Ogawa Sienna T, Zhang Weiwei, Staiger Christopher J, Kessler Sharon A
Department of Botany and Plant Pathology, Purdue University, 915 Mitch Daniels Blvd, West Lafayette, IN, 47907, USA.
Purdue Center for Plant Biology, Purdue University, 915 Mitch Daniels Blvd, West Lafayette, IN, 47907, USA.
New Phytol. 2025 Jul 13. doi: 10.1111/nph.70378.
Root hair tip-growth involves coordinated Ca and ROS signaling to promote growth while maintaining tip integrity. MILDEW RESISTANCE LOCUS-O (MLO) proteins act downstream of FERONIA (FER) receptor-like kinases in pollen tubes and synergids to regulate calcium dynamics. This study uses a constitutively active MLO (faNTA) to identify a new role for the FER/MLO signaling module in regulating [Ca] oscillations in growing root hairs. faNTA was used as a tool to manipulate Ca influx in fer mutants. Light sheet fluorescence imaging was used to image the reporter R-GECO1 to observe [Ca] dynamics during root hair elongation in various genotypes. We show that faNTA is sufficient to restore normal root hair development, [Ca] oscillations, and ROS levels to fer-4. MLO15 was identified as a regulator of root hair tip growth based on disrupted root hair growth and [Ca] signatures in mlo15-4. We also link the FER/MLO module to ROS accumulation by showing that faNTA is sufficient to restore ROS levels in fer-4 root hairs, but is unable to complement the burst root hairs of rbohc. We propose that MLOs act downstream of FER to mediate Ca influx and promote ROS production to regulate root hair tip growth.
根毛顶端生长涉及协调的钙和活性氧信号传导，以促进生长同时维持顶端完整性。抗白粉病基因座-O（MLO）蛋白在花粉管和助细胞中位于FERONIA（FER）类受体激酶的下游，以调节钙动态。本研究使用组成型活性MLO（faNTA）来确定FER/MLO信号模块在调节生长中的根毛钙振荡中的新作用。faNTA被用作操纵fer突变体中钙内流的工具。使用光片荧光成像对报告基因R-GECO1进行成像，以观察各种基因型根毛伸长过程中的钙动态。我们表明，faNTA足以将正常的根毛发育、钙振荡和活性氧水平恢复到fer-4。基于mlo15-4中根毛生长和钙信号的破坏，MLO15被鉴定为根毛顶端生长的调节因子。我们还通过表明faNTA足以恢复fer-4根毛中的活性氧水平，但无法补充rbohc的爆裂根毛，将FER/MLO模块与活性氧积累联系起来。我们提出，MLO在FER下游起作用，介导钙内流并促进活性氧产生，以调节根毛顶端生长。
