Abstract：
ETHYLENE-INSENSITIVE3 (EIN3) or EIN3-Like (EIL) proteins, play critical roles in integrating ethylene signaling and physiological regulation in plants by modulating the expression of various downstream genes, such as ethylene-response factors (ERFs). However, little is known about the characteristics of EIN3/EILs in the gymnosperm Ginkgo biloba. In the present study, a genome-wide comparative analysis of Ginkgo EIN3/EIL gene family was performed with those from an array of species, including bryophytes (Physcomitrella patens), gymnosperms (Cycas panzhihuaensis), and angiosperms (Arabidopsis thaliana, Gossypium raimondii, Gossypium hirsutum, Oryza sativa, and Brachypodium distachyon). Within the constructed phylogenetic tree for the 53 EIN3/EILs identified, 5 GbEILs from G. biloba, 2 PpEILs from P. patens, and 3 CpEILs from C. panzhihuaensis were assigned to one cluster, suggesting that their derivation occurred after the split of their ancestors and angiosperms. Although considerable divergence accumulated in amino acid sequences along with the evolutionary process, the specific EIN3_DNA-binding domains were evolutionarily conserved among the 53 EIN3/EILs. Collinearity analysis indicated that whole-genome or segmental duplication and subsequent purifying selection might have prompted the generation and evolution of EIN3/EIL multigene families. Based on the expression patterns of five GbEILs at the four developmental stages of Ginkgo ovules, one GbEIL gene (Gb_03292) was further investigated for its role in mediating ethylene signaling. The functional activity of Gb_03292 was closely related to ethylene signaling, as it complemented the triple response via ectopic expression in ein3eil1 double mutant Arabidopsis. Additionally, GbEIL likely modulates the expression of a Ginkgo ERF (Gb_15517) by directly binding to its promoter. These results demonstrated that the GbEIL gene could have participated in mediating ethylene signal transduction during ovule development in G. biloba. The present study also provides insights into the conservation of ethylene signaling across the gymnosperm G. biloba and angiosperm species.
摘要：
乙烯不敏感蛋白3(EIN3)或EIN3样蛋白(EIL),通过调节各种下游基因的表达，在植物中整合乙烯信号和生理调节中起关键作用，如乙烯响应因子(ERF)。然而,关于裸子植物银杏中EIN3/EIL的特征知之甚少。在本研究中,对银杏EIN3/EIL基因家族进行了全基因组比较分析，包括苔藓植物（Physcomitrellapatens），裸子植物（攀枝花苏铁），和被子植物（拟南芥，灵蒙地棉,陆地棉,水稻,和短臂远齿）。在已确定的53个EIN3/EIL的构建的系统发育树中，5GbEIL来自G.biloba,2PpEIL来自P.patens,将来自攀枝花的3个CpEIL分配到一个簇，这表明它们的起源发生在它们的祖先和被子植物分裂之后。尽管随着进化过程在氨基酸序列中积累了相当大的差异，在53个EIN3/EIL中，特定的EIN3_DNA结合域在进化上是保守的。共线性分析表明，全基因组或节段复制以及随后的纯化选择可能促使EIN3/EIL多基因家族的产生和进化。基于五个GbEIL在银杏胚珠四个发育阶段的表达模式,进一步研究了一个GbEIL基因（Gb_03292）在介导乙烯信号传导中的作用。Gb_03292的功能活性与乙烯信号密切相关,因为它通过ein3eil1双突变体拟南芥中的异位表达补充了三重反应。此外,GbEIL可能通过直接结合其启动子来调节银杏ERF(Gb_15517)的表达。这些结果表明，GbEIL基因可能参与了银杏叶胚珠发育过程中乙烯信号转导的介导。本研究还提供了对裸子植物G.biloba和被子植物物种中乙烯信号的保守性的见解。
