Transcriptional Regulation of Brassinosteroid Accumulation during Carrot Development and the Potential Role of Brassinosteroids in Petiole Elongation

Abstract

It is widely known that brassinosteroids (BRs) are involved in various physiological processes during plant growth and development. Roles of BRs have been reported in many plants. However, relevant report is yet not found in carrot. Carrot is a nutrient-rich vegetable from the Apiaceae family. Here, we measured the bioactive contents of BRs at five successive stages and analyzed the expression profiles of genes involved in BR biosynthesis, signaling pathway and catabolism. We found that most biosynthesis regulated genes had higher expression level at the first development stage of carrot and the catabolism gene BAS1/CYP734A1 had significantly high expression level at the first stage in carrot roots and petioles. In addition, we treated carrot plants with exogenous 24-epibrassinolide (24-EBL) and examined the morphological changes after treating. Compared with control plants, carrot plants treated with 24-EBL had higher plant height, more number of petioles and heavier aboveground weight. The expression levels of DcBRI1, DcBZR1, and DcBSU1 in the petioles were significantly up-regulated by treating with exogenous 24-EBL. The expression profiles of DcCYP734A1 were all significantly up-regulated in the three organs when treated with 0.5 mg/L 24-EBL. The elongation of carrot petioles can be promoted by treating with exogenous 24-EBL. These results indicate that BRs playing potential roles during the growth and development of carrot.

Auxin-to-Gibberellin Ratio as a Signal for Light Intensity and Quality in Regulating Soybean Growth and Matter Partitioning

“…These results indicated that the stem elongation was regulated by IAA and/or GA interactions with other hormones besides the IAA-to-GA1 ratio in different light intensity and quality conditions ( Figure 8 ). For example, brassinosteroid is considered as another factor stimulating elongation ( Que et al, 2017 ).…”

Effects of 24-epibrassinolide on root-knot nematode, Meloidogyne incognita (Kofoid & White, 1919) Chitwood, 1949 (Tylenchida: Meloidogynidae) in tomatoes

“…It was observed in the current study that the increase in stem length was higher with the application of 24-epibrassinolide and radial growth of the roots were compromised at the expense of longitudinal growth. This effect of 24-epibrassinolide was also observed in carrot by Que et al (2017). Meloidogyne incognita infected tomato plants had slight increase in plant height when exposed to 28-homobrassinolide (Kaur et al, 2013(Kaur et al, , 2014.…”

Transcriptome profiling of Ricinus communis L. provides new insights underlying the mechanisms towards thermotolerance during seed imbibition and germination

“…RcP450b showed high homology to cytochrome P450 CYP734A1 in Arabidopsis. CYP734A1 encodes a member of the cytochrome P450 family that serves as a control point between multiple photoreceptor systems and brassinosteroid (BR) signal transduction (Que et al, 2017;Sandhu et al, 2012). CYP734A1 also inactivates castasterone and brassinolide by means of C-26 hydroxylation (Fig.…”

“…CYP734A1 also inactivates castasterone and brassinolide by means of C-26 hydroxylation (Fig. 3d) (Que et al, 2017;Sandhu et al, 2012). Brassinosteroid (BR) are steroid hormones which regulate plant development, physiology, and responses to biotic and abiotic stresses (Hou et al, 2017;Lv et al, 2018;Unterholzner et al, 2015;Wang et al, 2013).…”