Dimorphic conidia exhibit different life styles during early colony development in the corn pathogen Colletotrichum graminicola

Daniela Nordzieke 1 Anja Raschke 2 Holger Deising 2 Stefanie Pöggeler 1
1Genetics of Eukaryotic Microorganisms, University of Göttingen, Göttingen, Germany
2Institute for Agricultural and Nutritional Sciences, University of Halle Wittenberg, Halle, Germany

Since the late 1980s the formation of dimorphic conidia by the hemibiotrophic corn pathogen Colleotrichum graminicola is known [1]. Nevertheless, research is focusing exclusively on the investigation of deep colored, falcate conidia produced on solid media and leaf surfaces in light. Here we describe that the smaller, oval conidia are generated under deviant conditions and furthermore show highly divergent behavior in early colony development. Among others, we report for the first time the formation of conidial anastomosis tubes (CAT) in C. graminicola, a process conducted exclusively by oval conidia and strictly absent from falcate spores. Outgoing from these results, we are investigating a putative aberrant role of falcate and oval conidia in the infection of different plant tissues.

[1] Pannacione DG, Vaillancourt LJ and Hanau RM (1989) Conidial Dimorphism in Colletotrichum graminicola. Mycologia (81): 876-883