Xanthomonas oryzae pv. oryzicola effector Tal10a directly activates rice OsHXK5 expression to facilitate pathogenesis.

Bacterial leaf streak (BLS), caused by Xanthomonas oryzae pv. oryzicola (Xoc), is a major bacterial disease in rice. Transcription activator-like effectors (TALEs) from Xanthomonas can induce host susceptibility (S) genes and facilitate infection. However, knowledge of the function of Xoc TALEs in promoting bacterial virulence is limited. In this study, we demonstrated the importance of Tal10a for the full virulence of Xoc. Through computational prediction and gene expression analysis, we identified the hexokinase gene OsHXK5 as a host target of Tal10a. Tal10a directly binds to the gene promoter region and activates the expression of OsHXK5. CRISPR/Cas9-mediated gene editing in the effector binding element (EBE) of OsHXK5 significantly increases rice resistance to Xoc, while OsHXK5 overexpression enhances the susceptibility of rice plants and impairs rice defense responses. Moreover, simultaneous editing of the promoters of OsSULTR3;6 and OsHXK5 confers robust resistance to Xoc in rice. Taken together, our findings highlight the role of Tal10a in targeting OsHXK5 to promote infection and suggest that OsHXK5 represents a potential target for engineering rice resistance to Xoc.

Ethanol responsive lnc171 promotes migration and invasion of HCC cells via mir-873-5p/ZEB1 axis.

BACKGROUNDS: Long nonconding RNAs (lncRNAs) have been found to be a vital regulatory factor in the development process of human cancer, and could regarded as diagnostic or prognostic biomarkers for human cancers. Here, we aim to confirm the expression and molecular mechanism of RP11-171K16.5 (lnc171) in hepatocellular carcinoma (HCC). METHODS: Screening of differentially expressed lncRNAs by RNA sequencing. Expression level of gene was studied by quantitative real-time PCR (qRT-PCR). The effects of lnc171, mir-873-5p, and ethanol on migration and invasion activity of cells were studied used transwell assay, and luciferase reporter assay was used to confirm the binding site. RESULTS: RNA sequencing showed that lnc171 was markedly up-regulated in HCC. siRNA-mediated knockdown of lnc171 repressed the migration and invasion ability of HCC cells. Bioinformatic analysis, dual luciferase reporter assay, and qRT-PCR indicated that lnc171 interacted with mir-873-5p in HCC cells, and Zin-finger E-box binding homeobox (ZEB1) was a downstream target gene of mir-873-5p. In addition, lnc171 could enhance migration and invasion ability of HCC cells by up-regulating ZEB1 via sponging mir-873-5p. More interestingly, ethanol stimulation could up-regulate the increase of lnc171, thereby regulating the expression of competing endogenous RNA (ceRNA) network factors which lnc171 participated in HCC cells. CONCLUSIONS: Our date demonstrates that lnc171 was a responsive factor of ethanol, and plays a vital role in development of HCC via binding of mir-873-5p.

Increased hsa-miR-100-5p Expression Improves Hepatocellular Carcinoma Prognosis in the Asian Population with PLK1 Variant rs27770A>G.

Hepatocellular carcinoma (HCC) has the highest incidence and mortality in the Asian population, and race is an independent risk factor affecting survival time in liver cancer. Micro RNAs (miRNAs) are remarkably dysregulated in HCC and closely associated with HCC prognosis. Recent studies show that genetic variability between ethnic groups may result in differences in the specificity of HCC miRNA biomarkers. Here, we reveal a high expression level of hsa-miR-100-5p, an HCC prognosis-related miRNA, which improves HCC prognosis in the Asian Population with Polo-like kinase 1 (PLK1) variant rs27770A>G. In this study, we discovered that hsa-miR-100-5p was downregulated in various HCC cell lines. While mimics transient transfection and mouse liver cancer model confirmed the interaction between hsa-miR-100-5p and PLK1, a stratified analysis based on the Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC) data suggest both low hsa-miR-100-5p expression level and high PLK1 expression level associated with poor HCC prognosis, especially in the Asian population. According to the 1000 Genomes Project database, the SNP rs27770 located in 3'UTR of PLK1 had a significantly higher G allele frequency in the East Asian population. Bioinformatics analysis suggested that rs27770 A>G affects PLK1 mRNA secondary structure and alters the hsa-miR-100-5p/PLK1 interaction by forming an additional seedless binding site. This racial variation caused PLK1 to be more vulnerable to hsa-miR-100-5p inhibition, resulting in hsa-miR-100-5p being more favorable for HCC prognosis in the Asian population.

