Physiological and metabolic alterations in basil (Ocimum basilicum L) varieties under distinct soil water levels / Alteraciones fisiológicas y metabólicas en variedades de albahaca (Ocimum basilicum L) bajo distintos niveles de agua del suelo

Basil (Ocimum basilicumL.) is a medicinal species used in several areas, such as food, medicines and cosmetics, and the understanding of its physiological behavior under environmental conditions is of paramount importance for the improvement of cultivation methods. The objective of this study was to evaluate the influence of different water availability under physiological, biochemical and metabolic characteristics, in three distinct genotypes: 'Alfavaca basilicão', 'Gennaro de menta' and 'Grecco à palla', during two different phenological stages (vegetative and reproductive). It was found that the water deficit promotes physiological changes to tolerate water stress, and the studied genotypes have different routes to achieve this physiological tolerance, which culminates in a distinct accumulation of metabolites in plants, and can be considered interesting if the final product is the production of essential oils.

La albahaca (Ocimum basilicum L.) es una planta medicinal utilizada en varias áreas: alimenticia, medicinal e industria cosmética; es de suma importancia el entendimiento de su comportamiento fisiológico bajo diferentes condiciones ambientales con el fin de mejorar los procesos del cultivo. El objetivo de este estudio fue evaluar la influencia de diferentes disponibilidades hídricas en las características fisiológicas, bioquímicas y metabólicas en tres genotipos de albahaca: "Alfavaca basilicão", "Gennaro de menta" y "Grecco à palla" durante dos etapas fenológicas (vegetativa y reproductiva). Fue encontrado que el déficit hídrico promueve cambios fisiológicos con el fin de tolerar el estrés hídrico. Los genotipos estudiados presentaron diferentes rutas para alcanzar esta tolerancia fisiológica, la cual culmina con distintas acumulaciones de metabolitos en las plantas, y puede ser considerado interesante si el producto final es la producción de aceites esenciales.

Effects of indoor, greenhouse, and field cultivation on bioactive compounds from parsley and basil.

BACKGROUND: Aromatic herbs are an important source of bioactive compounds. Different cultivation systems should give each plant a specific amount of those compounds, which should be of a particular quality. In this study, the effects of three cultivation systems (indoor, greenhouse, and organic field) on the composition of bioactive compounds in parsley (Petroselinum crispum cv. 'Flat Leaf'), green basil (Ocimum basilicum var. minimum cv. 'Greek'), and purple basil (Ocimum basilicum cv. 'Red Rubin') were evaluated. RESULTS: ß-Carotene and lutein were the carotenoids with the highest concentration in the three plants in all the cultivation systems. Overall, parsley proved to be a source of flavonoids. The major phenolic compound found in basil plants was rosmarinic acid, whereas most anthocyanins were derived from cyanidin aglycone. Among the three plants studied, the highest vitamin C content was found in parsley from the field. This was 2.6 and 5.4 times higher than the indoor and greenhouse cultivation, respectively. CONCLUSION: The results suggest that different cultivation systems influence and modulate the concentration of bioactive compounds in plants differently, varying according to their class, and that, above all, an indoor system is an effective cultivation system for the production of bioactive compounds. © 2021 Society of Chemical Industry.

Invisible signals from the underground: A practical method to investigate the effect of microbial volatile organic compounds emitted by rhizobacteria on plant growth.

Rhizobacteria that colonize plant roots and promote plant growth are referred to as plant growth-promoting rhizobacteria, and this can stimulate plant growth either indirectly or directly. Volatile organic compounds (VOCs) emitted by rhizobacteria have the capacity to promote plant growth as well as perform biocontrol of fungal pathogens. The microbial volatile organic compounds (mVOCs) are characterized by a low molecular weight and a high vapor pressure, which facilitate evaporation and diffusion at normal temperatures and at above-ground and below-ground pressures. mVOCs can travel far from the point of production through the atmosphere, porous soils and liquids, thereby making them ideal infochemicals for mediating interspecific interactions. However, knowledge about the biological and ecological roles of microbial VOCs is still limited compared with that of plant VOCs. Here, we describe a simple and inexpensive laboratory class aimed at biotechnology or soil microbiology students, which uses techniques to increase their understanding of the mechanisms of plant growth promoting rhizobacteria and also illustrate the effects of mVOCs emitted by rhizobacteria on plant growth promotion, as well as evaluating their potential as a biocontrol. The laboratory class is divided into two sessions: an initial 3-hour experimental session and a second 2-hour analytical one. The experimental session involves two separate experiments: one of which is dedicated to illustrating the effect of mVOCs on plant growth parameters, while the second explores the capacity of VOCs as a biocontrol. Also, the class provides students with an opportunity to perform useful assays, draw conclusions from their results, and discuss possible extensions of the study. © 2019 International Union of Biochemistry and Molecular Biology, 47(4):388-393, 2019.

Phenylpropanoid biosynthesis in leaves and glandular trichomes of basil (Ocimum basilicum L.).

Basil (Ocimum basilicum L.) essential oil phenylpropenes are synthesized and accumulate in peltate glandular trichomes and their content and composition depend on plant developmental stage. Studies on gene expression and enzymatic activity indicate that the phenylpropene biosynthetic genes are developmentally regulated. In this study, the methylchavicol accumulation in basil leaves and the enzyme activities and gene expression of both chavicol O-methyltransferase (CVOMT) and eugenol O-methyltransferase (EOMT) were investigated in all leaves at four plant developmental stages. Methylchavicol accumulation decreased over time as leaves matured. There was a significant correlation between methylchavicol accumulation and CVOMT (r(2) = 0.88) enzyme activity, suggesting that the levels of biosynthetic enzymes control the essential oil content. CVOMT and EOMT transcript expression levels, which decreased with leaf age, followed the same pattern in both whole leaves and isolated glandular trichomes, providing evidence that CVOMT transcript levels are developmentally regulated in basil glandular trichomes themselves and that differences in CVOMT expression observed in whole leaves are not solely the result of differences in glandular trichome density.