Wound- and systemin-inducible calmodulin gene expression in tomato leaves.
ABSTRACT Using a calmodulin (CaM) cDNA as a probe in northern analyses, transgenic tomato plants that overexpress the prosystemin gene were found to express increased levels of CaM mRNA and protein in leaves compared to wild-type plants. These transgenic plants have been reported previously to express several wound-inducible defense-related genes in the absence of wounding. Calmodulin mRNA and protein levels were found to increase in leaves of young wild-type tomato plants after wounding, or treatment with systemin, methyl jasmonate, or linolenic acid. CaM mRNA appeared within 0.5 h after wounding or supplying young tomato plants with systemin, and peaked at 1 h. The timing of CaM gene expression is similar to the expression of the wound- or systemin-induced lipoxygenase and prosystemin genes, signal pathway genes whose expression have been reported to begin at 0.5-1 h after wounding and 1-2 h earlier than the genes coding for defensive proteinase inhibitor genes. The similarities in timing between the synthesis of CaM mRNA and the mRNAs for signal pathway components suggests that CaM gene expression may be associated with the signaling cascade that activates defensive genes in response to wounding.
- Annual Review of Biochemistry 02/1994; 63:1045-83. · 27.68 Impact Factor
Article: MAP kinases and plant defenceTrends in Plant Science - TRENDS PLANT SCI. 01/1997; 2(11):406-408.
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ABSTRACT: Eight genomic clones of potato calmodulin (PCM1 to 8) were isolated and characterized. Sequence comparisons of different genes revealed that the deduced amino acid sequence of PCM1 had several unique substitutions, especially in the fourth Ca(2+)-binding area. The expression patterns of different genes were studied by northern analysis using the 3'-untranslated regions as probes. The expression of PCM1, 5, and 8 was highest in the stolon tip and it decreased during tuber development. The expression of PCM6 did not vary much in the tissues tested, except in the leaves, where the expression was lower; whereas, the expression of PCM4 was very low in all the tissues. The expression of PCM2 and PCM3 was not detected in any of the tissues tested. Among these genes, only PCM1 showed increased expression following touch stimulation. To study the regulation of PCM1, transgenic potato plants carrying the PCM1 promoter fused to the beta-glucuronidase (GUS) reporter gene were produced. GUS expression was found to be developmentally regulated and touch-responsive, indicating a positive correlation between the expression of PCM1 and GUS mRNAs. These results suggest that the 5'-flanking region of PCM1 controls developmental and touch-induced expression. X-Gluc staining patterns revealed that GUS localization is high in meristematic tissues such as the stem apex, stolon tip, and vascular regions.Plant Molecular Biology 03/1995; 27(4):693-703. · 3.52 Impact Factor