A common F-box gene regulates the leucine homeostasis of Medicago truncatula and Arabidopsis thaliana

Transcriptional and Metabolic Profiling of Arabidopsis thaliana Transgenic Plants Expressing Histone Acetyltransferase HAC1 upon the Application of Abiotic Stress-Salt and Low Temperature

Augmented knowledge of plant responses upon application of stress could help improve our understanding of plant tolerance under abiotic stress conditions. Histone acetylation plays an important role in gene expression regulation during plant growth and development and in the response of plants to abiotic stress. The current study examines the level of transcripts and free metabolite content in transgenic Arabidopsis thaliana plants expressing a gene encoding histone acetyltransferase from Medicago truncatula (MtHAC1) after its heterologous expression. Stable transgenic plants with HAC1 gain and loss of function were constructed, and their T5 generation was used. Transgenic lines with HAC1-modified expression showed a deviation in root growth dynamics and leaf area compared to the wild-type control. Transcriptional profiles were evaluated after the application of salinity stress caused by 150 mM NaCl at four different time points (0, 24, 48, and 72 h) in treated and non-treated transgenic and control plants. The content and quantity of free metabolites-amino acids, mono- and dicarbohydrates, organic acids, and fatty acids-were assessed at time points 0 h and 72 h in treated and non-treated transgenic and control plants. The obtained transcript profiles of HAC1 in transgenic plants with modified expression and control were assessed after application of cold stress (low temperature, 4 °C).

Pattern Recognition of Varieties of Peach Fruit and Pulp from Their Volatile Components and Metabolic Profile Using HS-SPME-GC/MS Combined with Multivariable Statistical Analysis

A fruit's aroma profile, composed of a complex mixture of volatile organic compounds, is among the core attributes related to the overall taste and consumer preference. Prunus persica L. is a preferred summer fruit with a distinct, favorable olfactory characteristic. The volatile compositions of both peach fruits and fruit pulps from eight peach cultivars (four native and four introduced) was investigated to compare their composition and assess flavor-contributing compounds. In total, 65 compounds were profiled after a HS-SPME-GC-MS analysis: 16 esters, 14 aldehydes, 5 alcohols, 7 hydrocarbons, 7 ketones, 8 acids, and 8 terpenes. The most common compounds were esters, acids, and aldehydes. Although the same compounds were identified in both fruit and pulp, their %TIC (total ion current) differed in favor of the whole fruit. Following the metabolic profiling of the whole fruit and fruit pulp, a total of 44 compounds were identified from the studied varieties. Among them, amino acids, organic acids, sugar alcohols, saccharides, fatty acids, and phenolic acids were identified as existing groups. According to the provided principal component analysis (PCA) and hierarchical cluster analysis (HCA), the relative %TIC of the identified volatile compounds fluctuated depending on the studied cultivar. No differences were visible in the PCA biplots, which suggested that the polar and lipid metabolites do not provide significant variations when considering different parts of the fruit, contrary to the volatile compounds. The obtained results could successfully be applied in the metabolic chemotaxonomy of peaches and the differentiation of the metabolites present in different parts of the peach.

In Vitro Multiplication and NMR Fingerprinting of Rare Veronica caucasica M. Bieb

Micropropagation of rare Veronica caucasica M. Bieb. was achieved by successful in vitro cultivation of mono-nodal segments on MS medium supplemented with 1.0 mg L^–1 6-benzylaminopurine (BA) and then transferring the regenerated plants on hormone free basal MS medium for root development. In vitro multiplicated plants were successively acclimated in a growth chamber and a greenhouse with 92% survival. The number of plastid pigments and the total phenolics content in in vitro cultivated and ex vitro adapted plants were unchanged, and no accumulation of reactive oxygen species (ROS) was detected by staining with 3-3′-diaminobenzidine (DAB) and 2′,7′-dichlorofluorescein diacetate (DCF-DA). Nuclear Magnetic Resonance (NMR) fingerprinting allowed for the identification of the major alterations in metabolome of V. caucasica plants during the process of ex situ conservation. Iridoid glucosides such as verproside, aucubin and catalpol were characteristic for in vitro cultivated plants, while in ex vitro acclimated plants phenolic acid–protocatechuic acid and caffeic acid appeared dominant. The successful initiation of in vitro and ex vitro cultures is an alternative biotechnological approach for the preservation of V. caucasica and would allow for further studies of the biosynthetic potential of the species and the selection of lines with a high content of pharmaceutically valuable molecules and nutraceuticals.