Abstract

GATA transcription factors play important roles in plant development as well as light and hormone responses. Carrot is a kind of valuable root vegetable. The above-ground part of the carrot is affected by light during growth, which in turn affects the growth status of taproots. The functions of GATA factors have been characterized in several plant species. Little is known about the GATA factors in carrot biological process. In this study, 30 GATA family members were first identified in the carrot genome and classified into four subfamilies, named A-GATA, B-GATA, C-GATA, and D-GATA. C-GATA and D-GATA have specific functional motifs suggesting evolutionary conservation among plants. Predicted cis -elements of GATA factors revealed their potential hormone-responsive and light-responsive functions. Among them, B-GATA has been studied extensively and is represented by the GNC and GNL genes. There were three GNC / GNL homologs in carrot: DcGATA18 , DcGATA20 , and DcGATA22 . Functional analysis revealed that the GNC homolog gene DcGATA20 was mainly expressed in carrot leaves, followed by petioles, and was barely detectable in taproots. Overexpression of DcGATA20 exhibited promotion of chlorophyll accumulation and increased the expression levels of DcGUN4 and DcCHLI1 , along with a significant increase in expression of the transcription factor, DcGLK1 , which is important for chlorophyll synthesis. In addition, the expression of the chlorophyll degradation gene DcSGR1 ( STAY GREEN 1 ) was decreased. These results indicated that GNC genes exhibit functional conservation in carrot and may be helpful for understanding other GATA members’ functions.