Mining for Candidate Genes Controlling Secondary Growth of the Carrot Storage Root.

Alicja Macko-Podgórni,Katarzyna Stelmach,Dariusz Grzebelus,Gabriela Machaj,Shelby Ellison,Philipp W Simon,Douglas A Senalik,Kornelia Kwolek

doi:10.3390/ijms21124263

Alicja Macko-Podgórni, Katarzyna Stelmach + Show 6 more

Open Access

https://doi.org/10.3390/ijms21124263

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Abstract

Background: Diverse groups of carrot cultivars have been developed to meet consumer demands and industry needs. Varietal groups of the cultivated carrot are defined based on the shape of roots. However, little is known about the genetic basis of root shape determination. Methods: Here, we used 307 carrot plants from 103 open-pollinated cultivars for a genome wide association study to identify genomic regions associated with the storage root morphology. Results: A 180 kb-long region on carrot chromosome 1 explained 10% of the total observed phenotypic variance in the shoulder diameter. Within that region, DcDCAF1 and DcBTAF1 genes were proposed as candidates controlling secondary growth of the carrot storage root. Their expression profiles differed between the cultivated and the wild carrots, likely indicating that their elevated expression was required for the development of edible roots. They also showed higher expression at the secondary root growth stage in cultivars producing thick roots, as compared to those developing thin roots. Conclusions: We provided evidence for a likely involvement of DcDCAF1 and/or DcBTAF1 in the development of the carrot storage root and developed a genotyping assay facilitating the identification of variants in the region on carrot chromosome 1 associated with secondary growth of the carrot root.

Highlights

Carrot is widely used as a fresh or processing vegetable
To confirm the functional association of the chromosome 1 region comprising DCAF1 and BTAF1 with carrot root width we developed an SDSNP genotyping assay based on the TaqMan technology and validated it on 90 plants from three half-sib carrot populations
The carrot storage root morphology is controlled by many loci with minor effects

Summary

Introduction

Carrot is widely used as a fresh or processing vegetable. It is the most significant source of beta-carotene in the human diet. Little is known about the genetic basis of the carrot root shape determination. DcDCAF1 and DcBTAF1 genes were proposed as candidates controlling secondary growth of the carrot storage root. Their expression profiles differed between the cultivated and the wild carrots, likely indicating that their elevated expression was required for the development of edible roots. They showed higher expression at the secondary root growth stage in cultivars producing thick roots, as compared to those developing thin roots. Conclusions: We provided evidence for a likely involvement of DcDCAF1 and/or DcBTAF1 in the development of the carrot storage root and developed a genotyping assay facilitating the identification of variants in the region on carrot chromosome 1 associated with secondary growth of the carrot root

Methods

Results

Discussion

Conclusion