Plants secrete defense molecules into the extracellular space (the apoplast) to combat attacking microbes. However, the mechanisms by which successful pathogens subvert plant apoplastic immunity remain poorly understood. In this study, we show that PsAvh240, a membrane-localized effector of the soybean pathogen Phytophthora sojae, promotes P. sojae infection in soybean hairy roots. We found that PsAvh240 interacts with the soybean-resistant aspartic protease GmAP1 in planta and suppresses the secretion of GmAP1 into the apoplast. By solving its crystal structure we revealed that PsAvh240 contain six a helices and two WY motifs. The first two a helices of PsAvh240 are responsible for its plasma membrane-localization and are required for PsAvh240's interaction with GmAP1. The second WY motifs of two PsAvh240 molecules form a handshake arrangement resulting in a handshake-like dimer. This dimerization is required for the effector's repression of GmAP1 secretion. Taken together, these data reveal that PsAvh240 localizes at the plasma membrane to interfere with GmAP1 secretion, which represents an effective mechanism by which effector proteins suppress plant apoplastic immunity.

Apple fruits of different cultivars were heat-treated at 38°C for 4 d immediately after harvest, then stored at 0°C for 6 weeks ('Gala') or 4 months ('Golden Delicious' and 'Red Fuji'). Upon removal from storage, fruits were kept for 7 d at 20°C as a shelf-life test. During storage and shelf-life, various ripeness parameters were measured. 'Golden Delicious' and 'Red Fuji' apples were artificially inoculated with Penicillium expansum or Botrytis cinerea before heat treatment, then stored at 20°C for 3 weeks, or 0°C for 6 weeks, and the development of fruit decay was recorded. The respiration rate decreased and the ratio of soluble solids contents (SSC): titratable acidity (TA) increased for all heattreated fruits. For 'Gala' and 'Golden Delicious' apples, heat treatment significantly reduced ethylene evolution, reduced softening during cold storage, and reduced membrane electrolyte leakage after cold storage and shelf-life. Better quality was maintained at the end of the shelf-life for these two cultivars. However, the effects of heat treatment on ethylene production, membrane electrolyte leakage and texture parameters of 'Red Fuji' apples were not significant. The rotting caused by P. expansum or B. cinerea was very severe, especially for apples stored at 20°C. However, decay was completely inhibited in 'Golden Delicious' and 'Red Fuji' apples that had been heat-treated after inoculation. It was concluded that the response to heat treatment varied according to cultivar. Pre-storage heat treatment could delay the ripening of 'Gala' and 'Golden Delicious' apples and maintain storage quality. Although heat treatment gave no beneficial effects on the quality of 'Red Fuji' apples, it could be applied to control disease in this apple cultivar.

To evaluate the effects of co-administration of inactivated avian influenza H9N2 virus and adjuvants in waterfowls, 10-d-old ducks were immunized intranasally with inactivated avian influenza virus (IAIV) combined with CpG DNA and sodium cholate. Immunoglobulin A and IgG antibody levels in throat and tracheal tissues increased significantly, as did specific IgA and IgG antibody levels in the serum after intranasal immunization with IAIV combined with CpG DNA and sodium cholate, compared with immunization with IAIV only. Furthermore, enhanced hemagglutination inhibition titers were also detected in serum samples taken between the third and seventh weeks after immunization with IAIV and both adjuvants compared with IAIV alone. The expression of IL-2 and IL-6 in tracheal and lung tissues increased significantly in the early period after booster immunization. However, the enhancement induced by a single adjuvant was insignificant, and no significant change was detected in the antibody titers or cytokine levels between the ducks that received IAIV alone or saline. In the viral challenge study, prior administration of both CpG DNA and sodium cholate with IAIV reduced the viral titers in the oropharynx and cloaca swabs. Our study suggests that the combination of CpG DNA and sodium cholate could be beneficial to immunization with inactivated H9N2 virus by enhancing the local and systemic immune responses.

Infectious bronchitis virus (IBV) produces infectious bronchitis (IB) disease in poultry worldwide. In spite of proper vaccinations against the IBV, new IBV strains are continually emerging worldwide. In this study, a new highly virulent nephropathogenic IBV strain named CK/CH/XDC-2/2013 was identified from a vaccinated flock with clinical signs of IB in the Jiangsu province of China. The full-length genome sequence of the isolate was 27,714 nucleotides long, and the genome was organized similarly to classical IBV strains. Minimum divergence, phylogenetic analysis, and distance matrix of the genome showed that the CK/CH/XDC-2/2013 isolate had the highest similarity to the IBV BJ strain. The spike glycoprotein (S) gene had the greatest similarity to the nephropathogenic BJ strain and showed an 8 amino acid insertion (YSNGNSDV) at 73 to 80 sites and 3 amino acid deletion at sites 126 to 128 compared to the IBV vaccine strains. A recombination analysis of the S gene showed that the new isolate evolved from the IBV BJ strain and the KM91 vaccine strain. An animal challenge experiment showed a mortality of 60 to 80% in early-age chickens by different inoculation routes. Pathological examinations of the kidneys revealed inflammation, distention with uric acid deposits, and tubular degeneration. It indicated that the CK/CH/XDC-2/2013 isolate has robust kidney tissue tropism, and new nephropathogenic IBV strains are continuously evolving in China.

This article is the first to report the significant effect of PPARG promoter polymorphisms on the expression and intramuscular fat (IMF) content in the longissimus dorsi (LD) muscle of Erhualian pigs. Polymorphic sites for the PPARG upstream transcriptional regulatory region were scanned by direct sequencing of two DNA pools consisting of individuals with significantly different IMF content (P < 0.05). Two SNPs (c.-1633C>T and c.-1572G>A) were identified, with different allele distribution between these two groups. A total of 66 Erhualian pigs and 24 Yorkshire × Large White (Y × L) pigs were genotyped for these two SNPs using PCR-SSCP (single-strand conformation polymorphism), which exhibited that only the T-A and C-G haplotypes existed. The T-A type promoter was found to have higher activity than G-C type promoter for PPARG gene transcription in the induced preadipocytes using luciferase assay. In addition, the frequency of the T-A type in Erhualian pigs was much higher than that in the Y × L pigs (35.6% vs. 8.3%), and in fact, no T-A/T-A samples were found in Y × L pigs. Therefore, we conclude that the T-A haplotype of PPARG is a desirable form that might contribute to the relatively higher IMF content in Erhualian pigs.