Thesis (MSc)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: This study (2 x 2 factor design) describes an investigation into the physiological interaction between the peripheral endocrine and cytokine systems after the organism has been exposed to psychological stress. An in vivo rodent model with two interventions was used: (1) mild psychological stress (immobilisation for 2 hours per day, for 4 days); (2) an antiinterleukin (IL)-6-antibody injection. Thirty-nine male Wi star rats were divided into 4 groups and given either the antibody (CA, control antibody) or stress (IP, immobilisation placebo), or both (IA, immobilisation antibody), or neither (CP, control placebo). Antibody and placebo (saline) were injected intraperitoneally. Differences between groups for the following parameters were determined in blood or metabolic tissues, viz. skeletal muscle and liver: 1) corticosterone concentrations, 2) glucocorticoid receptor (GR) binding capacity and 3) activities of metabolic enzymes, tyrosine aminotransferase (TAT) and glutamine synthetase (GS). Groups lP and lA showed a significant loss in body mass (CP vs. lP, p<O.01; CA vs. lA, p<O.001), indicating a main effect of stress. The corticosterone concentrations of only group lP were significantly elevated compared to that of group CP (CP vs. lP, p<O.01), again indicating a main effect of stress. All three intervention groups (CA, lP, lA) had decreased GR binding capacity, with group lA showing a statistically greater decrease (CP vs. CA, p<O.05; IP vs. IA, p<O.01; CP vs. IP, p<O.001; CA vs. IA, p<O.001), indicating main effects of stress and antibody treatment. In groups IP and IA increased activities of both enzymes (TAT and GS) were measured (main effect of stress), with IA again showing the greatest statistically significant increase for both enzymes. The liver tissue displayed greater sensitivity to the stress and antibody regimes. This study provides the first conclusive in vivo evidence for IL-6 modulation of glucocorticoid action in peripheral tissues in response to mild psychological stress. / AFRIKAANSE OPSOMMING: Hierdie studie (met 'n 2 X 2 faktorontwerp) beskryf 'n ondersoek oor die fisiologiese interaksie tussen die perifere endokrien- en sitokiensisteme in organismes blootgestel aan psigologiese stres. Daar word gebruik gemaak van 'n in vivo-rotmodel met twee intervensies: (1) matige psigologiese stres (immobilisering vir 2 uur per dag vir 4 dae); (2) 'n anti-interleukin (IL)-6-antiliggaam inspuiting. Nege-en-dertig manlike Wistar rotte is in vier groepe verdeel en het óf antiliggaam (CA, antiliggaam kontrole), óf stres (IP, immobilisasie placebo), óf beide stres en antiliggaam (lA, immobilisasie antiliggaam) of geen behandeling ontvang (CP, placebo kontrole). Die antiliggaam- en placebo (soutoplossing)- inspuitings is intraperitoneaal toegedien. Verskille tussen die groepe van die volgende parameters, in metaboliese weefsels (skeletspier en lewer), was bepaal: 1) kortikosteroon konsentrasies, 2) glukokortikoïed reseptor (GR) bindingskapasiteit en 3) aktiwiteite van die metaboliese ensieme, tirosien aminotransferase (TAT) en glutamien sintetase (GS). Groepe IP en IA het 'n beduidende afname in gewig getoon (CP vs. IP, p<O.01;CA vs. IA, p<O.001), wat 'n hoof-effek van stres aandui. Die kortikosteroon konsentrasies van slegs IP het beduidend toegeneem in vergelyking met CP (CP vs. IP, p<O.01),wat weereens 'n hoof-effek van stres aandui. AI drie intervensiegroepe (CA, IP, IA) het verlaagte GR bindingskapasiteit getoon, met lA wat 'n groot statistiese afname getoon het (CP vs. CA, p<O.05; IP vs. IA, p<O.01;CP vs. IP, p<O.001;CA vs. IA, p<O.001),wat hoof-effekte van beide stres en antiliggaam-behandeling aandui. In groepe IP and IA is toenames in beide ensiemaktiwiteitvlakke (TAT en GS ensieme) getoon (hoof-effek van stres), met IA wat weereens die grootste toename gewys het. Die lewer het ook verhoogde sensitiwiteit tot die stres- en antiliggaamregimente. Hierdie studie lewer die eerste daadwerklike in vivo bewyse vir IL-6 modulering van glukokortikoïedaksie in perifere weefsels na reaksie op psigologiese stres.

Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: This study investigated the activities of several of the enzymes involved in the alternative route of PEP metabolism via PEPc (EC 4.1.1.31). This reaction circumvents the adenyl ate-controlled PK (EC 2.7.1.40) reaction of the conventional glycolytic network under conditions of P stress. It was hypothesized that the synthesis of pyruvate under Pi stress would induce the PEPc alternative route and that C for pyruvate synthesis would primarily be imported via this route. This was assessed by looking at how total enzyme activities are perturbed under P stress and also by following the route of radioactive labelled 14C02 under sufficient (2 mM) and deficient P (2 JlM) conditions in either roots or nodules. The significance of the pathway under P stress, was further assessed by determining pool sizes of pyruvate that was synthesized from PEPc-derived C. The experiments were conducted under glasshouse conditions, as two separate studies: one to investigate the phenomenon of Pi stress and its consequences for PEPc-derived C metabolism, and the other one to study the enzymes involved. Seeds of Lupinus angustifolius (cv. Wonga) were inoculated with Rhizobium sp. (Lupinus) bacteria and grown in hydroponic culture. Tanks were supplied with either 2 JlM P04 (LP) or 2 mM P04 (control) and air containing 360 ppm CO2. Roots experienced pronounced P stress with a greater decline in Pi, compared to nodules. LP roots synthesized more pyruvate from malate than LP nodules, indicating the engagement of the PEPc route under Pi stress. In this regard, pyruvate is considered as a key metabolite under Pi stress. The role of pyruvate accumulation under Pi stress, was further highlighted by the metabolism of PEP via both the PK and PEPc routes. The enhanced PK activities supported these high pyruvate levels. Under P stress, PEPc activities increased in roots but not in nodules and these changes were not related to the expression of the enzyme. Root and nodular PEPc were not regulated by expression, but possibly by posttranslational control. The novelty of our results for symbiotic roots demonstrates that using metabolically available Pi is indeed a more sensitive indicator ofP stress. These results show that under Pi stress, nodules are able to maintain their Pi and adenylate levels, possibly at the expense of the root. It is suggested that nodules do not experience P stress to the same extent as roots or alternatively function optimally under conditions of low P availability. The increase in concentration of pyruvate synthesized from malate, indeed suggest that under LP conditions there is an increase requirement for pyruvate. It is clear from this data that the operation of bypass route in nodules should be investigated further. Nevertheless, this study provided incentives for understanding the role of C pathways in Ni-fixation, in particular under conditions ofP limitation. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die aktiwiteite van verskeie ensieme van die alternatiewe metaboliese roete via phosphoenolpirovaat karboksilase (pEPc, EC 4.1.1.31) te ondersoek. Dié reaksie omseil die adenilaat-beheerde pirovaatkinase (PK, EC 2.7.1.40) reaksie van die konvensionele glikolitiese weg onder toestande van fosfaat (P) stremming. Dit is gepostuleer dat die sintese van pirovaat onder toestande van Pstremming die alternatiewe roete via PEPc sou induseer en dat die koolstof (C) vir pirovaatsintese gevolglik hoofsaaklik vanaf hierdie roete sou kom. Dit is bepaal deur die veranderinge in die totale ensiemaktiwiteite wat sou plaasvind onder P-stremming te ondersoek. Daar is ook gekyk na die roete' wat radioaktiewe C C4C02) sou volg in wortles en wortelknoppies wat behandel is deur blootsteling aan eerder lae fosfaat (2 1lM) of genoegsame fosfaat (2 mM; kontrole), Die betekenis van die alternatiewe roete is ook ondersoek deur die poel-groottes van pirovaat, soos gesintetiseer via die PEPc reaksie, te bepaal. Twee eksperimente is in 'n glashuis uitgevoer. Eerstens is die verskynsel van Pstremming, asook die invloed daarvan op PEPc-afgeleide C-metabolisme, bepaal. Tweedens is die betrokke ensieme bestudeer. Sade van Lupinus angustifolius (cv. Wonga) is geïnokuleer met Rhizobium sp. (Lupinus) bakterieë en in 'n waterkultuur gekweek. Die houers is voorsien met óf2 IlM P04 (LP) óf 2 mM P04 (HP) en lug wat 360 ppm C02 bevat het. Wortels, anders as wortelknoppies, het 'n betekenisvolle afname in anorganiese P (Pi) ervaar. Onder P-stremming, het lae fosfaat wortels meer pirovaat vanaf malaat gesintetiseer as wortelknoppies, wat 'n definitiewe bydrae vanaf die PEPc roete impliseer. Hiervolgens is pirovaat 'n sleutel metaboliet onder P-stremming. Die belangrikheid van die akkumulering van pirovaat onder P-stremmende toestande is verder beklemtoon deur die toename in metabolisme van PEP via beide die PK- en die PEPcreaksies. Die toename in PK-aktiwiteite is goed gekorreleer met die verhoogde produksie van pirovaat. Onder toestande van P-stremming het die aktiwiteit van PEPc in wortels verhoog, maar nie in wortelknoppies nie. Dit was nie die gevolg van 'n verhoogde uitdrukking van die ensiem nie. Wortel- en wortelknoppie- uitdrukking van PEPc is derhalwe nie gereguleer deur die uitdrukking daarvan nie, maar eerder deur post-tranlasie kontrole. Hierdie resultate vir wortels met wortelknoppies demonstreer dat metaboliese Pi 'n beter maatstaf is om P-stres aan te dui. Hierdie resultate toon dat wortelknoppies beter daartoe instaat is om hul Pi-vlakke en adenilaatvlakke te reguleer, en dit mag ten koste van die gasheerwortel wees. Ons stel voor dat wortelknoppies nie P-stremming tot dieselfde mate ervaar as die gasheerwortel nie en dat dié knoppies optimaal funksioneer by lae Pi vlakke. Die verhoogde konsentrasie van pirovaat, wat vanaf malaat gesintetiseer is, impliseer dat daar 'n groter vereiste is vir dié metaboliet onder toestande van Pstremming. Hierdie studie het die rol van koolstofmetabolismein stikstofbindende organismes, spesifiek onder toestande van fosfaat-tekort, beklemtoon.

