The MdERF61-mdm-miR397b-<i>MdLAC7b</i> module regulates apple resistance to <i>Fusarium solani</i> via lignin biosynthesis
Zhe Zhou, H.J. Zhang, Jia‐Long Yao, Qiming Gao, Yarong Wang, Zhenzhen Liu, Yaru Zhang, Yi Tian, Zhenli Yan, Yanmin Zhu, Hengtao Zhang, Hengtao Zhang, Hengtao Zhang
Abstract
Apple replant disease (ARD) is a worldwide problem that threatens the industry. However, the genetic mechanism underlying plant disease resistance against ARD remains unclear. In this study, a negative regulatory microRNA in Malus domestica, mdm-miR397b, and its direct target MdLAC7b (Laccase) was selected for examination based on our previous small RNA and degradome sequencing results. Overexpressing the mdm-miR397b-MdLAC7b module altered the lignin deposition and jasmonic acid contents in apple roots, which also led to increased resistance to Fusarium solani. Additionally, Y1H library screening using mdm-miR397b promoter recombinants identified a transcription factor, MdERF61, that represses mdm-miR397b transcriptional activity by directly binding to 2 GCC-boxes in the mdm-miR397b promoter. In summary, our results suggest that the MdERF61-mdm-miR397b-MdLAC7b module plays a crucial role in apple resistance to F. solani and offers insights for enhancing plant resistance to soil-borne diseases in apples.