Functional deletion of ccsA. (A) Homologous recombination scheme for deletion of ccsA gene in A. clavatus. P stands for PvuII sites and 1, 4, 5, 8 represent primers ccsA-1, ccsA-4, ccsA-5, ccsA-8 respectively (Table S1). (B) Diagnostic PCR analysis of mutant ΔccsA-1, ΔccsA-2 and ΔccsA-3 using primer pairs described above. (C) Southern blotting analysis of transformant ΔccsA-3 and wild type A. clavatus. Probe positions are shown in (A).