Assessing the Biocontrol Potential of Clonostachys Species Isolated as Endophytes from Coffea Species and as Mycoparasites of Hemileia Rusts of Coffee in Africa

Abstract

During surveys conducted in South America and Africa to identify natural fungal enemies of coffee leaf rust (CLR), Hemileia vastatrix, over 1500 strains were isolated, either as endophytes from healthy tissues of Coffea species or as mycoparasites growing on rust pustules. Based on morphological data, eight isolates—three isolated from wild or semiwild coffee and five from Hemileia species on coffee, all from Africa—were provisionally assigned to the genus Clonostachys. A polyphasic study of their morphological, cultural and molecular characteristics—including the Tef1 (translation elongation factor 1 alpha), RPB1 (largest subunit of RNA polymerase II), TUB (β-tubulin) and ACL1 (ATP citrate lyase) regions—confirmed these isolates as belonging to three species of the genus Clonostachys: namely C. byssicola, C. rhizophaga and C. rosea f. rosea. Preliminary assays were also conducted to test the potential of the Clonostachys isolates to reduce CLR severity on coffee under greenhouse conditions. Foliar and soil applications indicated that seven of the isolates had a significant effect (p < 0.05) in reducing CLR severity. In parallel, in vitro tests that involved conidia suspensions of each of the isolates together with urediniospores of H. vastatrix resulted in high levels of inhibition of urediniospore germination. All eight isolates showed their ability to establish as endophytes in C. arabica during this study, and some proved to be mycoparasites of H. vastatrix. In addition to reporting the first records of Clonostachys associated with healthy coffee tissues and with Hemileia rusts of coffee, this work provides the first evidence that Clonostachys isolates have potential as biological control agents against CLR.

Diversity and antioxidant activity of endophytic fungi isolated from salam (Syzygium polyanthum)

“…This behavior is according to the activation of several mechanisms, such as secreted enzymes to degrade the cell wall, antifungal secondary metabolites production, and plant defense systems induction. Besides having significant biocontrol activity, C. rosea also functions in the biodegradation of plastic waste, biotransformation of bioactive compounds, and source of bioenergy (Sun et al 2020;El-Gendi et al 2022;Geiger et al 2022;Kiruba and Saeid 2022;Kapeua-Ndacnou et al 2023). The findings in this study complement the benefits provided by C. rosea that were previously studied.…”

Identification, Antimicrobial and Plant Growth Promoting Activities of Endophytic Fungi Associated with Cynomorium songaricum Rupr., a Traditional Medicinal Plant in Mongolia

“…Most of our isolates assigned to the genus Clonostachys were found in old rhizomes, absent from fresh rhizomes, and exhibited both antibacterial and antifungal activity. Recently, Kapeua-Ndacnou et al reported that certain Clonostachys endophytes from healthy tissues of Coffea species and mycoparasites of Hemileia, the coffee leaf rust (CLR), significantly reduced the severity of CLR [44].…”

Synergistic Antibacterial Effects of Combined Phytochemicals of Endophytic Fungi Extracts and Its Pure Compounds Isolated from Sungkai (Peronema canescens) Leaves

“…The use of bioactive compounds in plant extracts is more widely used in medicine than single bioactive compounds. Crude extracts are a source of components that might change resistance, according to studies on the antibacterial properties of herbal remedies utilizing clinical isolates [20]. Since medicinal plant extracts may include hundreds or even thousands of distinct bioactive compounds in varying abundances, identifying the bioactive molecules responsible for a given biological action is extremely challenging.…”