Forest tree associated bacteria for potential biological control of Fusarium solani and of Fusarium kuroshium, causal agent of Fusarium dieback

Phytophthora Root Rot Modifies the Composition of the Avocado Rhizosphere Microbiome and Increases the Abundance of Opportunistic Fungal Pathogens

“…The higher relative abundance of Pseudomonadales, Burkholderiales and other Beta- and Gamma-Proteobacteria in the rhizosphere of root-rot symptomatic trees is consistent with this hypothesis, as these fast-growing bacteria are known for rapidly colonizing the rhizosphere in response to the liberation of labile sources of carbon in root exudates ( Eilers et al, 2010 ; Trivedi et al, 2012 ). Moreover, these taxa have been associated with soil suppressiveness and plant protection against fungal diseases ( Mendes et al, 2011 ), for example through the production of antifungal 2,4-diacetylphloroglucinol (DAPG; Bergsma-Vlami et al, 2005 ), the emission of antifungal and anti-oomycete volatile organic compounds such as dimethyl disulfide or 1-undecene ( Hunziker et al, 2015 ; Báez-Vallejo et al, 2020 ) or through the production of siderophores ( Paulsen et al, 2005 ). Furthermore, the genus Pseudomonas has been reported to be able to evade or reduce plant defenses in order to colonize the rhizosphere ( Liu et al, 2018 ; Yu et al, 2019 ).…”

“…The rhizosphere is a densely populated area influenced by the plant root exudates, where complex interactions occur between microbial communities and the radicular system ( Yadav et al, 2015 ; Ahkami et al, 2017 ). The rhizosphere microbiota plays a fundamental role in plant growth, health, productivity, and in soil quality, as it may increase plant nutrient availability and uptake, abiotic stress tolerance, produce phytohormones and protect the plant against the attack of soil-borne pathogens ( Bulgarelli et al, 2013 ; Mendes et al, 2013 ; Báez-Vallejo et al, 2020 ). Therefore, any shift in the composition of the rhizosphere microbiome could potentially affect its ecological functions, the physiological state of the plant and the plant productivity ( Trivedi et al, 2012 ; Wei et al, 2018 ).…”

Bark from avocado trees of different geographic locations have consistent microbial communities

“…Methylobacterium, the second most abundant genus found in avocado bark microbial communities, is a facultative methylotroph (Vorholt, 2012), which might benefit from both plant (Wang et al 2016) and microbial methane emission, as many potentially methane-producing Archaea were present in the community. Interestingly, Methylobacterium isolates were also obtained from the phyllosphere of two Lauraceae species (the same plant family as P. americana) in Mexico, and displayed antifungal activity in vitro against Fusarium solani (Báez-Vallejo et al 2020). The dominance of Methylobacterium at the bark level could therefore play a potential role in the biocontrol of Fusarium dieback in avocado trees.…”

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“…The higher relative abundance of Pseudomonadales, Burkholderiales and other Beta-and Gamma-Proteobacteria in the rhizosphere of root-rot symptomatic trees is consistent with this hypothesis, as these fast-growing bacteria are known for rapidly colonizing the rhizosphere in response to the liberation of labile sources of carbon in root exudates (Eilers et al, 2010;Trivedi et al, 2012). Moreover, these taxa have been associated with soil suppressiveness and plant protection against fungal diseases (Mendes et al, 2011), for example through the production of antifungal 2,4-diacetylphloroglucinol (DAPG; Bergsma-Vlami et al, 2005), the emission of antifungal and anti-oomycete volatile organic compounds such as dimethyl disulfide or 1undecene (Hunziker et al, 2015;Báez-Vallejo et al, 2020) or through the production of siderophores (Paulsen et al, 2005). Furthermore, the genus Pseudomonas has been reported to be able to evade or reduce plant defenses in order to colonize the rhizosphere (Liu et al, 2018;Yu et al, 2019).…”

“…The rhizosphere is a densely populated area influenced by the plant root exudates, where complex interactions occur between microbial communities and the radicular system (Yadav et al, 2015;Ahkami et al, 2017). The rhizosphere microbiota plays a fundamental role in plant growth, health, productivity, and in soil quality, as it may increase plant nutrient availability and uptake, abiotic stress tolerance, produce phytohormones and protect the plant against the attack of soil-borne pathogens (Bulgarelli et al, 2013;Mendes et al, 2013;Báez-Vallejo et al, 2020). Therefore, any shift in the composition of the rhizosphere microbiome could potentially affect its ecological functions, the physiological state of the plant and the plant productivity (Trivedi et al, 2012;Wei et al, 2018).…”