1 This article is protected by copyright. All rights reserved. McpQ is a specific citrate chemoreceptor that responds preferentially to citrate/metal ion complexes 1 David Martín-Mora # , Jose-Antonio Reyes-Darias # , Álvaro Ortega, Andrés Corral-Lugo, Miguel A. Matilla and Tino Krell * Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain # Authors contributed equally to this work * Corresponding author: Tino Krell Estación Experimental del Zaidín Consejo Superior de Investigaciones Científicas C/ Prof. Albareda 1 18008 Granada Spain Phone: + 34 958 181600 (ext. 294) Fax: + 34 958 135740 E-mail: tino.krell@eez.csic.es Running title: specific chemoreceptor for citrate This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/1462-2920.13030 Accepted Article