Agricultural crops are severely affected by salinity. Recent studies have shown that salt stress signaling components affect plant metabolism and stimulate the accumulation of organic osmolytes and antioxidant substances. This work aimed at assessing the growth and development of lemon balm, Melissa officinalis L., subjected to salt stress, as well as its antioxidant response, essential oil composition, and essential oil yield (%). A completely randomized experimental design was conducted under greenhouse conditions, where 30-days-old lemon balm plants were treated with different NaCl concentrations (0, 50, 100, 150 and 200 mM) for sixty days. The highest concentrations (150 mM and 200 mM NaCl) caused significant reductions in shoot height, shoot fresh mass, relative water content, water activity and chlorophyll production due to changes in osmotic activity. The activities of superoxide dismutase (SOD) and catalase (CAT) increased in plants subjected to salinity. In addition, membrane damage (DM) increased with increase in NaCl concentration. The yield of the essential oils decreased but the number of compounds increased in all the NaCl treatments. The compounds neryl-acetate and geranyl-acetate were detected at 100, 150 and 200mM NaCl, suggesting that under salt stress, lemon balm plants activate the metabolic pathways for the production of terpenoids, consequently producing monoterpenes. Salinity negatively affected most of the parameters evaluated in lemon balm plants. Our results show that lemon balm plants are tolerant to low concentrations of salinity (up to 50mM) as proved by their distinct metabolic responses.

The Dof (DNA-binding with one finger) proteins are a class of plant-specific transcription factors that can trigger several processes involved in plant growth and development, as well as in stress responses. Here, we performed a systematic bioinformatics analysis to characterize all Dof genes in common bean, which included analysis of the genome sequence, conserved protein domains, chromosomal locations, subcellular locations, phylogenetic relationships, gene duplications, and gene expression profiles in different tissues.Bioinformatics analysis revealed 36 putative genes related to PvDof that were classified into seven subfamilies (A, B1, B2, C1, C2, D1, and, D2) by comparative phylogenetic analysis. Based on our genome duplication analysis, a total of 36 genes were found to be distributed on all 11 chromosomes, and they expanded through gene duplication in tandem, suggesting the involvement of segmental duplication events in the evolutionary process. Synteny events and phylogenetic comparisons of the Dof proteins of common bean with those of

Salinity is a major problem in agriculture because it can alter the metabolism of plants and affect crop yield. This study aimed to evaluate the effect of NaCl on growth, key antioxidants and changes in the expression of genes encoding antioxidant enzymes. Two popcorn genotypes, IAC125 and UFMV2, experienced reduction in growth as the salt concentration increased. Increase in chlorophyll content and damage to the plasma membrane was observed. Consequently, changes in osmotic activity led to reduced water content in the leaves. Increased concentration of salt increased the activity of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in two popcorn genotypes but maximum activity was observed in the IAC125 genotype. Such enzymatic activities occur in order to maintain the levels of lipid peroxidation under salt stress, indicating that this genotype is tolerant to salinity conditions. The ZmAPX, ZmCAT, ZmSOD (Cu/Zn) and ZmSOD (Mn) genes increased their expression as salinity increased. The ZmSOD (Fe) gene was highly regulated in the IAC125 genotype under salt stress, but low regulation was observed in the UFM2 genotype, regardless of the salt concentration. The enhancement in tolerance against salt stress indicates that the genes involved in the antioxidative process are triggered by oxidative stress induced by abiotic stresses. These results showed that the popcorn varieties have different levels of salt tolerance due to the differential expression pattern of the antioxidant genes. The up-regulation of antioxidant enzymatic activity could lead to increased scavenging of excessive free radicals and reduce oxidative stress.

