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.

中文翻译：

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墨西哥本土鳄梨中果皮中表达的两种油质蛋白，含油量的关键基因

细胞内脂滴 (LD) 提供植物的储油机制。由于覆盖它们的蛋白质，即使在低温胁迫和脱水条件下，它们也作为单独的结构存在于种子中。这种称为油质蛋白的蛋白质仅存在于植物中，并已在种子中得到广泛研究。鳄梨果实 (Persea americana Mill.) 富含油，储存在中果皮中，而不是种子中。据报道，鳄梨的中果皮组织中存在油质蛋白，但其生理作用尚不清楚。在这项研究中，我们确定了两种编码墨西哥本土鳄梨中果皮中油质蛋白的基因。这些序列与种子油质蛋白的序列非常不同。这两个基因都在果实成熟期间表达，而其中一个基因 PaOle1 在绿色果实阶段表达最高。PaOle1 的蛋白质在果实成熟过程中是稳定的，覆盖了所有的中果皮 LD。PaOle1 基因和蛋白的表达是鳄梨中果皮的器官特异性表达。在鳄梨品种中，油质蛋白丰度与含油量直接相关。