The gene fpk1, encoding a cAMP-dependent protein kinase catalytic subunit homolog, is required for hyphal growth, spore germination, and plant infection in Fusarium verticillioides

Abstract

Fusarium verticillioides is an important pathogen of maize responsible for ear rots, stalk rots and seeding blight worldwide. During the past decade F. verticillioides has caused several severe epidemics of maize seeding blight in many areas of china, which lead to significant losses. In order to understand molecular mechanisms regulating fungal development and pathogenicity in the pathogen, we isolated and characterized the gene fpk1 (GenBank accession NO. EF405959) encoding catalytic subunit of cAMP-dependent protein kinase, which include 1854 bp DNA sequence from ATG to TAA, with 1680 bp coding region, three intron (their length: 66bp, 54bp and 54bp), and the predicated protein had 559 aa. The mutantdeltafpk1, which was disrupted of fpk1 gene, showed reduced vegetative growth, fewer and shorter aerial mycelia, strongly impaired conidiation and reduced spore germination rate. After germinating, the fresh hypha was stubby and lack of branch. When inoculated in susceptible maize varieties, the infection of the mutantdeltafpk1 was delayed and the infection efficiency was reduced than that of the wild-type. All this indicated that the gene fpk1 participated in hyphal growth, conidiophore producing, spore germination and virulence in F. verticillioides.