New Urea Derivatives Are Effective Anti-senescence Compounds Acting Most Likely via a Cytokinin-Independent Mechanism

Stress-induced senescence is a global agro-economic problem. Cytokinins are considered to be key plant anti-senescence hormones, but despite this practical function their use in agriculture is limited because cytokinins also inhibit root growth and development. We explored new cytokinin analogs by synthesizing a series of 1,2,3-thiadiazol-5-yl urea derivatives. The most potent compound, 1-(2-methoxy-ethyl)-3-1,2,3-thiadiazol-5-yl urea (ASES - Anti-Senescence Substance), strongly inhibited dark-induced senescence in leaves of wheat (Triticum aestivum L.) and Arabidopsis thaliana. The inhibitory effect of ASES on wheat leaf senescence was, to the best of our knowledge, the strongest of any known natural or synthetic compound. In vivo, ASES also improved the salt tolerance of young wheat plants. Interestingly, ASES did not affect root development of wheat and Arabidopsis, and molecular and classical cytokinin bioassays demonstrated that ASES exhibits very low cytokinin activity. A proteomic analysis of the ASES-treated leaves further revealed that the senescence-induced degradation of photosystem II had been very effectively blocked. Taken together, our results including data from cytokinin content analysis demonstrate that ASES delays leaf senescence by mechanism(s) different from those of cytokinins and, more effectively. No such substance has yet been described in the literature, which makes ASES an interesting tool for research of photosynthesis regulation. Its simple synthesis and high efficiency predetermine ASES to become also a potent plant stress protectant in biotechnology and agricultural industries

Aeromycology - airborne fungi spores occurence

The seasonal variability of airborne fungi was detected in České Budějovice in the campus area during year 2009. The samples of airborne spores were collected and analysed monthly. The spores trapped on agar layer were divided into 10 morphological and 26 taxonomical groups according its morphological properties, size and colour. The highest biodiversity of airborne spores was confirmed in September and May. The opposite situation occurred in winter month. The number of fungal and bacterial colonies growing on Petri dished exposed during 24 hours in experimental site varied monthly. The fungal isolates obtained from Petri dishes represented genera belong to Deuteromycetes. The black mould fungus such as Cladosporium sp., was dominant

Saprotrophic growth and pathogenic properties in the genus \kur{Lecanicillium} (Sordaryomycetes; Clavicipitaceae)

Genus Lecanicillium (Sordaryomycetes; Clavicipitaceae) comprises the complex of well-known enthomopathogenic and mycoparasitic fungi. The quality and characteristics of isolates of Lecanicillium spp. can vary on the basis of the origin of fungal isolates and ecological factors. This study compares and evaluates five isolates of Lecanicillium spp. according to its morphological and pathogenic properties