Herrero Joaquín, Esteban Carrasco Alberto, Zapata José Miguel
Department of Life Sciences, University of Alcalá, E-28871 Alcalá de Henares, Madrid, Spain.
Department of Plant Biology, Complutense University, E-28040 Madrid, Spain.
Plant Physiol Biochem. 2014 Jul;80:192-202. doi: 10.1016/j.plaphy.2014.03.027. Epub 2014 Apr 3.
Phytohormones such as auxins, cytokinins, and brassinosteroids, act by means of a signaling cascade of transcription factors of the families NAC, MYB, AP2 (APETALA2), MADS and class III HD (homeodomain) Zip, regulating secondary growth. When the hormonal regulation of Zinnia elegans peroxidase (ZePrx), an enzyme involved in lignin biosynthesis, was studied, it was found that this peroxidase is sensitive to a plethora of hormones which control xylem lignification. In a previous study we sought Arabidopsis thaliana homologues to ZePrx. Peroxidases 4, 52, 49 and 72 are the four peroxidases that fulfill the restrictive conditions that a peroxidase involved in lignification must have. In the present study, we focus our attention on hormonal regulation in order to establish the minimal structural and regulatory elements contained in the promoter region which an AtPrx involved in lignification must have. The results indicate that of the four peroxidases selected in our previous study, the one most likely to be homologous to ZePrx is AtPrx52. The results suggest that hormones such as auxins, cytokinins and BRs directly regulate AtPrx52, and that the AtPrx52 promoter may be the target of the set of transcription factors (NAC, MYB, AP2 and class I and III HD Zip) which are up-regulated by these hormones during secondary growth. In addition, the AtPrx52 promoter contains multiple copies of all the putative cis-elements (the ACGT box, the OCS box, the OPAQ box, the L1BX, the MYCL box and the W box) known to confer regulation by NO and H2O2.
生长素、细胞分裂素和油菜素甾体等植物激素通过NAC、MYB、AP2（APETALA2）、MADS和III类HD（同源异型结构域）Zip家族转录因子的信号级联发挥作用，调节次生生长。在研究参与木质素生物合成的酶——百日草过氧化物酶（ZePrx）的激素调节时，发现这种过氧化物酶对控制木质部木质化的多种激素敏感。在之前的一项研究中，我们寻找了拟南芥中与ZePrx同源的基因。过氧化物酶4、52、49和72是满足参与木质化的过氧化物酶必须具备的严格条件的四种过氧化物酶。在本研究中，我们将注意力集中在激素调节上，以确定参与木质化的AtPrx的启动子区域中必须包含的最小结构和调节元件。结果表明，在我们之前研究中选择的四种过氧化物酶中，最有可能与ZePrx同源的是AtPrx52。结果表明，生长素、细胞分裂素和油菜素甾体等激素直接调节AtPrx52，并且AtPrx52启动子可能是次生生长期间被这些激素上调的一组转录因子（NAC、MYB、AP2以及I类和III类HD Zip）的作用靶点。此外，AtPrx52启动子包含所有已知的可赋予NO和H2O2调节作用的假定顺式元件（ACGT盒、OCS盒、OPAQ盒、L1BX、MYCL盒和W盒）的多个拷贝。
