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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Microbe and Virus Interactions with Plants
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1472449
This article is part of the Research Topic Mycorrhizal Symbioses: From Molecular and Functional Insights to Ecosystem Research and Application View all 3 articles

The SlDLK2 receptor, involved in the control of Arbuscular Mycorrhizal symbiosis, regulates hormonal balance in roots

Provisionally accepted
Martin Ramos-Alvelo1 Martin Ramos-Alvelo1 1Nuria Molinero Rosales Nuria Molinero Rosales 1María Isabel Tamayo-Navarrete María Isabel Tamayo-Navarrete 1Sanja Ćavar Zeljković Sanja Ćavar Zeljković 2,3Petr Tarkowski Petr Tarkowski 2,3Jose Manuel García-Garrido Jose Manuel García-Garrido 1Tania Ho Plágaro Tania Ho Plágaro 1*
  • 1 Department of Soil Microbiology and Symbiotic Systems, Experimental Station of Zaidín, Spanish National Research Council (CSIC), Granada, Spain
  • 2 Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Olomouc, Czechia
  • 3 Czech Advanced Technology and Research Institute, Palacký University in Olomouc, Olomouc, Olomouc, Czechia

The final, formatted version of the article will be published soon.

    Arbuscular mycorrhiza (AM) represents a symbiotic mutualistic association between most land plants and Glomeromycota fungi. AM fungi develops specialized intraradical and highly branched structures, called arbuscules, where bidirectional exchange of nutrients between plant and fungi partners occurs, improving plant growth and fitness. Transcriptional reprogramming and hormonal regulation are necessary for the formation of the arbuscules. SlDLK2, a member of the third clade from the DWARF14 family of α,β-hydrolases closely related to the strigolactone receptor D14, is a negative regulator of arbuscule branching in tomato, but the underlying mechanisms are unknown. We explored the possible role of SlDLK2 on the regulation of hormonal balance. RNA-seq analysis was performed on roots from composite tomato plants overexpressing SlDLK2 and in control plants transformed with the empty vector. Analysis of transcriptomic data predicted that significantly repressed genes were enriched for genes related to hormone biosynthesis pathways, with a special relevance of carotenoid/apocarotenoid biosynthesis genes. Stable transgenic SlDLK2 overexpressing (OE) tomato lines were obtained and hormone contents were analyzed in their roots and leaves. Interesting significant hormonal changes were found in roots of SlDLK2 OE lines with respect to the control lines, with a strong decrease on jasmonic acid and ABA. Also, SlDLK2 OE roots showed a slight reduction in auxin contents and in one of the major strigolactones in tomato, solanacol. Overall, our results suggest that the negative regulation of AM symbiosis by SlDLK2 is associated to the repression of genes involved in the biosynthesis of AM-promoting hormones.

    Keywords: arbuscular mycorrhiza, plant hormones, DLK2, Transcriptomics, Tomato

    Received: 29 Jul 2024; Accepted: 22 Nov 2024.

    Copyright: © 2024 Ramos-Alvelo1, Molinero Rosales, Tamayo-Navarrete, Ćavar Zeljković, Tarkowski, García-Garrido and Ho Plágaro. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Tania Ho Plágaro, Department of Soil Microbiology and Symbiotic Systems, Experimental Station of Zaidín, Spanish National Research Council (CSIC), Granada, Spain

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