Abscisic Acid Induces Adventitious Rooting in Cucumber (Cucumis sativus L.) by Enhancing Sugar Synthesis

Abstract

Abscisic acid (ABA) affects many important plant processes, such as seed germination, root elongation and stomatal movement. However, little information is available about the relationship between ABA and sugar synthesis during adventitious root formation. The aim of this study was to evaluate the effect of ABA on adventitious root formation in cucumber and whether the effect of this plant hormone on sugar synthesis could be included as a causative factor for adventitious root development. We determined the contents of glucose, sucrose, starch, total sugar and sugar-related enzymes, including sucrose synthase (SS), sucrose phosphate synthase (SPS), hexokinase (HK) and pyruvate kinase (PK) activities in ABA treatment. We also quantified the relative expression of sucrose or glucose synthesis genes during this process. Increasing ABA concentrations significantly improved adventitious root formation, with the most considerable effect at 0.05 μM. Compared to the control, ABA treatment showed higher glucose, sucrose, starch and total sugar contents. Moreover, ABA treatment increased glucose-6-phosphate (G6P), fructose-6-phosphate (F6P) and glucose-1-phosphate (G1P) contents in cucumber explants during adventitious root development, which was followed by an increase of activities of sucrose-related enzymes SS and SPS, glucose-related enzymes HK and PK. ABA, meanwhile, upregulated the expression levels of sucrose or glucose synthesis-related genes, including CsSuSy1, CsSuSy6, CsHK1 and CsHK3. These results suggest that ABA may promote adventitious root development by increasing the contents of glucose, sucrose, starch, total sugar, G6P, F6P and G1P, the activities of SS, SPS, HK, SPS and the expression levels of CsSuSy1, CsSuSy6, CsHK1 and CsHK3 genes. These findings provide evidence for the physiological role of ABA during adventitious root formation and provide a new understanding of the possible relationship between ABA and sugar synthesis during adventitious rooting in plants.

Cloning and Function Analysis of the CsTAU1 in Response to Salt–Alkali Stress

“…When the seedlings had grown to three true-leaf seedlings, different stress treatments and hormone induction treatments were carried out. Abscisic acid (ABA)-induced treatment: foliar spraying with 100 µmol/L ABA [20]; Salicylic acid (SA)-induced treatment: foliar spraying with 0.5 mmol/L SA; Methyl jasmonate (JA)-induced treatment: foliar spraying with 100 µmol/L JA; cold treatment (low temperature stress): the day and night temperatures were set to 10 ± 0.5 • C/5 ± 0.5 • C with a 16 h photoperiod, the light intensity was 4000 lx, and the low temperature stress was 10 days; Drought stress (PEG): each plant was irrigated with 50 mL of 40% PEG4000, and leaves were harvested 8 days after treatment; Disease treatment (Cor): inoculated Corynespora multicaulis on cucumber leaves by spray method, and the inoculation concentration was 1 × 10 5 conidia/mL; And leaves were harvested 24 h after treatment. For each of the above treatments, 5 plants with consistent growth were selected as replicates, and leaves were taken as experimental materials after 24 h treatment.…”

Comparative transcriptome analysis of molecular mechanisms underlying adventitious root developments in Huangshan Bitter tea (Camellia gymnogyna Chang) under red light quality

“…Interestingly, the effects of gibberellic acid (GA), abscisic acid (ABA) and jasmonic acid (JA) on AR formation depend on the plant species. For instance, GA promotes AR formation in pea ( Pisum sativum ) but inhibits it in hybrid aspen and Arabidopsis Gutierrez et al., 2012 ; Rasmussen et al., 2015 ; Zeng et al., 2021 ; Li et al., 2022 ). Therefore, the role of hormones in AR formation needs to be further explored through classical molecular biology techniques combined with high-throughput sequencing technology, to provide new insights into the functions of hormones in AR formation and development.…”