Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Department of Horticulture, Northeast Agricultural University, Changjiang 600, Harbin 150030, P.R. China.
Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Weigang No.1, Nanjing 210095, P.R. China.
Mol Plant. 2023 May 1;16(5):849-864. doi: 10.1016/j.molp.2023.03.009. Epub 2023 Mar 20.
Terrestrial plants can affect the growth and health of adjacent plants via interspecific interaction. Here, we studied the mechanism by which plant root exudates affect the recruitment of the rhizosphere microbiome in adjacent plants-with implications for plant protection-using a tomato (Solanum lycopersicum)-potatoonion (Allium cepa var. agrogatum) intercropping system. First, we showed that the intercropping system results in a disease-suppressive rhizosphere microbiome that protects tomato plants against Verticillium wilt disease caused by the soilborne pathogen Verticillium dahliae. Second, 16S rRNA gene sequencing revealed that intercropping with potatoonion altered the composition of the tomato rhizosphere microbiome by promoting the colonization of specific Bacillus sp. This taxon was isolated and shown to inhibit V. dahliae growth and induce systemic resistance in tomato plants. Third, a belowground segregation experiment found that root exudates mediated the interspecific interaction between potatoonion and tomato. Moreover, experiments using split-root tomato plants found that root exudates from potatoonion, especially taxifolin-a flavonoid compound-stimulate tomato plants to recruit plant-beneficial bacteria, such as Bacillus sp. Lastly, ultra-high-pressure liquid chromatography-mass spectrometry analysis found that taxifolin alters tomato root exudate chemistry; thus, this compound acts indirectly in modulating root colonization by Bacillus sp. Our results revealed that this intercropping system can improve tomato plant fitness by changing rhizosphere microbiome recruitment via the use of signaling chemicals released by root exudates of potatoonion. This study revealed a novel mechanism by which interspecific plant interaction modulates the establishment of a disease-suppressive microbiome, thus opening up new avenues of research for precision plant microbiome manipulations.
陆生植物可以通过种间相互作用影响相邻植物的生长和健康。在这里，我们研究了植物根系分泌物通过番茄（Solanum lycopersicum）-马铃薯洋葱（Allium cepa var. agrogatum）间作系统影响根际微生物组在相邻植物中的定殖的机制——这对植物保护具有重要意义。首先，我们表明，间作系统导致了一种抑制病原菌的根际微生物组，保护番茄植物免受由土壤病原菌茄镰孢引起的黄萎病。其次，16S rRNA 基因测序显示，与马铃薯洋葱间作改变了番茄根际微生物组的组成，促进了特定芽孢杆菌的定殖。该分类群被分离出来，并被证明可以抑制茄镰孢的生长并诱导番茄植物的系统抗性。第三，地下分离实验发现，根分泌物介导了马铃薯洋葱和番茄之间的种间相互作用。此外，使用分根番茄植物的实验发现，马铃薯洋葱的根分泌物，特别是黄酮类化合物圣草酚，刺激番茄植物招募植物有益细菌，如芽孢杆菌。最后，超高压液相色谱-质谱分析发现，圣草酚改变了番茄根分泌物的化学性质；因此，这种化合物通过调节芽孢杆菌对根的定殖间接作用。我们的结果表明，这种间作系统可以通过使用马铃薯洋葱根系分泌物释放的信号化学物质改变根际微生物组的定殖，从而改善番茄植物的适应性。本研究揭示了种间植物相互作用通过调节抑制病原菌的微生物组的建立来调节植物生长和健康的新机制，为精确的植物微生物组操作开辟了新的研究途径。
