Studies on avocado oil have focused on the most common commercial cultivars, Hass, Fuerte, and Bacon, rather than the less common varieties, P. americana var. drymifolia and P. americana var. americana, even though the drymifolia variety has a higher oil content and the americana variety is the most common avocado grown in the tropics. The most abundant storage structures for plant oils are the oleosomes, and the aim of this study was to determine the oleosome size, oil yield, and fatty acid composition of the americana and drymifolia varieties, using the Hass cultivar as a reference. Differences were found between the three avocado types for 1) oil yield, with drymifolia having higher and americana lower oil content (p < 0.05%), 2) oleosome size, with Hass having a larger (41.53 µm) and americana a smaller (11.96 µm) size, and 3) fatty acid composition, with the americana and drymifolia varieties showing less monounsaturated fatty acids (oleic) and more polyunsaturated fatty acids (linoleic) and saturated fatty acids (palmitic); while Hass had a high level (60%) of monounsaturated fatty acids. Small but significant differences were also found between oleosome and mesocarp oils isolated from the drymifolia and Hass types.

Avocado native “Mexicano” (Persea americana var drymifolia) has been a really important species in agricultural and indigenous medicine. In the agricultural world, it has been the germplasm source for the generation of economically important cultivars like Hass and it is the main source of rootstocks for the world production of Hass avocado fruit. In spite of its importance, little is known about the molecular network of seed-fruit development. The aim of this work was to know the expressed genes (ESTs) during the early avocado native “Mexicano” seed development. Using total RNA we constructed cDNA libraries of fourth months seed development, sequencing, assembling and bioinformatic analysis was made. For validation, a semi-quantitative PCR experiments with the most abundant genes were made. About 5005 ESTs from the 5’ representing 1653 possible unigenes were isolated. After assembling process, we have 171 genes that are closely related to Nelumbo nucifera sequences. The transcriptome is dominating by one bHLH transcription factor, three metallothioneins and snakin, suggesting its main role in seed development. Until now, there are no molecular studies in avocado seed development.

Soil salinity is a major environmental constraint affecting avocado (Persea americana Mill.) productivity. In this study, we evaluate the physio-morphological and molecular responses of two avocado varieties, drymifolia (sensitive) and americana (tolerant), subjected to increasing NaCl concentrations for 60 days. Our results reveal distinct adaptive strategies. While salinity reduced total biomass in both genotypes, var. americana exhibited superior resilience, characterized by preferential biomass allocation to the root system. Ion analysis demonstrated that tolerance was not mediated by K⁺ homeostasis, but rather by the differential management of toxic ions. var. americana effectively sequestered chloride Cl⁻ in the roots, whereas var. drymifolia exhibited a breakdown of the exclusion mechanism at 60 mM NaCl, with shoot Cl⁻ concentrations exceeding those of the root, leading to severe toxicity. At the molecular level, qPCR analysis of the Na⁺ transporters PaHKT1 and PaSOS1 showed no expression pattern correlated with salt stress. Bioinformatic assessment revealed significant structural divergences and a lack of conserved functional domains in these proteins. These findings challenge the applicability of the classical sodium-exclusion model (typical of Liliopsida and Magnoliopsida) to avocado. We conclude that salt tolerance in this Lauraceae species is primarily driven by root-mediated Cl⁻ exclusion rather than canonical Na⁺ transport pathways.