Rehmannia glutinosa RgMATE35 Participates in the Root Secretion of Phenolic Acids and Modulates the Development of Plant Replant Disease

Phenolic allelochemicals from root exudates dominate rhizosphere formation, lead to autotoxicity in plants subjected to continuous monoculture (CM) stress and induce the emergence of replant disease. However, the regulatory mechanisms governing the transport of phenolics from plant roots to the rhizosphere remain poorly understood. A potential phenolic efflux transporter from <i>Rehmannia glutinosa</i>, designated RgMATE35, has been preliminarily characterized. The objective of this study was to elucidate the molecular function of RgMATE35 in the secretion of phenolics and to investigate its role in the development of plant replant disease using quantitative real-time PCR (qRT-PCR), genetic transformation, HPLC-Q-TOF-MS and other analytical techniques. A tissue expression pattern analysis of <i>RgMATE35</i> revealed that it is highly expressed in plant roots. Transient expression analysis confirmed the localization of the protein in plasma membranes. An assessment of the transport activity of RgMATE35 in <i>Xenopus oocytes</i> indicated that it plays a role in facilitating the efflux of labeled ferulic acid ([²H₃]-FA) and trans-<i>p</i>-coumaric acid [²H₆]-<i>p</i>CA. The results of functional studies in <i>R. glutinosa</i> demonstrated that RgMATE35 positively mediates the secretion of FA and <i>p</i>CA from plant roots into the rhizosphere. A molecular and physiological analysis of <i>RgMATE35</i> transgenic plants subjected to CM stress revealed that the overexpression or repression of <i>RgMATE35</i> resulted in notable changes in the degree of autotoxic injury in plants. These findings demonstrate that RgMATE35 plays a positive role in the development of replant disease through the secretion of phenolic acids from plant roots. They also provide a fundamental framework for elucidating the molecular regulatory mechanism through which MATEs regulate replant disease through the root secretion of allelochemicals.