The cytosolic invertase NI6 affects vegetative growth, flowering, fruit set, and yield in tomato

Fil: Coluccio Leskow, Carla. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto De Investigación Biotecnología (IB). Hurlingham, Buenos Aires, Argentina.Fil: Coluccio Leskow, Carla. CONICET - Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto De Investigación Biotecnología (IB). Hurlingham, Argentina.Fil: Conte, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto De Investigación Biotecnología (IB). Hurlingham, Buenos Aires, Argentina.Fil: Conte, Mariana. CONICET - Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto De Investigación Biotecnología (IB). Hurlingham, Argentina.Fil: Del Pozo, Talia. Universidad Mayor. Escuela de Agronomía. Centro Tecnológico de Recursos Vegetales. Huechuraba, Santiago, Chile.Fil: Bermúdez, Luisa. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto De Investigación Biotecnología (IB). Hurlingham, Buenos Aires, Argentina.Fil: Bermúdez, Luisa. CONICET - Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto De Investigación Biotecnología (IB). Hurlingham, Argentina.Fil: Bermúdez, Luisa. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Genética. Buenos Aires, Argentina.Fil: Silvestre Lira, Bruno. Universidade de São Paulo. Instituto de Biociências. Departamento de Botânica. São Paulo, SP, Brazil.Fil: Gramegna, Giovanna. Universidade de São Paulo. Departamento de Botânica. Instituto de Biociências. São Paulo, SP, Brazil.Fil: Baroli, Irene. Instituto de Biodiversidad y Biología Experimental Aplicada (IBBEA). Buenos Aires, Argentina.Fil: Baroli, Irene. CONICET - Instituto de Biodiversidad y Biología Experimental Aplicada (IBBEA). Buenos Aires, Argentina.Fil: Carrari, Fernando. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Genética. Buenos Aires, Argentina.Fil: Carrari, Fernando. Universidad de Buenos Aires. Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE, CONICET-UBA). Buenos Aires, Argentina.Fil: Carrari, Fernando. CONICET - Universidad de Buenos Aires. Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE, CONICET-UBA). Buenos Aires, Argentina.Sucrose metabolism is important for most plants, both as the main source of carbon and via signaling mechanisms that have been proposed for this molecule. A cleaving enzyme, invertase (INV) channels sucrose into sink metabolism. Although acid soluble and insoluble invertases have been largely investigated, studies on the role of neutral invertases (A/N-INV) have lagged behind. Here, we identified a tomato A/N-INV encoding gene (NI6) co-localizing with a previously reported quantitative trait locus (QTL) largely affecting primary carbon metabolism in tomato. Of the eight A/N-INV genes identified in the tomato genome, NI6 mRNA is present in all organs, but its expression was higher in sink tissues (mainly roots and fruits). A NI6-GFP fusion protein localized to the cytosol of mesophyll cells. Tomato NI6- silenced plants showed impaired growth phenotype, delayed flowering and a dramatic reduction in fruit set. Global gene expression and metabolite profile analyses of these plants revealed that NI6 is not only essential for sugar metabolism, but also plays a signaling role in stress adaptation. We also identified major hubs, whose expression patterns were greatly affected by NI6 silencing; these hubs were within the signaling cascade that coordinates carbohydrate metabolism with growth and development in tomato.grafs., tbls., fot

Plant degreening: evolution and expression of tomato\ud (Solanum lycopersicum) dephytylation enzymes

Chlorophyll is the most abundant pigment on earth and even though it is known that its high photo-excitability necessitates a tight regulation of its degradation pathway, to date there are still several steps in chlorophyll breakdown that remain obscure. In order to better understand the ‘degreening’ processes that accompany leaf senescence and fruit ripening, we characterized the enzyme-encoding genes involved in dephytylation from tomato (Solanum lycopersicum). A single pheophytinase (PPH) gene and four chlorophyllase (CLH) genes were identified in the tomato genome. A phenetic analysis revealed two groups of CLHs in eudicot species and further evolutionary analysis indicated that these enzymes are under diverse selection pressures. A comprehensive expression profile analysis also suggested functional specificity for these dephytylating enzymes. The integrated analysis allows us to propose three general roles for chlorophyll dephytylation: i) PPH, which is under high selective constraint, is responsible for chlorophyll degradation during developmentally programed physiological processes; ii) Group I CLHs, which are under relaxed selection constraint, respond to environmental and hormonal stimuli and play a role in plant adaptation plasticity; and iii) Group II CLHs, which are also under high selective constraint, are mostly involved in chlorophyll recycling.BSL and JA were recipients of FAPESP fellowships and MR was funded by a fellowship from CNPq. This work was supported by FAPESP2012-12531-8 (Brazil). The authors thank Rohm and Haas Company for generous donation of the 1-methylcyclopropene (SmartFresh®) used for the experiments

