Nuclear dynamics during germination, conidiation, and hyphal fusion of Fusarium oxysporum.
In many fungal pathogens, infection is initiated by conidial germination. Subsequent stages involve germ tube elongation, conidiation, and vegetative hyphal fusion (anastomosis). Here, we used live-cell fluorescence to study the dynamics of green fluorescent protein (GFP)- and cherry fluorescent protein (ChFP)-labeled nuclei in the plant pathogen Fusarium oxysporum. Hyphae of F. oxysporum have uninucleated cells and exhibit an acropetal nuclear pedigree, where only the nucleus in the apical compartment is mitotically active. In contrast, conidiation follows a basopetal pattern, whereby mononucleated microconidia are generated by repeated mitotic cycles of the subapical nucleus in the phialide, followed by septation and cell abscission. Vegetative hyphal fusion is preceded by directed growth of the fusion hypha toward the receptor hypha and followed by a series of postfusion nuclear events, including mitosis of the apical nucleus of the fusion hypha, migration of a daughter nucleus into the receptor hypha, and degradation of the resident nucleus. These previously unreported patterns of nuclear dynamics in F. oxysporum could be intimately related to its pathogenic lifestyle.
Ruiz-Roldán
M Carmen
MC
Departamento de Genética, Universidad de Córdoba, Edificio Gregor Mendel, Campus de Rabanales, 14071 Córdoba, Spain. ge2rurom@uco.es
Köhli
Michael
M
Roncero
M Isabel G
MI
Philippsen
Peter
P
Di Pietro
Antonio
A
Espeso
Eduardo A
EA
D002467:Cell Nucleus / Q000378:metabolism*; D016764:Cell Polarity; D005456:Fluorescent Dyes / Q000378:metabolism; D005670:Fusarium / Q000166:cytology* / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D018525:Germination / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D025301:Hyphae / Q000166:cytology* / Q000254:growth & development / Q000502:physiology*; D018551:Solanum lycopersicum / Q000382:microbiology / Q000648:ultrastructure; D008938:Mitosis; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology / Q000648:ultrastructure; D013172:Spores, Fungal / Q000166:cytology / Q000502:physiology*; D013997:Time Factors
D005456:Fluorescent Dyes; D006657:Histones; D049452:Green Fluorescent Proteins