Rice sheath blight (SB), caused by necrotrophic pathogen Rhizoctonia solani, is one of the most destructive rice diseases, and no major resistance genes are available. Polygalacturonase-inhibiting proteins (PGIP) are extracellular leucine-rich repeat proteins and play important roles in plant defense against different pathogenic fungi by counteracting secreted fungal polygalacturonases (PG). However, the role of PGIP in conferring resistance to rice SB remains to be thoroughly investigated. Here, we showed that OsPGIP1 is capable of inhibiting PG derived from R. solani. Our real-time reverse-transcription polymerase chain reaction results indicated that resistant rice ‘YSBR1’ and ‘Jasmine 85’ express significantly higher levels of OsPGIP1 than susceptible ‘Lemont’. Our results also show that OsPGIP1 is most highly expressed at the late tillering stage in the sheath of YSBR1, coinciding with the critical stage of SB development in field. More importantly, the OsPGIP1 level is highly elevated by inoculation with R. solani in resistant cultivars but not in susceptible Lemont. Overexpression of OsPGIP1 significantly increased rice resistance to SB and inhibited tissue degradation caused by R. solani-secreted PG. Furthermore, OsPGIP1 overexpression did not affect rice agronomic traits or yield components. Together, our results not only demonstrate the important role of OsPGIP1 in combatting the rice SB disease but also provide a new avenue to the improvement of rice SB resistance by manipulating an endogenous gene.

1. The objective of this study was to investigate the effects of dietary probiotic supplementation on liver X receptor alpha (LXRα) and cholesterol 7α-hydroxylase (CYP7α1) mRNA levels, protein enzymatic activities and fat metabolism in Cherry Valley Pekin ducks. 2. A total of 750 one-day-old Cherry Valley Pekin ducks were randomly divided into 5 groups with three replicates of 50 ducks each in a completely randomised experiment. Each group was fed on a basal diet supplemented with 0, 500, 1000, 1500 or 2000 mg probiotics/kg. 3. Body rate and feed conversion ratio were highest and abdominal subcutaneous fat % was lowest at 1000 mg probiotic/kg. 4. The mRNA levels of LXRα and CYP7α1 in liver tissue was estimated by RT-PCR; serum triglyceride (TG) and total cholesterol (TC) concentrations were measured by ELISA. 5. The expression levels and enzyme activity of LXRα and CYP7α1 increased in conjunction with decreases in TG and TC concentrations following probiotic supplementation to a maximum at 1000 mg probiotics/kg and decreased thereafter. 6. It is concluded that dietary probiotics can enhance LXRα and CYP7α1 enzyme activities in the liver and reduce lipid concentrations and fat deposition in ducks.

1. The aim of this study was to identify the active control area of the duck retinoic acid-inducible gene I (duRIG-I) core promoter, to predict the binding sites of transcription factors and to provide a theoretical basis for the study of duRIG-I function and mechanism of regulation. 2. The promoter region of duRIG-I was obtained from Ensembl; the CpG island in the duRIG-I promoter was predicted online; and the methylation status of the duRIG-I promoter was detected by the bisulphite sequencing PCR method. 3. There was an obvious CpG island in the duRIG-I promoter, with a total of 44 CG dinucleotides. However, the level of methylation was hypomethylation (0.2%). 4. The core transcriptional regulatory region was identified, localised between -301 and ~+14 bp, where multiple transcription factor binding sites including IRF1, RXRβ, AP-2αA, RAP1, NF-1 and SP1 motifs were identified that significantly enhanced RIG-I promoter activity.

1. Albumin (ALB) is a serum protein most highly expressed in liver and regarded as an effective indicator for liver pathologies. The objectives of this study were to determine the expression of duck ALB gene (duALB) in various non-hepatic tissues and identify the potential cis-regulatory elements in the promoter. 2. A model was established to assess duALB promoter activity in different cell lines by construction of a duALB promoter-driven GFP (Green Fluorescent Protein)-expressing vector, which exhibited high expression activity in liver-derived cells and lower expression in other cells. Through the firefly luciferase reporter gene driven by a series of constructs carrying progressive deletions, the core transcriptional regulatory region within the duALB promoter was identified. Mutations in candidate-binding sites were made by site-directed mutagenesis. 3. The core transcriptional regulatory region was located in the -190/-51 bp region. This region contains three potential transcription factor-binding sites, one each for hepatocyte nuclear factor (HNF-3β) (-158/-149), CCAAT/Enhancer-binding protein element (C/EBPα) (-119/-107) and nuclear factor-1 (HNF-1) (-67/-57). Site-directed mutagenesis of HNF-1 and C/EBPα-binding sites resulted in a significant reduction in duALB promoter activity. Two potential cis-regulatory elements (C/EBPα and HNF-1) were responsible for its transcriptional activity in liver-derived cells. 4. These findings contribute to the further understanding of the fundamental mechanisms of ALB gene regulation and the use of tissue-specific gene promoters to regulate tissue-specific expression of exogenous genes in vivo.

Mothers against decapentaplegic homolog 4 (SMAD4) is an important protein in animal reproduction. It plays pivotal roles in cellular pathways, including apoptosis. The expression profile of the SMAD4 gene in goose ovarian follicles has not been reported. In this study, the SMAD4 coding sequence was cloned from the Yangzhou goose. A phylogenetic analysis was performed and mRNA expression was examined in various tissues using quantitative real-time PCR. An alternative splice form of SMAD4, SMAD4-b having 1656 bp, was identified. SMAD4-a mRNA was widely expressed in various healthy tissues, whereas SMAD4-b was very weakly expressed. SMAD4 mRNA in the ovary and oviduct was significantly higher than that in the pituitary and hypothalamus. SMAD4 mRNA expression analysis in hierarchical follicles showed that the level of SMAD4 mRNA was higher in large white follicles and post-ovulatory follicles than in the other follicles. The results indicate that SMAD4 might be involved in the recruitment of hierarchical follicles.