AUTHOR=Ling Lijun , Luo Hong , Yang Caiyun , Wang Yuanyuan , Cheng Wenting , Pang Mingmei , Jiang Kunling 

TITLE=Volatile organic compounds produced by Bacillus velezensis L1 as a potential biocontrol agent against postharvest diseases of wolfberry

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.987844

DOI=10.3389/fmicb.2022.987844

ISSN=1664-302X

ABSTRACT=<p>Volatile organic compounds (VOCs) produced by antagonistic microorganisms have good biocontrol prospects against postharvest diseases. Infection caused by <italic>Alternaria iridiaustralis</italic> and 10 other significant fungal diseases can be successfully inhibited by VOCs produced by an identified and screened endophytic strain L1 (<italic>Bacillus velezensis</italic>). This study revealed the <italic>in vivo</italic> and <italic>in vitro</italic> biocontrol effects of VOCs released by <italic>B. velezensis</italic> L1 on <italic>A. iridiaustralis</italic>, a pathogenic fungus responsible for rot of wolfberry fruit. The inhibition rates of VOCs of <italic>B. velezensis</italic> L1 on the mycelial growth of <italic>A. iridiaustrali</italic>s <italic>in vitro</italic> were 92.86 and 90.30%, respectively, when the initial inoculum concentration on the plate was 1 × 10<sup>9</sup> colony forming unit (CFU)/ml. Spore germination and sporulation were 66.89 and 87.96%, respectively. VOCs considerably decreased the wolfberry’s disease index and decay incidence <italic>in vivo</italic>. Scanning electron microscopy revealed that the morphological and structural characteristics of <italic>A. iridiaustralis</italic> could be altered by VOCs. Ten VOCs were identified through headspace-gas chromatography-ion mobility spectrometry. Pure chemical tests revealed that 2.3-butanedione had the strongest antifungal effects, totally inhibiting <italic>A. iridiaustralis</italic> in wolfberry fruit at a 60 μl/L concentration. The theory underpinning the potential application of VOCs from <italic>B. velezensis</italic> is provided herein. This is also the first study to document the antifungal capabilities of the <italic>B. velezensis</italic> strain on postharvest wolfberry fruit.</p><p><fig position="float" id="fig7"><label>GRAPHICAL ABSTRACT</label><graphic xlink:href="fmicb-13-987844-g007.tif" xmlns:xlink="http://www.w3.org/1999/xlink" /></fig></p>