(a) Flow diagram of constructing Tn5 mutant library. (b) Gel electrophoresis of polymerase chain reaction (PCR) products of Kmr gene from the kanamycin-resistant colonies. M: 2000 bp DNA marker; 1: wild type; 2–12: Tn5-30, -45, -63, -145, -146, -158, -216, -225, -273, -331, -355. (c) Antagonistic effect of the 11 Tn5 transposon mutants and the wild type of B. seminalis strain R456 against R. solani. (d) Index of resistance (IR) of the 11 Tn5 transposon mutants. IR was determined as described in Section 3.3. Data were presented as means ± standard errors (n = 3). Columns with different letters (a–c) are significantly different according to LSD test (p < 0.05).