Fusarium graminearum is an important plant pathogenic fungus that causes disease and yield reduction in many cereal crops, such as wheat and barley.  Gyp8 stimulates GTP hydrolysis on Ypt1 in yeast.  However, the functions of Gyp8 in plant pathogenic fungi are still unknown.  In this study, we investigated the roles of FgGyp8 in F. graminearum by genetic and pathological analyses.  Through gene knockout and phenotypic analyses, we found that FgGyp8 is required for vegetative growth in F. graminearum.  The conidiation, conidial size and number of septa per conidium of ΔFggyp8 mutant are significantly reduced when compared to the wild type PH-1.  Furthermore, FgGyp8 is crucial for pathogenicity on wheat coleoptiles and wheat heads.  FgGyp8 contains a conserved TBC domain.  Domain deletion analysis showed that the TBC domain, C- and N-terminal regions of FgGyp8 are all important for its biological functions in F. graminearum.  Moreover, we showed that FgGyp8 catalyzes the hydrolysis of the GTP on FgRab1 to GDP in vitro, indicating that FgGyp8 is a GTPase-activating protein (GAP) for FgRab1.  In addition, we demonstrated that FgGyp8 is required for FgSnc1-mediated fusion of secretory vesicles with the plasma membrane in F. graminearum.  Finally, we showed that FgGyp8 has functional redundancy with another FgRab1 GAP, FgGyp1, in F. graminearum.  Taken together, we conclude that FgGyp8 is required for vegetative growth, conidiogenesis, pathogenicity and acts as a GAP for FgRab1 in F. graminearum.

In 2009, an emerging citrus viral disease caused by Citrus chlorotic dwarf-associated virus (CCDaV) was discovered in Yunnan Province of China.  However, the occurrence and spread of CCDaV in other citrus-growing provinces in China is unknown to date.  To better understand the distribution and molecular diversity of CCDaV in China, a total of 1 772 citrus samples were collected from 11 major citrus-growing provinces and were tested for CCDaV by PCR.  Among these, 134 citrus samples from Guangxi, Yunnan and Guangdong were tested positive for CCDaV, demonstrating that the occurrence and spread of CCDaV are increasing in China.  The complete genome sequences of 17 CCDaV isolates from different provinces and hosts were sequenced.  Comparisons of the whole-genome sequences of the 17 CCDaV isolates as well as the 15 isolates available in GenBank revealed that the sequence identity was about 99–100%, showing that the CCDaV isolates were highly conserved.  Phylogenetic studies showed that the 32 CCDaV isolates belonged to four different groups based on geographical origins and host species, and that CCDaV isolates from China and Turkey were clustered into different groups.  The results provide important information for clarifying the distribution and genetic diversity of CCDaV in China.

This experiment was conducted to evaluate the effects of Bupleurum extract (BE) on blood metabolites, antioxidant status, and immune function in dairy cows under heat stress.  Forty lactating Holstein cows were randomly assigned to 1 of 4 treatments.  The treatments consisted of 0, 0.25, 0.5, and 1.0 g of BE kg^–1 dry matter.  Supplementation with BE decreased (P<0.05) blood urea nitrogen (BUN) contents and increased blood total protein (TP) and albumin (ALB) levels compared with control cows, but it had no effects (P>0.05) on blood glucose (GLU), nonesterified fatty acid (NEFA), total triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high density lipoprotein cholesterol (HDL-C).  Compared with control cows, cows fed BE had higher (P<0.05) superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity.  However, supplementation with BE had no effect (P>0.05) on total antioxidant capacity (T-AOC) or malondialdehyde (MDA) levels.  The immunoglobulin (Ig) A and G contents increased (P<0.05) in cows fed 0.25 or 0.5 g of BE kg^–1.  Interleukin (IL)-2 and IL-4 levels were higher (P<0.05) in cows fed 0.5 and 1.0 g of BE kg^–1, and IL-6 was significantly elevated (P<0.05) in cows fed 0.5 g of BE kg^–1.  There were no treatment effects (P>0.05) on the CD4⁺ and CD8⁺ T lymphocyte ratios, CD4⁺/CD8⁺ ratio, or tumor necrosis factor-α (TNF-α) level among the groups.  These findings suggest that BE supplementation may improve protein metabolism, in addition to enhancing antioxidant activity and immune function in heat-stressed dairy cows.  