Stress by salt and aluminum (Al+3) causes significant loss in the growth of popcorn. Effects on the initial growth, especially of leaves and stomata, are poorly investigated, while no information is available for some cultivars. This work aims at verifying the effect of stress caused by salt and Al+3 on the initial growth, morphometry, and morphology of popcorn stomata (IAC-125), as well as on its foliar anatomy. In the presence of 50 mM or higher concentrations of NaCl, popcorn seedlings showed a reduction of 50% in shoot mass gains as compared to the control. With 150 mM or higher concentrations, mass gains reduced by 33% in popcorn root system as compared to the control. Small increases in shoot length were observed in seedlings treated with Al+3.The root system was highly affected by 160 µM or higher Al+3 concentrations. Pore opening and stomatal subsidiary cell width were altered under both salt and Al+3 stress. Stomatal density changes were observed only under salt stress. Tissue disruptions and cell numberreductions were verified in the epidermis and parenchyma under high Al+3 and saltconcentrations. The largest xylem and phloem cells were preserved in all treatments. Stress resulted in dehydration of plant tissues, which showed retraction under high concentrations of salt and Al+3due to anatomical changes in the leaves and morphometry of the stomata. Our results demonstrated that these characteristics contributed to a remarkable tolerance to salinity and aluminum, since they have an important protective role against different environmental stresses.

CANTÚ, T.; TREVIZAN, C. B.; VIEIRA, C. E.; PIFFER, R. D.; CARNEIRO LUIZ, G.; SOUZA, S. G. H. de. Caracterização in silico dos genes envolvidos no metabolismo do nitrogênio em milho (Zea mays). Arq. Ciênc. Vet. Zool. UNIPAR, Umuarama, v. 19, n. 4, p. 231-239, out./dez. 2016. RESUMO:O N é o nutriente mineral requerido pelas plantas em maior quantidade e frequentemente limita o crescimento e produtividade. A partir de uma análise in silico foram identificados 26 genes envolvidos na assimilação do nitrogênio: quatro genes que codificam a enzima nitrato redutase (ZmNR), oito nitrato redutase de transporte (ZmNRT), uma nitrito redutase (ZmNRi), uma nitrito de transporte (ZmNRiT), seis glutamina sintetase (ZmGS), quatro glutamato sintase (ZmGOGAT) e duas glutamato desidrogenase (ZmGDH). A árvore filogenética foi construída onde foi possível observar a formação de cinco grupos distintos de acordo com as funções. A análise da estrutura dos genes mostrou que o número de íntrons variou de 0 a 32. A análise dos domínios conservados mostrou que a maioria dos genes identificados possuem o domínios específicos a função que desempenham na rota de assimilação do N em milho. Além disso, esses genes apresentaram padrões de expressão diferenciais em tecidos e órgãos. Os dados gerados neste trabalho forneceram subsídios para selecionar genes-candidatos para futuras análises funcionais a serem utilizados nos programas de melhoramento de milho. PALAVRAS-CHAVE: Assimilação de N. Eficiente uso do Nitrogênio. Filogenia. IN SILICO CHARACTERIZATION OF GENES INVOLVED IN NITROGEN METABOLISM IN MAIZE (Zea mays)ABSTRACT: Nitrogen is a mineral highly requested by plants and often limits both growth and productivity. From an in--silico analysis, a total of 26 genes were identified as being involved in nitrogen assimilation: four genes encoding nitrate reductase enzyme (ZmNR), eight encoding nitrate reductase transporters (ZmNRT), one encoding nitrite reductase (ZmNRi), one encoding nitrite transporter (ZmNRiT), six encoding glutamine synthesis (ZmGOGAT) and two encoding glutamate dehydrogenase (ZmGDH). A phylogenetic tree was generated where the formation of five distinct clusters could be observed according to gene function. Structural genes analysis showed that introns varied from 0 to 32. The analysis of conserved domains showed that most of the identified genes play a domain-specific function in the N assimilation pathway in maize. Moreover, these genes present a differential expression pattern in tissues and organs. Data from this study will provide subsidies to select candidate genes for further functional analyses in maize breeding programs. KEYWORDS: Efficient use of nitrogen. N-assimilation. Phylogeny. CARACTERIZACIÓN IN SILICO DE GENES IMPLICADOS EN EL METABOLISMO DE NITRÓGENO EN MAÍZ (Zea mays)RESUMEN: N es el nutriente mineral requerido por las plantas en mayor cantidad y a menudo limita el crecimiento y la productividad. Desde un análisis in silico se ha identificado 26 genes implicados en la asimilación de nitrógeno: cuatro genes q...

Germinação e crescimento inicial de plântulas de manjericão submetidas ao estresse salino Germination and initial growth of basil seedlings subject to saline stress