Li Hong-Liang, Wang Xun, Ji Xing-Long, Qiao Zhi-Wen, You Chun-Xiang, Hao Yu-Jin
State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, China.
Front Plant Sci. 2020 Jul 24;11:1109. doi: 10.3389/fpls.2020.01109. eCollection 2020.
SINA (Seven in absentia) proteins are a small family of ubiquitin ligases that play important roles in regulating plant growth and developmental processes as well as in responses to diverse types of biotic and abiotic stress. However, the characteristics of the apple SINA family have not been previously studied. Here, we identified 11 members in the apple genome based on their conserved, N-terminal RING and C-terminal SINA domains. We also reconstructed a phylogeny of these genes; characterized their chromosomal location, structure, and motifs; and identified two major groups of genes. Subsequent qRT-PCR analyses were used to characterize the expression of genes in various tissues and organs, and levels of expression were highest in leaves. were significantly induced under ABA and carbon- and nitrate-starvation treatment. Except for MdSINA1 and MdSINA7, the other MdSINA proteins could interact with each other. Moreover, MdSINA2 was found to be localized in the nucleus using -mediated transient expression. Western-blot analysis showed that MdSINA2 accumulated extensively under light, decreased under darkness, and became insensitive to light when the RING domain was disrupted. Finally, ABA-hypersensitive phenotypes were confirmed by transgenic calli and the ectopic expression of in . In conclusion, our results suggest that genes participate in the responses to different types of stress, and that might act as a negative regulator in the ABA stress response.
SINA（缺席七）蛋白是泛素连接酶的一个小家族，在调节植物生长和发育过程以及对多种生物和非生物胁迫的反应中发挥重要作用。然而，苹果SINA家族的特征此前尚未被研究。在这里，我们基于其保守的N端RING结构域和C端SINA结构域，在苹果基因组中鉴定出11个成员。我们还重建了这些基因的系统发育；表征了它们的染色体定位、结构和基序；并鉴定出两个主要的基因组。随后进行的qRT-PCR分析用于表征基因在各种组织和器官中的表达，叶片中的表达水平最高。在ABA以及碳和氮饥饿处理下，基因表达被显著诱导。除了MdSINA1和MdSINA7外，其他MdSINA蛋白可以相互作用。此外，利用介导的瞬时表达发现MdSINA2定位于细胞核中。蛋白质免疫印迹分析表明，MdSINA2在光照下大量积累，在黑暗中减少，并且当RING结构域被破坏时对光不敏感。最后，通过转基因愈伤组织和在中的异位表达证实了ABA超敏表型。总之，我们的结果表明基因参与了对不同类型胁迫的反应，并且可能在ABA胁迫反应中作为负调节因子起作用。
