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The effect of the elicitor tryptophan and drought stress on some physiological characteristics of the Madagascar periwinkle (Catharanthus roseus L.) medicinal plant and the alteration of the expression pattern of the Str and Tdc genes
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Farshid Yousefi   , Alireza Abdali Mashhadi , Amin Lotfi , Alireza Shafeinia * , Saeed Jalili , Narges Soltani |
| Production Engineering and Plant Genetics Department, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran , Shafeinia@asnrukh.ac.ir |
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Abstract: (204 Views) |
Periwinkle (Catharanthus roseus L.) leaves serve as the sole source of the alkaloids vinblastine and vincristine, both of which are administered in cancer therapy. Due to the notably low biosynthetic yield of these alkaloids, efforts to enhance their concentrations in the foliage have gained considerable attention. Tryptophan amino acid, is considered as the main precursor in periwinkle alkaloids production. Furthermore, the application of drought stress may potentially enhance the levels of C. roseus valuable metabolites, including vinblastine and vincristine. This study aimed to examine the combined effects of tryptophan and drought stress treatments on the expression patterns of Str and Tdc genes involved in vinblastine and vincristine synthesis as well as root volume, root dry weight, and root length of C. roseus. The experiment was conducted in a 6×3 factorial experiment arranged in a completely randomized design with three replications. The treatments consisted of six tryptophan treatments (0 (control), 50, 100, 150, 200, and 250 mg/L) and three drought stress level (100%, 70%, and 40% of field capacity). The experiment was carried out in 2023 at Khuzestan University of Agricultural Sciences and Natural Resources under greenhouse conditions. The interaction between drought stress and tryptophan application significantly (P<0.05) affected root volume and dry weight, whereas root length did not significantly changed. Root length was increased with as drought stress levels intensified, while both root volume and root dry weight were decreased relative to the control. In contrast, increasing concentrations of tryptophan level led to an increase in root volume, root dry weight, and root length. The combined treatment of 250 mg/L of tryptophan application alongside severe drought stress (40% FC) resulted in an upregulation of the relative expression of the Tdc and Str genes in the leaf tissue of C. roseus at the 24-hour post treatment, followed by a subsequent decline. An increase in the Tdc and Str genes expression can be expected to lead to elevated levels of the secondary metabolite biosynthetic pathway products, including ajmalicine, vinblastine, and vincristine alkaloids. Given tryptophan's beneficial effects on root volume, root weight, and root length of C. roseus as well as its role in upregulating genes involved in vincristine and vinblastine biosynthesis, its use as an elicitor appears to be a promising strategy for enhancing the production of such valuable alkaloids. |
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| Keywords: Alkaloids, Madagascar periwinkle, Root, Vinblastine, Vincristine |
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Type of Study: Research |
Subject:
Molecular genetics
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| Send email to the article author |
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