Location: Plant, Soil and Nutrition ResearchTitle: Molecular characterization and transcriptome analysis of orange head Chinese cabbage (brassica rapa L. ssp.pekinensis)
|ZHANG, JUNXIANG - Cornell University - New York|
|YUAN, HUI - Cornell University - New York|
|FEI, ZHANGJUN - Boyce Thompson Institute|
|POGSON, BARRY - Australian National University|
Submitted to: Planta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2015
Publication Date: 2/17/2015
Citation: Zhang, J., Yuan, H., Fei, Z., Pogson, B.J., Li, L. 2015. Molecular characterization and transcriptome analysis of orange head Chinese cabbage (brassica rapa L. ssp.pekinensis). Planta. 241:1381-1394.
Interpretive Summary: Carotenoids are indispensable to plants and humans. In spite of significant progress in uncovering the mechanism of carotenoid biosynthesis and accumulation in model plants, the molecular basis in many non-model species is still poorly understood. In this study, we examined the orange head Chinese cabbage that accumulates prolycopene. We demonstrate that the orange phenotype is due to a mutation that produces a non-functional BrCRTISO. We show that the BrCRTISO mutation does not affect expression of the other carotenoid biosynthetic genes and proteins, but exerts specific effects on many genes in the functional groups involved in RNA and protein processes. A new orange-trait specific marker was developed for marker-assisted breeding. This work provides new insights into understanding of the molecular basis underlying head leaf color. It also provides a molecular tool to accelerate breeding new Chinese cabbage cultivars with unique health quality and visual appearance.
Technical Abstract: Orange head leaves are a desirable quality trait for Chinese cabbage. Our previous fine mapping identified BrCRTISO as the Br-or candidate gene for the orange Chinese cabbage mutant. Here we examined the BrCRTISO gene from white and orange head Chinese cabbage. While BrCRTISO from the white control plant was able to complement the Arabidopsis Atcrtiso mutant phenotype, Brcrtiso with a large insertion from the orange head Chinese cabbage failed to rescue the Arabidopsis mutant phenotype. The results show that Brcrtiso was non-functional, concomitant with the accumulation of prolycopene in Br-or to yield orange head. Comparative transcriptome analysis by RNA-seq identified 372 differentially expressed genes between the control and Br-or mutant using two near-isogenic lines with white and orange inner leaves. The mutation in BrCRTISO specifically affected many genes in the functional groups involved in RNA, protein, transport, and signaling. Particularly, expressions of many transcription factor genes were dramatically altered in Br-or, suggesting a potential role of BrCRTISO or carotenoid metabolites in affecting transcription. A novel co-dominant gene-specific marker was developed that co-segregated with orange color phenotype and would be useful for marker-assisted selection with enhanced selection efficiency. Our study provides new insights into understanding of the molecular basis of Br-or in mediating head leaf color and depicts a global view of the effect of BrCRTISO on cellular processes in plant. It also provides a molecular tool to accelerate breeding new Chinese cabbage cultivars with unique health quality and visual appearance.