Development of a Selective Medium for the Fungal Pathogen Fusarium graminearum Using Toxoflavin Produced by the Bacterial Pathogen Burkholderia glumae.

The ascomycete fungus Fusarium graminearum is a major causal agent for Fusarium head blight in cereals and produces mycotoxins such as trichothecenes and zearalenone. Isolation of the fungal strains from air or cereals can be hampered by various other airborne fungal pathogens and saprophytic fungi. In this study, we developed a selective medium specific to F. graminearum using toxoflavin produced by the bacterial pathogen Burkholderia glumae. F. graminearum was resistant to toxoflavin, while other fungi were sensitive to this toxin. Supplementing toxoflavin into medium enhanced the isolation of F. graminearum from rice grains by suppressing the growth of saprophytic fungal species. In addition, a medium with or without toxoflavin exposed to wheat fields for 1 h had 84% or 25%, respectively, of colonies identified as F. graminearum. This selection medium provides an efficient tool for isolating F. graminearum, and can be adopted by research groups working on genetics and disease forecasting.

Pathogen resistance of transgenic rice plants expressing mitogen-activated protein kinase 1, MK1, from Capsicum annuum.

Mitogen-activated protein kinase 1 (MK1) from Capsicum annuum was previously cloned and characterized. MK1 is highly conserved in plants and its amino acid sequence is 92% identical to wound-inducible protein kinase (WIPK) from tobacco. In C. annuum, MK1 is transcriptionally activated by wounding. In the present work, the MK1 gene was introduced into the rice genome by Agrobacterium-mediated transformation. Seven independent transgenic rice plants were isolated and characterized. All seven lines had a single-copy insertion of the MK1 transgene. MK1 mRNA and protein were detected in the transgenic rice, but not in wild type rice. In unwounded transgenic rice plants, the level of jasmonic acid was 3-fold higher than in the wild type, whereas in wounded leaves the level of jasmonic acid was the same in transgenic and wild type plants. Expression of the wound-inducible pathogenesis-related gene PR1a was also higher in transgenic than in wild type plants. Either overexpression of PR1a or increased PR1b and PR10 expression in transgenic rice plants may confer increased resistance to rice blast.

Academic performance of Korean children is associated with dietary behaviours and physical status.

The purpose of this study was to obtain a fuller understanding of the association of dietary behaviours, physical status and socio-economic status with academic performance in Korean teenagers. The subjects in this study were 6,463 boys and girls, in grade 5, 8, and 11 in Korea. A self-administered questionnaire and the food-frequency form were used. Grade point average (GPA), height, weight, and physical fitness score for the year were recorded from the school record. The academic performance of students was strongly associated with dietary behaviours, especially with regularity of three meals even after control for parent's education level. Regular breakfast and lunch were more important in grades 5 and 8, while regular dinner was more related with academic performance in grade 11. Small, positive associations of height and physical fitness to academic performance were also found. The relative importance of regularity of meals was greater than that of socio-economic status and physical status in older teenagers. The results of this study suggest that accommodation of better dietary environment and nutrition education for three regular meals is recommended.