Open AccessInterrelationships of VEL1 and ENV1 in light response and development in Trichoderma reesei
Author(s) -
Hoda Bazafkan,
Christoph Dattenböck,
Eva Stappler,
Sabrina Beier,
Monika Schmoll
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0175946
Subject(s) - trichoderma reesei , conidiation , aspergillus nidulans , mutant , biology , sterility , phenotype , wild type , microbiology and biotechnology , genetics , mating type , gene , biochemistry , enzyme , cellulase
Sexual development is regulated by a complex regulatory mechanism in fungi. For Trichoderma reesei , the light response pathway was shown to impact sexual development, particularly through the photoreceptor ENVOY. Moreover, T . reesei communicates chemically with a potential mating partner in its vicinity, a response which is mediated by the velvet family protein VEL1 and its impact on secondary metabolism. We therefore studied the regulatory interactions of ENV1 and VEL1 with a focus on sexual development. Although individual mutants in both genes are female sterile under standard crossing conditions (light—dark cycles), an altered light regime enabled sexual development, which we found to be due to conditional female sterility of Δ env1 , but not Δ vel1 . Phenotypes of growth and asexual sporulation as well as regulation of the peptide pheromone precursors of double mutants suggested that ENV1 and VEL1 balance positive and negative regulators of these functions. Additionally, VEL1 contributed to the strong deregulation of the pheromone system observed in env1 mutants. Female sterility of Δ vel1 was rescued by deletion of env1 in darkness in MAT1-1, indicating a block of sexual development by ENV1 in darkness that is balanced by VEL1 in the wild-type. We conclude that ENV1 and VEL1 exert complementing functions in development of T . reesei . Our results further showed that the different developmental phenotypes of vel1/veA mutants in T . reesei and Aspergillus nidulans are not due to the presence or function of ENV1 in the VELVET regulatory pathway in T . reesei .