Genome-wide identification of the TIFY gene family in tobacco and expression analysis in response to Ralstonia solanacearum infection

The TIFY gene family plays an essential role in plant development and abiotic and biotic stress responses. In this study, genome-wide identification of TIFY members in tobacco and their expression pattern analysis in response to Ralstonia solanacearum infection were performed. A total of 33 TIFY genes were identified, including the TIFY, PPD, ZIM&ZML and JAZ subfamilies. Promoter analysis results indicated that a quantity of light-response, drought-response, SA-response and JA-response cis-elements exist in promoter regions. The TIFY gene family exhibited expansion and possessed gene redundancy resulting from tobacco ploidy change. In addition, most NtTIFYs equivalently expressed in roots, stems and leaves, while NtTIFY1, NtTIFY4, NtTIFY18 and NtTIFY30 preferentially expressed in roots. The JAZ III clade showed significant expression changes after inoculation with R. solanacearum, and the expression of NtTIFY7 in resistant varieties, compared with susceptible varieties, was more stably induced. Furthermore, NtTIFY7-silenced plants, compared with the control plants, were more susceptible to bacterial wilt. These results lay a foundation for exploring the evolutionary history of TIFY gene family and revealing gene function of NtTIFYs in tobacco bacterial wilt resistance.

Transcriptomics and virus-induced gene silencing identify defence-related genes during Ralstonia solanacearum infection in resistant and susceptible tobacco

Bacterial wilt (BW) caused by Ralstonia solanacearum is a globally prevalent bacterial soil-borne disease. In this study, transcriptome sequencing were subjected to roots after infection with the R. solanacearum in the resistant and susceptible tobacco variety. DEGs that responded to R. solanacearum infection in both resistant and susceptible tobacco contributed to pectinase and peroxidase development and were enriched in plant hormone signal transduction, signal transduction and MAPK signalling pathway KEGG terms. Core DEGs in the resistant tobacco response to R. solanacearum infection were enriched in cell wall, membrane, abscisic acid and ethylene terms. qRT-PCR indicated that Nitab4.5_0004899g0110, Nitab4.5_0004234g0080 and Nitab4.5_0001439g0050 contributed to the response to R. solanacearum infection in different resistant and susceptible tobacco. Silencing the p450 gene Nitab4.5_0001439g0050 reduced tobacco resistance to bacterial wilt. These results improve our understanding of the molecular mechanism of BW resistance in tobacco and solanaceous plants.

Comprehensive Analysis Reveals the Genetic and Pathogenic Diversity of Ralstonia solanacearum Species Complex and Benefits Its Taxonomic Classification

Ralstonia solanacearum species complex (RSSC) is a diverse group of plant pathogens that attack a wide range of hosts and cause devastating losses worldwide. In this study, we conducted a comprehensive analysis of 131 RSSC strains to detect their genetic diversity, pathogenicity, and evolution dynamics. Average nucleotide identity analysis was performed to explore the genomic relatedness among these strains, and finally obtained an open pangenome with 32,961 gene families. To better understand the diverse evolution and pathogenicity, we also conducted a series of analyses of virulence factors (VFs) and horizontal gene transfer (HGT) in the pangenome and at the single genome level. The distribution of VFs and mobile genetic elements (MGEs) showed significant differences among different groups and strains, which were consistent with the new nomenclatures of the RSSC with three distinct species. Further functional analysis showed that most HGT events conferred from Burkholderiales and played a great role in shaping the genomic plasticity and genetic diversity of RSSC genomes. Our work provides insights into the genetic polymorphism, evolution dynamics, and pathogenetic variety of RSSC and provides strong supports for the new taxonomic classification, as well as abundant resources for studying host specificity and pathogen emergence.

