Data were analyzed using one-way ANOVA
with Duncan’s comparison. Different letters indicated
a significant difference at the level p< 0.05. The
symbol, *, represented numbers of dead plants
resulted as a mean of four replicates.
Rhizobacteria from lettuce roots and its
inhibitory capacity
Fourteen isolates of rhizobacteria were
recovered from both symptomatic infected roots and
normal appearance lettuce roots, as shown in Table
2. It was found that all isolates of rhizobacteria
could inhibit the growth of mycelium of all Pythium isolates when compared to the control. There were three isolates of the rhizobacteria, which showed the highest inhibitory capability, i.e., Acinetobacter baumannii, Serratia marcescens strain XJtx10.1, and S. marcescens strain R9-8A, respectively, whereas the isolate that showed the lowest inhibitory capability was Serratia entomophila strain M6. Results of inhibitory capabilities of all isolates are summarized, as shown in Figures 2 and 3.
Results of inhibitory capabilities of each isolate were compared based on the distance of inhibition zone and were further analyzed by one-way ANOVA with Duncan’s comparison. Different letters indicated a significant difference at the level p< 0.05.
Each value represented the value of mean of inhibition zone + SD.
Identification of the rhizobacteria isolates recovered from lettuces All isolates of rhizobacteria that showed inhibitory capabilities were identified by DNA sequence. The amplified DNA was run on 1% agarose gel and the results indicated that its size
was 1,600 bp, as shown in Figure 5. The DNA sequence was further analyzed in comparison of the nucleotide sequence with the database stored in the GenBank (FASTA format). Results in Table