HAG2/MYB76 and HAG3/MYB29 exert a specific and coordinated control on the regulation of aliphatic glucosinolate biosynthesis in Arabidopsis thaliana
HAG2/MYB76 and HAG3/MYB29 exert a specific and coordinated control on the regulation of aliphatic glucosinolate biosynthesis in Arabidopsis thaliana
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DOI：
10.1111/j.1469-8137.2007.02295.x
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发表时间：
2008-01-01
期刊：
影响因子：
9.4
通讯作者：
Fluegge, Ulf-Ingo
中科院分区：
文献类型：
--
作者：
Gigolashvili, Tamara;Engqvist, Martin;Fluegge, Ulf-Ingo
在先前的一次反式激活筛选中，两种拟南芥R2R3 - MYB转录因子，HAG2/MYB76和HAG3/MYB29，以及已经被鉴定特征的HAG1/MYB28，被确定为脂肪族芥子油苷生物合成的假定调节因子。通过使用转录水平升高或受抑制的转化体，对HAG2/MYB76和HAG3/MYB29的功能进行了分子和生化特性鉴定。采用实时定量PCR分析、共转化分析以及芥子油苷含量测定来评估这两种MYB因子对芥子油苷生物合成基因的稳态水平以及脂肪族芥子油苷积累的影响。结果表明，HAG2/MYB76和HAG3/MYB29均为脂肪族芥子油苷生物合成的正调节因子。启动子 - β - 葡萄糖醛酸酶（GUS）融合基因的表达表明，在营养器官和生殖器官中均有GUS活性，且每种MYB因子具有不同的特征。在脂肪族芥子油苷生物合成的调控中，HAG1/MYB28、HAG2/MYB76和HAG3/MYB29相互反式激活，并且下调参与吲哚族芥子油苷生物合成调控的基因的表达，这表明这两条途径存在相互的负调控。所有这三种HAG转录因子对脂肪族芥子油苷生物合成进行协同调控。
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.