Expression of rice chitinase gene triggered by the direct injection of Ca2+.
In response to an elicitor, the Ca2+-dependent fluorescence (Fluo-3-Ca2+) increased transiently and then the expression of the chitinase gene (chi) followed. The gene expression was detected by Northern analysis. The deletion of Ca2+ from the medium or the addition of a Ca2+ channel blocker, verapamil, to the medium caused no gene expression, which supported the key role of Ca2+ in the signaling towards the chi expression. Then the Ca2+-injection experiment was done in order to investigate if it could trigger the chi expression. The plasmid pCHI-GFP (promoter: chi, reporter: green fluorescent protein gene (gfp)) was injected into the single-protoplasts, then after 1 day of incubation at 25 degrees C, 100 microM CaCl2 was injected into the same cells. After successive incubation for 1 day, 41 out of 85 cells showed the gene expression. The injection of 100 microM MgCl2, however, caused no gene expression. Therefore, Ca2+ could induce the chi of rice in the absence of the elicitor stimulus.
D002118:Calcium / Q000378:metabolism*; D002688:Chitinases / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000502:physiology; D008845:Microinjections; D012275:Oryza / Q000235:genetics* / Q000378:metabolism*; D011523:Protoplasts / Q000378:metabolism; D015398:Signal Transduction
D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D002688:Chitinases; D002118:Calcium