55º Congresso Brasileiro de Genética Resumos do 55º Congresso Brasileiro de Genética • 30 de agosto a 02 de setembro de 2009 Centro de Convenções do Hotel Monte Real Resort • Águas de Lindóia • SP • Brasil www.sbg.org.br - ISBN 978-85-89109-06-2 74 Analysis of gene expression in transgenic Nicotiana tabacum that overexpress the pea Lhcb1*2 and N. plumbaginifolia nia2 genes Felipe Garbelini Marques; Ivan Miletovic Mozol; José Matheus Camargo Bonatto; Fernanda Salvato; Mônica Teresa Veneziano Labate; Daniela Defavari-do-Nascimento; Carlos Alberto Labate. Laboratório Max Feffer de Genética de Plantas, Departamento de Genética, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo Keywords: qRT-PCR, photosynthesis, nitrogen metabolism, Nicotiana tabacum, Lhcb1*2, nia2 Recently, many methods have been used to study aspects of plant physiology that influence agriculturally important factors, such as productivity. Photosynthesis and nitrogen fixation are two of the most important plant processes involved in plant growth and development. Labate et al. (2004) transformed Nicotiana tabacum plants with the pea Lhcb1*2 gene, which codes for a protein involved in the formation of the light-harvesting complex, resulting in two lineages TR1 and TR2, with one and four copies of the transgene, respectively. Several modifications were observed in leaf anatomy, morphology, biochemistry and the physiology of these plants. Another exogenous gene was inserted in these lineages, nia2 from Nicotiana plumbaginifolia, which is responsible for the production of nitrate reductase, an important enzyme in nitrogen metabolism. From this genetic transformation, six lineages: TR1-10, TR1-11, TR2-9, TR2-12, TR2-16 and TR2-19 were obtained. As the first gene is related to photosynthesis and the second one related to nitrogen fixation, experiments were designed to investigate the effects of these genes on others metabolic pathways. Total RNA was extracted from the wild type, single transformants (TR-1 and TR-2) and double transformants (TR1-10, TR1-11, TR2-9, TR2-12, TR2-16 and TR2-19) and used in qRT-PCR analysis to investigate the gene expression related to respiration, carbohydrate, lignin and cellulose biosynthesis in the leaf tisSignificant differences (Tukey P<0.05), using OriginPro 8 software) were found in gene expression between the wild type and transgenic plants using the following genes: glutamine synthetase (GS1), gene of nitrogen metabolism; Lhcb1*2 which forms part of the antenna complex; 4-coumarate-CoA ligase (4Cl), lignin biosynthesis; UDP-glucose 6-dehydrogenase (Ugdh), UDP-glucuronate decarboxylases (uxs1, uxs2, uxs3 and uxs4), sucrose synthase-like (SuSy) and sucrose-phosphate synthase (SPS) involved in carbohydrate metabolism; Isocitrate dehydrogenase (NADH), citrate synthase (CS) involved in respiration and cellulose synthase (Ces) involved in the synthesis of cellulose. The most significant changes in gene expression were observed in the TR-2 lineage and to a lesser extent TR1-11. This preliminary data shows that it is possible to use transgenic plants as models to study the relationship between photosynthesis and nitrogen metabolism, and also verify the effects on other important biosynthetic pathways.