Protein That Controls Strawberry's Red Color Identified

A research group from the University of Córdoba characterizes a new transcription factor that regulates, during strawberry ripening, the production of anthocyanins responsible for giving it the red color.

Strawberries are a fruit that stands out for its color, aroma, flavor and texture. These aspects, known as organoleptic properties and which determine their quality and the preference of those who are going to consume them and of the insects in charge of dispersing the seeds and favoring the subsequent growth of future plants, occur in the strawberry ripening process. The research group of the University of Córdoba Biotechnology and plant pharmacognosy, which under the direction of Juan Muñoz Blanco has been studying the genetic regulation of strawberry ripening for several years, has taken a further step in the knowledge of this key process by identifying a new protein that is involved in the control of the production of the red color of strawberries. It is a protein, known as a transcription factor (FaMYB123).

According to the study, which is part of the doctoral thesis of the UCO-trained researcher Félix J. Martínez-Rivas and which has been published in  The Plant Journal , this transcription factor is fundamentally responsible for the production of anthocyanins, which are the pigments which, in the case of strawberries, give their characteristic red colour. To verify this, they created a transgenic strawberry plant in which they repressed the expression of the FaMYB123 transcription factor and what they saw is that the amount of anthocyanins was more repressed in these transgenic plants than in normal fruits. That is, without the described transcription factor, the strawberry does not produce all of its red color.

But this protein alone does not do this, since the transcription factors do not work in isolation, but rather combine with each other. And, in this case, the research team has found that FaMYB123 is related to another previously known factor (FabHLH3) that was also related to pigmentation in strawberries. The interaction of both contributes to the increase in the production of anthocyanins during ripening.

The study, in short, provides new knowledge on the control of strawberry ripening. As explained by Francisco Javier Molina Hidalgo, from the research team, "knowing which piece of the puzzle controls each part of the ripening process, in this case, the color red, allows us to then manipulate it genetically or use it as a tool in breeding programs  in  which that different varieties are mixed to have new ones”. Knowing in more detail how strawberries ripen is key in a country like Spain, which is the main European producer of strawberries, with the province of Huelva leading the way.

Reference: Martínez-Rivas FJ, Blanco-Portales R, Serratosa MP, et al. FaMYB123 interacts with FabHLH3 to regulate the late steps of anthocyanin and flavonol biosynthesis during ripening. Plant J. 2023;114(3):683-698. doi:10.1111/tpj.16166

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