The evolution of C4 plants: acquisition of cis‐regulatory sequences in the promoter of C4‐type pyruvate, orthophosphate dikinase gene

作者：Mika Nomura, Naoki Sentoku, Asuka Nishimura, Jenq‐Horng Lin, C. Honda, Mitutaka Taniguchi, Yuji Ishida, Shozo Ohta, Toshihiko Komari, Mitsue Miyao‐Tokutomi, Yuriko Kano‐Murakami, Shigeyuki Tajima, Maurice S. B. Ku, Makoto Matsuoka · 发表于：The Plant Journal · 年份：2000 · 被引用次数：53 · 研究领域：Plant tissue culture and regeneration、Photosynthetic Processes and Mechanisms、Plant Molecular Biology Research

In a previous study, we identified the C4-like pyruvate, orthophosphate dikinase gene (Pdk) in the C3 plant rice, with a similar structure to the C4-type Pdk in the C4 plant maize. In order to elucidate the differences between C4-type and C4-like Pdk genes in C4 and C3 plants, we have produced chimeric constructs with the beta-glucuronidase (GUS) reporter gene under the control of the Pdk promoters. In transgenic rice, both rice and maize promoters directed GUS expression in photosynthetic organs in a light-dependent manner. However, the maize promoter exhibited a much higher transcriptional activity than the rice promoter did. These results indicate that the rice C4-like Pdk gene resembles the maize C4-type Pdk gene in terms of regulation of expression. We also tested the activity of the rice promoter in transgenic maize. GUS activity was seen in both photosynthetic and non-photosynthetic organs. Thus, the rice promoter does not confer a strict organ-specific gene expression, as the maize promoter does. Moreover, the rice promoter directed GUS expression not only in mesophyll cells but also in bundle sheath cells, whereas the maize promoter directed expression only in mesophyll cells. Taken together, the results obtained from both transgenic maize and rice demonstrate that the rice and maize promoters differ not only quantitatively, but also qualitatively, in terms of their cell- and organ-specificity. Experiments with swapped promoters using the rice and maize promoters fur...