Alterations in the phenylpropanoid pathway affect poplar ability for ectomycorrhizal colonisation and susceptibility to root-knot nematodes

Abstract

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Abscisic acid supports colonization of Eucalyptus grandis roots by the mutualistic ectomycorrhizal fungus Pisolithus microcarpus

“…(2021a), found that phenylpropanoid and flavonoids were increased during the early stages of EcM colonization, compounds that Behr et al . (2020) were able to positively correlate with EcM colonization. In our results, however, we found these pathways were downregulated during the physical integration stage of colonization in E. grandis before being positively expressed during the functional symbiosis phase.…”

“…Similar gene classes have been found to be regulated in EcM interaction with Populus, Pinus, and aspen, although the direction and magnitude of how these pathways are impacted is not consistent (Weiss et al, 1997;Li et al, 2014;Liao et al, 2014;Plett et al, 2015b;Basso et al, 2019). Transcriptomically Weiss et al (1997), and metabolomically Plett et al (2021a), found that phenylpropanoid and flavonoids were increased during the early stages of EcM colonization, compounds that Behr et al (2020) were able to positively correlate with EcM colonization. In our results, however, we found these pathways were downregulated during the physical integration stage of colonization in E. grandis before being positively expressed during the functional symbiosis phase.…”

“…In our results, however, we found these pathways were downregulated during the physical integration stage of colonization in E. grandis before being positively expressed during the functional symbiosis phase. Terpenoid associated genes, meanwhile, identified as being enriched during EcM colonization of host roots both here and by previous research (Behr et al ., 2020) are known to be partially responsible for differentiation between different stages of the colonization process (Liao et al ., 2014; Basso et al ., 2019).…”

Novel Microdialysis Technique Reveals a Dramatic Shift in Metabolite Secretion during the Early Stages of the Interaction between the Ectomycorrhizal Fungus Pisolithus microcarpus and Its Host Eucalyptus grandis

“…Plant contact with ECM fungi has previously been shown to induce phenylpropanoid metabolism, and it has been suggested that the presence of these metabolites aids in limiting over-colonisation by the fungus [ 47 , 48 , 49 ]. However, more recent work involving transgenic down-regulation of genes within the phenylpropanoid pathway suggests that production of these compounds is, in fact, beneficial for mycorrhiza formation, though this could also stem from secondary hormone effects [ 50 ]. Flavonoids are also important attractants of ECM fungi, inducing spore germination, hyphal growth or the production of effector proteins within the fungus [ 16 , 17 , 51 ].…”

Genetic modification of the shikimate pathway to reduce lignin content in switchgrass (Panicum virgatumL.) significantly impacts plant microbiomes

“…For example, the silencing of cinnamoyl-CoA reductase gene reduced lignin in poplar trees, but also significantly changed the bacterial community in roots, stems, and leaves (Beckers et al, 2016). Similarly, poplar trees downregulated in genes encoding for the lignin biosynthetic enzymes caffeoyl-CoA O-methyltransferase, caffeic acid O-methyltransferase, cinnamoyl-CoA reductase, and cinnamyl alcohol dehydrogenase all displayed a lower mycorrhizal colonization in vitro (Behr et al, 2020). Thus, although growing engineered switchgrass with reduced lignin could have obvious industrial advantages regarding deconstruction and conversion processes, the impact of the engineered trait on the structure and functioning of the plant microbiome needs to be evaluated.…”