Emerging Salt Marshes As A Source Oftrichoderma Arenariumsp. Nov. And Other Fungalbioeffectors Forbiosaline Agriculture

Aims Sustainable agriculture requires effective and safebiofertilizers andbiofungicides with low environmental impact. Natural ecosystems that closely resemble the conditions ofbiosaline agriculture may present a reservoir for fungal strains that can be used as novelbioeffectors. Methods and Results We isolated a library of fungi from the rhizosphere of three natural halotolerant plants grown in the emerging tidal salt marshes on the south-east coast of China. DNA barcoding of 116 isolates based on the rRNA ITS1 and 2 and other markers (tef1orrpb2) revealed 38 fungal species, including plant pathogenic (41%), saprotrophic (24%) and mycoparasitic (28%) taxa. The mycoparasitic fungi were mainly species from the hypocrealean genusTrichoderma, including at least four novel phylotypes. Two of them, representing the taxaTrichoderma arenariumsp. nov. (described here) andT. asperelloides, showed antagonistic activity against five phytopathogenic fungi, and significant growth promotion on tomato seedlings under the conditions of saline agriculture. Conclusions Trichodermaspp. of salt marshes play the role of natural biological control in young soil ecosystems with a putatively premature microbiome. Significance and Impact of the Study The saline soil microbiome is a rich source of halotolerantbioeffectors that can be used inbiosaline agriculture.