Isolation and characterization of the 4-coumarate:coenzyme A ligase (4CL1) promoter from Eucalyptus camaldulensis

Abstract

The most important enzyme of the phenylpropanoid pathway, 4-coumarate:coenzyme A ligase (4CL), is encoded by several homologous genes including 4CL1. The 4CL1 promoter is a tissue-specific gene expression element, particularly active in the secondary xylem or older stems. In this study, the 1127 bp 5 0 -upstream region of the 4CL1 coding sequence from Eucalyptus camaldulensis, Euc4CL1, was isolated and characterized. Essential putative cis-elements in the Euc4CL1 promoter included: a TATA-box at -22/-28 position, two CCAAT-boxes at -256/-260 and -277/-281 positions, respectively, an AC-element at -328/-336 and A-boxes at -115/-120 and -990/-995 positions. To investigate the effect of the Euc4CL1 promoter on gene expression, a plant transformation vector, pEuc4CL1p, containing the reporter gene for b-glucuronidase (GUS) under the control of Euc4CL1 promoter was constructed based on the pBI101 backbone and introduced in tobacco plants. Stable expression of the GUS gene in transgenic lines was analysed by a histochemical GUS assay. The results indicated the specific expression of the GUS gene in the stem xylem cells of transgenic tobacco lines was controlled by the Euc4CL1 promoter. The observations suggest the isolated Euc4CL1 promoter is a potential candidate for driving the expression of a foreign gene in plant xylem tissues.

Identification of the 4cl Family in Cassava and Expression Pattern Analysis of the Me4cl32 Gene

“…The 4-coumarate: CoA ligase (4CL) gene family has been identi ed as a category of stress-resistant genes [8]. Under salt stress conditions, the gene expression levels of the 4CL family are upregulated, ultimately enhancing the plant's salt resistance [9]. As for potatoes (Solanum tuberosum L), when subjected to stressors such as ABA and MeJA, they increase the expression of St4CL6, St4CL8, and St4CL5, thereby enhancing stress tolerance [10].…”