RESUMO
KEY MESSAGE: EaCHS1 functions in the tolerance of plantlets to salinity stress by maintaining ROS homeostasis. Chalcone synthase (CHS) is an essential enzyme in the biosynthesis of flavonoids. Expression of CHS is governed by a wide range of environmental stimuli, including UV light, pathogen attack, and circadian clocks. However, little research exists on the relationship between CHS and salinity stress. In this work, we constructed separate overexpression and RNA interference vectors of EaCHS1, and transferred them into tobacco. Overexpression of EaCHS1 increased the production of downstream flavonoids and the expressions of related genes in the phenylpropanoid pathway. It also improved resistance to salinity stress during seed germination and root development. In contrast, heterologous silencing of endogenous CHS in tobacco by a conserved EaCHS1 fragment had opposite effect. Together, our results indicated that changing the expression level of EaCHS1 in plants alters the accumulation of flavonoids and regulates plantlet tolerance to salinity stress by maintaining ROS homeostasis.
Assuntos
Aciltransferases/metabolismo , Ageratina/enzimologia , Flavonoides/metabolismo , Regulação da Expressão Gênica de Plantas , Espécies Reativas de Oxigênio/metabolismo , Aciltransferases/genética , Ageratina/genética , Expressão Gênica , Homeostase , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Interferência de RNA , Tolerância ao Sal , Plântula/enzimologia , Plântula/genética , Plântula/fisiologia , Cloreto de Sódio/farmacologia , Estresse Fisiológico , Nicotiana/enzimologia , Nicotiana/genética , Nicotiana/fisiologiaRESUMO
In this study, conserved sequence regions of HMGR, DXR, and CHS (encoding 3-hydroxy-3-methylglutaryl-CoA reductase, 1-deoxyxylulose-5-phosphate reductoisomerase and chalcone synthase, respectively) were amplified by reverse transcriptase (RT)-PCR from Eupatorium adenophorum. Quantitative real-time PCR showed that the expression of CHS was related to the level of HHO, an allelochemical isolated from E. adenophorum. Semi-quantitative RT-PCR showed that there was no significant difference in expression of genes among three different tissues, except for CHS. Southern blotting indicated that at least three CHS genes are present in the E. adenophorum genome. A full-length cDNA from CHS genes (named EaCHS1, GenBank ID: FJ913888) was cloned. The 1,455 bp cDNA contained an open reading frame (1,206 bp) encoding a protein of 401 amino acids. Preliminary bioinformatics analysis of EaCHS1 revealed that EaCHS1 was a member of CHS family, the subcellular localization predicted that EaCHS1 was a cytoplasmic protein. To the best of our knowledge, this is the first report of conserved sequences of these genes and of a full-length EaCHS1 gene in E. adenophorum. The results indicated that CHS gene is related to allelopathy of E. adenophorum.
