London plane tree is widely grown as a landscaping and street tree, but the release of its trichomes creates a serious air-borne pollution problem. Identifying the key genes that regulate the development of trichomes is, therefore, an important tool for the molecular breeding of Platanus acerifolia. In this study, a sequence homologous with the Arabidopsis Class II TCP subfamily was identified from London plane, and named PaTCP4. The expression of PaTCP4 was detected in various organs of London plane trees, significantly in the trichomes. Overexpression of PaTCP4 in Arabidopsis reduced the trichome density on the first pair of true leaves, and atypical 5-branched trichomes were also detected on those leaves. The expression of endogenous AtCPC and AtTCL2 was significantly increased in PaTCP4 transgenic lines, and was associated with a decrease in the expression of endogenous AtGL2. Furthermore, the expression of endogenous AtGL3 was significantly increased. In addition, the protein product of PaTCP4 was shown to directly activate AtCPC, AtTCL2, AtGL3, AtGIS, PaGIS, and PaGL3 in yeast one-hybrid assays and in the dual-luciferase reporter system. Taken together, these results identify a role for PaTCP4 in trichome initiation and branching in Arabidopsis. Thus, PaTCP4 represents a strong candidate gene for regulating the development of trichomes in London plane trees.

中文翻译：

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来自梧桐树的 II 类 TCP 转录因子 PaTCP4 调节拟南芥中的毛状体形成

伦敦梧桐树作为园林绿化和行道树被广泛种植，但其毛状体的释放造成了严重的空气污染问题。因此，确定调控毛状体发育的关键基因是悬铃木分子育种的重要工具。在这项研究中，从伦敦平面鉴定了一个与拟南芥 II 类 TCP 亚科同源的序列，并命名为PaTCP4。在伦敦梧桐的各个器官中检测到PaTCP4的表达，在毛状体中显着。PaTCP4的过度表达在拟南芥中降低了第一对真叶上的毛状体密度，并且在这些叶子上也检测到了非典型的 5 分枝毛状体。内源性AtCPC和AtTCL2的表达在PaTCP4转基因株系中显着增加，并且与内源性AtGL2表达的降低有关。此外，内源性AtGL3的表达显着增加。此外，PaTCP4的蛋白质产物显示直接激活AtCPC、AtTCL2、AtGL3、AtGIS、PaGIS和PaGL3在酵母单杂交试验和双荧光素酶报告系统中。总之，这些结果确定了PaTCP4在拟南芥毛状体起始和分支中的作用。因此，PaTCP4代表了一个强有力的候选基因，用于调节伦敦梧桐树毛状体的发育。