Isolation and Molecular Level Identification of DNase Producing Halophilic Bacillus cereus Family Isolates from Marine Sediment Sample

Draft Genome Sequence of Bacillus pacificus KVCMST-8A-12, Isolated from a Marine Sediment Sample from the Kanyakumari Coast, India

A DNase-producing Bacillus pacificus strain was isolated, and the whole-genome sequence is reported in this paper. The draft genome sequence of Bacillus pacificus KVCMST-8A-12 constitutes 2.4 Gbp of raw reads, with a GC content of 35.24%. In total, 5,661 protein-coding genes, 64 tRNA genes, and 4 rRNA genes were predicted.

The effect of crop species on DNase-producing bacteria in two soils

Purpose

Extracellular deoxyribonucleases (exDNases) from microbial origin contribute substantially to the restriction of extracellular DNA (exDNA) in the soil. Hence, it is imperative to understand the diversity of bacterial species capable of performing this important soil function and how crop species influence their dynamics in the soil. The present study investigates the occurrence of DNase-producing bacteria (DPB) in leachate samples obtained from soils in which the crop species of alfalfa (Medicago sativa L.), canola (Brassica napus L.), soybean (Glycine max [L.] Merr.) and wheat (Triticum aestivum L.) were raised in a growth room.

Methods

Selective media containing methyl green indicator was used to screen for DPB from leachate samples, whereas the 16S rRNA sequence analysis was employed to identify the isolates.

Results

The proportion of culturable DPB ranged between 5.72 and 40.01%; however, we did observe specific crop effects that shifted throughout the growing period. In general, higher proportions of exDNase producers were observed when the soils had lower nutrient levels. On using the 16S rRNA to classify the DPB isolates, most isolates were found to be members of the Bacillus genera, while other groups included Chryseobacterium, Fictibacillus, Flavobacterium, Microbacterium, Nubsella, Pseudomonas, Psychrobacillus, Rheinheimera, Serratia and Stenotrophomonas. Five candidate exDNase/nuclease-encoding proteins were also identified from Bacillus mycoides genomes using online databases.

Conclusion

Results from this study showed that crop species, growth stage and soil properties were important factors shaping the populations of DPB in leachate samples; however, soil properties seemed to have a greater influence on the trends observed on these bacterial populations. It may be possible to target soil indigenous bacteria that produce exDNases through management to decrease potential unintended effects of transgenes originating from genetically modified organisms (GMOs) or other introduced nucleic acid sequences in the environment.