AUTHOR=Sarwar Arslan , Latif Zakia , Zhang Songya , Hao Jianjun , Bechthold Andreas 

TITLE=A Potential Biocontrol Agent Streptomycesviolaceusniger AC12AB for Managing Potato Common Scab

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.00202

DOI=10.3389/fmicb.2019.00202

ISSN=1664-302X

ABSTRACT=<p>Potato common scab (PCS) is an economically important disease worldwide. In this study we demonstrated the possible role of <italic>Streptomyces violaceusniger</italic> AC12AB in controlling PCS. Isolates of <italic>Streptomyces scabies</italic> were obtained from CS infected tubers collected from Maine United States, which were confirmed by morphological and molecular analysis including 16S rRNA sequencing and RFLP analysis of amplified 16S-23S ITS. Pathogenicity assays related genes including <italic>txtAB</italic>, <italic>nec1</italic>, and <italic>tomA</italic> were also identified in all <italic>S. scabies</italic> strains through PCR reaction. An antagonistic bacterial strain was isolated from soil in Punjab and identified as <italic>S. violaceusniger</italic> AC12AB based on 16S rRNA sequencing analysis. Methanolic extract of <italic>S. violaceusniger</italic> AC12AB contained azalomycin RS-22A which was confirmed by <sup>1</sup>H and <sup>13</sup>C-NMR, <sup>1</sup>H/<sup>1</sup>H-COSY, HMBC and HMQC techniques. <italic>S. violaceusniger</italic> AC12AB exhibited plant growth promotion attributes including Indole-3-acetic acid production with 17 μgmL<sup>-1</sup> titers, siderophores production, nitrogen fixation and phosphates solubilization potential. When tubers were inoculated with <italic>S. violaceusniger</italic> AC12AB, significant (<italic>P</italic> &lt; 0.05) PCS disease reduction up to 90% was observed in greenhouse and field trials, respectively. Likewise, <italic>S. violaceusniger</italic> AC12AB significantly (<italic>P</italic> &lt; 0.05) increased potato crop up to 26.8% in field trial. Therefore, plant growth promoting <italic>S. violaceusniger</italic> AC12AB could provide a dual benefit by decreasing PCS disease severity and increasing potato yield as an effective and inexpensive alternative strategy to manage this disease.</p>