Fig 1.
Spore after surface sterilization with disinfection solution at different duration.
a, b, c, d—Type 1 spore after surface sterilization at 0, 10, 20 and 30 min. e, f, g, h—Type 2 spore after surface sterilization at 0, 10, 20 and 30 min. i, j, k, l—Type 3 spore after surface sterilization at 0, 10, 20 and 30 min. Arrow marks indicate bacterial cells of various shapes adhering to the spore wall; filamentous bacterial cells (a, i), coccus-shaped bacterial cells (c). Arrowhead indicates the formation of mucilaginous product replacing outer hyaline layer (b, j, k).
Fig 2.
Dendrogram showing the genetic relationship as estimated by cluster analysis of BOX-PCR products of spore associated bacteria isolated form the spore walls of AMF.
SAB isolated from all three types of spores at different time interval disinfection were analyzed. Dendrogram was constructed using the Dice coefficient with UPGMA algorithm.
Fig 3.
Spore associated characters of SAB.
(a)–chitinase activity; (b)–protease activity; (c) cellulase activity; (d) EPS production. Means with same letter do not differ significantly according to DMRT test at P < 0.05 (arcsine transformed data).
Fig 4.
Venn diagram showing the spore association characters of SAB isolated from 0, 10 and 20 min disinfected spores.
Fig 5.
Neighbor-joining phylogenetic tree based on 16S rDNA sequence analysis, illustrating phylogenetic relationship of spore associated bacteria isolated from spore walls of AMF.
SAB isolated from three types of spores at different disinfection time intervals possessing a minimum of three association characters were sequenced. The numbers at the nodes indicate the bootstrap support levels based on a neighbor joining analysis of 1000 resampled data sets. The SAB 16S rDNA sequences obtained from AMF spore are shown in bold. The numbers in the parenthesis are the nucleotide sequence accession numbers in the GenBank.
Table 1.
AMF spore and its associated bacteria isolated at different time intervals of surface sterilization.
The molecular identification of these SAB were chosen based on their ability to possess at least three spore association characters.