Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico.
Centro Multidisciplinario de Estudios en Biotecnología, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico.
Plant Foods Hum Nutr. 2021 Mar;76(1):20-25. doi: 10.1007/s11130-020-00868-2. Epub 2020 Nov 13.
Intracellular lipid droplets (LD) provide the oil storage mechanism of plants. They are found within seeds as individual structures, even under conditions of cold stress and dehydration, due to the protein that covers them. This protein, called oleosin, is found exclusively in plants and has been widely studied in seeds. Avocado fruits (Persea americana Mill.) are rich in oil, which is stored in the mesocarp, not in the seeds. The presence of oleosin in the mesocarp tissue of avocadoes has been reported, but its physiological role is still unknown. In this study, we identify two genes that code for oleosin in the mesocarp of the native Mexican avocado. These sequences are very different from those of seed oleosins. Both genes are expressed during fruit ripening, while one, PaOle1, has the highest expression in the green fruit stage. The protein of PaOle1 is stable during the fruit ripening process and covers all the mesocarp LDs. The expression of PaOle1 gene and protein is organ specific to avocado mesocarp. Among avocadoes varieties oleosin abundance is directly related to oil content.
细胞内脂滴 (LD) 为植物提供了油脂储存机制。由于覆盖在它们表面的蛋白质，这些脂滴即使在寒冷和脱水等条件下也可以作为单个结构存在于种子中。这种蛋白质称为油体蛋白，仅存在于植物中，在种子中得到了广泛研究。鳄梨果实（Persea americana Mill.）富含油脂，储存在中果皮中，而不是种子中。已经报道了油体蛋白存在于鳄梨的中果皮组织中，但它的生理作用尚不清楚。在这项研究中，我们在原产于墨西哥的鳄梨的中果皮中鉴定出了两个编码油体蛋白的基因。这些序列与种子油体蛋白的序列有很大的不同。这两个基因都在果实成熟过程中表达，其中一个，PaOle1，在绿色果实阶段的表达量最高。PaOle1 蛋白在果实成熟过程中保持稳定，并覆盖了所有的中果皮 LD。PaOle1 基因和蛋白的表达具有鳄梨中果皮的器官特异性。在鳄梨品种中，油体蛋白的丰度与含油量直接相关。
