Barnyardgrass (Echinochloa crusgalli) is a C4 weed commonly found in rice field. To fully utilize the photosynthestic potential of Barnyardgrass C4gene, we transformed Barnyardgrass root Phosphoenolpyruvate Carboxylase gene into rice plant with vectors contained promoters of Ubiqitin gene and Rubisco small unit gene byAgrobactirium- mediated transformation. Both marker genesHygrandppc were detected by PCR in regenerated plants. RT-PCR and Western blot analysis confirmed that theppc gene was incorporated into rice plant and expressed with stable transcripts and proteins. PEPC activity as measured in most of the transgenic rice plants was higher than that in control, being up to 5.85-fold of that in untransformed rice. At T0 generation, net photosynthetic rate (Pn) in most of transgenic rice plantswas 20.00% higher than that in untransformed rice, with the highest in-crease of 47.16%. Water utilization efficiency (WUE) in transgenic rice was also improved. At T6 generation, PEPC activity and Pn of transgenic lines remained higher than those of the wild type. These indicate that over-expressing C3Eppc gene also can im-prove rice photosynthesis.%稗草(Echinochloa crusgalli)是稻田中的C4光合型杂草,为了探索稗草ppc基因(Eppc)对水稻遗传转化的可行性及其对光合速率的调节效应,首次将含有稗草根型磷酸烯醇式丙酮酸羧化酶(phosphoenolpyruvate carboxylase, PEPC)基因ppc cDNA的2个植物表达载体pUbi-Eppc、pRbcS-Eppc通过农杆菌介导法对水稻进行了遗传转化。对分化植株进行的 PCR、RT-PCR、克隆测序和 Western 杂交等结果均表明稗草 ppc 基因已经整合到了水稻基因组中,并且在转录和翻译水平都得到了表达。转基因水稻 PEPC 活性和气体交换参数测定结果表明 T0代多数植株的 PEPC 活性高于对照,最高达到了对照的5.85倍； T0代大多数转基因植株叶片的净光合速率(Pn)比对照提高了20.00%,最大地提高了47.16%,同时叶片水分利用效率(WUE)也得到增强； T6代大部分转化植株的PEPC活性及Pn仍保持高于对照,本研究表明C3根型ppc基因过量表达也可以提高水稻的Pn,且证明稗草PEPC对光合作用具有较强的调节作用。
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