The role of γ -aminobutyric acid (Gaba) in somatic embryogenesis of Acca sellowiana Berg. (Myrtaceae)

Abstract

The γ-aminobutyric acid (Gaba) is a non-protein amino acid found in prokaryotes and eukaryotes. Its role in plant development has not been fully established. This study reports a quantification of the levels of endogenous Gaba, as well as investigation of its role in different stages of somatic embryogenesis in Acca sellowiana Berg. (Myrtaceae). Zygotic embryos were used as explants and they were inoculated into the culture medium contained different concentrations of Gaba (0,2, 4, 6, 8 and 10 μM). The highest concentrations of endogenous Gaba were detected between the third and nine days after inoculation, reaching the value of 12.77 μmol.g -1 FW. High frequency of somatic embryogenesis was observed in response to 10 μM Gaba. This treatment also resulted in a large number of normal embryos, and the lowest percentage of formation of fused somatic embryos, phenotypic characteristic of most deformed embryos in all treatments. Also, all treatments promoted the formation of the somatic embryos with positive characteristics of development resumption, which however did not originate the seedlings.Key words: Amino acid, pineapple guava, plant growth resuMo O ácido γ-aminobutírico (Gaba) é um aminoácido não protéico encontrado em procariontes e eucariontes. Seu papel em plantas ainda não está bem estabelecido. No presente estudo procurou-se quantificar os teores endógenos de Gaba, bem como investigar seu papel nos diferentes estágios da embriogênese somática em Acca sellowiana Berg. (Myrtaceae). Foram empregados embriões zigóticos como explantes e os mesmos foram inoculados em meio de cultura contendo diferentes concentrações de Gaba: 0 (controle), 2, 4, 6, 8 e 10 μM. As maiores concentrações de gaba endógeno foram detectadas no período compreendido entre o 3º e o 9º dia após a inoculação, tendo alcançado, neste último dia, o valor de 12,77 μmol.g -1 FW. Alta freqüência de embriogênese somática foi observada em resposta a 10 μM de Gaba. Este tratamento também resultou em grande número de embriões normais, bem como o menor percentual de formação de embriões cupuliformes, característica fenotípica da maioria dos embriões deformados em todos os tratamentos. Em todos os tratamentos ocorreram embriões somáticos que apresentaram características positivas quanto à retomada de desenvolvimento, mas que não resultaram na formação de plântulas.

Biochemical events during somatic embryogenesis in Coffea arabica L.

“…They remained statistically constant until the end of cultivation, i.e., until the start of the plant's regeneration stage (390 days), with averages that varied around 450 µg/mg MS. Gomes et al (2014) also detected amino acid content stabilization after callus formation during E. guineensis somatic embryogenesis. Current results were different from those obtained by Booz et al (2009) who detected an ongoing decline in total free amino acid levels during different stages of A. sellowiana somatic embryogenesis. According to the authors, decline in total free amino acid content in the course of cultivation occurred due to the continuous increase in protein synthesis.…”

BIOCHEMICAL PROFILE OF BACTERISED CALLI AND EMBRYOGENIC CALLI OF OIL PALM (Elaeis guineensis Jacq.)

“…It is also believed that amino acids production decreased during the progress of regeneration and maturation of embryos in order to support cells development. This result corroborates with the work of Booz et al (2009) which reported a continuous decrease of the total free amino acid levels throughout the stages of differentiation in embryogenesis of Acca sellowiana Berg. As mentioned previously, amino acid is important for nitrogen regulators, but also have an impact on plant developmental processes.…”

“…Biochemical studies are essential in order to have a better understanding of the morphological and physiological features of plant cells which may be due to the artificial symbiotic association. Amino acid is important in plant development pathway and several studies had reported that drastic increment and reduction of amino acids production occurred during different stages of somatic embryogenesis process (Sen et al, 2002;Booz et al, 2009;Kumar and Kumari, 2011;Gomes et al, 2014). Generally, proteins are involved in cell expansion regulation and establishment of biophysical characteristics which are required for plant cell morphogenesis (Jiménez, 2001).…”

Comparative biochemical profiling during the stages of acquisition and development of somatic embryogenesis in African oil palm (Elaeis guineensis Jacq.)

“…However, the levels of total free amino acids present in the explant tissues stabilize from 90 days cultivation, after the formation of embryogenic calluses, and remain constant until the plant regeneration phase, verified after 360 days. Different results were found by Booz et al (2009), when studying the biochemistry of the processes of maturation and regeneration of somatic embryos of A. sellowiana, who observed a continuous decrease of the levels of total free amino acid in the explants throughout the different stages of development. According to the authors, this decrease in the total free amino acid content throughout the later stages of SE is most likely related to the increase of protein synthesis.…”

“…In SE, studies have shown that the quantity of amino acids, particularly proline, serine and tyrosine, increase and decrease quickly during the different stages of the process, thus demonstrating the link of these compounds with this important plant developmental pathway (Sen et al 2002;Niemenak et al 2008;Booz et al 2009;Kumar and Kumari 2011). Therefore, aimed at fostering the development of embryogenic cultures, researchers are often supplementing the culture media with amino acids (Scherwinski-Pereira et al 2010).…”