Vasorin Deletion in C57BL/6J Mice Induces Hepatocyte Autophagy through Glycogen-Mediated mTOR Regulation.

Abnormal vasorin (Vasn) expression occurs in multiple diseases, particularly liver cancers. Vasn knockout (KO) in mice causes malnutrition, a shortened life span, and decreased physiological functions. However, the causes and underlying mechanisms remain unknown. Here, we established Vasn KO C57BL/6J mice by using the CRISPR/Cas9 system. The animals were weighed, and histology, immunohistochemistry, electronic microscopy, and liver function tests were used to examine any change in the livers. Autophagy markers were detected by Western blotting. MicroRNA (miRNA) sequencing was performed on liver samples and analyses to study the signaling pathway altered by Vasn KO. Significant reductions in mice body and liver weight, accompanied by abnormal liver function, liver injury, and reduced glycogen accumulation in hepatocytes, were observed in the Vasn KO mice. The deficiency of Vasn also significantly increased the number of autophagosomes and the expression of LC3A/B-II/I but decreased SQSTM1/p62 levels in hepatocytes, suggesting aberrant activation of autophagy. Vasn deficiency inhibited glycogen-mediated mammalian target of rapamycin (mTOR) phosphorylation and activated Unc-51-like kinase 1 (ULK1) signaling, suggesting that Vasn deletion upregulates hepatocyte autophagy through the mTOR-ULK1 signaling pathway as a possible cause of diminished life span and health. Our results indicate that Vasn is required for the homeostasis of liver glycogen metabolism upstream of hepatocyte autophagy, suggesting research values for regulating Vasn in pathways related to liver physiology and functions. Overall, this study provides new insight into the role of Vasn in liver functionality.

Type III effectors xopN and avrBS2 contribute to the virulence of Xanthomonas oryzae pv. oryzicola strain GX01.

Xanthomonas oryzae pv. oryzicola (Xoc) depends on its type III secretion system (T3SS) to translocate type III secreted effectors (T3SEs), including transcription activator-like effectors (TALEs) and non-transcription activator-like effectors (non-TALEs), into host cells. T3SEs can promote the colonization of Xoc and contribute to virulence by manipulating host cell physiology. We annotated 25 genes encoding non-TALEs in Xoc strain GX01, an isolate from Guangxi in the South China's rice growing region. Through systematic mutagenesis of non-TALEs, we found that xopN, the virulence contribution of which was previously unknown for Xoc, significantly contributes to the virulence of Xoc GX01, as does avrBs2.

Dual RNA-seq of Xanthomonas oryzae pv. oryzicola infecting rice reveals novel insights into bacterial-plant interaction.

The Gram-negative bacterium Xanthomonas oryzae pv. oryzicola (Xoc) is the causal agent of rice bacterial leaf streak (BLS), one of the most destructive diseases of rice (Oryza sativa L.) that is the important staple crop. Xoc can invade host leaves via stomata and wounds and its type three secretion system (T3SS) is pivotal to its pathogenic lifestyle. In this study, using a novel dual RNA-seq approach, we examined transcriptomes of rice and Xoc in samples inoculated with wild type Xoc GX01 and its T3SS defective strain (T3SD), to investigate the global transcriptional changes in both organisms. Compared with T3SD strain, rice inoculated with wild type Xoc GX01 resulted in significant expression changes of a series of plant defence related genes, including ones altered in plant signalling pathway, and downregulated in phenylalanine metabolism, flavonoid and momilactone biosynthesis, suggesting repression of plant defence response and reduction in both callose deposition and phytoalexin accumulation. Also, some known transcription activator-like effector (TALE) targets were induced by Xoc GX01, e.g. OsSultr3;6 which contributes to rice susceptibility. Some cell elongation related genes, including several expansin genes, were induced by GX01 too, suggesting that Xoc may exploit this pathway to weaken cell wall strength, beneficial for bacterial infection. On the other hand, compared with wild type, the T3SD strain transcriptome in planta was characterized by downregulation of ATP, protein and polysaccharide synthesis, and upregulation of antioxidation and detoxification related genes, revealing that T3SD strain faced serious starvation and oxidation stresses in planta without a functional T3SS. In addition, comparative global transcript profiles of Xoc in planta and in medium revealed an upregulation of virulence factor synthesis and secretion in planta in favour of bacterial infection. Collectively, this study provides a comprehensive representation of cross talk between the host and bacterial pathogen, revealing insights into the Xoc-rice pathogenic dynamic and reveals novel strategies exploited by this important pathogen to cause disease.