Molecular cloning of cDNAs for three tau-type glutathione S-transferases in pumpkin (Cucurbita maxima) and their expression properties

• Published in: Physiologia plantarum Vol. 117; no. 1; pp. 85 - 92
• Main Authors: Fujita, Masayuki, Hossain, Mohammad Z.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Munksgaard International Publishers 01.01.2003; Blackwell
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Cucurbita maxima; Economic plant physiology; Enzymes; Fundamental and applied biological sciences. Psychology; Metabolism; Nutrition. Photosynthesis. Respiration. Metabolism; Plant physiology and development; 2,4-D; Enzyme; Transferases; Cucurbitaceae; Homology; Growth regulator treatment; Gene expression; Vegetable crop; Glutathione transferase; Dicotyledones; Angiospermae; Plant growth substance; Cucurbita maxima; Spermatophyta; Organ specificity; Aminoacid sequence
• ISSN: 0031-9317; 1399-3054
• DOI: 10.1034/j.1399-3054.2003.1170111.x

cDNAs of three major glutathione S‐transferases (GSTs), Puga, Pugb and Pugc, in 2,4‐D‐treated pumpkin (Cucurbita maxima Duch.) callus were individually obtained through immuno‐screenings with corresponding antisera from a pumpkin cDNA library. Comparison of the predicted protein sequences with ones of other plant GSTs reported previously and recognition of the presence of a single intron in each genomic gene indicated that they could be classified into tau‐type GST group. Hence, Puga, Pugb and Pugc were named CmGSTU1, CmGSTU2 and CmGSTU3, respectively. Expression of the GSTs in various organs of pumpkin plants, and in hypocotyls of seedlings under various stress conditions were examined by Western blotting and Northern blotting analyses. CmGSTU1 tended to be expressed more in fully expanded mature organs, and CmGSTU2 seemed to be expressed preferentially in leaves and petioles. CmGSTU1 and CmGSTU2 were induced by dehydration. CmGSTU1 was also induced by high temperature stress. In this study, the expression pattern of CmGSTU3 could not be determined because the contents were too low to detect with the antiserum. After 2,4‐d treatment, GST activity in the pumpkin callus increased rapidly until day one and then slowly increased at a constant rate up to day 6. The increase seemed to be dependent on post‐transcriptional enhancement as well as transcriptional induction.