Aspergillus terreus obtained from mangrove exhibits antagonistic activities against Pythium aphanidermatum-induced damping-off of cucumber

Hanaa Al-Shibli; Sergey Dobretsov; Abdulrahman Al-Nabhani; Sajeewa S N Maharachchikumbura; Velazhahan Rethinasamy; Abdullah M Al-Sadi

doi:10.7717/peerj.7884

Aspergillus terreus obtained from mangrove exhibits antagonistic activities against Pythium aphanidermatum-induced damping-off of cucumber

PeerJ. 2019 Oct 21:7:e7884. doi: 10.7717/peerj.7884. eCollection 2019.

Authors

Hanaa Al-Shibli¹, Sergey Dobretsov^{2

3}, Abdulrahman Al-Nabhani⁴, Sajeewa S N Maharachchikumbura¹, Velazhahan Rethinasamy¹, Abdullah M Al-Sadi¹

Affiliations

¹ Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoudh, Muscat, Oman.
² Department of Marine Science and Fisheries, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoudh, Oman.
³ Center of Excellence in Marine Biotechnology, Sultan Qaboos University, Al-Khoudh, Oman.
⁴ Department of Pathology, College of Medicine and Health Sciences, Sultan Qaboos University, Al-Khoudh, Oman.

Abstract

A study was conducted to investigate the potential of Aspergillus terreus obtained from Avicennia marina mangrove roots in inhibiting Pythium aphanidermatum and damping-off disease of cucumber. Aspergillus terreus exhibited in vitro inhibition of Pythium aphanidermatum growth. Electron microscope examination revealed that the antagonistic fungal isolate resulted in shrinking and groves in Pythium hypha. When Aspergillus terreus culture filtrate was added to Pythium aphanidermatum, it resulted in a significant increase (by 73%) in electrolyte leakage from Pythium hypha compared to the control, as well as significant reduction (by 71%) in oospore production. The Aspergillus terreus culture was also found to produce a cellulase enzyme, which is suggested to be involved in the antagonism against Pythium aphanidermatum. Adding Aspergillus terreus to soil infested with Pythium aphanidermatum significantly reduced percent mortality in cucumber seedlings by 70%. Aspergillus terreus, when applied alone on cucumber seedlings, did not show any suppressive effects on cucumber growth (length and fresh and dry weight). This appears to be the first report of isolation from mangrove of Aspergillus terreus with antagonistic activity against Pythium aphanidermatum-induced damping-off of cucumber. The study indicates that fungal isolates obtained from marine environments may serve as potential biocontrol agents against some plant pathogens.

Keywords: Avicennia marina; Biocontrol; Mangrove; Marine fungi; Oomycete.

Grants and funding

This work was supported by the TRC project (RC/AGR/FISH/16/01), the EG/AGR/CROP/16/01 project, Sultan Qaboos University, and the Oman Animal and Plant Genetic Resources Center. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.