A lineage-specific Exo70 is required for receptor kinase-mediated immunity in barley

Holden, S.; Bergum, M.; Green, P.; Bettgenhaeuser, J.; Hernandez-Pinzon, I.; Thind, A.; Clare, S. J.; Russell, J. M.; Hubbard, A.; Taylor, J.; Smoker, M.; Gardiner, M.; Civolani, L.; Cosenza, F.; Rosignoli, S.; Strugala, R.; Molnar, I.; Simkova, H.; Dolezel, J.; Schaffrath, U.; Barrett, M.; Salvi, S.; Moscou, M. J.

doi:10.1101/2021.12.19.473371

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bioRxiv · 10.1101/2021.12.19.473371

A lineage-specific Exo70 is required for receptor kinase-mediated immunity in barley

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Abstract

In the evolution of land plants, the plant immune system has experienced expansion in immune receptor and signaling pathways. Lineage-specific expansions have been observed in diverse gene families that are potentially involved in immunity, but lack causal association. Here, we show that Rps8-mediated resistance in barley to the fungal pathogen Puccinia striiformis f. sp. tritici (wheat stripe rust) is conferred by a genetic module: LRR-RK and Exo70FX12, which are together necessary and sufficient. The Rps8 LRR-RK is the ortholog of rice extracellular immune receptor Xa21 and Exo70FX12 is a member of the Poales-specific Exo70FX clade. The Exo70FX clade emerged after the divergence of the Bromeliaceae and Poaceae, and comprises from 2 to 75 members in sequenced grasses. These results demonstrate the requirement of a lineage-specific Exo70FX12 in Rps8 LRR-RK immunity and suggest that the Exo70FX clade may have evolved a specialized role in receptor kinase signaling.

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Holden, S., Bergum, M., Green, P., Bettgenhaeuser, J., Hernandez-Pinzon, I., Thind, A., Clare, S. J., Russell, J. M., Hubbard, A., Taylor, J., Smoker, M., Gardiner, M., Civolani, L., Cosenza, F., Rosignoli, S., Strugala, R., Molnar, I., Simkova, H., Dolezel, J., Schaffrath, U., Barrett, M., Salvi, S., Moscou, M. J.. 2021-12-21. A lineage-specific Exo70 is required for receptor kinase-mediated immunity in barley. https://doi.org/10.1101/2021.12.19.473371

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