Horizontal transmission of SmEV1 from the donor strain LC22 (D, donor; SmEV1+) to the recipient strain LC41 (R, recipient; SmEV1−) through hyphal contact in a pair culture, with comparison of the strains in single cultures. Top row: two single cultures of the donor strain LC22 and the recipient strain LC41, respectively, and a pair culture of LC22/LC41 (D/R) on PDA (20 °C, seven days). “*” in the pair-culture indicates the area where a mycelial agar plug was removed for generating a derivative of the recipient strain designated as RV. Bottom row, PDA cultures (20 °C, three days) of the donor strain LC22 (D, SmEV1+) and the recipient strain LC41 (R, SmEV1−), and three derivative isolates generated from the recipient strain LC41 in the pair cultures of LC22/LC41 (D/R).