Carrot DcALFIN4 and DcALFIN7 Transcription Factors Boost Carotenoid Levels and Participate Differentially in Salt Stress Tolerance When Expressed in <i>Arabidopsis thaliana</i> and <i>Actinidia deliciosa</i>
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 (<i>Daucus carota</i>), the expression of <i>DcPSY2</i>, a gene encoding phytoene synthase requi...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-10-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/20/12157 |
| Summary: | 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 (<i>Daucus carota</i>), the expression of <i>DcPSY2</i>, a gene encoding phytoene synthase required for carotenoid biosynthesis, is induced after salt and abscisic acid (ABA) treatment. Interestingly, the <i>DcPSY2</i> promoter contains multiple ALFIN response elements. By in silico analysis, we identified two putative genes with the molecular characteristics of ALs, <i>DcAL4</i> and <i>DcAL7</i>, in the carrot transcriptome. These genes encode nuclear proteins that transactivate reporter genes and bind to the carrot <i>DcPSY2</i> promoter in yeast. The expression of both genes is induced in carrot under salt stress, especially <i>DcAL4</i> which also responds to ABA treatment. Transgenic homozygous T3 <i>Arabidopsis thaliana</i> lines that stably express <i>DcAL4</i> and <i>DcAL7</i> show a higher survival rate with respect to control plants after chronic salt stress. Of note is that <i>DcAL4</i> lines present a better performance in salt treatments, correlating with the expression level of <i>DcAL4</i>, <i>AtPSY</i> and <i>AtDXR</i> and an increase in carotenoid and chlorophyll contents. Likewise, <i>DcAL4</i> transgenic kiwi (<i>Actinidia deliciosa</i>) lines show increased carotenoid and chlorophyll content and higher survival rate compared to control plants after chronic salt treatment. Therefore, <i>DcAL4</i> and <i>DcAL7</i> encode functional transcription factors, while ectopic expression of <i>DcAL4</i> provides increased tolerance to salinity in Arabidopsis and Kiwi plants. |
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| ISSN: | 1661-6596 1422-0067 |