Fusarium seedling blight of wheat and oats: effects of infection level and fungicide seed treatments on agronomic characters

The effects of seed-borne Fusarium spp. and Microdochium nivale infection in spring wheat, winter wheat, and oats in Sweden was investigated in field trials for the agronomic characters yield, thousand kernel weight, grain volume weight, gluten, protein, starch, straw strength, and plant density. Seed with high and low levels of infection was mixed to obtain six infection levels in the proportions of 100/0, 80/20, 60/40, 40/60, 20/80, and 0/100 percent. The seed was untreated or treated with Celest Extra Formula M (CEFM, difenoconazole + fludioxonil) or Celest Formula M (CFM, fludioxonil). In the field trials using untreated seed, there were significant differences between infection levels only for some agronomic characters and levels. Fungicide seed treatment with CEFM in spring wheat had no significant effect on most agronomic characters including yield. In winter wheat and oats, seed treatment with CFM increased yield by 7–11% and plant density by up to 33% while having no effect on other characters. The percentage discoloration of crown roots and stem bases due to Fusarium/Microdochium spp. was also investigated visually in winter wheat and oats and found to increase with higher infection level. Fungicide seed treatment thus mainly increased plant emergence in seed lots with low-to-moderate Fusarium/Microdochium spp. infection and had little or no effects on other agronomic characters.     

Development and characterization of a potential diagnostic monoclonal antibody against capsid protein VP1 of the chicken anemia virus

Chicken anemia virus (CAV) is an important viral pathogen that causes anemia and severe immunodeficiency syndrome in chickens worldwide. In this study, a potential diagnostic monoclonal antibody against the CAV VP1 protein was developed which can precisely recognize the CAV antigen for diagnostic and virus recovery purposes. The VP1 gene of CAV encoding the N-terminus-deleted VP1 protein, VP1Nd129, was cloned into an Escherichia (E.) coli expression vector. After isopropyl-β-D-thiogalactopyronoside induction, VP1Nd129 protein was shown to be successfully expressed in the E. coli. By performing an enzyme-linked immunoabsorbent assay using two coating antigens, purified VP1Nd129 and CAV-infected liver tissue lysate, E3 monoclonal antibody (mAb) was found to have higher reactivity against VP1 protein than the other positive clones according to the result of limiting dilution method from 64 clones. Using immunohistochemistry, the presence of the VP1-specific mAb, E3, was confirmed using CAV-infected liver and thymus tissues as positive-infected samples. Additionally, CAV particle purification was also performed using an immunoaffinity column containing E3 mAb. The monoclonal E3 mAb developed in this study will not only be very useful for detecting CAV infection and performing histopathology studies of infected chickens, but may also be used to purify CAV particles in the future.     

The role of seed infection level and fungicide seed treatments in control of net blotch in barley

The effect of seed-borne net blotch infection in barley on the agronomic characters yield, thousand kernel weight, grain volume weight, protein, starch and plant density was investigated in field trials using six net blotch infection levels (100/0, 80/20, 60/40, 40/60, 20/80 and 0/100 % high/low infected seed) and four fungicide seed treatments. The untreated trials showed significant differences between infection levels only for some agronomic characters, years and levels. Seed treatment with Anchor (carboxin + thiram) reduced net blotch by nearly 100 %, compared to 81 % by Fungazil A 25 (imazalil), 60 % by Rancona i-MIX (ipconazole + imazalil) and 54 % by Rubin TT (triticonazole + prochloraz + pyrimethanil). Anchor significantly increased yield 3–7 %, thousand kernel weight 3–13 %, grain volume weight 3–9 % and protein content 1–7 % in the first year, but not in the second. Fungazil A 25 had a low positive effect on agronomic characters, while Rancona i-MIX and Rubin TT had a positive, negative or no effect. The correlation between percent infected kernels in the conventional osmotic method and real-time PCR results was high, showing a potential for complementing traditional plate test methods with molecular methods that needs further optimization. The development of net blotch and its effect on agronomic characters thus depended on many other factors than the seed infection level. The current recommendations for seed treatment could be considered a preventative measure.