Modulation of Organogenesis and Somatic Embryogenesis by Ethylene: An Overview

Abstract

Ethylene is a plant hormone controlling physiological and developmental processes such as fruit maturation, hairy root formation, and leaf abscission. Its effect on regeneration systems, such as organogenesis and somatic embryogenesis (SE), has been studied, and progress in molecular biology techniques have contributed to unveiling the mechanisms behind its effects. The influence of ethylene on regeneration should not be overlooked. This compound affects regeneration differently, depending on the species, genotype, and explant. In some species, ethylene seems to revert recalcitrance in genotypes with low regeneration capacity. However, its effect is not additive, since in genotypes with high regeneration capacity this ability decreases in the presence of ethylene precursors, suggesting that regeneration is modulated by ethylene. Several lines of evidence have shown that the role of ethylene in regeneration is markedly connected to biotic and abiotic stresses as well as to hormonal-crosstalk, in particular with key regeneration hormones and growth regulators of the auxin and cytokinin families. Transcriptional factors of the ethylene response factor (ERF) family are regulated by ethylene and strongly connected to SE induction. Thus, an evident connection between ethylene, stress responses, and regeneration capacity is markedly established. In this review the effect of ethylene and the way it interacts with other players during organogenesis and somatic embryogenesis is discussed. Further studies on the regulation of ERF gene expression induced by ethylene during regeneration can contribute to new insights on the exact role of ethylene in these processes. A possible role in epigenetic modifications should be considered, since some ethylene signaling components are directly related to histone acetylation.

Effect of Light Conditions onIn VitroAdventitious Organogenesis of Cucumber Cultivars

“…In the initiation of shoots in lightand dark-grown tobacco callus, the ethylene produced in dark culture was much higher (Huxter et al 1981). A link has been established between ethylene, responses to stress, and the ability to regenerate (Neves et al 2021). Light conditions also play a role in the biosynthesis of secondary metabolites (Mir et al 2017).…”

Histological Approach to the Study of Morphogenesis in Callus Cultures In Vitro: A Review

“…Morphogenesis pathways lead to the regeneration of full-fledged plants under further favorable in vitro conditions. The plant regeneration system in calli is called "de novo plant regeneration" [9,16], "in vitro plant regeneration" [15] or "indirect plant regeneration" [43].…”

Ethylene Action Inhibition Improves Adventitious Root Induction in Adult Chestnut Tissues

“…For instance, ET biosynthesis might be enhanced or reduced by the application of its precursor 1-aminocyclopropane-1-carboxylate (ACC) or aminoethoxyvinylglycine (AVG), respectively. On the other hand, the use of silver ions allows for the inhibition of ET perception (reviewed in [ 31 ]). To test the effects of ET on the root system development of chestnut, ACC, silver nitrate (AgNO 3 ) and AVG were applied to the root induction media of juvenile and mature chestnut microshoots.…”