A cAMP-Dependent Protein Kinase Gene, aapk1, Is Required for MyceliaGrowth, Toxicity and Pathogenicity of Alternaria alternata on Tobacco

摘要

The fungus Alternaria alternata is a common spot-producingplant pathogen. During the past decade,tobacco brown spot disease caused by this fungus hasbecame prevalent in China and lead to significantlosses. To better understand the molecular pathogenesisof this fungus, the aapk1 gene encoding a cAMPdependentprotein kinase catalytic subunit was cloned,sequenced and characterized. The aapk1 deletionmutants were identified from hygromycin-resistanttransformants by PCR strategy and confirmed bySouthern blot analysis and RT-PCR. The aapk1 deletionmutant exhibited reduced vegetative growth andwas less toxic than the wild-type strain sd1. Deletion ofaapk1 also delayed disease development on detachedtobacco leaves. Thus, we propose that the cAMP signallingpathway is involved in mycelia growth andpathogenic phenotype of Alternaria alternata.