KNOTTED1-LIKE HOMEOBOX (KNOX) genes are a family of plant-specific homeobox transcription factors with important roles in plant development that have been classified into two subfamilies with differential expression domains and functions. Studies in angiosperms have shown that class I members are related to the maintenance of meristem homeostasis and leaf development, whereas class II members promote differentiation of tissues and organs. However, little is known about its diversification and function in gymnosperms. By combining PCR-based detection and transcriptome data analysis, we identified four class I and two class II KNOX genes in Pinus pinaster. Expression analyses showed that class I members were mainly expressed in meristematic regions and differentiating tissues, with practically no expression in lateral organs, whereas expression of class II members was restricted to lateral organs. Furthermore, overexpression of P. pinaster KNOX genes in Arabidopsis thaliana caused similar phenotypic effects to those described for their angiosperms counterparts. This is the first time to our knowledge that functional analyses of class II members are reported in a conifer species. These results suggest a high conservation of the KNOX gene family throughout seed plants, as the functional differentiation of both subfamilies observed in angiosperms might be partially conserved in gymnosperms.

中文翻译：

---

松树 Ait 中 KNOTTED1-LIKE HOMEOBOX (KNOX) 基因家族的表征

KNOTTED1-LIKE HOMEOBOX (KNOX) 基因是植物特异性同源盒转录因子家族，在植物发育中具有重要作用，已被分为具有差异表达域和功能的两个亚家族。对被子植物的研究表明，I 类成员与维持分生组织稳态和叶片发育有关，而 II 类成员促进组织和器官的分化。然而，对其在裸子植物中的多样化和功能知之甚少。通过结合基于 PCR 的检测和转录组数据分析，我们在松树中鉴定了四个 I 类和两个 II 类 KNOX 基因。表达分析表明 I 类成员主要在分生组织区和分化组织中表达，在侧向器官中几乎不表达，而 II 类成员的表达仅限于侧器官。此外，拟南芥中 P. pinaster KNOX 基因的过度表达引起了与其被子植物对应物相似的表型效应。据我们所知，这是第一次在针叶树物种中报告 II 类成员的功能分析。这些结果表明 KNOX 基因家族在整个种子植物中高度保守，因为在被子植物中观察到的两个亚家族的功能分化可能在裸子植物中部分保守。据我们所知，这是第一次在针叶树物种中报告 II 类成员的功能分析。这些结果表明 KNOX 基因家族在整个种子植物中高度保守，因为在被子植物中观察到的两个亚家族的功能分化可能在裸子植物中部分保守。据我们所知，这是第一次在针叶树物种中报告 II 类成员的功能分析。这些结果表明 KNOX 基因家族在整个种子植物中高度保守，因为在被子植物中观察到的两个亚家族的功能分化可能在裸子植物中部分保守。