During 450 million years of diversification on land, plants and microbes have evolved together. This is reflected in today’s continuum of associations, ranging from parasitism to mutualism. Through phylogenetics, cell biology, and reverse genetics extending beyond flowering plants into bryophytes, scientists have started to unravel the genetic basis and evolutionary trajectories of plant-microbe associations. Protection against pathogens and support of beneficial, symbiotic, microorganisms are sustained by a blend of conserved and clade-specific plant mechanisms evolving at different speeds. We propose that symbiosis consistently emerges from the co-option of protection mechanisms and general cell biology principles. Exploring and harnessing the diversity of molecular mechanisms used in nonflowering plant-microbe interactions may extend the possibilities for engineering symbiosis-competent and pathogen-resilient crops.

在 4.5 亿年的陆地多样化过程中，植物和微生物共同进化。这反映在今天的连续联系中，从寄生到互惠互利。通过系统发育学、细胞生物学和从开花植物延伸到苔藓植物的反向遗传学，科学家们已经开始解开植物-微生物关联的遗传基础和进化轨迹。通过以不同速度进化的保守和进化枝特异性植物机制的混合来维持对病原体的保护和对有益共生微生物的支持。我们建议共生始终来自保护机制和一般细胞生物学原理的共同选择。