Department of Horticulture, Gansu Agricultural University, Lanzhou 730000, China.
Department of Horticulture, Gansu Agricultural University, Lanzhou 730000, China.
Gene. 2021 Feb 5;768:145302. doi: 10.1016/j.gene.2020.145302. Epub 2020 Nov 9.
Auxin is a necessary phytohormone for fruit development, accompanying the whole process of fruit growth and development. The Aux/IAA gene family is one of the early auxin-responsive gene families. At present, there were few reports involved in Aux/IAA genes in the fruit, especially in apple. In our study, we identified 42 MdAux/IAAs, phylogenetic analysis showed that Aux/IAA proteins from apple, tomato, and strawberry were clustered into 5 groups, 42 MdAux/IAAs randomly distributed on 13 chromosomes. Additionally, a comprehensive analysis of Aux/IAA gene family was completed, including gene structures, conserved motifs, phylogenetic analysis, chromosome mapping, orthologous identification, selection pressure analyses, synteny analysis, and protein interaction. We also tested the expression of MdAux/IAAs in different tissues and fruit development stages using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), we found that the most members of Aux/IAA showed higher expression in seeds compared within stem and leaves, indicating they may play a role in regulating fruit development. We also declared that the expression of Aux/IAA gene was not consistent in the pericarp and seeds at the same developmental stage, 3 MdAux/IAAs of the pericarp were upregulated over 20-fold at 90 d and 5 MdAux/IAAs of the seeds were upregulated over 40-fold at 90 d. It was MdAux/IAA23 that showed extreme up-regulated expression in both pericarp and seeds. This study proved that the Aux/IAA gene families may perform a different function in apple fruit development and ripening, more importantly, it provided a foundation for further exploring the biological function of these MdAux/IAAs.
生长素是果实发育所必需的植物激素，伴随果实生长发育的全过程。Aux/IAA 基因家族是早期生长素响应基因家族之一。目前，关于果实，特别是苹果中 Aux/IAA 基因的报道较少。在本研究中，我们鉴定了 42 个 MdAux/IAAs，系统进化分析表明，来自苹果、番茄和草莓的 Aux/IAA 蛋白聚为 5 组，42 个 MdAux/IAAs 随机分布在 13 条染色体上。此外，我们还完成了对 Aux/IAA 基因家族的综合分析，包括基因结构、保守基序、系统进化分析、染色体定位、直系同源基因鉴定、选择压力分析、共线性分析和蛋白互作。我们还使用定量逆转录聚合酶链反应（qRT-PCR）检测了 MdAux/IAAs 在不同组织和果实发育阶段的表达，发现 Aux/IAA 基因家族的大多数成员在种子中的表达水平明显高于茎和叶，表明它们可能在调控果实发育中发挥作用。我们还发现 Aux/IAA 基因在同一发育阶段的果皮和种子中的表达并不一致，果皮中有 3 个 MdAux/IAAs 在 90 d 时上调 20 多倍，种子中有 5 个 MdAux/IAAs 在 90 d 时上调 40 多倍。MdAux/IAA23 在果皮和种子中均表现出极端上调表达。本研究证明 Aux/IAA 基因家族在苹果果实发育和成熟过程中可能发挥不同的功能，更重要的是，为进一步探索这些 MdAux/IAAs 的生物学功能提供了基础。