   Flowering time and branching type are important agronomic traits related to the adaptability and yield of soybean. Molecular bases for major flowering time or maturity loci, E1 to E4, have been identified. However, more flowering time genes in cultivars with different genetic backgrounds are needed to be mapped and cloned for a better understanding of flowering time regulation in soybean. In this study, we developed a population of Japanese cultivar (Toyomusume)×Chinese cultivar (Suinong 10) to map novel quantitative trait locus (QTL) for flowering time and branch number. A genetic linkage map of a F₂ population was constructed using 1 306 polymorphic single nucleotide polymorphism (SNP) markers using Illumina SoySNP8k iSelect BeadChip containing 7 189 (SNPs). Two major QTLs at E1 and E9, and two minor QTLs at a novel locus, qFT2_1 and at E3 region were mapped. Using other sets of F₂ populations and their derived progenies, the existence of a novel QTL of qFT2_1 was verified. qBR6_1, the major QTL for branch number was mapped to the proximate to the E1 gene, inferring that E1 gene or neighboring genetic factor is significantly contributing to the branch number.

The tetracycline (Tet)-off gene expression regulation system based on the TetR-VP16/Top10 construct has not been widely utilized in plants, for its highly expressed TetR-VP16 activator is toxic to some plants and repeatedly replenishing tetracycline to turn off the constitutively active system is a tedious process.  To solve these problems, a Tet-off and heat shock (HS)-on gene expression regulation system was constructed in this study.  This system is composed of a chimeric transactivator gene TetR-HSF that is derived from a Tet repressor (TetR) and a HS transcription factor (HSF) controlled by a HS promoter HSP70m, and a Tet operator containing hybrid promoter, Om35S, that drives expression of the β-glucuronidase (GUS) gene.  The resultant system yields a GUS expression pattern similar to that of the HSP70m promoter under inducing temperatures and at 35 and 40°C drives GUS expression to a similar level as the Cauliflower mosaic virus (CaMV) 35S promoter.  Further examination revealed that the TetR-HSF and GUS genes were induced by HS, reaching peak expression after 1 and 6 h treatment, respectively, and the HS induction of the expression system could be inhibited by Tet.  This system will provide a useful tool for transgenic studies of plants in the laboratory and in the field, including transgene function analysis, agronomic trait improvement, biopharmaceutical protein production and others.

Leaves are the main organs of photosynthesis in green plants.  Leaf area plays a vital role in dry matter accumulation and grain yield in maize (Zea mays L.).  Thus, investigating the genetic basis of leaf area will aid efforts to breed maize with high yield.  In this study, a total of 150 F₇ recombinant inbred lines (RILs) derived from a cross between the maize lines Xu 178 and K12 were used to evaluate three ear-leaves area (TELA) under multi-environments.  Inclusive composite interval mapping (ICIM) was used to identify quantitative trait loci (QTLs) for TELA under a single environment and estimated breeding value (EBV).  A total of eight QTLs were detected under a single environmental condition, and four QTLs were identified for EBV which also can be detected in single environment.  This indicated that the EBV-detected QTLs have high genetic stability.  A major QTL (qTELA_2-9) located in chromosome bin 2.04/2.05 could be detected in four environments and has a high phenotypic contribution rate (ranging from 10.79 to 16.51%) that making it a good target for molecular breeding.  In addition, joint analysis was used to reveal the genetic basis of leaf area in six environments.  In total, six QTL×environment interactions and nine epistatic interactions were identified.  Our results reveal that the genetic basis of the leaf area is not only mainly determined by additive effects, but also affected by epistatic effects environmental interaction effects.

Classical swine fever (CSF) and porcine reproduction and respiratory syndrome (PRRS) are both economically important, highly contagious diseases of swine worldwide. To develop an effective vaccine to control these two diseases, we constructed a recombinant adenovirus rAdV-GP52AE2, using a replication-defective human adenovirus serotype 5 as a delivery vector, to co-express the GP5 protein of highly pathogenic porcine reproduction and respiratory syndrome virus (PRRSV) and the E2 protein of classical swine fever virus (CSFV). Foot-and-mouth disease virus (FMDV) 2A peptide was used as a linker between the GP5 and E2 proteins to allow automatic self-cleavage of the polyprotein. The GP5 and E2 genes were expressed as demonstrated by immunofluorescence assay and Western blotting. Immunization of mice resulted in a CSFV-neutralizing antibody titer of 1:128 and a PRRSV-neutralizing antibody titer of 1:16. The lymphoproliferative responses were detected by Cell Counting Kit-8 assay and the stimulation index of CFSV-specific and PRRSV-specific lymphocytes in the rAdV-GP52AE2 group was significantly higher than that in the negative control group. The results show that rAdV-GP52AE2 can induce both effective humoral and cell-mediated immune responses in mice. The protective efficacy of the recombinant virus against CSF was evaluated in immunized rabbits, which were protected from fever induced by challenge with C-strain. Our study provides supporting evidence for the use of FMDV 2A to develop a bivalent genetically-engineered vaccine.