Abstract

Seed development may be divided up into embryonic morphogenesis and seed maturation, while diverse genes were connected and disconnected in order to bring about such processes.  Features such as desiccation tolerance, dormancy and germination capacity are acquired throughout development and regulated by the presence and interaction of phytohormones such as abscisic acid (ABA), gibberellin (GA) and ethylene. The purpose of this study was to analyze the expression of genes connected with ABA, GA and ethylene biosynthesis during the development of lettuce seeds. For that reason, expression of the LsNCED, LsGAox and ACO-B genes was evaluated by means of the real time polymerase chain reaction (PCR) technique in seeds from seven lettuce cultivars harvested at the maturation stages of 5, 10, 15 and 20 days after anthesis. It may be concluded that expression of the LsNCED gene was related to the imposition of dormancy at the final stages of development; expression of the LsGA3ox gene occurred at the initial stages of development; the expression of theACO-B was greater in the initial (5 DAA) and late (20 DAA) stages during development, inducing germination. The expression profile of the LsNCED, LsGA3oxand ACO-B genes was dependent on the cultivar.

Key words: Phytohormones, seed maturation, real time polymerase chain reaction (PCR).

Abbreviation

Abbreviations: ABA, Abscisic acid; GA, gibberellin; NCEDs, 9-cis-epoxycarotenoid dioxygenases; ACC, aminocyclopropane-1-carboxylic; ACS, aminocyclopropane-1-carboxylic synthase; ACO, aminocyclopropane-1-carboxylic oxydase; PMF, physiological maturity; BOD, biological oxygen demand; qRT-PCR, quantitative real time polymerase chain reaction; CTs, threshold cycle; PP2A, protein phosphatase 2;DAA, after anthesis; GA3 ox, gibberellin 3-oxidase.