The multi-subunit Elongator complex plays key roles in transcription by interacting with RNA polymerase II and chromatin modeling. Kti proteins have been identified as the auxiliary protein for the elongator complex. However, our knowledge of Kti proteins in woody plants remains limited. In this study, in total 16 KTI gene homologs were identified in Populus trichocarpa. Among them, the two KTI12 candidates were named PtKTI12A and PtKTI12B. Although PtKTI12A and PtKTI12B were largely different in gene expression level and tissue-specificity, both genes were induced by heat and drought stresses. PtKTI12A and PtKTI12B RNAi transgenic poplar plants showed reduced levels of modified nucleosides, in particular ncm⁵U (5-carbamoylmethyluridine) and mcm⁵s²U (5-methoxycarbonylmethyl-2-thiouridine). Meanwhile, their tolerance to drought was improved when subjected to withdrawal of watering. In addition, the protein products of PtKTI12A and PtKTI12B had similar subcellular localisation and predicted tertiary structure. The results suggest that Kti12 proteins are involved in tRNA wobble uridine modification, stress response and drought stress tolerance in hybrid poplar.

中文翻译：

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PtKTI12基因影响杂种杨的摆动尿苷修饰和干旱胁迫耐受性。

通过与RNA聚合酶II和染色质建模相互作用，多亚基Elongator复合物在转录中起关键作用。Kti蛋白已被鉴定为延伸复合物的辅助蛋白。但是，我们对木本植物中Kti蛋白的了解仍然有限。在这项研究中，在毛果杨中共鉴定出16个KTI基因同源物。其中，两个KTI12候选者分别命名为PtKTI12A和PtKTI12B。尽管PtKTI12A和PtKTI12B在基因表达水平和组织特异性方面有很大差异，但是这两个基因都是受高温和干旱胁迫诱导的。PtKTI12A和PtKTI12BRNAi转基因杨树植物显示出降低的修饰核苷水平，尤其是ncm ⁵ U（5-氨基甲酰基甲基尿苷）和mcm ⁵ s ² U（5-甲氧基羰基甲基-2-硫尿苷）。同时，当停止浇水时，它们对干旱的耐受性得到提高。此外，PtKTI12A和PtKTI12B的蛋白质产物具有相似的亚细胞定位和预测的三级结构。结果表明Kti12蛋白参与杂种杨的tRNA摆动尿苷修饰，应激反应和干旱胁迫耐受性。