Zaxinone synthase controls arbuscular mycorrhizal colonization level in rice

0562817 - ÚEB 2023 RIV GB eng J - Journal Article
Votta, C. - Fiorilli, V. - Haider, I. - Wang, J.Y. - Balestrini, R. - Petřík, Ivan - Tarkowská, Danuše - Novák, Ondřej - Serikbayeva, A. - Bonfante, P. - Al-Babili, S. - Lanfranco, L.
Zaxinone synthase controls arbuscular mycorrhizal colonization level in rice.
Plant Journal. Roč. 111, č. 6 (2022), s. 1688-1700. ISSN 0960-7412. E-ISSN 1365-313X
R&D Projects: GA MŠMT(CZ) EF16_019/0000738
Institutional support: RVO:61389030
Keywords : apocarotenoids * arbuscular mycorrhizal symbiosis * gr24 * in situ hybridization * Oryza sativa * OsPT11 * strigolactones * zaxinone * zaxinone synthase
OECD category: Biochemical research methods
Impact factor: 7.2, year: 2022
Method of publishing: Open access
https://doi.org/10.1111/tpj.15917

The Oryza sativa (rice) carotenoid cleavage dioxygenase OsZAS was described to produce zaxinone, a plant growth-promoting apocarotenoid. A zas mutant line showed reduced arbuscular mycorrhizal (AM) colonization, but the mechanisms underlying this behavior are unknown. Here, we investigated how OsZAS and exogenous zaxinone treatment regulate mycorrhization. Micromolar exogenous supply of zaxinone rescued root growth but not the mycorrhizal defects of the zas mutant, and even reduced mycorrhization in wild-type and zas genotypes. The zas line did not display the increase in the level of strigolactones (SLs) that was observed in wild-type plants at 7 days post-inoculation with AM fungus. Moreover, exogenous treatment with the synthetic SL analog GR24 rescued the zas mutant mycorrhizal phenotype, indicating that the lower AM colonization rate of zas is caused by a deficiency in SLs at the early stages of the interaction, and indicating that during this phase OsZAS activity is required to induce SL production, possibly mediated by the Dwarf14-Like (D14L) signaling pathway. OsZAS is expressed in arbuscule-containing cells, and OsPT11prom::OsZAS transgenic lines, where OsZAS expression is driven by the OsPT11 promoter active in arbusculated cells, exhibit increased mycorrhization compared with the wild type. Overall, our results show that the genetic manipulation of OsZAS activity in planta leads to a different effect on AM symbiosis from that of exogenous zaxinone treatment, and demonstrate that OsZAS influences the extent of AM colonization, acting as a component of a regulatory network that involves SLs.
Permanent Link: https://hdl.handle.net/11104/0335011