Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in Taiwan
Foliar diseases caused by <i>Stemphylium</i> and <i>Colletotrichum</i> species are among the major biotic factors limiting Welsh onion production in Taiwan. Owing to concerns about the environment and the development of pathogen resistance to existing fungicides, biological c...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-07-01
|
| Series: | Microorganisms |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-2607/11/7/1801 |
| _version_ | 1797588131360276480 |
|---|---|
| author | Jian-Yuan Wang Himanshi Jayasinghe Yi-Tun Cho Yi-Chen Tsai Chao-Ying Chen Hung Kim Doan Hiran A. Ariyawansa |
| author_facet | Jian-Yuan Wang Himanshi Jayasinghe Yi-Tun Cho Yi-Chen Tsai Chao-Ying Chen Hung Kim Doan Hiran A. Ariyawansa |
| author_sort | Jian-Yuan Wang |
| collection | DOAJ |
| description | Foliar diseases caused by <i>Stemphylium</i> and <i>Colletotrichum</i> species are among the major biotic factors limiting Welsh onion production in Taiwan. Owing to concerns about the environment and the development of pathogen resistance to existing fungicides, biological control using endophytes is emerging as an eco-friendly alternative to chemical control. The aim of the present study was to isolate endophytes from healthy Welsh onion leaves and investigate their antagonistic potential against the major phytopathogenic fungi associated with Welsh onion plants in Taiwan. A total of 109 bacterial and 31 fungal strains were isolated from healthy Welsh onion leaves and assigned to 16 bacterial and nine fungal genera using morphological and molecular characterization based on DNA sequence data obtained from nuclear internal transcribed spacer (nrITS) (fungi) and 16S rRNA (bacteria). Evaluation of these endophytic isolates for biocontrol activity against leaf blight pathogens <i>Colletotrichum spaethianum</i> strain SX15-2 and <i>Stemphylium vesicarium</i> strain SX20-2 by dual culture assay and greenhouse experiments resulted in the identification of two bacterial isolates (GFB08 and LFB28) and two fungal isolates (GFF06 and GFF08) as promising antagonists to leaf blight pathogens. Among the four selected isolates, <i>Bacillus</i> strain GFB08 exhibited the highest disease control in the greenhouse study. Therefore, <i>Bacillus</i> strain GFB08 was further evaluated to understand the mechanism underlying its biocontrol efficacy. A phylogenetic analysis based on six genes identified <i>Bacillus</i> strain GFB08 as <i>B. velezensis</i>. The presence of antimicrobial peptide genes (<i>baer</i>, <i>bamC</i>, <i>bmyB</i>, <i>dfnA</i>, <i>fenD</i>, <i>ituC</i>, <i>mlna</i>, and <i>srfAA</i>) and the secretion of several cell wall degrading enzymes (CWDEs), including cellulase and protease, confirmed the antifungal nature of <i>B. velezensis</i> strain GFB08. Leaf blight disease suppression by preventive and curative assays indicated that <i>B. velezensis</i> strain GFB08 has preventive efficacy on <i>C. spaethianum</i> strain SX15-2 and both preventive and curative efficacy on <i>S. vesicarium</i> strain SX20-2. Overall, the current study revealed that healthy Welsh onion leaves harbour diverse bacterial and fungal endophytes, among which the endophytic bacterial strain, <i>B. velezensis</i> strain GFB08, could potentially be used as a biocontrol agent to manage the leaf blight diseases of Welsh onion in Taiwan. |
| first_indexed | 2024-03-11T00:49:25Z |
| format | Article |
| id | doaj.art-fbe9fc9fff0d45279fbc987de2ad14f4 |
| institution | Directory Open Access Journal |
| issn | 2076-2607 |
| language | English |
| last_indexed | 2024-03-11T00:49:25Z |
| publishDate | 2023-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Microorganisms |
| spelling | doaj.art-fbe9fc9fff0d45279fbc987de2ad14f42023-11-18T20:36:38ZengMDPI AGMicroorganisms2076-26072023-07-01117180110.3390/microorganisms11071801Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in TaiwanJian-Yuan Wang0Himanshi Jayasinghe1Yi-Tun Cho2Yi-Chen Tsai3Chao-Ying Chen4Hung Kim Doan5Hiran A. Ariyawansa6Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 106319, TaiwanDepartment of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 106319, TaiwanDepartment of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 106319, TaiwanHualien District Agricultural Research and Extension Station, Hualien 973044, TaiwanDepartment of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 106319, TaiwanSmall Farms & Specialty Crops Advisor, University of California Cooperative Extension, 2980 Washington Street, Riverside, CA 92504, USADepartment