03384naa a2200193 a 450000100080000000500110000800800410001910000190006024501070007926000090018630000110019549000370020650001800024352024490042370000310287270000190290370000220292277302460294414667542007-07-27       2004    bl uuuu     u00u1 u    #d1 aMARTINS, C. M.  aCalcium/calmodulin effect on spore germination and appressorium formation in Colletotrichum truncatum.  c2004  ap. 77.  a(Embrapa Soja. Documentos, 228).  aEditado por Flávio Moscardi, Clara Beatriz Hoffmann-Campo, Odilon Ferreira Saraiva, Paulo Roberto Galerani, Francisco Carlos Krzyzanowski, Mercedes Concordia Carrão-Panizzi.  aThe effect of physicochemical signals such as hydrophobicity of hard contact surfaces on germination of spores of C. gloeosporioides, C. trifolii and C. graminicola is well known in the literature. Also, the effect of calmodulin a ubiquitous Ca+2 receptor protein has been mentioned for its action on both spore germination and appressorium formation. A similar study was undertaken with C. truncatum a pathogen involved with antrachnose in soybeans and responsible for significant losses to the farmers in the central regions of Brazil where moisture and temperatures are typically higher during the growing season. The effects of different surface wettabilities on spore germination and appressorium formation were evaluated using glass slides, PVC shrink film, eppendorf tubes and 7% agarose. CaCl2 (1 mM), glucose and maltose (100 mM), yeast (1%), neomycin (100 mM) and EGTA (calcium chelator, 10 mM) were tested to confirm effects observed on different species of Colletotrichum and other fungi. The data showed that germination was higher on glass slides (100%), followed by PVC shrink film (96%), agarose (68%) and eppendorf tube (2%). The percentage of appressorium formation was higher on PVC shrink film (84%), followed by glass slides (56%), agarose (33%) and ependorf tubes (3%). Spore germination and apressorium formation were not connected according to these data. The carbon sources used and exogenous CaCl2 had an important effect on increasing spore germination and appressorium formation. The highest germination (98.5%) and appressorium formation (85.6%) was obtained with yeast, followed by glucose (64.3%, 56.7%), maltose (60%, 48.6%) CaCl2 (56%, 47.3%) and water (40.3%, 33.2%). The role of Ca+2 could be observed when the concentration in the suspension was reduced through the use of a chelating agent (EGTA): spore germination and appressorium formation were 6.33 and 4.1%, respectively. The effect on Ca+2 was evaluated with the addition of neomycin, a compound that acts on the inhibition of phospholipase C (PLC), an enzyme also associated with spore germination and appressorium formation. The spore germination and appressorium formation were 1% and 0.55%, respectively, after addition of neomycin to the spore suspension. This report confirms that C. truncatum behaves like other species of Colletotrichum in relation to the stimuli of spore germination and appressorium formation, steps necessary for infection.1 aRIBEIRO DO VALLE, P. Z. R.1 aFREITAS, A. M.1 aALMEIDA, A. M. R.  tIn: WORLD SOYBEAN RESEARCH CONFERENCE, 7.; INTERNATIONAL SOYBEAN PROCESSING AND UTILIZATION CONFERENCE, 4.; CONGRESSO BRASILEIRO DE SOJA, 3., 2004, Foz do Iguassu. Abstracts of contributed papers and posters. Londrina: Embrapa Soybean, 2004.