Background

Lonicera macranthoides is an important woody plant with high medicinal values widely cultivated in southern China. WRKY, one of the largest transcription factor families, participates in plant development, senescence, and stress responses. However, a comprehensive study of the WRKY family in L. macranthoides hasn’t been reported previously.

Objective

To establish an extensive overview of the WRKY family in L. macranthoides and identify senescence-responsive members of LmWRKYs.

Methods

RNA-Seq and phylogenetic analysis were employed to identify the LmWRKYs and their evolutionary relationships. Quantitative real-time (qRT-PCR) and transgenic technology was utilized to investigate the roles of LmWRKYs in response to developmental-, cold-, and ethylene-induced senescence.

Results

A total of 61 LmWRKY genes with a highly conserved motif WRKYGQK were identified. Phylogenetic analysis of LmWRKYs together with their orthologs from Arabidopsis classified them into three groups, with the number of 15, 39, and 7, respectively. 17 LmWRKYs were identified to be differentially expressed between young and aging leaves by RNA-Seq. Further qRT-PCR analysis showed 15 and 5 LmWRKY genes were significantly induced responding to tissue senescence in leaves and stems, respectively. What’s more, five LmWRKYs, including LmWRKY4, LmWRKY5, LmWRKY6, LmWRKY11, and LmWRKY16 were dramatically upregulated under cold and ethylene treatment in both leaves and stems, indicating their involvements commonly in developmental- and stress-induced senescence. In addition, function analysis revealed LmWRKY16, a homolog of AtWRKY75, can accelerate plant senescence, as evidenced by leaf yellowing during reproductive growth in LmWRKY16-overexpressing tobaccos.

Conclusion

The results lay the foundation for molecular characterization of LmWRKYs in plant senescence.

中文翻译：

---

大花忍冬 WRKY 家族基因的全转录组特征及 LmWRKY16 在植物衰老中的作用

背景

大花忍冬是我国南方广泛栽培的重要木本植物，具有很高的药用价值。WRKY 是最大的转录因子家族之一，参与植物发育、衰老和应激反应。然而，之前没有报道过对L. macranthoides中 WRKY 家族的全面研究。

客观的

建立对L. macranthoides中 WRKY 家族的广泛概述，并确定 LmWRKYs 的衰老响应成员。

方法

RNA-Seq 和系统发育分析用于鉴定 LmWRKY 及其进化关系。定量实时 (qRT-PCR) 和转基因技术用于研究 LmWRKYs 在响应发育、寒冷和乙烯诱导的衰老中的作用。

结果

共鉴定了 61个具有高度保守基序 WRKYGQK 的LmWRKY基因。LmWRKYs及其拟南芥直系同源物的系统发育分析将它们分为三组，数量分别为15、39和7。RNA-Seq 鉴定出17 个LmWRKYs在幼叶和老化叶之间存在差异表达。进一步的 qRT-PCR 分析显示，15 和 5 个LmWRKY基因分别显着诱导了叶和茎的组织衰老。更重要的是，五个LmWRKY，包括LmWRKY4、LmWRKY5、LmWRKY6、LmWRKY11和LmWRKY16在冷和乙烯处理下在叶片和茎中均显着上调，表明它们通常参与发育和胁迫诱导的衰老。此外，功能分析显示LmWRKY16是AtWRKY75的同源物，可以加速植物衰老，这在LmWRKY16过表达烟草的生殖生长过程中叶片变黄就证明了这一点。

结论

该结果为LmWRKYs在植物衰老中的分子表征奠定了基础。