CLE11 and CLE10 Suppress Mycorrhizal Colonisation in Tomato

Abstract

AbstractSymbioses with beneficial microbes are widespread in plants, but these relationships must balance the energy invested by the plants with the nutrients acquired. Symbiosis with arbuscular mycorrhizal (AM) fungi occurs throughout land plants but our understanding of the genes and signals that regulate colonisation levels is limited. Here, we demonstrate that in tomato two CLV3/EMBRYO-SURROUNDING REGION (CLE) peptides,SlCLE10 andSlCLE11, act to suppress AM colonisation of roots. Mutant studies and overexpression via hairy transformation indicateSlCLE11acts locally in the root to limit AM colonisation. Indeed,SlCLE11expression is strongly induced in AM colonised roots butSlCLE11is not required for phosphate suppression of AM colonisation.SlCLE11 may act through as yet uncharacterised signalling pathways, asSlCLE11does not suppress AM colonisation by acting through two previously characterised receptors with roles in regulating AM colonisation,SlFAB (CLAVATA1 orthologue) orSlCLV2.SlCLE10 appears to play a more minor or redundant role, ascle10mutants did not influence AM, although the fact that ectopic overexpression ofSlCLE10did suppress colonisation suggestsSlCLE10may play a role in regulating AM colonisation. Our findings show that CLE peptides regulate AM colonisation in the non-legume species tomato.