ALFIN-like transcription factors (ALs) are involved in several physiological processes such as seed germination, root development and abiotic stress responses in plants. In carrot (
Daucus carota), the expression of
DcPSY2, a gene encoding phytoene synthase required for carotenoid biosynthesis, is
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ALFIN-like transcription factors (ALs) are involved in several physiological processes such as seed germination, root development and abiotic stress responses in plants. In carrot (
Daucus carota), the expression of
DcPSY2, a gene encoding phytoene synthase required for carotenoid biosynthesis, is induced after salt and abscisic acid (ABA) treatment. Interestingly, the
DcPSY2 promoter contains multiple ALFIN response elements. By in silico analysis, we identified two putative genes with the molecular characteristics of ALs,
DcAL4 and
DcAL7, in the carrot transcriptome. These genes encode nuclear proteins that transactivate reporter genes and bind to the carrot
DcPSY2 promoter in yeast. The expression of both genes is induced in carrot under salt stress, especially
DcAL4 which also responds to ABA treatment. Transgenic homozygous T3
Arabidopsis thaliana lines that stably express
DcAL4 and
DcAL7 show a higher survival rate with respect to control plants after chronic salt stress. Of note is that
DcAL4 lines present a better performance in salt treatments, correlating with the expression level of
DcAL4,
AtPSY and
AtDXR and an increase in carotenoid and chlorophyll contents. Likewise,
DcAL4 transgenic kiwi (
Actinidia deliciosa) lines show increased carotenoid and chlorophyll content and higher survival rate compared to control plants after chronic salt treatment. Therefore,
DcAL4 and
DcAL7 encode functional transcription factors, while ectopic expression of
DcAL4 provides increased tolerance to salinity in Arabidopsis and Kiwi plants.
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