Comparative Transcriptome Profiling Reveals Defense-Related Genes Against Ralstonia solanacearum Infection in Tobacco

Bacterial wilt (BW) caused by Ralstonia solanacearum (R. solanacearum), is a vascular disease affecting diverse solanaceous crops and causing tremendous damage to crop production. However, our knowledge of the mechanism underlying its resistance or susceptibility is very limited. In this study, we characterized the physiological differences and compared the defense-related transcriptomes of two tobacco varieties, 4411-3 (highly resistant, HR) and K326 (moderately resistant, MR), after R. solanacearum infection at 0, 10, and 17 days after inoculation (dpi). A total of 3967 differentially expressed genes (DEGs) were identified between the HR and MR genotypes under mock condition at three time points, including1395 up-regulated genes in the HR genotype and 2640 up-regulated genes in the MR genotype. Also, 6,233 and 21,541 DEGs were induced in the HR and MR genotypes after R. solanacearum infection, respectively. Furthermore, GO and KEGG analyses revealed that DEGs in the HR genotype were related to the cell wall, starch and sucrose metabolism, glutathione metabolism, ABC transporters, endocytosis, glycerolipid metabolism, and glycerophospholipid metabolism. The defense-related genes generally showed genotype-specific regulation and expression differences after R. solanacearum infection. In addition, genes related to auxin and ABA were dramatically up-regulated in the HR genotype. The contents of auxin and ABA in the MR genotype were significantly higher than those in the HR genotype after R. solanacearum infection, providing insight into the defense mechanisms of tobacco. Altogether, these results clarify the physiological and transcriptional regulation of R. solanacearum resistance infection in tobacco, and improve our understanding of the molecular mechanism underlying the plant-pathogen interaction.

[Study on the relationship between occupational stress and metabolic syndrome in operating room nursing staff of a third-class A hospital]

Objective: To explore the relationship between occupational stress and metabolic syndrome (MS) in operating room nurses. Methods: In July 2019, 179 nurses in the operating room of a third-class A hospital in Shandong Province were selected as the research objects. The self-designed questionnaire was used to investigate the general situation, and "Nurse Job Stressor Scale" was used to investigate the occupational stress level of nursing staff. The height, weight, waist circumference, blood pressure, fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, ischemia-modified albumin, lipoprotein associated phospholipase A2 were measured. The nursing staff were divided into MS group and non-MS group, and the occupational stress levels of the two groups were compared. Chi square test or Fisher test were used to compare the counting data between groups; the measurement data were expressed by Mean±SD, and the comparison between groups was performed with t test. Multiple logistic regression analysis was used to analyze the influencing factors of MS. Results: The overall occupational stress level of nurses in operating room was (450.58±141.77) points, which was significantly lower than the norm score (P<0.05) ; Compared with non-MS group, the overall occupational stress level, work nature, workload and patient related factors in MS group were significantly higher, and the differences were statistically significant (P<0.05) ; The prevalence of abdominal obesity, hypertriglyceridemia, hyperglycemia and hypertension were significantly different among the groups with different occupational stress levels (P<0.05) . After adjusting waist circumference, triglyceride, systolic blood pressure, high density lipoprotein, ischemia modified albumin and lipoprotein associated phospholipase A2, the total score of occupational stress was the risk factor of MS in operating room nurses (P<0.05) . Conclusion: The occupational stress level of nurses in operating room is related to the prevalence of MS.

Genetic diversity and fingerprinting of 33 standard flue-cured tobacco varieties for use in distinctness, uniformity, and stability testing

BACKGROUND

At present, the distinctness, uniformity, and stability (DUS) testing of flue-cured tobacco (Nicotiana tabacum L.) depends on field morphological identification, which is problematic in that it is labor intensive, time-consuming, and susceptible to environmental impacts. In order to improve the efficiency and accuracy of tobacco DUS testing, the development of a molecular marker-based method for genetic diversity identification is urgently needed.

RESULTS

In total, 91 simple sequence repeats (SSR) markers with clear and polymorphic amplification bands were obtained with polymorphism information content, Nei index, and Shannon information index values of 0.3603, 0.4040, and 0.7228, respectively. Clustering analysis showed that the 33 study varieties, which are standard varieties for flue-cured tobacco DUS testing, could all be distinguished from one another. Further analysis showed that a minimum of 25 markers were required to identify the genetic diversity of these varieties. Following the principle of two markers per linkage group, 48 pairs of SSR markers were selected. Correlation analysis showed that the genetic relationships revealed by the 48 SSR markers were consistent with those found using the 91 SSR markers.

