Location: Plant, Soil and Nutrition ResearchTitle: A SEPALLATA gene is involved in the development and ripening of strawberry (Fragaria x ananassa Duch.) fruit, a non-climacteric tissue Author
Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2010
Publication Date: 3/24/2011
Citation: Seymour, G., Ryder, C., Cevik, V., Hammond, J., Popovich, A., King, G., Vrebalov, J., Giovannoni, J.J., Manning, K. 2011. A SEPALLATA gene is involved in the development and ripening of strawberry (Fragaria x ananassa Duch.) fruit, a non-climacteric tissue. Journal of Experimental Botany. 62:1179-1188. Interpretive Summary: Fruits are reproductive organs unique to the Angiosperms that have evolved to promote seed dispersal. They are also one of the most important components of the human diet. Classically two broad classes of fruits have been recognized. In climacteric fruits, e.g. tomato, banana and melon, the onset of ripening is marked by increased ethylene synthesis and respiration. Non-climacteric fruits such as strawberry do not show these physiological changes in association with ripening. We have identified a transcription factor, RIN that regulates climacteric ripening in tomato. Here we show that a similar gene regulates ripening in non-climacteric strawberry fruit suggesting this function is well conserved among fruit species.
Technical Abstract: Climacteric and non-climacteric fruits have traditionally been viewed as representing two distinct programs of ripening associated with differential respiration and ethylene hormone effects. In climacteric fruits, such as tomato and banana, the ripening process is marked by increased respiration and is induced and coordinated by ethylene, while in non-climacteric fruits, such as strawberry and grape, it is controlled by an ethylene-independent process and exhibits little change in respiration rate. The two contrasting mechanisms, however, both lead to texture, color and flavor changes that likely reflect common regulatory control. Recently it has been shown that a SEPALLATA(SEP)4-like gene is necessary for normal ripening in tomato. Here we demonstrate that silencing a fruit-related SEP1/2-like (FaMADS-9) gene in strawberry leads to inhibition of normal development and ripening in the petal, achene and receptacle tissues. Additionally, analysis of transcriptome profiles reveals pleiotropic effects of FaMADS-9 on fruit development and ripening-related gene expression. We conclude that SEP genes play a central role in the developmental regulation of ripening in both climacteric and non-climacteric fruits. Our discovery also extends the ability for molecular control of ripening in a non-climacteric fruit beyond the limited genetic and cultural options currently available.