331 AJCS 10(3):331-335 (2016) ISSN:1835-2707 DOI: 10.21475/ajcs.2016.10.03.p7075 Nutrition in tomato (Solanum lycopersicum L) as affected by light: revealing a new role of phytochrome A Rogério F. Carvalho 1 , Leandro R. Moda 2 , Gilmara P. Silva 2 , Marina A. Gavassi 1 and Renato M. Prado 2* 1 Department of Biology Applied to Agriculture, São Paulo State University, Via de Acesso Prof. Paulo Donato Castellane s/n, 14884-900, Brazil 2 Department of Soil and Fertilizer, São Paulo State University, Via de Acesso Prof. Paulo Donato Castellane s/n, 14884-900, Brazil *Correspomnding author: rmprado@fcav.unesp.br Abstract The far red light insensitive (fri) mutant of tomato, which is phytochrome A (phyA) deficient, displays some characteristics that have recently indicated important functions of this photoreceptor in water relations. With respect to the relationship between nutrition and water relations, we investigated the growth and nutritional status of fri supplied with Hoagland's complete solution and solutions with the individual omission of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S). For this purpose, 20-day-old tomato plants of the WT (cv. Moneymaker) and fri mutant were transplanted into pots (one plant per pot) that contained Hoagland and Arnon (1950) solution diluted to 50 per cent in the first week and to 100 per cent from the second week of cultivation until the end of the experiment (50 DAT). Seven treatments were performed: a complete nutrient solution (KH 2 PO 4 , KNO 3 , Ca(NO 3 ) 2 .5H 2 O, MgSO 4 .7H 2 O, KCl, CaCl 2 , H 3 BO 3 , MnCl 2 .4H 2 O, ZnCl 2 , CuCl 2 , H 2 MoO 4 H 2 O and Fe EDTA) and the individual omission N (KNO 3, Ca(NO 3 ) 2 .5H 2 O); P (KH 2 PO 4 ); K (KH 2 PO 4 , KNO 3 ); Ca (CaCl 2 ); Mg and S (MgSO 4 .7H 2 O) from a balanced nutrient solution. The experiment was arranged in a completely randomized factorial design with two genotypes and seven types of nutrient solutions with three replications. Upon harvest, the following measurements were performed: the height of the plants, measured from the base of the stem of each plant to the insertion of the first fully expanded leaf; the stem diameter; the total number of leaves per plant; an indirect chlorophyll measurement, which we called the green color index, and the leaf area. Statistical analysis was performed using analysis of variance (ANOVA) followed by Tukey’s test. First, based on growth analyses, fri showed an enhanced dry weight of the shoot, root and whole plant in complete solution compared with the wild type (WT). In addition, the phyA mutant had a multifaceted response compared with that of the WT when the nutrients were omitted. For the fri mutant, the height and green color index were reduced without N and K; the leaf area without P, K and S; the dry weight of the root and shoot without N, P, K and S, and the root, shoot and total plant dry weight without P, K and S. On the other hand, the green color index of the fri mutant was enhanced without Ca and Mg. Together, these results show that in addition to revealing an altered response to nutrition in the fri mutant, phyA can play a role in light signaling in the nutrition and nutritional stress of tomato. Keywords: Tomato; nutrition; abiotic stress; phytochrome; mutant. Abbreviations: fri_far red light insensitive mutant; DAT_days after transplanting; HY5_LONG HYPOCOTYL 5; WT_wild type. Introduction Phytochromes are a widespread family of red/far-red- responsive photoreceptors that are ~120-kDa peptides (apoproteins) with a covalently linked linear tetrapyrrole bilin chromophore (forming a complex referred to as the holoprotein) (Bae and Choi, 2008). These molecules control a range of physiological responses from seed germination (Dechaine et al., 2009; Oh et al., 2009) to flowering (Andres et al., 2009; Brock et al., 2010) and each year, a considerable number of studies are published describing new biochemical and molecular roles of phytochromes. Many of these discoveries have been identified using genetic tools, mainly plant transgenics and mutants, with Arabidopsis thaliana as the flagship species. In this plant model, many phytochrome signaling components have been identified, revealing how, on what and where phytochromes act (Chen and Chory, 2011). Moreover, phytochrome mutants of economically important species, such as tomato (Solanum lycopersicum), have also permitted the discovery of agronomic traits that appear to be controlled by phytochromes. For example, the hypocotyls of the au tomato mutant, which is phytochrome-deficient (Muramoto et al., 2005), have reduced levels of anthocyanins, which are important antioxidant molecules (Carvalho et al., 2010). Moreover, the leaves of au exhibited reduced lipid peroxidation and enhanced H 2 O 2 (Monteiro et al., 2012), generating strong perspectives on the biochemical and molecular manipulation of light signaling. In addition, the far red light insensitive (fri) mutant of tomato (van Tuinen et al., 1995), which is phyA-deficient, produces fruits with important qualities for the paste industry, such as an increased dry weight/fresh weight ratio, total soluble solids, and paste viscosity, and fewer seeds per fruit compared with the wild type (Alba et al., 1999). Curiously, in addition to the improved traits that are displayed by the fri mutant, this genotype rapidly wilts after exposure to high levels of