从通过分子标记辅助选择育成的含玉米C4型pepc基因蜀恢881中筛选10株,利用530对SSR引物进行遗传背景分析,发现与蜀恢881表现差异的位点仅有1~4个,相似度在95.15%以上,最高的达99.03%。进一步对相似度为99.03%的转育玉米C4型pepc基因蜀恢881的6个生长时期测定有关光合指标,表明6个时期的PEPC酶活性均比蜀恢881增强,PEPC酶活性值最大时期是拔节期,为1264.2μmol/(mg·h),分蘖初期增加的幅度最大达到23.3倍;其净光合速率与蜀恢881相比,在分蘖初期、分蘖盛期、拔节期和始穗期都得到不同程度的提高,其中拔节期最高,达到22.3%。研究表明通过杂交利用C4型pepc基因特征引物对C4型pepc基因进行分子标记辅助选择,能够获得携有c4型pepc基因且与受体亲本遗传背景十分接近的籼型水稻材料,而且C4型pepc基因在新的遗传背景下能够高水平表达和稳定地遗传。据此,建立了分子标记辅助选择、光合生理生化指标鉴定和田间综合农艺性状考查相结合的筛选玉米C4型pepc基因水稻的技术体系;同时认为在拔节期进行转育c4型pepc基因水稻光合生理指标的测定和筛选的效果可能较理想。
The genetic background of ten improved plants of Shuhui 881 with maize C4-type pepc gene (pepc Shuhui 881) were analyzed with 530 pairs of SSR primers, only 1-4 differential SSR loci were found compared with Shuhui 881, and the similarities of genetic background were 95.15%-99.03%. By using pepc Shuhui 881 with a similarity at 99.03% as materials, the photosynthetic characteristics were determined at the six different developmental stages. The PEPCase activities in the improved Shuhui 881 were higher than those in Shuhui 881. The highest PEPCase activity was 1264.2μmol/(mg ·h) at the elongation stage and the largest increased value of PEPCase activity in the pepc Shuhui 881 was 23.3-fold than that in Shuhui 881 at the initial-tillering stage. The net photosynthesis rates of the pepc Shuhui 881 increased at the initial-tillering, full-tillering, elongation and initial-heading stages, and peaked at 22.3% at the elongation stage. The results showed that the genetic background of the pepc Shuhui 881 were almost the same as Shuhui 881 by molecular marker-assisted selection(MAS) and the high expression level of maize C4-type pepc gene was stably inherited in indica genetic background. Therefore, the system for selecting high photosynthetic efficiency rice had been established, which included selecting rice by MAS with the characteristic primers of C4-type pepc gene marker, determining PEPCase activity and net photosynthesis rate and investigating phenotype performance in field. Meanwhile, it would be better to determine photosynthetic characteristics at the elongation stage.