Synergistic mechanism of endophytic fungi and host plants against arsenic stress

Abstract:

Arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) are the two key types of root symbiotic fungi that enhance plant growth and resistance of plants to heavy metal stress. Arsenic (As) and As compounds are highly toxic, which accumulate in plants and then enter biologic chain. Our team has been committed to the study of relationship between endophytic fungi and the growth, synthesis of active substances, and arsenic absorption and accumulation of medicinal plants and has made some progress. According to our previous research outcomes and available research results, we summarized the role of AMF colonization in the growth and As uptake and accumulation in host plants under As stress, expounded the responses of host plants to AMF regulation under As stress in terms of physiological activities, antioxidant system, hormone level, and transcription level. In addition, 7 synergistic regulatory mechanisms involved in improving the As resistance were summarized at cellular level: ‘growth dilution effect’, ‘isolation of hyphae’, ‘chelating and filtration’, ‘mycorrhizal immobilization’, ‘transporter inhibition’, ‘biotransformation’, and ‘protecting the host and reducing oxidative stress’. The interaction among mechanisms was plotted. There are limited studies on the regulation of As stress by DSE-host plants. We found that the mechanism of DSE in enhancing arsenic tolerance of plants is similar to that of AMF. Our work has important reference value for studying synergistic antagonistic mechanism of endophytic fungi and host plants against As stress, alleviating As-polluted soil, implementing ecological agriculture or ecological planting of Chinese medicinal materials, and reducing As accumulation in key parts of plants.