Regulation of auxin accumulation and perception at different developmental stages in carrot

Auxins are a class of small indolic compounds that affect plant growth and developmental processes. However, the molecular mechanisms underlying auxin accumulation and perception during carrot growth and development are still unclear. To address this, carrot samples from five stages were collected. Morphological characteristics and auxin accumulation were also investigated during carrot development. IAA levels underwent great changes at five successive stages, and IAA contents in the petioles and leaves were relatively higher than those in the roots. A total of 18 genes related to auxin biosynthesis and signaling were identified and their expression profiles were determined using quantitative real-time PCR. Transcript levels of most genes were not well correlated with auxin accumulation, indicating that IAA biosynthesis pathway may be regulated through a complex network. The results indicated that auxin may regulate carrot growth and development in tissue-specific and stage-dependent manner. This study would provide valuable resources for genetic and molecular research focused on carrot growth and development.