Enhanced gene replacement frequency in KU70 disruption strain of Stagonospora nodorum

To improve the efficiency of gene disruption in Stagonospora nodorum, the putative KU70 gene encoding the Ku70 protein involved in the nonhomologous end-joining double DNA break repair pathway was identified and deleted. The KU70 disruption strain showed no apparent defect in vegetable growth, conidiation and pathogenicity on wheat and barley compared with the wild-type strain. The effect of the absence of KU70 on gene replacement frequency was tested by disruption of TOXA encoding toxin A and LIP2 encoding a putative lipase. Frequency of gene replacement for both genes was dramatically increased in the KU70 disruption strain, compared with the low frequency in the wild-type recipient.