Galacturonosyltransferase 4 silencing alters pectin composition and carbon partitioning in tomato

Pectin is a main component of the plant cell wall and is the most complex family of polysaccharides in nature. Its composition is essential for the normal growth and morphology pattern, as demonstrated by pectin-defective mutant phenotypes. Besides this basic role in plant physiology, in tomato, pectin structure contributes to very important quality traits such as fruit firmness. Sixty-seven different enzymatic activities have been suggested to be required for pectin biosynthesis, but only a few genes have been identified and studied so far. This study characterized the tomato galacturonosyltransferase (GAUT) family and performed a detailed functional study of the GAUT4 gene. The tomato genome harbours all genes orthologous to those described previously in Arabidopsis thaliana, and a transcriptional profile revealed that the GAUT4 gene was expressed at higher levels in developing organs. GAUT4-silenced tomato plants exhibited an increment in vegetative biomass associated with palisade parenchyma enlargement. Silenced fruits showed an altered pectin composition and accumulated less starch along with a reduced amount of pectin, which coincided with an increase in firmness. Moreover, the harvest index was dramatically reduced as a consequence of the reduction in the fruit weight and number. Altogether, these results suggest that, beyond its role in pectin biosynthesis, GAUT4 interferes with carbon metabolism, partitioning, and allocation. Hence, this cell-wall-related gene seems to be key in determining plant growth and fruit production in tomatoFil: Godoy, Fabiana de. Universidade de São Pablo. Departamento de Botânica; BrasilFil: Bermúdez, Luisa. Universidade de São Pablo. Departamento de Botânica; BrasilFil: Lira, Bruno Silvestre. Universidade de São Pablo. Departamento de Botânica; BrasilFil: Souza, Amanda Pereira de. Universidade de São Pablo. Departamento de Botânica; BrasilFil: Elbl, Paula. Universidade de São Pablo. Departamento de Botânica; BrasilFil: Demarco, Diego. Universidade de São Pablo. Departamento de Botânica; BrasilFil: Alseekh, Saleh. Max Planck Institute for Molecular Plant Physiology; AlemaniaFil: Insani, Ester Marina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Buckeridge, Marcos. Universidade de São Pablo. Departamento de Botânica; BrasilFil: Almeida, Juliana. Universidade de São Pablo. Departamento de Botânica; BrasilFil: Grigioni, Gabriela Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; ArgentinaFil: Fernie, Alisdair Robert. Max Planck Institute for Molecular Plant Physiology; AlemaniaFil: Carrari, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Rossi, Magdalena. Universidade de São Pablo. Departamento de Botânica; Brasi

Pheophytinase knockdown impacts carbon metabolism and nutraceutical content under normal growth conditions in tomato

