pubs.acs.org/JAFC Published on Web 11/05/2010 © 2010 American Chemical Society 12392 J. Agric. Food Chem. 2010, 58, 12392–12398 DOI:10.1021/jf1031263 Effect of Fusarium oxysporum f. sp. lycopersici on the Soil-to-Root Translocation of Heavy Metals in Tomato Plants Susceptible and Resistant to the Fungus ALMA ROSA CORRALES ESCOBOSA, † KATARZYNA WROBEL, ‡ JULIO ALBERTO LANDERO FIGUEROA, ‡ J. FELIX GUTI ´ ERREZ CORONA, † AND KAZIMIERZ WROBEL* ,‡ ‡ Department of Chemistry, University of Guanajuato, L. de Retana 5, 36000 Guanajuato, Mexico, and † Department of Biology, University of Guanajuato, L. de Retana 5, 36000 Guanajuato, Mexico The purpose of this work was to gain an insight on the potential role of the phytopathogenic fungus Fusarium oxysporum f. sp. lycopersici in the translocation of metals and metalloids from soil to plant roots in tomato (Lycopersicum esculentum). Two varieties of tomato (one susceptible and another resistant to infection by Fusarium oxysporum f. sp. lycopersici) were challenged with the fungus for different periods of time, and several elements (V, Cr, Mn, Co, Cu, Zn, As, Se, Mo, Ag, Cd, Pb) were determined in roots and in soil substrate. Additionally, phenolic plant products were also analyzed for the evaluation of the plant response to biotic stress. In order to obtain representative results for plants cultivated in noncontaminated environments, the infected and control plants were grown in commercial soil with natural, relatively low metal concentrations, partly associated with humic substances. Using such an experimental design, a specific role of the fungus could be observed, while possible effects of plant exposure to elevated concentrations of heavy metals were avoided. In the infected plants of two varieties, the root concentrations of several metals/metalloids were increased compared to control plants; however, the results obtained for elements and for phenolic compounds were significantly different in the two plant varieties. It is proposed that both Lycopersicum esculentum colonization by Fusarium oxysporum f. sp. lycopersici and the increase of metal bioavailability due to fungus-assisted solubilization of soil humic substances contribute to element traffic from soil to roots in tomato plant. KEYWORDS: Lycopersicum esculentum; plant - pathogen interaction; trace elements INTRODUCTION Actual status of metals/metalloids in plants is of interest in various research areas related to human nutrition and possible health hazards and also in the context of phytoremediation ( 1 ). It is well-established that the soil -plant traffic of chemical elements depends on plant genotype, total element concentrations and their physicochemical forms in soil, and several soil parameters such as organic matter composition, pH conditions, and micro- bial activity ( 2 -5 ). In particular, the uptake of heavy metals by tomato plants has been studied in different contaminated envir- onments, or while using certain soil fertilizers ( 6 -9 ). The molec- ular mechanisms underlying element transport, their potential toxicity and defensive plant response have also been approached ( 2 , 10 , 11 ). It should be stressed, however, that the great majority of studies were performed in the presence of elevated metal concentrations. It is also relevant that tomato plant was reported as a relatively salt tolerant and heavy metal resistant crop ( 10 , 12 , 13 ). With regard to microbial activity, several studies pursued the role of rhizobacteria and mycorrhizal fungi in different soil -crop systems ( 14-16 ), yet the relationship between colonization by pathogens and metal status in plants has rarely been consid- ered ( 17 ). F. oxysporum is a common fungal species occurring in soil environments. Several formae speciales are known as pathogens of economically important crops ( 18 ). In particular, F. oxysporum f. sp. lycopersici causes a tomato plant disease called Fusarium wilt ( 19 ). The mycelium invades the plant through the roots, either by direct incursion of penetration hyphae or via wounds and cracks formed at the emerging lateral roots ( 20 ). During 10 to 14 days after infection, the fungus penetrates the plant through the cortex until it reaches the vascular tissue, and then it uses xylem vessels to colonize the entire plant. Typical wilt symptoms occur later, as a result of aggressive fungal growth and destruction of the infected vessels ( 21 ). The F. oxysporum colonization mecha- nisms as well as the plant response have been the focus of intensive research ( 22-25 ); however, to the best of our knowledge, possible effect of fungus on heavy metals translocation from soil to the infected plants has not been approached. *Corresponding author. E-mail: kazimier@quijote.ugto.mx. Tel: (þ52) 473 7327555. Fax: (þ52) 473 7326252.