CONCLUSIONS

The genetic fingerprints of the 33 standard varieties of flue-cured tobacco were constructed using 48 SSR markers, and an SSR marker-based identification technique for new tobacco varieties was developed. This study provides a reliable technological approach for determining the novelty of new tobacco varieties and offers a solid technical basis for the accreditation and protection of new tobacco varieties.

Myeloid leukemia with high EVI1 expression is sensitive to 5-aza-2'-deoxycytidine by targeting miR-9

PURPOSE

High expression of ecotropic viral integration site 1 (EVI1) has been associated with a poor prognosis in leukemia patients, but the underlying mechanism remains unclear. Aberrant expression of microRNAs plays critical roles in leukemia development. MiR-9 is a putative potential target of EVI1. We have investigated the regulating mechanism of miR-9 by EVI1 in leukemia cells.

METHODS

We first examined the relationship between miR-9 and EVI1 expression levels in nine leukemia cell lines by RT-PCR. Then we forced high expression of EVI1 in UoCM1 and K562 cells to confirm the downregulation of miR-9 by EVI1. Methylation of the miR-9 promoter region was detected by DNA bisulfite sequencing. We treated the EVI1-overexpressing cells with the hypomethylating agent 5-aza-2'-deoxycytidine (5-AZA) to reverse EVI1-induced hypermethylation of miR-9.

RESULTS

EVI1 and miR-9 expression was negative related. Forced expression of EVI1 downregulated miR-9 by inducing hypermethylation of the miR-9 promoter. 5-AZA reversed high EVI1-induced hypermethylation of the miR-9 promoter and restored the expression of miR-9. 5-AZA induced extensive apoptosis and inhibited proliferation through cell cycle arrest in EVI1-overexpressing leukemia cells.

CONCLUSIONS

Our results suggest that EVI1 may be involved in leukemia cell proliferation and apoptosis via the regulation of miR-9 promoter methylation. 5-AZA may represent a promising therapeutic option for EVI1-high leukemia patients.

Downregulation of CDC27 inhibits the proliferation of colorectal cancer cells via the accumulation of p21Cip1/Waf1

Dysregulated cell cycle progression has a critical role in tumorigenesis. Cell division cycle 27 (CDC27) is a core subunit of the anaphase-promoting complex/cyclosome, although the specific role of CDC27 in cancer remains unknown. In our study, we explored the biological and clinical significance of CDC27 in colorectal cancer (CRC) growth and progression and investigated the underlying molecular mechanisms. Results showed that CDC27 expression is significantly correlated with tumor progression and poor patient survival. Functional assays demonstrated that overexpression of CDC27 promoted proliferation in DLD1 cells, whereas knockdown of CDC27 in HCT116 cells inhibited proliferation both in vitro and in vivo. Further mechanistic investigation showed that CDC27 downregulation resulted in G1/S phase transition arrest via the significant accumulation of p21 in HCT116 cells, and the upregulation of CDC27 promoted G1/S phase transition via the attenuation of p21 in DLD1 cells. Furthermore, we also demonstrated that CDC27 regulated inhibitor of DNA binding 1 (ID1) protein expression in DLD1 and HCT116 cells, and rescue assays revealed that CDC27 regulated p21 expression through modulating ID1 expression. Taken together, our results indicate that CDC27 contributes to CRC cell proliferation via the modulation of ID1-mediated p21 regulation, which offers a novel approach to the inhibition of tumor growth. Indeed, these findings provide new perspectives for the future study of CDC27 as a target for CRC treatment.

[High frequency oscillatory ventilation with perfluorocarbon in rabbits with acute lung injury]

OBJECTIVE

To investigate the efficacy of high frequency oscillation with perfluorocarbon (PFC) in rabbits with acute lung injury (ALI).

METHODS

Twenty four rabbits with ALI induced by repeated saline lung lavage were randomly assigned to four groups: conventional mechanical ventilation (CMV) group, CMV + PFC group, high frequency oscillation (HFO) group and HFO + PFC group. All rabbits were ventilated for two hours. Blood gases, respiratory system dynamic compliance (Cdyn) and intrapulmonary shunt fraction (Qs/Qt) were measured and calculated at 30, 60, and 120 min during experiment.