Although chlorophyll (Chl) degradation is an essential biochemical pathway for plant physiology, our knowledge regarding this process still has unfilled gaps. Pheophytinase (PPH) was shown to be essential for Chl breakdown in dark-induced senescent leaves. However, the catalyzing enzymes involved in pigment turnover and fruit ripening-associated degreening are still controversial. Chl metabolism is closely linked to the biosynthesis of other isoprenoid-derived compounds, such as carotenoids and tocopherols, which are also components of the photosynthetic machinery. Chls, carotenoids and tocopherols share a common precursor, geranylgeranyl diphosphate, produced by the plastidial methylerythritol 4-phosphate (MEP) pathway. Additionally, the Chl degradation-derived phytol can be incorporated into tocopherol biosynthesis. In this context, tomato turns out to be an interesting model to address isoprenoid-metabolic cross-talk since fruit ripening combines degreening and an intensely active MEP leading to carotenoid accumulation. Here, we investigate the impact of PPH deficiency beyond senescence by the comprehensive phenotyping of SlPPH-knockdown tomato plants. In leaves, photosynthetic parameters indicate altered energy usage of excited Chl. As a mitigatory effect, photosynthesis-associated carotenoids increased while tocopherol content remained constant. Additionally, starch and soluble sugar profiles revealed a distinct pattern of carbon allocation in leaves that suggests enhanced sucrose exportation. The higher levels of carbohydrates in sink organs down-regulated carotenoid biosynthesis. Additionally, the reduction in Chl-derived phytol recycling resulted in decreased tocopherol content in transgenic ripe fruits. Summing up, tocopherol and carotenoid metabolism, together with the antioxidant capacity of the hydrophilic and hydrophobic fractions, were differentially affected in leaves and fruits of the transgenic plants. Thus, in tomato, PPH plays a role beyond senescence-associated Chl degradation that, when compromised, affects isoprenoid and carbon metabolism which ultimately alters the fruit's nutraceutical content

TENDÊNCIAS DA SÍNTESE DA ZEÓLITA MORDENITA COM O USO DE SEMENTES DE CRISTALIZAÇÃO

Devido a sua alta estabilidade térmica e acidez, a zeólita mordenita é utilizada como adsorvente na separação de gases ou misturas líquidas, e como catalisador nos processos de hidrocraqueamento, hidroisomerização, alquilação, reforma catalítica, desparafinação e síntese de dimetilaminas. A busca por novas propriedades das zeólitas conhecidas, a redução do tempo de cristalização e dos custos dos reagentes, torna o processo de síntese uma etapa crucial para sua viabilidade comercial. Este trabalho teve como finalidade destacar a importância do desenvolvimento de rotas para obtenção da mordenita, visto seu potencial de aplicação na indústria petroquímica. Para tanto, se desenvolveu uma fundamentação teórica a partir de patentes e artigos acessíveis nas bases de dados do INPI, Espacenet, WIPO, USPTO e Periódicos Capes. Como resultados destas análises foram estabelecidas as tendências para obtenção da zeólita mordenita

Manipulação da senescência foliar e da degradação de clorofila visando o melhoramento de frutos

