Molecular characterization, expression pattern and function analysis of the <i>OsHSP90</i> family in rice

<p>The HSP90 is an abundant chaperone protein that is conserved in all eukaryotes. The main function of HSP90 is to assist other proteins to fold properly. In this study, we uncovered and analysed nine OsHSP90 (OsHSP90-1--OsHSP90-9) family members in rice <i>Nipponbare</i>, in which three distinct motifs were identified. All the HSP90 proteins were classified into three major groups (I, II, III) by phylogenetic analysis. The expression of <i>OsHSP90</i> family in 10 tissues was examined by real-time polymerase chain reaction (PCR). <i>OsHSP90-4</i>, <i>OsHSP90-6</i> and <i>OsHSP90-7</i> had high expression, while <i>OsHSP90-5</i> and <i>OsHSP90-8</i> had very low expression across almost all 10 samples. The gene that encodes <i>OsHSP90-1</i> was preferentially expressed in embryo at 14 days after flowering. It has been reported that some heat shock proteins were up-regulated in response to heat or other stresses. However, in our study the expression pattern of <i>OsHSP90</i> genes is heterogeneous under a range of stress conditions. The expression of <i>OsHSP90-2</i> and <i>OsHSP90-4</i> was up-regulated under drought, salt, cold and heat conditions, while the expression of <i>OsHSP90-3</i> and <i>OsHSP90-5</i> was down-regulated under salt and drought conditions. <i>OsHSP90-7</i> and <i>OsHSP90-9</i> were down-regulated only under drought conditions. <i>OsHSP90-6</i> did not change its expression across all conditions compared to control. Overexpression of <i>OsHSP90-2</i> in <i>E. coli</i> could enhance cell viability and significantly improved resistance to heat, high salinity and drought stress conditions. The results presented here may provide new insights into the function of <i>OsHSP90</i> family in rice.</p

Molecular characterization, expression pattern and function analysis of the rice <i>OsDUF866</i> family

<p>Domain-of-unknown function (DUF) proteins represent a number of gene families with no functional annotation in the Pfam database. So far, the <i>DUF866</i> family has not been characterized, and no member has been functionally studied. In this study, we uncovered and analysed four OsDUF866 (OsDUF866.1–OsDUF866.4) family members in rice <i>Nipponbare</i>, in which three distinct motifs were identified. The expression of <i>OsDUF866</i> family in nine tissues was examined by real-time polymerase chain reaction (PCR), and the highest expression of four genes members was found in embryos at 14 days after flowering. We performed real-time PCR to examine the expression of <i>OsDUF866</i> family under abiotic stress and abscisic acid (ABA) treatment conditions. The expression level of <i>OsDUF866.1</i> displayed significant decrease under drought and salt conditions, while significant increase under heat conditions. The expression level of <i>OsDUF866.2</i> displayed significant decrease under drought conditions. The expression level of <i>OsDUF866.3</i> was significantly elevated under drought and cold, while lowered under heat conditions. The expression level of <i>OsDUF866.4</i> was increased under cold and heat conditions, while decreased under drought conditions. Interestingly, the expression level of <i>OsDUF866</i> members was approximately constant under ABA treatment conditions. Overexpression of <i>OsDUF866.1</i> in <i>Escherichia coli</i> could enhance cell viability and significantly improve the resistance to heat stress conditions. The results may provide new insights into the function of <i>OsDUF866</i> family in rice.</p

Defense-related gene expression.

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The primer sequences of defense-related genes and internal reference gene.

The primer sequences of defense-related genes and internal reference gene.</p

The antifungal substances of ZW10 induced rice capacity to resist <i>M</i>. <i>oryzae</i>.

The expression of relevant defense genes in rice leaves after inoculation with 1% CFB of ZW10 (a), and differential content of H2O2 as indicated by diaminobenzidine (DAB) staining (b). Data are presented as means of three replicates ± SD. Means with different letters have significant differences (P < 0.05). Scale bar, 50 μm.</p

In the field conditions, the antifungal substances of ZW10 were evaluated regarding control of rice blast.

The outbreak of leaf blast was different in different treatments (a), resulting in significant treatment differences in disease index (b). The treatment effects on the neck blast disease index and its thousand-seed weight (c). Data are presented as means of three replicates ± SD.</p

Effects of the antifungal substances of ZW10 on <i>M</i>. <i>oryzae</i> conidia germination and appressorium formation.

Morphological changes in conidia of M. oryzae in different periods after 1% CFB of ZW10 treatment (a); germination rate (b) and appressorium formation rate (c) of M. oryzae conidia after ZW10 treatment. Data are presented as means of three replicates ± SD. **, the treatment difference was significant at P<0.01. Scale bar, 10 μm.</p

Combining pangenome analysis to identify potential cross-protective antigens against avian pathogenic <i>Escherichia coli</i>

Avian pathogenic Escherichia coli (APEC) is the bacterial pathogen of poultry colibacillosis, which causes significant economic losses to the poultry industry. The lack of an effective vaccine against multiple serotypes and the emergence of multi-resistant isolates have made the control of avian colibacillosis troublesome. To identify conserved potential vaccine candidates, 58 genomes of APEC were obtained (54 sequenced by our laboratory and four downloaded from NCBI). A reverse vaccinology (RV) method based on the pangenome – called Pan-RV analysis – was performed in APEC-protective protein mining for the first time. Finally, four proteins were selected, and their immunoreactivity with anti-O1, O2, and O78 serum was verified by western blotting. Our in silico method of analysis will pave the way for rapid screening of vaccine candidates and will lay the foundation for the development of a highly effective subunit vaccine controlling APEC infection. RESEARCH HIGHLIGHTSPan-RV analysis was used for the first time in the discovery of APEC-protective proteins.A total of 53 potential protective proteins were screened out.Four proteins were verified as potential vaccine candidates using western blotting. Pan-RV analysis was used for the first time in the discovery of APEC-protective proteins. A total of 53 potential protective proteins were screened out. Four proteins were verified as potential vaccine candidates using western blotting.</p

Fig 1 -

Isolation and IC50 of active components in the ZW10 cell-free culture filtrate extracted by different organic solvents (a, 1–4: N-hexane extract, dichloromethane extract, ethyl acetate extract, and N-butanol extraction), and the activity of various fractions of ethyl acetate extract in the CH2Cl2/MeOH system (b, 5–10 fractions were: 0% MeOH, 20% MeOH, 40% MeOH, 60% MeOH, 80% MeOH, and 100% MeOH). (c), IC50 of the 60% MeOH extraction against M. oryzae. Data are presented as means of three replicates ± SD. Scale bar, 10 mm.</p

Field trial with the antibacterial antifungal substances of ZW10 against leaf blast and neck blast.

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