RESULTS

Compared with the CMV, statistically improvements were shown in gas exchange, Cdyn and Qs/Qt at 30 min in the CMV + PFC group [PaO(2) 122 mm Hg +/- 15 mm Hg vs. 692 mm Hg +/- 82 mm Hg, PaCO(2) 29.1 mm Hg +/- 2.7 mm Hg vs. 47.1 mm Hg +/- 2.9 mm Hg, Cdyn (1.35 +/- 0.13) vs (0.97 +/- 0.13) ml.cm H(2)O(-1).kg(-1), Qs/Qt 18.1 +/- 1.1 vs.24.5 +/- 2.9] (P < 0.01 approximately 0.05) and remained stable for two hours. Compared with HFO, HFO + PFC improved oxygenation and ventilation more rapidly than HFO did. At 30 min intervals gas exchange and Qs/Qt were significantly improved (PaO(2) 174.9 +/- 18.5 vs 132.3 +/- 19.4, PaCO(2) 26.1 +/- 2.6 vs 34.9 +/- 4.6, Qs/Qt 17.1 +/- 2.4 vs 19.8 +/- 0.9) (P < 0.05)and remained stable to 60 min. The same differences were seen at 60 min.

CONCLUSION

In rabbits with ALI, CMV + PFC could induce a significant improvement in gas exchange and Cdyn. HFO + PFC leads more rapidmy to reach best gas exchange and Cdyn.

Experimental study of double-lumen, two-stage endotracheal tube during conventional mechanical ventilation in rabbits

OBJECTIVE

To evaluate the effects of a double-lumen, two-stage endotracheal tube on gas exchanges (ventilatory efficiency) during conventional mechanical ventilation, using a ventilator in rabbits.

DESIGN

Prospective, randomized, crossover laboratory animal trial.

SETTING

Research laboratory in the Beijing Children's Hospital.

SUBJECTS

Five adult New Zealand rabbits, weighing 3.2 to 3.7 kg.

INTERVENTIONS

A new type of endotracheal tube-the double-lumen two-stage endotracheal tube-was designed and tested for ventilation efficiency in rabbits with normal and injured lungs. The new tube (size 3.0 mm) was made out of two Portex endotracheal tubes (size 3.0 mm) by adhering two vertical cross-sections at the distal end of the two tubes. The new tube and a conventional endotracheal tube of the same size (inner diameter 3.0 mm) were randomly used in pressure control ventilation. Each trial was maintained for 30 mins.

MEASUREMENTS AND MAIN RESULTS

Effects from the two endotracheal tubes on pulmonary mechanics, hemodynamics, and gas exchange were observed. We measured peak inspiratory pressure, positive end-expiratory pressure (PEEP), intrinsic PEEP, mean airway pressure, and arterial blood and mixed expired gas variables (Pao2, Paco2, pH, and mixed expired gas Pco2). The new endotracheal tube acutely increased CO2 elimination in all animals with normal and injured lungs. Paco2 decreased from 46 +/- 4 to 36 +/- 5 torr (6.1 +/- 0.5 to 4.8 +/- 0.7 kPa; p < .01) in normal lungs and from 48 +/- 5 to 36 +/- 5 (6.4 +/- 0.7 to 4.8 +/- 0.7 kPa; p < .01). Meanwhile, tidal volume fraction decreased from 0.48 +/- 0.07 to 0.35 +/- 0.05 (p < .01) and from 0.56 +/- 0.07 to 0.40 +/- 0.07 (p < .01) in normal and injured lungs, respectively. Intrinsic PEEP of the new tube slightly increased, but there were no significant differences in comparison with the conventional tube.

CONCLUSION

Compared with the conventional endotracheal tube, the new double-lumen, two-stage endotracheal tube reduced Paco2 by decreasing anatomical deadspace in rabbits with normal and injured lungs under pressure control ventilation, thus enhancing ventilatory efficiency and reducing ventilator-induced injury.