Analysis of the Involvement of Hydroxyanthranilate Hydroxycinnamoyltransferase and Caffeoyl-CoA 3-O-Methyltransferase in Phytoalexin Biosynthesis in Oat

Abstract

Two oat genes encoding hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyltransferase (HHT) and S-adenosyl-L-methionine:trans-caffeoyl-CoA 3-O-methyltransferase (CCoAOMT), both of which are possibly involved in the biosynthesis of oat avenanthramide phytoalexins, were cloned and their expression profiles in response to biological stress were studied. Four distinct cDNAs of oat HHT (AsHHT1-4) were isolated with the degenerative polymerase chain reaction method. The enzymatic activity of AsHHT1 expressed in E. coli was found using hydroxyanthranilate and hydroxycinnamoyl-CoAs as cosubstrates. Cloned oat CCoAOMT (AsCCoAOMT) encoded a polypeptide of 130 amino acid residues with 77.7 to 80.8% identities to the CCoAOMT sequences from other plant species. The accumulation of AsHHT1 and AsCCoAOMT transcripts increased concomitantly with phytoalexin accumulation by the treatment of victorin, a specific elicitor in oat lines carrying the Pc-2/Vb gene. Pharmacological approaches indicated the involvement of Ca2+, NO, and protein kinases in the signaling pathways of AsHHT1 and AsCCoAOMT mRNA induction. When oat leaves were inoculated with Puccinia coronata, the mRNA expression of AsHHT1 and AsCCOAOMT increased in both incompatible and compatible interactions but more rapidly in incompatible interaction. Interestingly, however, significant phytoalexin accumulation was observed only in incompatible interaction during the experimental period, suggesting that phytoalexin accumulation may be inhibited in one or more posttranscriptional processes in the compatible interaction.

Accumulation of hydroxycinnamic acid amides induced by pathogen infection and identification of agmatine coumaroyltransferase in Arabidopsis thaliana

“…The enzyme catalyzes the condensation reaction between hydroxycinnamoyl-/benzoyl-CoA and anthranilate, and generates dianthramides. Since then, several acyltransferases have been identiWed and characterized including HHT (hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyltransferase) in Avena sativa, ACT (agmatine coumaroyltransferase) in Hordeum vulgare, and THT (hydroxycinnamoyl-CoA:tyramine hydroxycinnamoyltransferase) in Solanum tuberosum (Schmidt et al 1999;Burhenne et al 2003;Yang et al 2004). Except THT which shows low similarity to other enzymes, these enzymes have been classiWed into the BAHD acyltransferase family (D'Auria 2006).…”

A hydroxycinnamoyltransferase responsible for synthesizing suberin aromatics in Arabidopsis

“…The name ''BAHD family'' originated from its first 4 characterized enzymes: Clarkia breweri benzyl alcohol Oacetyltransferase (BEAT); Gentiana triflora anthocyanin Ohydroxycinnamoyltransferase (AHCT); Dianthus caryophyllus anthranilate N-hydroxycinnamoyl/benzoyl transferase (HCBT); and Catharanthus roseus deacetylvindoline 4-O-acetyltransferase (DAT). The characterized BAHD enzymes use a range of CoAthioester donors, including the aromatic CoAs, to modify a variety of plant metabolites, such as shikimate-phenylpropanoid derivatives, alkaloids, terpenoids, polyamines, and the short-or middle chain aliphatic alcohols (27)(28)(29)(30)(31). The BAHD enzymes' broad spectrum of substrate specificity and diverse biological functions lead us to assume their potential involvement in the acylation of cell wall associated biopolymer components, such as polysaccharides, lignin, and suberin (32).…”

Análise de seqüências expressas em raízes de cana-de-açúcar colonizadas por Glomus clarum

“…As Puccinia coronata f. sp. avenae demonstrando que é uma resposta de defesa vegetal induzida pela infecção por patógenos (Yang et al, 2004).…”

“…Este gene teve indução de 1,8 vezes em raízes micorrizadas cultivadas em condições de baixo P. Cafeoil-CoA-O-metiltransferase está envolvida nas respostas de defesa da planta sendo que seu produto é utilizado na produção de fitoalexinas e no enrijecimento da parede celular. Em relações patógeno-hospedeiro incompatíveis, cafeoil-CoA-O-metiltransferase é induzida poucas horas após a inoculação do patógeno causando reação de hipersensibilidade e morte celular programa (Yang et al, 2004).…”