Isolation and identification of endophytic fungi involved in the promotion of sesquiterpene accumulation in Syringa pinnatifolia

Abstract

Background The stem of Syringa pinnatifolia is used as traditional Mongolian medicine for the treatment of cardiopulmonary diseases, in which sesquiterpenes are regarded as the primary medicinal compounds. However, only S. pinnatifolia from natural stands is able to produce medicinal-grade stems when compared with that from cultivated stands. Despite the need to develop an effective technique to promote sesquiterpene accumulation in cultivated stands to ensure sustainable resource production, studies on the potential use of fungal endophytes as fungal elicitors were limited. Objective This study explored the potential of selected endophytic fungi isolated from the stems of wild and cultivated S. pinnatifolia and further examined their efficacy in promoting sesquiterpene production in S. pinnatifolia calli. Results Among the 11 fungal groups, Valsa sp, isolated from wild S. pinnatifolia, emerged as a promising fungal elicitor for promoting sesquiterpene accumulation in S. pinnatifolia. This conclusion is drawn from the production of a humulane-type sesquiterpene, known to be one of the most prevalent subtypes of sesquiterpenes in S. pinnatifolia. In addition, it was demonstrated that methyl jasmonate and salicylic acid displayed little effect on sesquiterpene accumulation in S. pinnatifolia. Conclusions The findings of this study lay a foundation for using fungal endophytes to promote sesquiterpene production in S. pinnatifolia. This contribution could subsequently advance the development of the local traditional medicine industry and aid in the protection of wild S. pinnatifolia.