of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 106319, TaiwanFoliar diseases caused by <i>Stemphylium</i> and <i>Colletotrichum</i> species are among the major biotic factors limiting Welsh onion production in Taiwan. Owing to concerns about the environment and the development of pathogen resistance to existing fungicides, biological control using endophytes is emerging as an eco-friendly alternative to chemical control. The aim of the present study was to isolate endophytes from healthy Welsh onion leaves and investigate their antagonistic potential against the major phytopathogenic fungi associated with Welsh onion plants in Taiwan. A total of 109 bacterial and 31 fungal strains were isolated from healthy Welsh onion leaves and assigned to 16 bacterial and nine fungal genera using morphological and molecular characterization based on DNA sequence data obtained from nuclear internal transcribed spacer (nrITS) (fungi) and 16S rRNA (bacteria). Evaluation of these endophytic isolates for biocontrol activity against leaf blight pathogens <i>Colletotrichum spaethianum</i> strain SX15-2 and <i>Stemphylium vesicarium</i> strain SX20-2 by dual culture assay and greenhouse experiments resulted in the identification of two bacterial isolates (GFB08 and LFB28) and two fungal isolates (GFF06 and GFF08) as promising antagonists to leaf blight pathogens. Among the four selected isolates, <i>Bacillus</i> strain GFB08 exhibited the highest disease control in the greenhouse study. Therefore, <i>Bacillus</i> strain GFB08 was further evaluated to understand the mechanism underlying its biocontrol efficacy. A phylogenetic analysis based on six genes identified <i>Bacillus</i> strain GFB08 as <i>B. velezensis</i>. The presence of antimicrobial peptide genes (<i>baer</i>, <i>bamC</i>, <i>bmyB</i>, <i>dfnA</i>, <i>fenD</i>, <i>ituC</i>, <i>mlna</i>, and <i>srfAA</i>) and the secretion of several cell wall degrading enzymes (CWDEs), including cellulase and protease, confirmed the antifungal nature of <i>B. velezensis</i> strain GFB08. Leaf blight disease suppression by preventive and curative assays indicated that <i>B. velezensis</i> strain GFB08 has preventive efficacy on <i>C. spaethianum</i> strain SX15-2 and both preventive and curative efficacy on <i>S. vesicarium</i> strain SX20-2. Overall, the current study revealed that healthy Welsh onion leaves harbour diverse bacterial and fungal endophytes, among which the endophytic bacterial strain, <i>B. velezensis</i> strain GFB08, could potentially be used as a biocontrol agent to manage the leaf blight diseases of Welsh onion in Taiwan.https://www.mdpi.com/2076-2607/11/7/180116S rRNAantimicrobial peptide genescurative assayintegrated disease managementITSpreventive assay |
| spellingShingle | Jian-Yuan Wang Himanshi Jayasinghe Yi-Tun Cho Yi-Chen Tsai Chao-Ying Chen Hung Kim Doan Hiran A. Ariyawansa Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in Taiwan Microorganisms 16S rRNA antimicrobial peptide genes curative assay integrated disease management ITS preventive assay |
| title | Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in Taiwan |
| title_full | Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in Taiwan |
| title_fullStr | Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in Taiwan |
| title_full_unstemmed | Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in Taiwan |
| title_short | Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in Taiwan |
| title_sort | diversity and biocontrol potential of endophytic fungi and bacteria associated with healthy welsh onion leaves in taiwan |
| topic | 16S rRNA antimicrobial peptide genes curative assay integrated disease management ITS preventive assay |
| url | https://www.mdpi.com/2076-2607/11/7/1801 |
| work_keys_str_mv | AT jianyuanwang diversityandbiocontrolpotentialofendophyticfungiandbacteriaassociatedwithhealthywelshonionleavesintaiwan AT himanshijayasinghe diversityandbiocontrolpotentialofendophyticfungiandbacteriaassociatedwithhealthywelshonionleavesintaiwan AT yituncho diversityandbiocontrolpotentialofendophyticfungiandbacteriaassociatedwithhealthywelshonionleavesintaiwan AT yichentsai diversityandbiocontrolpotentialofendophyticfungiandbacteriaassociatedwithhealthywelshonionleavesintaiwan AT chaoyingchen diversityandbiocontrolpotentialofendophyticfungiandbacteriaassociatedwithhealthywelshonionleavesintaiwan AT hungkimdoan diversityandbiocontrolpotentialofendophyticfungiandbacteriaassociatedwithhealthywelshonionleavesintaiwan AT hiranaariyawansa diversityandbiocontrolpotentialofendophyticfungiandbacteriaassociatedwithhealthywelshonionleavesintaiwan |