一株拟南芥宽叶形突变体atscamp的分离鉴定

Isolation and Identification of a Novel Enlarged Leaf Mutant atscamp in Arabidopsis thaliana

叶片是主要的光合作用器官,选育利于光合作用的叶片形态已成为重要的育种目标。atscamp是从拟南芥(Arabidopsis thaliana)突变体库(约6000株系)中筛选获得的1株叶片宽大突变体。Tail-PCR分析该突变体为AT1G11180位点的插入,该基因位点编码1个分泌载体膜蛋白(SCAMP)。RT-PCR检测显示,该基因转录表达水平基本为零。进一步研究发现,该突变体叶片的宽度和叶面积极显著大于野生型植株(P<0.01),但是冠幅基本保持不变;同时atscamp突变体叶绿素含量增加,叶绿素最大荧光、PSⅡ潜在光化学效率显著增加(P<0.05);相应地,突变体植株蒸腾系数(Tr)、净光合速率(Pn)和叶片水分利用效率(WUE)显著增加(P<0.05)。拟南芥AT1G11180基因的时空特异性表达分析显示,该基因仅在叶片中高表达,在其他器官中表达量很低;且随着植物发育成熟,该基因表达量逐渐增加。研究结果表明AtSCAMP基因在叶形发育中发挥着重要作用。

Leaf is the main photosynthetic organ,and the leaf morphology beneficial for photosynthesis has become an important breeding target.atscamp was screened from the Arabidopsis thaliana mutant library(about 6000 lines)with wide leaves.Tail-PCR analysis revealed a T-DNA insertion at the AT1G11180 locus,which encodes a secretory carrier membrane protein(SCAMP).RT-PCR showed that the transcriptional expression level of the gene was basically zero.The leaf width and area of the mutant were significantly larger than those of wild type plants(P<0.01),while the crown diameter was essentially unchanged.Additionally,chlorophyll content,chlorophyll maximium fluorescence,and photosystem II potential photochemical efficiency were all increased in the atscamp mutant(P<0.05).Correspondingly,the mutants showed significant increases in transpiration coefficien(t Tr),net photosynthetic rate(Pn),and leaf water use efficiency(WUE)(P<0.05).Spatialtemporal specific expression analysis of the AT1G11180 gene revealed that the gene was highly expressed only in leaves,with low expression levels in other organs,and the gene expression gradually increased with the development and maturity of plants.The results suggested that AtSCAMP might play an important role in leaf shape development.