Location: Plant, Soil and Nutrition ResearchTitle: The tomato UV-damaged DNA binding protein 1 (DDB1) plays a role in organ size control via an epigenetic manner) Author
Submitted to: PLoS One
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/29/2013
Publication Date: 10/27/2012
Publication URL: DOI: 10.1371/journal.pone.0042621
Citation: Liu, J., Tang, X., Gao, L., Sun, X., Miao, M., Guo, X., Niu, X., Giovannoni, J.J., Xiao, F., Liu, Y. 2012. The tomato UV-damaged DNA binding protein 1 (DDB1) plays a role in organ size control via an epigenetic manner. PLoS One. 7(8):e42621. Interpretive Summary: The DNA or genetic code of an organism is a function of both the four base DNA sequence (made up of A,C, G, T) and DNA modifications which do not alter the DNA code itself and are termed “epigenetic” modifications including DNA methylation. It has been demonstrated that epigenetic modifications play a role in various plant processes from growth and reproduction to stress responses. In this report we show through analysis of tomato plants altered in expression of a gene, DDB1, previously associated with fruit nutrient content, that this gene also contributes to broader epigenetic regulation of plant processes through DNA methylation.
Technical Abstract: Epigenetic regulation, including various covalent modifications of histone proteins and methylation of cytosine bases in DNA, participates broadly in many fundamentally physiological and developmental processes. The repressed or active states of transcription resulted from epigenetic modifications are maintained faithfully through successive rounds of cell division and transmitted over generations. In this study, we found that DDB1, a protein originally identified as a factor involved in DNA repair, plays an important role in regulation of organogenesis in tomato via an epigenetic pathway. We generated transgenic tomato plants over-expressing an alternatively spliced DDB1 transcript (DDB1F) and found the primary transgenic lines displayed reduced-size organs, including flowers, fruits, seeds, leaves and stems. Interestingly, this phenotype did not segregate with the DDB1F transgene in subsequent generations. These results suggest that the effect of DDB1F on organogenesis is implemented via an epigenetic manner and is not normally heritable. Our further analysis demonstrated that SlWEE1, a gene encoding a negative regulator of cell division, is upregulated in the small organ phenotype T2 plants, possibly due to less methylation at its promoter region. Overall, our work provides evidence suggesting that DDB1 is involved in regulation of the epigenetic state of genes controlling developmental processes in tomato.