Cascaded regulatory network composed of small RNAs involves in the symbiosis of Panax notoginseng and fungus Acremonium sp. D212

Panax notoginseng (P. notoginseng) is a valuable traditional Chinese medical herb with multiple pharmacological effects, and Acremonium sp. D212 is a symbiotic fungus. The symbiotic relationship between fungi and plants is widely present in nature, but the molecular mechanism of the symbiotic relationship between P. notoginseng and its symbiotic microorganisms is unknown. This study found that Acremonium sp. D212 altered the gene expression of P. notoginseng under different lights, and this change was associated with the miRNAs transferred from Acremonium sp. D212 to P. notoginseng. Transferred miRNAs can not only regulate P. notoginseng target genes, but also trigger the production of phased siRNAs to regulate more target genes, thereby forming a cascaded regulatory network. P. notoginseng target genes are associated with trans-membrane transporting and plant hormone metabolism, suggesting that these small RNAs may have potential influence on the growth and development of P. notoginseng. This study discovers an underlying molecular mechanism of the interactions between P. notoginseng and its symbiotic fungus Acremonium sp. D212, and provide a new perspective for further research on the gene interaction between plants and symbiotic fungi.