The Biocontrol Root-Oomycete, Pythium Oligandrum, Triggers Grapevine Resistance and Shifts in the Transcriptome of the Trunk Pathogenic Fungus, Phaeomoniella Chlamydospora

Abstract

The worldwide increase in grapevine trunk diseases, mainly esca, represents a major threat for vineyard sustainability. Biocontrol of a pioneer fungus of esca, Phaeomoniella chlamydospora, was investigated here by deciphering the tripartite interaction between this trunk-esca pathogen, grapevine and the biocontrol-oomycete, Pythium oligandrum. When P. oligandrum colonizes grapevine roots, it was observed that the wood necroses caused by P. chlamydospora were significantly reduced. Transcriptomic analyses of plant and fungus responses were performed to determine the molecular events occurring, with the aim to relate P.chlamydospora degradation of wood to gene expression modulation. Following P. oligandrum-root colonization, major transcriptomic changes occurred both, in the grapevine-defense system and in the P. chlamydospore-virulence factors. Grapevine-defense was enhanced in response to P. chlamydospora attacks, with P. oligandrum acting as a plant-systemic resistance inducer, promoting jasmonic/ethylene signaling pathways and grapevine priming. P. chlamydospora pathogenicity genes, such as those related to secondary metabolite biosynthesis, carbohydrate-active enzymes and transcription regulators, were also affected in their expression. Shifts in grapevine responses and key-fungal functions were associated with the reduction of P. chlamydospora wood necroses. This study provides evidence of wood fungal pathogen transcriptional changes induced by a root biocontrol agent, P. oligandrum, in which there is no contact between the two microorganisms.

Cultivar Contributes to the Beneficial Effects of Bacillus subtilis PTA-271 and Trichoderma atroviride SC1 to Protect Grapevine Against Neofusicoccum parvum

“…and Trichoderma spp. can possibly exert direct beneficial or detrimental interplays within the host’s microbiome, and especially on the other BCA and pathogens such as GTDs fungi ( Di Marco et al, 2002 ; Kloepper et al, 2004 ; Ongena and Jacques, 2008 ; Haidar et al, 2016 ; Trotel-Aziz et al, 2019 ; Yacoub et al, 2020 ; Úrbez-Torres et al, 2020 ; Blundell et al, 2021 ). In vitro dual confrontation tests confirmed the antagonistic activity of Bs PTA-271 or Ta SC1 toward Np- Bt67 since each of them significantly inhibits the mycelium growth of Np -Bt67 (see Figures 6A,B ).…”

Grapevine rootstock and soil microbiome interactions: Keys for a resilient viticulture

“…Recently Jaarsveld et al . (2021) [ 102 ] showed the higher colonization capacity by six Trichoderma products on graftlings (Sauvignon blanc cv. Grafted onto Ramsey) basal ends compared to middle or root tip part, even though Trichoderma spp.…”

The Grapevine Microbiome to the Rescue: Implications for the Biocontrol of Trunk Diseases

“…In a different trial, P. oligandrum Po37 was able to significantly reduce P. chlamydospora and P. minimum infections [ 83 ]. Finally, P. oligandrum is also able to induce defense mechanisms against the trunk pathogen N. parvum [ 92 ].…”