Leaves are responsible for the majority of the fixed carbon in most plant species. Along leaf development, the photosynthetic capacity increases until the organ reaches maturity. Consequently, at the onset of senescence the leaves have the highest photosynthetic activity, then, as the chloroplasts are dismantled and the photosynthetic machinery is degraded, leaves gradually lose the rate of carbon assimilation. Although the capacity to fix carbon declines as senescence progresses, nutrient remobilization from macromolecule degradation nourishes the developing sink organs. In this regard, delaying leaf senescence stands out as a promising strategy to increase plant yield as extends the window of time with maximum carbon fixation rate. Another approach that is receiving much attention is the manipulation of chlorophyll degradation once it potentially regulates photosynthetic capacity and affects the nutritional quality of harvestable organs. As chlorophyll is degraded, the released phytol is recycled and can be either stored (i.e. as fatty acid phytyl esters), used for chlorophyll synthesis or be incorporated in tocopherol biosynthesis. Tocopherols have high nutraceutical value due to their antioxidant properties. However, the majority of the studies regarding senescence and chlorophyll degradation were carried out in the model plant Arabidopsis thaliana or grasses, creating a knowledge gap about these processes in fleshy fruit-bearing plants of human diet interest. In this regard, the tomato, Solanum lycopersicum, is an excellent model not only for the genetic and genomic resources, but also for its agronomic and nutritional importance. Thus, this project aims to extend what is known about the effects of chlorophyll degradation and senescence manipulation over the metabolism and yield of tomato plants, as well as fruit nutritional quality. In order to evaluate the consequences of alteration in chlorophyll degradation, first the enzymes chlorophyllase and pheophytinase, both capable of dephytylating the chlorophyll molecule, were identified and characterised. An extensive phylogenetic, evolutive and transcriptional analysis allowed the identification of two groups of chlorophyllases, one putatively involved in the response to different stimuli, while the other may act in chlorophyll homeostasis. As for pheophytinase, only one group was identified, being related to physiologically programmed processes that trigger chlorophyll degradation (i.e. leaf senescence and fruit ripening). Given this scenario, pheophytinase was chosen to be constitutively knocked-down in order to evaluate the effects over the metabolism of leaves and fruits. As consequence of this manipulation, transgenic plants were impaired in the leaf senescence-associated chlorophyll breakdown, but, although with an initial delay, fruit ripening-associated degreening was not compromised. Several photosynthetic and biochemical parameters were signs of photoinhibition, possibly due to a deficiency in chlorophyll recycling in leaves. This led to an increase in sugar exportation towards fruits, ultimately increasing soluble sugar content of ripe fruits. However, as a consequence, carotenoid levels were reduced, what, at least partially, it was compensated by an increase in tocopherol content. The results indicated that pheophytinase plays a role beyond senescence-associated chlorophyll degradation and its manipulation led to the development of fruit with increased soluble sugars and tocopherols at the cost of lowering carotenoid levels. Thus, these evidences support the manipulation of chlorophyll breakdown as a strategy for improvement of fleshy fruit plants. In order to address the effects of senescence over yield and fruit quality, the transcription factor ORESARA1, which has been widely characterised in A. thaliana and is considered a key regulator of senescence initiation, was targeted. After a comprehensive phylogenetic analysis and the characterization of the regulatory mechanisms, one putative ortholog was selected to be silenced. As consequence of this manipulation, leaves displayed increased chlorophyll content. Moreover, as senescence was delayed, the extent of photosynthetic activity of the leaves was also expanded. As the number of fruits was increased in the knockdown lines, this reflected in an increment in the harvest index. Ripe fruits accumulated more soluble sugars and tocopherols. Collectively, the results support the manipulation of leaf senescence as a strategy for tomato yield improvement. Altogether, data obtained enhance the knowledge about the impacts of chlorophyll degradation and leaf senescence over the metabolism of fleshy-fruit plants, providing strategies to increase yield and nutritional quality of fruitsAs folhas, para a maioria das espécies vegetais, são o principal órgão responsável pela fixação de carbono. Durante o desenvolvimento foliar, o potencial fotossintético aumenta até a folha atingir a sua maturidade. Consequentemente, no momento que o programa de senescência se inicia, a folha apresenta a maior taxa de fotossíntese, a qual passa então a declinar conforme o cloroplasto se desorganiza e a maquinaria fotossintética é degradada. Apesar da redução na fixação de carbono, o catabolismo de macromoléculas possibilita a remobilização de nutrientes para os órgãos dreno em desenvolvimento. Neste contexto, atrasar a senescência destaca-se como uma promissora estratégia para aumento da produtividade, uma vez que estende o período de máxima fixação de carbono das folhas. Outra estratégia que tem recebido atenção por, potencialmente, regular a capacidade fotossintética e afetar a qualidade nutricional dos órgãos coletáveis é a manipulação da degradação da clorofila. Durante o catabolismo deste pigmento, o fitol liberado é reciclado podendo ser armazenado (i.e. na forma de ésteres de fitil com ácidos graxos), ser utilizado na síntese de novas moléculas de clorofila ou ser incorporado na rota biossintética de tocoferóis. Estes últimos compostos, por seu potencial antioxidante, possuem alto valor nutracêutico. No entanto, a maior parte dos estudos sobre senescência e degradação de clorofila foi realizada na planta modelo Arabidopsis thaliana ou em gramíneas, tornando escassas as informações relativas a plantas com frutos carnosos de interesse para a dieta humana. Nesse âmbito, o tomateiro, Solanum lycopersicum, é um excelente modelo de estudo não apenas pela disponibilidade de recursos genético e genômicos, mas também pela importância agronômica e nutricional desta espécie. Assim, este trabalho pretende expandir o conhecimento acerca dos efeitos da manipulação da degradação de clorofila e da senescência sobre o metabolismo e produtividade do tomateiro, bem como sobre a qualidade nutricional dos frutos. De modo a se avaliar as consequências de alterações na degradação de clorofila, iniciou-se por identificar e caracterizar em tomateiro as enzimas clorofilase e feofitinase, as quais catalisam a defitilação da molécula de clorofila. Uma vasta análise filogenética, evolutiva e transcricional permitiu a identificação de dois grupos de clorofilases, um dos quais estaria envolvido na plasticidade de respostas a estímulos e o outro na homeostase dos níveis de clorofila. Já para feofitinase, somente um grupo foi identificado, o qual está relacionado a processos fisiologicamente programados que levam à degradação de clorofila (i.e. senescência foliar e amadurecimento de frutos). Dado o panorama obtido, a feofitinase foi escolhida para ser constitutivamente silenciada de modo a se avaliar as consequências para o metabolismo de folhas e frutos. Como consequência do silenciamento, as linhagens transgênicas mostraram-se incapazes de degradar clorofila durante a senescência, mas, embora com um atraso nas etapas iniciais, a degradação ao longo do amadurecimento de frutos não foi comprometida. Diversos parâmetros fotossintéticos e bioquímicos foram indicativos de fotoinibição, possivelmente em virtude de uma deficiência na reciclagem da clorofila em folhas. Isto acarretou em um aumento na exportação de açúcares para frutos, incrementando a concentração de açúcares solúveis nos frutos maduros, que, em contrapartida, resultou na queda nos teores de carotenoides. A queda nestes compostos antioxidantes foi, ao menos parcialmente, compensada por um aumento nos níveis de tocoferóis. Os resultados indicaram que a feofitinase possui um papel além da degradação de clorofila associada à senescência, e que sua manipulação leva ao desenvolvimento de frutos com maior teor de açúcares solúveis e de tocoferóis ao custo da redução no de carotenoides. Desta forma, estas evidências suportam a manipulação da clorofila como estratégia para o melhoramento de frutos carnosos. Para investigar o efeito da senescência sobre a produtividade e qualidade de frutos foi escolhido o fator de transcrição ORESARA1, o qual está amplamente caracterizado em A. thaliana e é considerado um regulador chave no desencadeamento deste processo. A partir de uma extensa análise filogenética e da caracterização de sua regulação, um putativo ortólogo foi selecionado como alvo para silenciamento. Como consequência desta manipulação, folhas apresentaram os níveis de clorofila incrementados. Além disto, taxas fotossintéticas maiores que as do genótipo controle foram mantidas por maior tempo indicando que a iniciação da senescência foi retardada. Assim, estas plantas produziram um maior número de frutos, consequentemente, aumentando o índice de colheita dessas linhagens. Os frutos maduros apresentaram maiores teores de açúcares solúveis e de tocoferóis. Os resultados demostraram que o retardo do início da senescência é uma estratégia efetiva para aumento da produtividade de tomateiro. Coletivamente, os resultados obtidos aprofundam o conhecimento acerta dos impactos da degradação de clorofila e senescência sobre o metabolismo de plantas com frutos carnoso, além de prover estratégias para se incrementar a produtividade e a qualidade nutricional de fruto

