Regulation of abscisic acid biosynthesis and signal transduction during carrot growth and development

Abstract

ABSTRACTAbscisic acid (ABA) is a common plant hormone that participates in growth and development processes and responds to abiotic stress. Carrot is a globally highly appreciated vegetable crop that shows obvious changes in tissues during growth. However, limited studies have investigated ABA biosynthesis and signalling in carrot. In this study, the ABA levels and expression levels of ABA-related genes in the roots, leaf blades, and petioles of carrot at five successive growth stages were measured. The endogenous ABA levels changed with the carrot tissue and growth stage. ABA content was highest in the leaf blades at each growth stage, and higher in the petioles than in the roots, except at Stage 2. The expression levels of most ABA-related genes were also highest in the leaf blades. The genes whose expression trends could reflect the ABA content may change with tissue in carrot. The results also indicated that the genes related to ABA biosynthesis and signal transduction may be influenced not only by ABA but also by other regulatory mechanisms such as carotenogenesis in carrot.