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The biocontrol effects of Bacillus licheniformis W10 bacterial suspension and its antifungal protein on peach brown rot caused by Monilinia fructicola in storage peach fruits and the effects on fruit quality were investigated. The results showed that the fruit disease suppression of B. licheniformis W10 bacterial suspension and antifungal protein were significantly higher than that of the control. Inoculation of bacterial suspension and antifungal protein prior to M. fructicola gave a better biocontrol effect, and the higher concentrations of bacterial (1 × 1010 cfu · mL−1) and antifungal protein (3.0 mg · mL−1) performed better control effects. The environmental conditions, such as temperature and humidity, affected biocontrol effects of W10 bacterial suspension and antifungal protein. The influence of environment conditions on the activity of antifungal protein was less than that on bacterial suspension. Moreover, lower temperature (4 °C) and relative humidity (RH 70%–75%) were favorable to prevent peach brown rot by W10 bacterial suspension and its antifungal protein. The W10 bacterial suspension and antifungal protein amended with calcium [0.1% Ca(NO3)2] could enhance the biocontrol effects, and obviously put off the occurrence of peach brown rot. In addition, the bacterial suspension and antifungal protein significantly reduced the natural decay rates of peach fruits during storage, and the effects were equal to carbendazim. Moreover, both W10 bacterial suspension and antifungal protein treatments did not have effects on external and internal fruit appearance, such as chromatic aberration parameter L* of flesh, flesh firmness, soluble solids content and weight loss. Therefore, the B. licheniformis W10 is a potential biocontrol factor for peach brown rot.

Elicitins are a family of small elicitor proteins secreted by species of the genera Pythium and Phytophthora inducing a hypersensitive reaction and systemic acquired resistance in Nicotiana and Solanum spp. within the Solanaceae family and Brassica spp. within the Cruciferae family. The paper reports the mining of elicitin gene of Phytophthora capsici, their transcription levels at different stages, their cloning and transient expression in plants. These results contribute to better understanding the roles of elicitins in the interactions between P.capsici and its host plants as well as in the developmental stages. Elicitin candidate genes were mined from the recently released genome database of P.capsici using Phytophthora infestans INF1 and our Illumina transcriptome data as tBLASTx queries(an expected value cut-off of 1e-50). The transcriptional level of the predicted elicitin genes was investigated using RT-PCR technique during the development stages(mycelium, sporangium, zoospore and germinating cyst)of P.capsici and its infection phases of Nicotiana benthamiana roots(1.5,3,6,12,24,36,72 h post-inoculation). Primer pairs specific to the genes were employed to amplify their full lengths using high-fidelity DNA polymerase. Phylogenetic tree was constructed based on multiple sequence alignments of them with other Phytophthora and Pythium spp.elicitins. In the end, these elicitin genes were transiently expressed in N.benthamiana leaves using Potato virus X (PVX) agro-infiltration assay. Blasting search yielded 26 P.capsici sequences highly similar to P.infestans INF1 and our previous elicitin data from trans-criptome sequencing. Only 14 elicitin candidate genes with putative signal peptide-encoding sequences and full lengths were obtained. Transcriptional analysis discovered 6 novel ones from these elicitin genes that were differentially expressed during the developmental and infection stages of P.capsici. The transcriptional profiling showed major differences between the infection stages, which can classify the genes' expression into 3 different types:low or no transcripts detected at the early infection stages, but up-regulation at later stages; constant expression at designated time-points; weak expression at the early infection stages, and gradually increasing along with the proceeding time-points. The full lengths of 10 out of 11 elicitin genes(including 6 ones found in this study and 5 previously reported)were successfully cloned, and amino sequences deducted from these genes showed that they are acidic elicitins. Phylogenetic analysis displayed that these 10 elicitins were clustered into class III and I. Ectopic expression indicated that 2 elicitins genes(Pc508763 and Pc508770)can trigger the hypersensitive reaction in N.benthamiana. The results laid an essential foundation not only for elucidating the interaction mechanisms between P.capsici and its hosts but for future engineering of plant Phytophthora disease resistance. [ABSTRACT FROM AUTHOR]

Objective: The study was aimed at understanding the roles of polygalacturonases in the pathogenicity and the interaction between Rhizoctonia solani and rice., Methods: According to the sequences of Rspg1 of R. solani deposited in GenBank, a pair of specific primers was designed. The gene Rspg1 was cloned and expressed using prokaryotic expression tool to elucidate its biological characteristics. The structures of the protein RsPG1 were predicted using bioinformatics tools., Results: A 1395-bp fragment including an open reading frame (OFR) of Rspg1 was amplified from the genomic DNA of the pathogen. Compared with RT-PCR results, it was found that this sequence fragment contains five introns (positions 278-334, 545-601, 657-715, 1090-1155 and 1244-1304) and one 1095 bp ORF. The ORF was predicted to encode 364 amino acids. Bioinformatics analysis showed that RsPG1 contains an 18-amino acid signal peptide and 4 conserved sequence segments (180NTD, 202DD, 223GHG and 255RIK) characteristic of all the polygalacturonases. The main structural elements of the secondary structure are alpha-helix, beta-sheet and random coil. Six cysteines form three disulfide bonds (Cys24-Cys40, Cys204-Cys220 and Cys329-Cys333). Transmembrane prediction analysis suggested that RsPG1 could be secreted outside the cell. Tertiary structure is a right-handed helix which consisted of ten repeated beta-sheet, forming an opening activity cleft., Conclusion: RsPG1 is tentatively a 40 kDa protein with polygalacturonase enzyme activity at 277.78 U/mg. It is probably a secreted protein and has characteristics of all the polygalacturonases. The results can help to further understand the roles that R. solani polygalacturonases play during the pathogenicity and how the pathogen interacts with the host.

Objective: In order to obtain the antagonistic protein of Bacillus subtilis G87 and definitude its characterization., Methods: Methods of ammonium sulfate precipitating and column chromatography analyzing were used to isolate and purify the protein., Results: A purified protein (peak 6-2-1) was obtained which molecular weight was 50.8 kD by SDS-PAGE and isoelectric point was 5.90 by IEF-PAGE. The antifungal protein contained 0.62% saccharide and some proline or hydroxyproline, but no lipid and aromatic amino acid. The inhibitory activity of the antifungal protein would decreased distinctly at the higher temperature (> or = 60 degrees C) and in the condition of alkalinity (pH > 8), but tolerant to ultraviolet radiation, chloroform, trypsin, proteinase K and pepsin., Conclusion: Antifungal protein of Bacillus subtilis G87 was a kind of glycoprotein without aromatic hydrocarbon. It was sensitive to higher temperature and tight alkalinity but not to proteinase analog and ultraviolet radiation et al.