Host-dependent fungus-fungus competition suppresses fungal pathogenesis in Arabidopsis thaliana

Abstract

Like animals, plants accommodate a rich diversity of microbes, typically without discernible disease symptoms. How their pathogenesis is prevented in the host remains obscure. Here, we show that the root-infecting fungus Colletotrichum fructicola of the C. gloeosporioides clade (CgE), isolated from field-grown healthy Brassicaceae plants, inhibits growth of pathogenic fungi in Arabidopsis thaliana, in a phosphate status-dependent manner. Loss of host ethylene signaling or phytoalexins, camalexin or indole glucosinolates, however, allows CgE to display pathogenesis, suggesting host contributions to endophytic CgE colonization and benefit. Compared to a closely-related C. gloeosporioides pathogen (CgP), CgE is characterized by genome expansion and >700 fungal genes (4.34%) specifically induced in the host roots when co-inoculated with CgP, including genes related to fungal secondary metabolism. This may underlie antimicrobial tolerance of CgE and its dominance over pathogenic fungi within the host, pointing to a role for fungus-fungus competition in asymptomatic fungal colonization in plants.

The moss-specific transcription factor PpERF24 positively modulates immunity against fungal pathogens in Physcomitrium patens

“…Samples were frozen in liquid nitrogen, and DNA was extracted with DNeasy kit (Qiagen) and quantified using NanoDrop spectrophotometer. qPCR was performed using primers designed for the ubiquitin gene of P. patens (Ubi2), ITS for B. cinerea and P. irregulare , and CFP12895 for C. gloeosporioides ( Pathompitaknukul et al, 2020 ; Supplementary Table 1 ). qPCR was performed in an Applied Biosystems QuantStudio 3 thermocycler using the QuantiNova Probe SYBR Green PCR Kit (Qiagen).…”

Evolution of manipulative microbial behaviors in the rhizosphere

“…Pathogen protection for the plant is a beneficial, but dynamic and context‐dependent, by‐product. This context dependency is even more important in changing nutrient conditions: Under phosphate‐deficient conditions, the previously beneficial endophyte becomes pathogenic (Pathompitaknukul et al, 2020 ).…”