published_or_final_version / abstract / Ecology and Biodiversity / Doctoral / Doctor of Philosophy

Physiological responses of six sorghum (Sorghum bicolor (L.) Moench) hybrids and their respective parental lines were evaluated under high and low soil moisture conditions at Tucson, Arizona in 1980 and 1981. Apparent photosynthesis, transpiration, diffusive resistance, and temperature differential (ambient temperature minus leaf temperature) were measured under field conditions at weekly intervals. To measure apparent photosynthesis, a small plexiglas chamber was sealed over a section of leaf blade and gas was sampled with two syringes pulled at a 30 or 60 second interval. The gas samples were injected from the syringes into an infrared gas analyzer to measure CO(,2) concentrations. Transpiration, diffusive resistance, and temperature differential were measured with a steady state porometer. Regression analysis was used to compare the physiological performance of the germplasm sources over a wide range of environmental conditions. The physiological characteristics of the highest yielding sorghum hybrid in 1980 were the most stable across all environments. This hybrid was superior to both its male and female parent for all four physiological characteristics. In 1980, this hybrid was superior to the other hybrids in temperature differential and transpiration. The superior yielding hybrid had the highest mean apparent photosynthesis and the lowest mean diffusive resistance. All hybrids had higher yields than their respective male parents under both irrigation treatments. Thirty-five days after planting, the superior yielding hybrid had the greatest leaf, stem, and root dry weights. This hybrid also had the highest relative leaf area expansion rate. Heterosis for stomatal density was not observed either year. Regression analysis proved to be an effective tool for analyzing the sorghum germplasm over a diverse range of environmental conditions. By comparing the response of an individual germplasm against the mean response of the population under numerous environmental conditions, the slope, mean, and coefficient of correlation may be used to evaluate genotype-environment interactions.

