IAA, ABA, polyamines and free amino acids associated with zygotic embryo development of Ocotea catharinensis

Abstract

The aim of this work was to study morphological and biochemical aspects during zygotic embryogenesis in O. catharinensis, by measuring changes in the endogenous concentrations of proteins, amino acids, polyamines (PAs), indole-3-acetic acid (IAA) and abscisic acid (ABA). Buffer-soluble and insoluble protein contents were determined by spectrometry, and amino acids, PAs, IAA and ABA concentrations were determined by high performance liquid chromatography. Total amino acid accumulation, predominantly asparagine, occurred when the embryo showed completely developed cotyledons, with posterior reduction in the mature embryo. This decrease in total amino acid concentration in the mature embryo may result from their use in storage as well as for LEA protein synthesis. Free putrescine (Put) concentration decreased, while free spermine (Spm) increased during embryo development. This suggest a role for Put in the initial phases of embryogenesis when high rates of cell division occur, while elevated concentration of Spm are essential from the middle to the end of embryo development, when growth is mainly due to cell elongation. An IAA peak in zygotic embryos occurred during initial development, suggesting a link between growth and cellular division as well as with the establishment of bilateral symmetry. ABA concentration declined during initial stages of development then increased at the mature embryo stage, suggesting a possible relationship with dormancy and recalcitrance characteristics. Our results show that changes in the phytohormones (IAA, ABA and PAs) concentrations in combination with amino acids are likely important factors determining the developmental stages of O. catharinensis zygotic embryos.

Polyethylene glycol effects on somatic embryogenesis of papaya hybrid UENF/CALIMAN 01 seeds

“…Protein analysis: Protein extracts were prepared in biological triplicates (300 mg FM) for each maturation treatment. Soluble and insoluble proteins were extracted from these cultures according to the method described by Santa-Catarina et al (2006). Soluble proteins were extracted using a phosphate buffer (pH 7.5) containing 50 mM sodium phosphate dibasic, 10 mM 2-mercaptoethanol and 1 mM phenylmethylsulfonyl fluoride (PMSF).…”

Two-dimensional gel electrophoretic protein profile analysis during seed development of Ocotea catharinensis: a recalcitrant seed species

“…org). Natural propagation of O. catharinensis through seeds is hindered by its recalcitrancy, which means that seeds cannot be stored over long periods without a serious loss of viability (Silva et al1998;Viana and Mantell 1999;Santa-Catarina et al 2006). …”

“…It has been demonstrated that proteomic analysis can generate relevant information towards elucidating the identity of those molecular mechanisms involved in developmental processes. Furthermore, the search is under way to trace biochemical and molecular markers in specific stages of embryogenesis in tree species (Silveira et al 2004;Rossignol et al 2006;Santa-Catarina et al 2006;Silveira et al 2008). The characterization of profiles and changes in protein content during seed development allows for comparing in vitro and in vivo embryo development.…”

Dynamics of physiological and biochemical changes during somatic embryogenesis of Acca sellowiana

“…Amino acids determination was carried out according to Santa-Catarina et al (2006). Samples (200 mg) were ground in 6 mL of 80% (v/v) ethanol and concentrated in a SpeedVac.…”