Transcriptome analysis reveals that auxin promotes strigolactone-induced adventitious root growth in the hypocotyl of melon seedlings

Abstract

IntroductionStrigolactone (SL) and auxin are two important phytohormones involved in plant root development, but whether they show synergistic or mutual promotion effects during adventitious root (AR) formation has not been adequately explored.MethodsIn this study, we investigated the mechanisms of GR24 (synthetic SL) and indole-3-acetic acid (IAA; a type of auxin) in the formation of ARs using melon as the study material.ResultsMorphological measurements showed that the AR number, length, superficial area, and volume under the GR24 treatment were 1.60–3.27, 1.58–3.99, 2.06–3.42, and 3.00–6.11 times greater than those of the control group, respectively, at 6–10 days; the GR24+IAA treatment further promoted AR formation in melon seedlings, and the AR number, length, superficial area, and volume under the GR24+IAA treatment were 1.44–1.51, 1.28–1.73, 1.19–1.83, and 1.31–1.87 times greater than those obtained with the GR24 treatment, respectively. Transcriptome analysis revealed 2,742, 3,352, and 2,321 differentially expressed genes (DEGs) identified from the GR24 vs. control, GR24+IAA vs. control, and GR24+IAA vs. GR24 comparisons, respectively. The GR24 treatment and GR24+IAA treatment affected auxin and SL synthesis as well as components of the phytohormone signal transduction pathway, such as auxin, brassinosteroid (BR), ethylene (ETH), cytokinin (CK), gibberellin (GA), and abscisic acid (ABA). The concentrations of auxin, GA, zeatin (ZT), and ABA were evaluated using high-performance liquid chromatography (HPLC). From 6 to 10 days, the auxin, GA, and ZT contents in the GR24 treatment group were increased by 11.48%–15.34%, 11.83%–19.50%, and 22.52%–66.17%, respectively, compared to the control group, and these features were increased by 22.00%–31.20%, 21.29%–25.75%, 51.76%–98.96%, respectively, in the GR24+IAA treatment group compared with the control group. Compared to that in the control, the ABA content decreased by 10.30%–11.83% in the GR24 treatment group and decreased by 18.78%-24.00% in the GR24+IAA treatment group at 6–10 days.DiscussionOur study revealed an interaction between strigolactone and auxin in the induction of AR formation in melon seedlings by affecting the expression of genes related to plant hormone pathways and contents.

Novel Small Molecule Matrix Screening for Simultaneous MALDI Mass Spectrometry Imaging of Multiple Lipids and Phytohormones

“…Phytohormones play an important role in seed dormancy, germination, development, and biotic and abiotic stress responses as information transfer substances that control and coordinate cell division, growth, and differentiation processes to promote plant growth and development. , Phytohormones include the five major classes of auxins (3-indoleacetic acid, IAA; 2,4-dichlorophenoxyacetic acid, 2,4-D), gibberellins (gibberellin A 3 , GA 3 ; gibberellin A 4 , GA 4 ), cytokinins ( trans -zeatin, t Z; 6-benzylaminopurine, 6-BA), abscisic acid (ABA), and ethylene (ET), which appear at low concentrations and regulate the physiological and developmental responses of target tissues, thereby affecting plant morphology and regulating plant maturation and decline processes. − In addition, lipids are essential components of cell membranes, regulating various biological processes such as cell metabolism, cell adhesion and migration, signal transduction, and apoptosis. , Using MALDI-MSI technology to visualize the localization of phytohormones and lipids is helpful in understanding their physiological functions, metabolic pathways, and accumulation processes. Compounds such as 2,5-dihydroxybenzoic acid (DHB), α-cyano-4-hydroxycinnamic acid (CHCA), and 9-aminoacridine (9-AA) are currently the most widely employed MALDI matrices.…”