Abstract：
The petals of ornamental plants such as roses (Rosa spp.) are the most economically important organs. This delicate, short-lived plant tissue is highly susceptible to pathogens, in large part because the walls of petal cells are typically thinner and more flexible compared with leaf cells, allowing the petals to fold and bend without breaking. The cell wall is a dynamic structure that rapidly alters its composition in response to pathogen infection, thereby reinforcing its stability and boosting plant resistance against diseases. However, little is known about how dynamic changes in the cell wall contribute to resistance to Botrytis cinerea in rose petals. Here, we show that the B. cinerea-induced transcription factor RhbZIP17 is required for the defense response of rose petals. RhbZIP17 is associated with phenylpropanoid biosynthesis and binds to the promoter of the lignin biosynthesis gene RhCAD1, activating its expression. Lignin content showed a significant increase under gray mold infection compared with the control. RhCAD1 functions in the metabolic regulation of lignin production and, consequently, disease resistance, as revealed by transient silencing and overexpression in rose petals. The WRKY transcription factor RhWRKY30 is also required to activate RhCAD1 expression and enhance resistance against B. cinerea. We propose that RhbZIP17 and RhWRKY30 increase lignin biosynthesis, improve the resistance of rose petals to B. cinerea, and regulate RhCAD1 expression.
摘要：
观赏植物的花瓣，例如玫瑰（Rosasp.)是经济上最重要的器官。这个微妙的，短寿命的植物组织对病原体高度敏感，在很大程度上是因为花瓣细胞的壁通常比叶细胞更薄和更灵活，允许花瓣折叠和弯曲而不破裂。细胞壁是一种动态结构，可响应病原体感染而迅速改变其组成，从而增强其稳定性并增强植物对疾病的抗性。然而,关于细胞壁的动态变化如何导致玫瑰花瓣对灰葡萄孢的抗性知之甚少。这里,我们表明，灰霉病菌诱导的转录因子RhbZIP17是玫瑰防御反应所必需的。RhbZIP17与苯丙素生物合成相关，并与木质素生物合成基因RhCAD1的启动子结合，激活其表达。与对照相比，在灰霉病感染下木质素含量显着增加。RhCAD1在木质素生产的代谢调节中起作用，因此,抗病性,如玫瑰花瓣中的短暂沉默和过表达所揭示的。WRKY转录因子RhWRKY30也需要激活RhCAD1表达并增强对灰芽孢杆菌的抗性。我们建议RhbZIP17和RhWRKY30增加木质素的生物合成，提高玫瑰花瓣对B.cinerea的抵抗力，并调控RhCAD1的表达。
