Multigenic regulation in the ethylene biosynthesis pathway during coffee flowering

Iasminy Silva Santos; Thales Henrique Cherubino Ribeiro; Kellen Kauanne Pimenta de Oliveira; Jacqueline Oliveira Dos Santos; Rafael Oliveira Moreira; Renato Ribeiro Lima; André Almeida Lima; Antonio Chalfun-Junior

doi:10.1007/s12298-022-01235-y

Multigenic regulation in the ethylene biosynthesis pathway during coffee flowering

Physiol Mol Biol Plants. 2022 Sep;28(9):1657-1669. doi: 10.1007/s12298-022-01235-y. Epub 2022 Oct 18.

Authors

Iasminy Silva Santos¹, Thales Henrique Cherubino Ribeiro¹, Kellen Kauanne Pimenta de Oliveira¹, Jacqueline Oliveira Dos Santos², Rafael Oliveira Moreira¹, Renato Ribeiro Lima³, André Almeida Lima¹, Antonio Chalfun-Junior¹

Affiliations

¹ Plant Molecular Physiology Laboratory, Biology Department, Federal University of Lavras (UFLA), s/n, Cx., Postal 3037, Lavras, Minas Gerais 37200-900 Brazil.
² Minas Gerais Agricultural Research Company, EPAMIG, Federal University of Lavras (UFLA), s/n, Cx., Postal 3037, Lavras, Minas Gerais 37200-900 Brazil.
³ Statistics Department, Federal University of Lavras (UFLA), s/n, Cx., Postal 3037, Lavras, Minas Gerais 37200-900 Brazil.

Abstract

Ethylene regulates different aspects of the plant's life cycle, such as flowering, and acts as a defense signal in response to environmental stresses. Changes induced by water deficit (WD) in gene expression of the main enzymes involved in ethylene biosynthesis, 1-aminocyclopropane-1-carboxylic acid synthase (ACS) and oxidase (ACO), are frequently reported in plants. In this study, coffee (Coffea arabica) ACS and ACO family genes were characterized and their expression profiles were analyzed in leaves, roots, flower buds, and open flowers from plants under well-watered (WW) and water deficit (WD) conditions. Three new ACS genes were identified. Water deficit did not affect ACS expression in roots, however soil drying strongly downregulated ACO expression, indicating a transcriptional constraint in the biosynthesis pathway during the drought that can suppress ethylene production in roots. In floral buds, ACO expression is water-independent, suggesting a higher mechanism of control in reproductive organs during the final flowering stages. Leaves may be the main sites for ethylene precursor (1-aminocyclopropane-1-carboxylic acid, ACC) production in the shoot under well-watered conditions, contributing to an increase in the ethylene levels required for anthesis. Given these results, we suggest a possible regulatory mechanism for the ethylene biosynthesis pathway associated with coffee flowering with gene regulation in leaves being a key point in ethylene production and ACO genes play a major regulatory role in roots and the shoots. This mechanism may constitute a regulatory model for flowering in other woody species.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-022-01235-y.

Keywords: ACC oxidase; ACC synthase; Anthesis; Coffea arabica; RT-qPCR; Water deficit.

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