Phenylpropanoids Are Connected to Cell Wall Fortification and Stress Tolerance in Avocado Somatic Embryogenesis.

Somatic embryogenesis (SE) is a valuable model for understanding the mechanism of plant embryogenesis and a tool for the mass production of plants. However, establishing SE in avocado has been complicated due to the very low efficiency of embryo induction and plant regeneration. To understand the molecular foundation of the SE induction and development in avocado, we compared embryogenic (EC) and non-embryogenic (NEC) cultures of two avocado varieties using proteomic and metabolomic approaches. Although Criollo and Hass EC exhibited similarities in the proteome and metabolome profile, in general, we observed a more active phenylpropanoid pathway in EC than NEC. This pathway is associated with the tolerance of stress responses, probably through the reinforcement of the cell wall and flavonoid production. We could corroborate that particular polyphenolics compounds, including p-coumaric acid and t-ferulic acid, stimulated the production of somatic embryos in avocado. Exogen phenolic compounds were associated with the modification of the content of endogenous polyphenolic and the induction of the production of the putative auxin-a, adenosine, cellulose and 1,26-hexacosanediol-diferulate. We suggest that in EC of avocado, there is an enhanced phenylpropanoid metabolism for the production of the building blocks of lignin and flavonoid compounds having a role in cell wall reinforcement for tolerating stress response. Data are available at ProteomeXchange with the identifier PXD019705.

[Fatty acids profile and microstructure of avocado puree after microwave heating]. / Cambios en el perfil de ácidos grasos y microestructura de aguacate Hass tratado con microondas.

Changes in the fatty acid profile and the microstructure of avocado puree after microwave treatment were evaluated. The main components of the fatty acid profile were oleic, palmitic, linoleic and palmitoleic acids. Fatty acids profile of microwaved avocado puree did not show significant changes (p < 0.05). Trans fatty acids were not detected. Microwaved avocado puree showed significant changes in its microstructure. Samples treated with microwaves for less than 40 s preserved the cells shape, causing only a minimal modification. On the other hand, microwave treated avocado puree using more than 40 s, showed a disruption of idioblast oil cells, releasing the oil contained on them. The results might be explained based on the sensory evaluation that was performed on the microwaved avocado puree, where samples at 60 s showed oily texture and grassy flavor.

Effect of a novel oil extraction method on avocado (Persea americana Mill) pulp microstructure.

Avocado (Persea americana Mill) is an oil-rich fruit, the pulp containing up to 33% of the oil. It is rich in monounsaturated fatty acids, and has nutritional properties similar to olive oil. However, there is no widespread commercial method for oil recovery from avocado pulp. The aim of this study is to contribute to the limited knowledge about the micro- and ultrastructure of avocado. It presents a micro- and ultrastructural study of avocado pulp before and after three different oil recovery methods, in order to relate the quality and yielding of the oil to the cellular changes in the pulp. This study was made using light, scanning electron, and electron transmission microscopy. The microwave-squeezing method yielded 67% of the oil, preserved the shape of the cell by causing only a slight modification, and gave the best quality oil. Hexane extraction yielded 59%, causing the idioblastic oil cells to become irregularly shaped and rough-surfaced. Acetone extraction yielded 12%, and deformed the cellular wall while the oil remained inside, giving a poor quality oil. On the basis of these results, the microwave-squeezing method is suggested as a new option for oil recovery from avocadopulp. This method could be adapted for industrial processing.