EXPRESIÓN DIFERENCIAL DE GENES RELACIONADOS CON FOTOSÍNTESIS Y DEFENSA INDUCIDA POR MICORRIZACIÓN EN TOMATE (Solanum lycopersicum L.)

Abstract

Arbuscular mycorrhiza (AM) fungi form endosymbiosis with plant roots, which provides several benefits to plants such as improved phosphate uptake and resistance to pathogens (Azcón-Aguilar and Barea, 1996). Some studies have proved that AM symbiosis confers resistance to leaf pathogens such as Sclerotinia sclerotiorum and Xanthomonas campestris pv. vesicatoria in common bean and tomato, respectively, and supports the idea that the mechanism involved in such resistance is systemic. Tomato plants colonized with Rhizophagus intraradices showed differential regulation of several leaf proteins (Peinado-Guevara, 2010). Some down regulated proteins were similar in sequence to proteins associated to photosynthesis and defense and/or stress such as plastid lipid protein (CHRC), polypeptide CP29 (CP29), superoxide dismutase Cu-Zn (SOD), 14-3-3 protein, thioredoxin peroxidase (TRP), harpin binding protein (HBP), and annexin p34 (ANN). In this study we analyzed these proteins at the gene expression level in three independent experiments (2008, 2011-A, 2011-B) by real time-PCR and found that SOD, TRP, 14-3-3 CHRC, HBP and ANN transcripts did not changed their expression at the transcriptional level. Therefore, regulation must have occurred at the post-transcriptional level. These proteins can be related to the priming mechanism induced by arbuscular mycorrhiza to increase resistance to leaf pathogens. Arbuscular mycorrhizal symbiosis improved phosphate uptake and enhances the photosynthetic efficiency in 2011-A experiment. Mycorrhiza colonization induced resistance in tomato plants against X. campestris pv. vesicatoria (Experiment 2011-B) consistent with previous experiments. Also, PR1A, CP29 gene expression were up-regulated in leaves of mycorrhiza colonized plants, as well as non colonized plants, which suggests that this change is induced by the pathogen attack.