Location: Plant, Soil and Nutrition ResearchTitle: Overexpression of the class D MADS-box gene Sl-AGL11 impacts fleshy tissue differentiation and structure in tomato fruits Author
|Huang, Baowen - University Of Toulouse|
|Routaboul, Jean-marc - University Of Toulouse|
|Liu, Minching - University Of Toulouse|
|Mohamed, Zouine - University Of Toulouse|
|Vrebalov, Julia - Boyce Thompson Institute|
|Bouzayen, Mondher - University Of Toulouse|
Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2017
Publication Date: 9/14/2017
Citation: Huang, B., Routaboul, J., Liu, M., Mohamed, Z., Vrebalov, J., Giovannoni, J.J., Bouzayen, M. 2017. Overexpression of the class D MADS-box gene Sl-AGL11 impacts fleshy tissue differentiation and structure in tomato fruits. Journal of Experimental Botany. https://doi.org/10.1093/jxb/erx303.
Interpretive Summary: MADS-box transcription factor genes are key elements of the genetic networks controlling flower and fruit development. Tomato has two genes, Sl-AGL11 and Sl-MBP3, both of which are expressed in seeds and young fruits. The role of Sl-AGL11 on fruit development was addressed in genetically modified plants to ascertain its function. Overexpression of the gene triggered dramatic modifications of flower and fruit structure that include: the conversion of sepals into fleshy organs, reduced locular space (the jelly-like material of a tomato in which the seeds reside), starch and sugar accumulation, and an extreme softening that occurs well before the onset of ripening. This work demonstrates that this gene may be a useful target for modification of fruit softening, sugars and liquid center formation characteristics of tomato and additional species.
Technical Abstract: MADS-box transcription factors are key elements of the genetic networks controlling flower and fruit development. Among these, the class D clade are involved in seed, ovule, and funiculus development. The tomato genome comprises two class D genes, Sl-AGL11 and Sl-MBP3, both displaying high expression levels in seeds and in central tissues of young fruits. The potential effects of Sl-AGL11 on fruit development were addressed through RNAi silencing and ectopic expression strategies. Sl-AGL11-down-regulated tomato lines failed to show obvious phenotypes except a slight reduction in seed size. In contrast, Sl-AGL11 overexpression triggered dramatic modifications of flower and fruit structure that include: the conversion of sepals into fleshy organs undergoing ethylene-dependent ripening, a placenta hypertrophy to the detriment of locular space, starch and sugar accumulation, and an extreme softening that occurs well before the onset of ripening. RNA-Seq transcriptomic profiling highlighted substantial metabolic reprogramming occurring in sepals and fruits, with major impacts on cell wall-related genes. Our results suggest that class D MADS-box genes contribute to control of early fleshy fruit development.