HAG2/MYB76 and HAG3/MYB29 exert a specific and coordinated control on the regulation of aliphatic glucosinolate biosynthesis in Arabidopsis thaliana.
In a previous transactivation screen, two Arabidopsis thaliana R2R3-MYB transcription factors, HAG2/MYB76 and HAG3/MYB29, along with the already characterized HAG1/MYB28, were identified as putative regulators of aliphatic glucosinolate biosynthesis. Molecular and biochemical characterization of HAG2/MYB76 and HAG3/MYB29 functions was performed using transformants with increased or repressed transcript levels. Real-time PCR assays, cotransformation assays and measurements of glucosinolate contents were used to assess the impact of both MYB factors on the steady-state level of glucosinolate biosynthetic genes and accumulation of aliphatic glucosinolates. Both HAG2/MYB76 and HAG3/MYB29 were shown to be positive regulators of aliphatic glucosinolate biosynthesis. Expression of promoter-beta-glucuronidase (GUS) fusions indicated GUS activities in both vegetative and generative organs, with distinct characteristics for each MYB factor. HAG1/MYB28, HAG2/MYB76 and HAG3/MYB29 reciprocally transactivated each other in the control of aliphatic glucosinolate biosynthesis and downregulated the expression of genes involved in the control of indolic glucosinolate biosynthesis, pointing to a reciprocal negative regulation of these two pathways. All three HAG transcription factors exert a coordinated control on aliphatic glucosinolate biosynthesis.
Botanisches Institut der Universität zu Köln, Gyrhofstrasse 15, D-50931 Köln, Germany.
Tamara
T
Gigolashvili
Botanisches Institut der Universität zu Köln, Gyrhofstrasse 15, D-50931 Köln, Germany.
Martin
M
Engqvist
Botanisches Institut der Universität zu Köln, Gyrhofstrasse 15, D-50931 Köln, Germany.
Ruslan
R
Yatusevich
Abteilung für Chemische Ökologie, Universität Bielefeld, Universitätsstraße 25, D-33615 Bielefeld, Germany.
Caroline
C
Müller
Botanisches Institut der Universität zu Köln, Gyrhofstrasse 15, D-50931 Köln, Germany.
Ulf-Ingo
UI
Flügge
D000085:Acetates / Q000378:metabolism; D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005961:Glucosinolates / Q000096:biosynthesis*; D051548:Histone Acetyltransferases; D016254:Mutagenesis, Insertional; D054883:Oxylipins / Q000378:metabolism; D010641:Phenotype; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D000099224:p300-CBP-Associated Factor
D000085:Acetates; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D005961:Glucosinolates; D051548:Histone Acetyltransferases; D054883:Oxylipins; D014157:Transcription Factors; C528835:MYB76 protein, Arabidopsis; C523552:Myb29 protein, Arabidopsis; C072239:methyl jasmonate; C474636:GCN5 protein, Arabidopsis; D000099224:p300-CBP-Associated Factor