English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Flavan-3-ols including the monomeric catechin and the polymeric proanthocyanidins (PAs) are abundant phenolic metabolites in poplar ( Populus  spp.) previously described to protect leaves against pathogen infection. However, it is not known whether stems are also defended in this way. Here we investigated flavan-3-ol accumulation, activity, and the regulation of formation in black poplar ( P. nigra ) stems after infection by a newly described fungal stem pathogen,  Plectosphaerella populi , which forms canker-like lesions in stems. We showed that flavan-3-ol contents increased in  P. populi -infected black poplar stems over the course of infection compared to non-infected controls. Transcripts of leucoanthocyanidin reductase ( LAR ) and anthocyanidin reductase ( ANR ) genes involved in the last steps of flavan-3-ol biosynthesis were also upregulated upon fungal infection indicating  de novo  biosynthesis. Amending culture medium with catechin and PAs reduced the mycelial growth of  P. populi , suggesting that these metabolites act as anti-pathogen defenses in poplar  in vivo . Among the hormones, salicylic acid (SA) was higher in  P. populi -infected tissues compared to the non-infected controls over the course of infection studied, while jasmonic acid (JA) and JA-isoleucine (JA-Ile) levels were higher than controls only at the early stages of infection. Interestingly, cytokinins (CKs) were also upregulated in  P. populi -infected stems. Poplar saplings treated with CK showed decreased levels of flavan-3-ols and SA in stems suggesting a negative association between CK and flavan-3-ol accumulation. Taken together, the sustained upregulation of SA in correlation with catechin and PA accumulation suggests that this is the dominant hormone inducing the formation of antifungal flavan-3-ols during  P. populi  infection of poplar stems.

frontiers in plant science

Accumulation of Catechin and Proanthocyanidins in Black Poplar Stems After Infection by Plectosphaerella populi: Hormonal Regulation, Biosynthesis and Antifungal Activity