玉米光合突变体hcf136(high chlorophyll fluorescence 136)的转录组分析

Transcriptome Analysis on a Maize Photosynthetic Mutant hcf136(high chlorophyll fluorescence 136)

玉米是典型的C_4作物,其光合作用由花环结构的两种细胞(叶肉细胞和维管束鞘细胞)共同完成。玉米hcf136(high chlorophyll fluorescence 136)突变体叶肉细胞叶绿体不能形成基粒从而丧失了PSII活性,但维管束鞘细胞的叶绿体发育不受影响,是研究玉米C_4光合机理的好材料。本研究利用转录组测序(RNA-Seq)技术,通过对高光和低光下野生型和hcf136突变体不同叶片部位进行转录组分析发现,PSII相关基因的转录未发生明显差异,表明PSII复合体的缺失是非转录水平变化所引起。此外,突变体中淀粉合成受阻,糖降解、糖转运及Cu^(2+)转运等代谢过程加剧,且一些转录因子表达发生显著变化。该结果对进一步深入研究玉米HCF136基因的功能提供了参考。

Maize(Zea mays)is a typical C4 plant,which photosynthetic activities are partitioned by the cooperating of Kranz anatomy-mesophyll(M)cell and bundle sheath(BS)cell.The maize high chlorophyll fluorescence 136(hcf136)mutant is an ideal material for C4 photosynthesis study,due to it lacks PSII activity without normal thylakoid grana in M chloroplasts.However,the development of BS chloroplasts is not affected.In this study,we utilized RNA-Seq technology to monitor the transcriptome changes in different leaf sections between wild type and hcf136 mutant under different light intensities.The results indicated that the impairment of PSII is not caused by the transcription changes of PSII related genes.We also noticed that the starch biosynthesis was blocked in the mutant;and the sugar degradation,sugar transport and copper ion transport were triggered.In addition,the expression level of transcription factors was changed distinctly.These results provide valuable information for understanding a comprehensive function of HCF136 gene in future.