@Article{IPB-2391, author = {Yadav, H. and Dreher, D. and Athmer, B. and Porzel, A. and Gavrin, A. and Baldermann, S. and Tissier, A. and Hause, B.}, title = {{Medicago TERPENE SYNTHASE 10 is involved in defense against an oomycete root pathogen}}, year = {2019}, journal = {Plant Physiol}, doi = {10.1104/pp.19.00278}, url = {https://dx.doi.org/10.1104/pp.19.00278}, abstract = {In nature, plants interact with numerous beneficial or pathogenic soil-borne microorganisms. Plants have developed various defense strategies to expel pathogenic microbes, some of which function soon after pathogen infection. We used Medicago (Medicago truncatula) and its oomycete pathogen Aphanomyces euteiches to elucidate early responses of the infected root. A. euteiches causes root rot disease in legumes and is a limiting factor in legume production. Transcript profiling of seedlings and adult plant roots inoculated with A. euteiches zoospores for 2 hours revealed specific upregulation of a gene encoding a putative sesquiterpene synthase (Medicago TERPENE SYNTHASE 10; MtTPS10) in both developmental stages. MtTPS10 was specifically expressed in roots upon oomycete infection. Heterologous expression of MtTPS10 in yeast led to production of a blend of sesquiterpenes and sesquiterpene alcohols, with nuclear magnetic resonance identifying a major peak corresponding to himalachol. Moreover, plants carrying a tobacco (Nicotiana tabacum) retrotransposon Tnt1 insertion in MtTPS10 lacked the emission of sesquiterpenes upon A. euteiches infection, supporting the assumption that the identified gene encodes a multiproduct sesquiterpene synthase. Mttps10 plants and plants with reduced MtTPS10 transcript levels created by expression of an MtTPS10-amiRNA in roots were more susceptible to A. euteiches infection than the corresponding wild-type plants and roots transformed with the empty vector, respectively. Sesquiterpenes produced by expression of MtTPS10 in yeast also inhibited mycelial growth and A. euteiches zoospore germination. These data suggest that sesquiterpene production in roots by MtTPS10 plays a previously unrecognized role in the defense response of Medicago against A. euteiches.} }