Crosstalk between auxin and gibberellin during stalk elongation in flowering Chinese cabbage

Abstract

Plant growth and development are tightly regulated by phytohormones. However, little is known about the interaction between auxin and gibberellin acid (GA) during flower stalk elongation and how it is directly related to organ formation. Therefore, the effects of indole acetic acid (IAA) and GA3 treatments and their interaction on flower stalk elongation in flowering Chinese cabbage were investigated. The growth of flowering Chinese cabbage is regulated by IAA and GA3, and the opposite results were observed after treatments with uniconazole (GA synthesis inhibitor) and N-1-naphthylphthalamic acid (NPA) (auxin transport inhibitor). Anatomical analysis of the pith region in stalks revealed that IAA promoted expansion via signal transduction and transport pathways. GA3 regulated the elongation of flower stalks by controlling GA synthesis and partially controlling the IAA signaling pathway. GA3 also had a stronger effect on stalk elongation than IAA. The results of qRT-PCR and histological analysis revealed that GA3 and IAA induced the expansion of cell walls by activating the expression of genes encoding cell wall structural proteins such as Expansin (EXP). These findings provide new insights into the mechanism of stalk formation regulated by the combination of IAA and GA3.

BcSOC1 Promotes Bolting and Stem Elongation in Flowering Chinese Cabbage

“…Cell cycle regulation of the shoot apical meristem affects stem elongation and thickening, and BcEXPA11 and BcXTH3 are the key factors responsible for cell expansion [ 44 , 45 ]. EXPA11 promotes the sliding of polymers such as cell wall cellulose and hemicellulose by reducing the viscosity of polysaccharides between cell walls and enabling cell wall expansion [ 46 ].…”

Identification of DELLA Genes and Key Stage for GA Sensitivity in Bolting and Flowering of Flowering Chinese Cabbage

“…Stem elongation, thickening, and flowering are key characteristics of flowering Chinese cabbage stem development. Factors that affect the timing of the bolting and flowering of flowering Chinese cabbage include temperature and plant hormones [3][4][5]. Low temperature and exogenous gibberellin A3 (GA 3 ) treatment advance bolting time, stem elongation, and flowering time.…”

Identification of BcARR Genes and CTK Effects on Stalk Development of Flowering Chinese Cabbage

“…Moreover, several recent studies have shown reciprocal interactions between the two hormones where cytokinin inhibits the production GA and promotes its deactivation and GA inhibits cytokinin responses [11]. In flowering Chinese cabbage, endogenous plant hormones activities are closely relayed to bolting [3,24]. Three-true-leaf spraying of cytokinin promoted the thickening growth of diameter and inhibited stem elongation.…”

“…Three cyclin-related genes-CDKB2-1, CDKB2-2 and CYCD3-1-and one cell expansion gene-EXPA11-were selected to analyze the expression characteristics of these genes at bud emergence stage after different hormones. EXPA11 functions as a key factor responsible for cell expansion by promoting the sliding of polymers such as cell wall cellulose and hemicellulose [24,25]. In addition, cell cycle regulation affects stem elongation and thickening in the shoot meristem [26].…”