Bacillus altitudinis strain AMCC 101304: a novel potential biocontrol agent for potato common scab

Potato common scab, caused by Streptomyces spp., is one of the leading causes of heavy commercial losses in the potato industry and is thus one of the most serious plant diseases worldwide. This study identified and assessed potential biocontrol agents against potato common scab. In total, 110 isolates were obtained through antagonistic tests; among which, Bacillus sp. strain AMCC 101304 was found to be most effective at inhibiting the potato common scab pathogen, Streptomyces scabies. Bacillus sp. strain AMCC 101304 was finally identified as Bacillus altitudinis by morphological observation, physiological and biochemical experimentation, as well as 16S rRNA sequencing and phylogenetic analysis. Pot experiments were conducted twice (in spring and autumn) to verify the biocontrol effect of B. altitudinis AMCC 101304 against potato common scab. In spring, the control efficiency reached 76.34%. In autumn, the disease incidence was reduced from 100% to 34.19% (one treatment with strain AMCC 101304) and 38.42% (two treatments with strain AMCC 101304), and the control efficiency reached 82.50% (one application) and 78.43% (two applications). The present study demonstrated the potential of an isolate, identified as B. altitudinis AMCC 101304, as an effective biocontrol agent for future use in the field.