Crosstalk Between Ethylene and Abscisic Acid During Changes in Soil Water Content Reveals a New Role for 1-Aminocyclopropane-1- Carboxylate in Coffee Anthesis Regulation

Abstract

Coffee (Coffea arabica L.) presents an asynchronous flowering regulated by an endogenous and environmental stimulus, and anthesis occurs once plants are rehydrated after a period of water deficit. We evaluated the evolution of Abscisic Acid (ABA), ethylene, 1-aminocyclopropane-1-carboxylate (ACC) content, ACC oxidase (ACO) activity, and expression analysis of the Lysine Histidine Transporter 1 (LHT1) transporter, in the roots, leaves, and flower buds from three coffee genotypes (C. arabica L. cv Oeiras, Acauã, and Semperflorens) cultivated under field conditions with two experiments. In a third field experiment, the effect of the exogenous supply of ACC in coffee anthesis was evaluated. We found an increased ACC level, low ACO activity, decreased level of ethylene, and a decreased level of ABA in all tissues from the three coffee genotypes in the re-watering period just before anthesis, and a high expression of the LHT1 in flower buds and leaves. The ethylene content and ACO activity decreased from rainy to dry period whereas the ABA content increased. A higher number of opened and G6 stage flower buds were observed in the treatment with exogenous ACC. The results showed that the interaction of ABA-ACO-ethylene and intercellular ACC transport among the leaves, buds, and roots in coffee favors an increased level of ACC that is most likely, involved as a modulator in coffee anthesis. This study provides evidence that ACC can play an important role independently of ethylene in the anthesis process in a perennial crop.

The contrasting flowering-time among coffee genotypes is associated with ectopic and differential expressions of genes related to environment, floral development, and hormonal regulation

“…Connected to this model of transcriptional regulation of ethylene biosynthesis genes, it has been demonstrated that ethylene levels in coffee roots are reduced during the dry season and increased after rehydration, preceding anthesis (López et al, 2022). In this study, the ethylene level was measured in leaves and floral buds of the coffee genotypes Oeiras, Acauã and Sf (Fig.…”

“…Ethylene quantifications were made using leaves and floral bud tissues collected at different time points (see Fig. S1 for details), following the method described in López et al (2022), with the production rate expressed as ppm. g -1 FW.…”

“…Since floral development and flowering time (anthesis) are both related to sugar metabolism (Bolouri Moghaddam & Van den Ende, 2013;Cho et al, 2018;Ohto et al, 2001); and ethylene biosynthesis (Achard et al, 2007;López et al, 2022), the profile of these metabolics were evaluated in the leaves and floral buds of the three contrasting coffee genotypes at different periods of the year (Fig. 2).…”

Unveiling the phenology and associated floral regulatory pathways ofHumulus lupulusL. in subtropical conditions

“…Real-Time Quantitative PCR (RT-qPCR) was performed with the Rotor-Gene SYBR® Green PCR Kit (Qiagen), on a Rotor Gene-Q(R) thermocycler (Venlo, Netherlands) using three biological repetitions runned in three technical replicates as described by López et al, (2022). The expression rate and the confidence intervals were calculated according to the method proposed by Steibel et al, (2009), which considers the linear mixed-effect model.…”

“…Orthologs of FT have been identified in several species such as rice (Tamaki et al, 2007), coffee (Cardon et al, 2022) and many others (Pin and Nilsson, 2012). FT belongs to the PHOSPHATIDYLETHANOLAMINE-BINDING PROTEIN (PEBP) family, which is conserved in plants and animals (Jin et al, 2021).…”