AUTHOR=Shen Huoyun , Li Xiyang , Li Zilong 

TITLE=Detecting and identifying pathogens and antagonistic bacteria associated with Ginkgo biloba leaf spot disease

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1346318

DOI=10.3389/fmicb.2024.1346318

ISSN=1664-302X

ABSTRACT=<sec><title>Background</title><p>Leaf spot disease severely impacts <italic>Ginkgo biloba</italic> (<italic>G. biloba</italic>) yield and quality. While microbial agents offer effective and non-toxic biological control for plant diseases, research on controlling leaf spot disease in <italic>G. biloba</italic> is notably scarce.</p></sec><sec><title>Methods</title><p>The pathogenic fungi were isolated and purified from diseased and healthy leaves of <italic>G. biloba</italic>, Subsequent examinations included morphological observations and molecular identification via PCR techniques. A phylogenetic tree was constructed to facilitate the analysis of these pathogenic fungi, and Koch’s postulates were subsequently employed to reaffirm their pathogenic nature. The antagonistic experiment was employed to select biocontrol bacteria, and subsequently, the isolated biocontrol bacteria and pathogenic fungi were inoculated onto healthy leaves to assess the inhibitory effects of the biocontrol bacteria.</p></sec><sec><title>Results</title><p>Two pathologies responsible for the leaf spot disease on <italic>G. biloba</italic> were identified as <italic>Botryosphaeria dothidea</italic> and <italic>Neofusicoccum parvum</italic> via the analysis of phylogenetic tree and the application of Koch’s Postulates. Additionally, we isolated two strains of biocontrol bacteria, namely <italic>Bacillus velezensis</italic> and <italic>Bacillus amyloliquefaciens</italic>. Their average inhibitory zones were measured at 4.78 cm and 3.46 cm, respectively. The inhibition zone of <italic>B. velezensis</italic> against <italic>N. parvum</italic> was 4 cm. <italic>B. velezensis</italic> showed a stronger inhibitory effect compared to <italic>B. amyloliquefaciens</italic> on the development of lesions caused by <italic>B. dothidea</italic> via leaf culture experiment.</p></sec><sec><title>Conclusion</title><p>This research reports, for the first time, the presence of <italic>B. dothidea</italic> as a pathogenic fungus affecting <italic>G. biloba</italic>. Moreover, the biocontrol bacteria, <italic>B. velezensis</italic> and <italic>B. amyloliquefaciens</italic>, exhibited the capability to effectively inhibit the growth and reproduction of <italic>B. dothidea</italic>, indicating their promising potential as environmentally friendly biocontrol resources.</p></sec>