Antagonism of rhizosphere Trichoderma brevicompactum DTN19 against the pathogenic fungi causing corm rot in saffron (Crocus sativus L.) in vitro

Li Tian; Xinyu Zhu; Yingqiu Guo; Qianjun Zhou; Lili Wang; Wankui Li

doi:10.3389/fmicb.2024.1454670

Antagonism of rhizosphere Trichoderma brevicompactum DTN19 against the pathogenic fungi causing corm rot in saffron (Crocus sativus L.) in vitro

Front Microbiol. 2024 Sep 4:15:1454670. doi: 10.3389/fmicb.2024.1454670. eCollection 2024.

Authors

Li Tian^#¹, Xinyu Zhu^#¹, Yingqiu Guo¹, Qianjun Zhou¹, Lili Wang¹, Wankui Li¹

Affiliation

¹ Key Laboratory of New Resources and Quality Evaluation of Traditional Chinese Medicine State Administration of Traditional Chinese Medicine, Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.

^# Contributed equally.

Abstract

Introduction: Corm rot in saffron (Crocus sativus L.) significantly impacts yield and quality. Non-toxic fungi, particularly Trichoderma species, are valuable for biological control due to their production of diverse and biologically active secondary metabolites.

Methods: This study aimed to isolate an effective antagonistic fungus against the pathogenic fungi causing corm rot in saffron. Four pathogenic fungi (Fusarium oxysporum, Fusarium solani, Penicillium citreosulfuratum, and Penicillium citrinum) were isolated from diseased saffron bulbs in Chongming. Initial screening through dual culture with these pathogens re-screening from rhizosphere soil samples of C. sativus based on its inhibitory effects through volatile, nonvolatile, and fermentation broth metabolites. The inhibitory effect of biocontrol fungi on pathogenic fungi in vitro was evaluated by morphological observation and molecular biology methods.

Results: Antagonistic fungi were identified as Trichoderma brevicompactum DTN19. F. oxysporum was identified as the most severe pathogen. SEM (scanning electron microscope) and TEM (transmission electron microscope) observations revealed that T. brevicompactum DTN19 significantly inhibited the growth and development of F. oxysporum mycelium, disrupting its physiological structure and spore formation. Additionally, T. brevicompactum DTN19 demonstrated nitrogen fixation and production of cellulase, IAA (Indole acetic acid), and siderophores. Whole-genome sequencing of strain DTN19 revealed genes encoding protease, cellulase, chitinase, β-glucosidase, siderophore, nitrogen cycle, and sulfate transporter-related proteins.

Discussion: T. brevicompactum DTN19 may inhibit the propagation of pathogenic fungi by destroying their cell walls or producing antibiotics. It can also produce IAA and iron carriers, which have the potential to promote plant growth. Overall, T. brevicompactum DTN19 showed the development prospect of biological agents.

Keywords: PGPR; Trichoderma brevicompactum; antagonistic activity; biological control; rhizosphere; saffron.

Grants and funding

The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This research was funded by the Science and Technology Innovation Action Plan for Sustainable Development of Chongming District, Shanghai (CK2022-01) and the Science and Technology Development Project of Shanghai University of Traditional Chinese Medicine (A4-Q230250249).