【摘要】 【目的】在已构建GOC（乙醇酸氧化酶OsGLO、草酸氧化酶OsOXO和过氧化物酶OsCAT）光呼吸支路的工程水稻中，敲除乙醇酸转运体编码基因OsPLGG1a或OsPLGG1b，以优化光呼吸支路的改造，提高水稻光合效率。【方法】以GOC工程水稻为背景材料，通过CRISPR-Cas9技术分别敲除OsPLGG1a或OsPLGG1b基因，通过抗性筛选和测序鉴定osplgg1a-GOC和osplgg1b-GOC纯合敲除株系，并测定光合速率。【结果】获得敲除OsPLGG1a或OsPLGG1b的GOC代谢支路的纯合株系（osplgg1a-GOC和osplgg1b-GOC）。osplgg1a-GOC植株与ZH11背景中OsPLGG1a敲除突变体表型相似，均表现出黄化矮小生长抑制的表型；osplgg1b-GOC植株相比GOC水稻的净光合速率提高，说明OsPLGG1b突变有利于叶绿体中滞留乙醇酸，增加GOC支路的代谢通量，进一步提高叶绿体中的CO2浓度。【结论】相对于GOC水稻，osplgg1b-GOC部分株系的净光合速率和气孔导度增加，暗示敲除OsPLGG1b可用于光呼吸代谢支路的优化。更多还原

【Abstract】 【Objective】 By deleting either OsPLGG1a or OsPLGG1b to optimize the pathway in the pre-engineered GOC rice for enhancing photosynthesis and photorespiration of the plant was postulated. 【Method】 The knockout vectors osplgg1aCas9 or osplgg1b-Cas9 were constructed and transformed into the GOC rice to obtain transgenic homozygous lines with OsPLGG1a or OsPLGG1b deleted. Resulting photosynthesis and photorespiration of the rice plant were measured to determine the validity of the proposed hypothesis. 【Result】 The transgenic homozygous lines were successfully obtained to show a similar phenotype of osplgg1a-GOC and osplgg1a plants with stunted growth. The osplgg1b-GOC plants displayed a net photosynthetic rate increase over that of GOC rice. That indicated the OsPLGG1b mutation to be conducive to the retention of chloroplast glycolate, rise of metabolic flux through GOC bypass, and reduction of plant photorespiration metabolism manifested with enriched CO2 in the chloroplasts. 【Conclusion】 Compared with the GOC rice, the transgenic osplgg1b-GOC plants had an elevated net photosynthetic rate and stomatal conductance. It suggested that the deletion of OsPLGG1b could be a means to enhance the photorespiration metabolism in a rice plant.更多还原