Caffeine fostering of mycoparasitic fungi against phytopathogens

Abstract

Abbreviation: PDA, potato dextrose agar Caffeine (1,3,7-trimethixanthine) is a typical purine alkaloid produced in more than 80 plant species. Its biological role is considered to strengthen plant's defense capabilities, directly as a toxicant to biotic attackers (allelopathy) and indirectly as an activator of defense system (priming). Caffeine is actively secreted into rhizosphere through primary root, and possibly affects the structure of microbe community nearby. The fungal community in coffee plant rhizosphere is enriched with particular species, including Trichoderma family, a mycoparasite that attacks and kills phytopathogens by coiling and destroying their hyphae. In the present study, the caffeine response of 8 filamentous fungi, 4 mycoparasitic Trichoderma, and 4 prey phytopathogens, was examined. Results showed that allelopathic effect of caffeine on fungal growth and development was differential, being stronger on pathogens than on Trichoderma species. Upon confronting, the prey immediately ceased the growth, whereas the predator continued to grow, indicating active mycoparasitism to have occurred. Caffeine enhanced mycoparasitism up to 1.7-fold. Caffeine thus functions in a double-track manner against fungal pathogens: first by direct suppression of growth and development, and second by assisting their natural enemy. These observations suggest that caffeine is a powerful weapon in the arms race between plants and pathogens by fostering enemy's enemy, and we propose the idea of "caffeine fostering" as the third role of caffeine.

Inhibition of Candida albicans growth by steeping freeze-dried robusta ground coffee

“…Caffeine and its derivatives, methylxanthines, are powerful inhibitor of cAMP-phosphodiesterases from mammals, plants, insects, bacteria and fungi. One of methylxanthine functions is thus established to modulate endogenous cAMP, which critically regulates fungal life, including morphogenesis, virulence, nutrient sensing and reproduction (Sugiyama et al, 2016). Flavonoids have proven ability as an antifungal.…”

Uptake of adenine by purine permeases of Coffea canephora

“…accumulates predominantly in seeds and leaves, where caffeine restricts development and growth of other organisms [16] and also stimulates plant defense response by affecting signaling pathways [17,18]. In addition, caffeine is secreted from the roots during germination, when it is thought to modulate interactions with pathogens and mycoparasites [19,20].…”

Inhibition Mechanism of Caffeine in Tea Pathogenic Fungi Botryosphaeria Dothidea and Colletotrichum Gloeosporioides

“…Caffeine (1,3,7-trimethylxanthine) is a purine alkaloid and can be found in more than 80 plant species [9].…”

“…Caffeine also acts as a powerful inhibitor of cAMP phosphodiesterase in bacteria, fungi and insects [14]. Sugiyama et al [9] and Harren et al [20] reported that fungal growth inhibition by caffeine varied according to the role and quantity of phosphodiesterase. Furthermore, Sugiyama et al [9] found that caffeine played dual roles by both suppressing the growth of bene cial fungi, such as Trichoderma sp., and enhancing the antagonistic activity of the bene cial fungi against fungal pathogens.…”