Induced genes expression pattern in response to drought stress at seedling stage of wheat

Document Type : Research Paper

Authors

Department of Plant Breeding and Biotechnology, Faculty of Plant Production, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran.

Abstract

Molecular studies have shown that several genes with various functions are induced by drought stress and various transcription factors are involved in the regulation of the stress-inducible genes. To evaluate the effects of drought stress on gene expression, CRTBF2, DREB6 and DBF transcription factors as well as the expression pattern of Acyl, SuT5 and SuT4 genes were studied using qRT-PCR. The experiment was carried out as factorial based on completely randomized design. One factor included drought stress levels of -1, -2, -4 and -6 bar imposed by polyethylene glycol plus a control. The second factor consisted of four wheat cultivars as follows: Qaboos and Koohdasht (as drought tolerant), and Ehsan and Morvarid (as drought sensitive). Assessing the seedling morphological traits, such as germination percentage, plumule length and radicle length showed that with an increase in drought stress, the tolerant cultivars of Qaboos and Koohdasht showed lower decrease for these traits compared to the sensitive cultivars of Ehsan and Morvarid. The results of evaluating the gene expressions demonstrated that the DREB6 gene expression was higher in the tolerant cultivars of Qaboos and Koohdasht as compared to the sensitive cultivars of Ehsan and Morvarid, indicating the possible role of the product of this gene, as a transcription factor, in inducing promoters of drought tolerance genes and transcribing such genes. However, the CRTBF2 and DBF genes acted as repressor transcription factors in expressing the genes involved in the drought stress tolerance in the cultivars under study. The expressions of the Acyl and SuT5 genes were greater in the tolerant cultivars compared to the sensitive cultivars. The SuT4 gene expression was lower in both tolerant and sensitive cultivars than the expression of this gene in the corresponding control treatment. Therefore, it seems that the Acyl and SuT5 genes, through lipid decomposition and carbohydrate transport pathways, respectively, increased the tolerance of Qaboos and Koohdasht cultivars in this study.

Keywords


Article Title [فارسی]

الگوی بیان ژن‌های القایی در پاسخ به تنش خشکی در مرحله گیاهچه گندم

Abstract [فارسی]

مطالعات مولکولی نشان داده ­اند که تعدادی ژن با عملکرد گوناگون به وسیله تنش خشکی القا شده و عوامل رونویسی مختلف در تنظیم ژن‌های القا شده از تنش نقش دارند. به منظور ارزیابی اثر تنش خشکی بر بیان ژن، عوامل رونویسی CRTBF2، DREB6 و DBF و الگوی بیان ژن‌های Acyl، SuT5 و SuT4 با استفاده از qRT-PCR مطالعه شد. آزمایش به صورت فاکتوریل در قالب طرح کاملا تصادفی اجرا شد. فاکتور تنش شامل شاهد و 1-، 2-، 4- و 6- بار و فاکتور رقم شامل ارقام گندم قابوس و کوهدشت (متحمل به خشکی)، و احسان و مروارید (حساس به خشکی) بود. ارزیابی صفات مورفولوژیکی گیاهچه، از جمله درصد جوانه‌زنی، طول ساقه‌چه و طول ریشه‌چه در گیاهان مورد مطالعه نشان داد که با افزایش تنش خشکی، ارقام متحمل قابوس و کوهدشت از نظر این صفات نسبت به ارقام حساس احسان و مروارید کاهش کمتری داشتند. نتایح ارزیابی بیان ژن نشان داد که بیان ژن DREB6 در ارقام متحمل قابوس و کوهدشت در مقایسه با ارقام حساس احسان و مروارید بیشتر بوده و نشان‌دهنده نقش محصول این ژن به عنوان عامل رونویسی در القای راه‌انداز ژن‌های تحمل به خشکی و رونویسی از ژن‌ها بود. از طرف دیگر بیان ژن‌های CRTBF2 و DBF حاکی از آن بود که این ژن‌ها در بیان ژن‌های دخیل در تحمل به تنش خشکی در ارقام مورد بررسی، ظاهرا به عنوان عامل رونویسی بازدارنده عمل می‌کنند. بیان ژن‌های Acyl و SuT5 در ارقام متحمل نسبت به ارقام حساس بیشتر بود. با این حال، بیان ژن SuT4 در ارقام متحمل و حساس کمتر از بیان این ژن در تیمار شاهد مربوطه بود. بنابراین، ژن‌های Acyl و SuT5 به‌ترتیب از طریق مسیرهای تجزیه چربی و انتقال کربوهیدرات، تحمل ارقام قابوس و کوهدشت را افزایش دادند.

Keywords [فارسی]

  • بیان ژن
  • تنش خشکی
  • عامل رونویسی
  • گندم
  • مرحله گیاهچه
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