Integrated ATAC-Seq and RNA-Seq Data Analysis to Reveal OsbZIP14 Function in Rice in Response to Heat Stress.

Transcription factors (TFs) play critical roles in mediating the plant response to various abiotic stresses, particularly heat stress. Plants respond to elevated temperatures by modulating the expression of genes involved in diverse metabolic pathways, a regulatory process primarily governed by multiple TFs in a networked configuration. Many TFs, such as WRKY, MYB, NAC, bZIP, zinc finger protein, AP2/ERF, DREB, ERF, bHLH, and brassinosteroids, are associated with heat shock factor (Hsf) families, and are involved in heat stress tolerance. These TFs hold the potential to control multiple genes, which makes them ideal targets for enhancing the heat stress tolerance of crop plants. Despite their immense importance, only a small number of heat-stress-responsive TFs have been identified in rice. The molecular mechanisms underpinning the role of TFs in rice adaptation to heat stress still need to be researched. This study identified three TF genes, including OsbZIP14, OsMYB2, and OsHSF7, by integrating transcriptomic and epigenetic sequencing data analysis of rice in response to heat stress. Through comprehensive bioinformatics analysis, we demonstrated that OsbZIP14, one of the key heat-responsive TF genes, contained a basic-leucine zipper domain and primarily functioned as a nuclear TF with transcriptional activation capability. By knocking out the OsbZIP14 gene in the rice cultivar Zhonghua 11, we observed that the knockout mutant OsbZIP14 exhibited dwarfism with reduced tiller during the grain-filling stage. Under high-temperature treatment, it was also demonstrated that in the OsbZIP14 mutant, the expression of the OsbZIP58 gene, a key regulator of rice seed storage protein (SSP) accumulation, was upregulated. Furthermore, bimolecular fluorescence complementation (BiFC) experiments uncovered a direct interaction between OsbZIP14 and OsbZIP58. Our results suggested that OsbZIP14 acts as a key TF gene through the concerted action of OsbZIP58 and OsbZIP14 during rice filling under heat stress. These findings provide good candidate genes for genetic improvement of rice but also offer valuable scientific insights into the mechanism of heat tolerance stress in rice.

Molecular detection of Francisella tularensis in rodents collected from certain areas of Changbai Mountain / 中国热带医学

@#Abstract: Objective To explore the prevalence and bacterial strains of Francisella tularensis (F. tularensis) in wild rodents in Changbai Mountain area of China, and to further understand the epidemiological characteristics of F. tularensis infections in this area. Methods Wild rodents were captured from forest and forest-edge farmland from Kuandian County and Jianshi Forest District in the Changbai Mountain area, 2012-2014. DNA was extracted from the spleen tissues of the rodents, and the fopA gene of F. tularensis in wild rodents was detected using nested PCR. The infection rates were calculated for different areas and rat species. The bacterial subspecies of positive samples were identified using type-specific primers (C1/C4), and sequencing and comparative analysis were performed. Results A total of 133 wild rodents belonging to 6 rat species were captured. Among them, eight samples from three rat species (Apodemus agrarius, Apodemus peninsulae, Tscherskia triton ) were detected positive, with the overall positive rate of 6.01%. The positive rates of F. tularensis of Ji'an and Kuandian were 7.46% and 4.54%, respectively, and there was no difference in positive rates for different regions (χ2=0.117, P=0.732) and different rat species (χ2=0.641, P=0.986). The subspecies analysis showed that the detected 8 trains of F.tularensisall belonged to F.tularensis type B (F.subspecies subsp. holarctica). Genetic evolution analysis was performed on the fopA gene sequences of three positive samples (JA56, JA33, and JA38), which clustered together with Russia strains(CP009694.1, CP044004.1) and China strains (HM371344.1, HM371343.1) F.tularensis type B, with sequence similarities ranging from 99.21% to 99.47%. Conclusions Infection of F.tularensis subsp. holarctica existed in wild rodents in Changbai Mountain area of China, which suggests the existence of F.tularensis infection risks in this area.

Changes in the synaptic structure of hippocampal neurons and impairment of spatial memory in a rat model caused by chronic arsenite exposure.

Many epidemiological studies and in vitro experiments have found that chronic arsenic exposure may influence memory formation. The goal of this study was to create an animal model of memory impairment induced by chronic arsenite exposure and to study the underlying mechanisms. Sixty male Sprague-Dawley (SD) male rats were randomly divided into a control group, a low-dose sodium arsenite exposure group and a high-dose sodium arsenite exposure group. Sodium arsenite was administered by adding it to drinking water for 3 months. Then, the spatial memory of the rats was examined with Morris water maze and Y maze. The concentration of arsenic in the blood and the brain was determined by an atomic fluorescence absorption spectrometer. The ultra-structure of hippocampal neurons was observed by an electron microscope. Timm staining was used for observing mossy fibers. We found that the concentration of arsenic in the blood and the brain increased in a dose-response manner (P<0.05). The performance of rats in the arsenite exposed group (15 mg/kg) was significantly impaired in the Morris water maze and Y maze tasks than those in the control group (P<0.05). Sodium arsenite exposure resulted in abnormal structural changes in the myelin sheaths of nerve fibers and decreases in the terminals of mossy fibers. Together, chronic sodium arsenite exposure through drinking water results in detrimental changes in the neuronal synapses, which may contribute to the arsenite-induced impairment of spatial memory.