Different mechanisms are responsible for chlorophyll dephytylation during fruit ripening and leaf senescence in tomato

Chlorophyll breakdown occurs in different green plant tissues (e.g. during leaf senescence and in ripening fruits). For different plant species, the PHEOPHORBIDE A OXYGENASE (PAO)/phyllobilin pathway has been described to be the major chlorophyll catabolic pathway. In this pathway, pheophorbide (i.e. magnesium- and phytol-free chlorophyll) occurs as a core intermediate. Most of the enzymes involved in the PAO/phyllobilin pathway are known; however, the mechanism of dephytylation remains uncertain. During Arabidopsis (Arabidopsis thaliana) leaf senescence, phytol hydrolysis is catalyzed by PHEOPHYTINASE (PPH), which is specific for pheophytin (i.e. magnesium-free chlorophyll). By contrast, in fruits of different Citrus spp., chlorophyllase, hydrolyzing phytol from chlorophyll, was shown to be active. Here, we enlighten the process of chlorophyll breakdown in tomato (Solanum lycopersicum), both in leaves and fruits. We demonstrate the activity of the PAO/phyllobilin pathway and identify tomato PPH (SlPPH), which, like its Arabidopsis ortholog, was specifically active on pheophytin. SlPPH localized to chloroplasts and was transcriptionally up-regulated during leaf senescence and fruit ripening. SlPPH-silencing tomato lines were impaired in chlorophyll breakdown and accumulated pheophytin during leaf senescence. However, although pheophytin transiently accumulated in ripening fruits of SlPPH-silencing lines, ultimately these fruits were able to degrade chlorophyll like the wild type. We conclude that PPH is the core phytol-hydrolytic enzyme during leaf senescence in different plant species; however, fruit ripening involves other hydrolases, which are active in parallel to PPH or are the core hydrolases in fruits. These hydrolases remain unidentified, and we discuss the question of whether chlorophyllases might be involved

