsPP2C68, and OsRAB-21. CONCLUSIONS: This study shows that rice OsNAC3 is an important regulatory factor in ABA signal response and salt tolerance.

Overexpression of OsGASR1 promotes Al tolerance in rice.

Aluminum (Al) toxicity in acid soils poses a significant threat to rice, which exhibits highly complex genetic mechanisms for both external detoxification and internal tolerance among cereal crops. Although several genes involved Al tolerance have been identified, the molecular mechanisms underlying Al tolerance in rice remain to be fully explored. Here, we functionally characterized the gibberellin-stimulated transcription gene OsGASR1, which encodes a small cysteine-rich peptide localized to the nucleus and cytoplasm and plays a significant role in Al tolerance in rice. The expression of OsGASR1 is rapidly up-regulated by Al in rice root tips but not in the shoots. Its expression is not regulated by the central regulator Aluminum Resistance Transcription Factor 1 (ART1), indicating that OsGASR1 functions as a novel gene in rice Al resistance independent of ART1. Knockout of OsGASR1 reduced root length but did not affect Al tolerance in rice, whereas overexpression of OsGASR1 enhanced Al tolerance without affecting Al distribution and accumulation and promoted the accumulation of reactive oxygen species (ROS) in the root tips. RNA-seq analysis revealed that overexpression of OsGASR1 upregulated the expression of genes associated with cell wall modification, oxidative stress, and Al tolerance. Collectively, these findings suggest that OsGASR1 is involved in Al tolerance in rice independently of ART1, and the up-regulation of this gene is necessary for rice Al tolerance.

[Analysis of characteristics and products of chlorobenzene degradation with dielectric barrier discharge].

For non-biodegradable volatile organic compounds (VOCs) with low water solubility, the tradition biological method can not achieve a satisfactory removal efficiency, so development of high efficiency pre-treatment technology is a hot issue of research. In this experiment, using poor biodegradable chlorobenzene as the target pollutant and dielectric barrier discharge (DBD) non-thermal plasma as the pretreatment technology for biotrickling filter (BTF) , the effect of DBD on the degradation of chlorobenzene was studied by adjusting the technical parameters of DBD. The effects of the inlet concentration, residence time, humidity and peak voltage on decomposition efficiency were investigated and the decomposition products of chlorobenzene were analyzed. Experimental results showed that DBD could effectively remove waste gaseous chlorobenzene, the removal rate of chlorobenzene increased with the increasing peak voltage. When the peak voltage was ≥ 12kV, less effect of residence time on the degradation of chlorobenzene was found. The optimal humidity range of degradation chlorobenzene was 65% - 75%. Through the analysis of degradation products, the species and concentrations of degradation products increased with the increase of discharge voltage. The products were mainly consisted of organic acids and chlorinated hydrocarbons. The water solubility of degradation products was preferable. Furthermore, with the increase of discharge voltage, the biodegradability of degradation products became higher and higher and the biological toxicity was reduced. It had a promoting effect on the degradation of chlorobenzene when the voltage reached 20 kV. Meanwhile, the O3 concentration increased with the increasing discharge voltage and also enhanced with the rising humidity under the same voltage.