Fruit-localized phytochromes regulate plastid biogenesis, starch synthesis and carotenoid metabolism in tomato

Light signaling has long been reported to influence fruit biology, though the regulatory impact of fruit-localized photoreceptors on fruit development and metabolism remains elusive. Studies performed in phytochrome(PHY)-deficient tomato (Solanum lycopersicum) mutants suggest that SlPHYA, SlPHYB2 and to a lesser extent SlPHYB1 influence fruit development and ripening. By employing fruit-specific RNAi-mediated silencing of SlPHY genes, we demonstrated that fruit-localized SlPHYA and SlPHYB2 play contrasting roles in regulating plastid biogenesis and maturation in tomato. Data revealed that fruit-localized SlPHYA, rather than SlPHYB1 or SlPHYB2, positively influence tomato plastid differentiation and division machinery via changes in both light and cytokinin signaling-related gene expression. Fruit-localized SlPHYA and SlPHYB2 were also shown to modulate sugar metabolism in early developing fruits via overlapping, yet distinct, mechanisms involving the coordinated transcriptional regulation of sink- and starch biosynthesis-related genes. Fruit-specific SlPHY silencing also drastically altered the transcriptional profile of genes encoding light repressor proteins and carotenoid biosynthesis regulators, leading to reduced carotenoid biosynthesis during fruit ripening. Therefore, besides providing conclusive evidence on the regulation of tomato quality by fruit-localized phytochromes, our data also demonstrate the existence of an intricate PHY-hormonal interplay during fruit development and ripening

<i>Phytochrome Interacting Factors</i> (<i>PIFs</i>) in <i>Solanum lycopersicum</i>: Diversity, Evolutionary History and Expression Profiling during Different Developmental Processes

<div><p>Although the importance of light for tomato plant yield and edible fruit quality is well known, the PHYTOCHROME INTERACTING FACTORS (PIFs), main components of phytochrome-mediated light signal transduction, have been studied almost exclusively in <i>Arabidopsis thaliana</i>. Here, the diversity, evolution and expression profile of <i>PIF</i> gene subfamily in <i>Solanum lycopersicum</i> was characterized. Eight tomato <i>PIF loci</i> were identified, named <i>SlPIF1a</i>, <i>SlPIF1b</i>, <i>SlPIF3</i>, <i>SlPIF4</i>, <i>SlPIF7a</i>, <i>SlPIF7b</i>, <i>SlPIF8a</i> and <i>SlPIF8b</i>. The duplication of <i>SlPIF1</i>, <i>SlPIF7</i> and <i>SlPIF8</i> genes were dated and temporally coincided with the whole-genome triplication event that preceded tomato and potato divergence. Different patterns of mRNA accumulation in response to light treatments were observed during seedling deetiolation, dark-induced senescence, diel cycle and fruit ripening. <i>SlPIF4</i> showed similar expression profile as that reported for <i>A</i>. <i>thaliana</i> homologs, indicating an evolutionary conserved function of PIF4 clade. A comprehensive analysis of the evolutionary and transcriptional data allowed proposing that duplicated <i>SlPIFs</i> have undergone sub- and neofunctionalization at mRNA level, pinpointing the importance of transcriptional regulation for the maintenance of duplicated genes. Altogether, the results indicate that genome polyploidization and functional divergence have played a major role in diversification of the <i>Solanum PIF</i> gene subfamily.</p></div

Expression profile of PIF genes during ripening under contrasting light conditions.

<p>Fruits were harvested at MG (mature-green) stage and left to ripen under constant light or dark conditions. Pericarp samples were harvested at MG (two days after the beginning of treatment), BR (breaker), BR1 (1 day after BR), BR3, BR6 and BR12 stages. Asterisks and letters represent significant (P<0.05) differences between treatments and stages, respectively. Values shown are means ± SE of at least three biological replicates.</p