The development, yield and water use of six sorghum (Sorghum bicolor (L.) Moench) hybrids and their respective male and female parents were evaluated under stressed and well irrigated conditions during 1980 and 1981 at Tucson, Arizona. Changes in soil moisture storage were measured by neutron modulation on a semiweekly schedule. Transpiration, diffusive resistance and leaf-ambient temperature differentials were monitored biweekly using a steady state porometer. Meteorological data was collected on a daily basis. The 1980 season had higher maximum temperatures and pan evaporation than the 1981 season. Differences in soil moisture extraction among sorghum entries were not apparent within water treatments. Mean cumulative evapotranspiration (ET) for the stressed treatment was 270 and 261 mm, for 1980 and 1981, respectively. Mean cumulative ET for irrigated treatment was about twice that at 520 and 648 mm during 1980 and 1981, respectively. There were no apparent differences in cumulative ET for entries in the stressed treatment while genotypic differences were manifested under well irrigated conditions. Temperature differential demonstrated a significant and negative correlation with diffusive resistance especially under stressed conditions (r = -.64 in 1981). Temperature differential was positively correlated with transpiration (r = .70 in 1980 stressed treatment). Plant height was significantly affected by water level both years while stem weight was affected by water level only in 1980. Soil moisture treatments did not affect leaf area either year and genotypic differences were demonstrated only in 1981. Hybrids produced greater grain yield than their male parents under both water treatments. This was due to greater seed number for hybrids. Seed number was also more stable for hybrids under both moisture levels. Hybrids four and seven had the greatest grain yield in 1980 and 1981, respectively. Harvest index was improved with increased water application due to increased seed number. Hybrid four in 1980 and hybrid seven in 1981 were extremely efficient in water use exhibiting ET ratios of 283 and 378, respectively under high water application. Reduced water application had little affect on the performance of these entries.

This study was conducted to investigate the effects of four drip irrigation treatments on five fruiting characteristics of cotton (Gossypium hirsutum L.) using periodic observations to gauge the relative impact of these effects over time. The fruiting characteristics measured were: (1) number of flowers, (2) percent boll set, (3) number of bolls, (4) weight boll-1, and (5) seedcotton production. The irrigation treatments included four levels that in total season applied irrigation equaled 60, 68, 76, and 83 cm of water. Periodic observations included three, 3-week-intervals from the onset of flowering (26 June) to cutout (29 August). Results indicate that irrigation treatments had a significant effect on all characters measured, only in the later stages of development (later in the season) with higher amounts of irrigation applied producing higher levels of each character measured. Significant differences were found among periods of observation for all characters measured.

M.A. / Violence exacts an enormous social cost which is concerned with the loss of self-respect in both the perpetrators, the victims as well as the family and the broader social community. The purpose of this study was to describe the link between environmental violence and family well-being so as to develop effective intervention strategies for social work practice and community development. This study was conducted within Zola Primary Health Care Clinic in Soweto. A questionnaire was used as a method of gathering data that was required. The researcher used an exploratory descriptive design. It was found in this study that environmental violence has an impact on family well-being. The results of the study indicated that there is a significant difference between the type of environmental violence that was experienced by the victim e.g. rape/sexual abuse especially whereby the perpetrator is a family member or relative. The results showed that family well-being was affected in a way that victims felt less power, less goal-inclined, less safe within their own families as well as within their own communities. The family well-being is also affected by several factors such as housing, marital status, age, education. For an example the results showed that victims of violence with a higher level of education felt more power, more goal-inclined and safer within their families and within their own communities. Recommendations for social work practice and community development were drawn whereby the importance of knowing and understanding the needs of the victims were highlighted – before effective intervention can take place. / Dr. E. Oliphant

Orientador: Sonia Marli Zingaretti / Coorientador: Durvalina Maria Mathias dos Santos / Banca: Isabela Cristina Gomes Honório / Banca; Jackson Antonio Marcondes de Souza / Resumo: A cana-de-açúcar é atualmente uma das principais culturas da agroindústria mundial. Devido à ampla expansão de seu plantio é submetida constantemente a solos não produtivos. A presença de moléculas tóxicas no solo, como o alumínio (Al3+), interfere diretamente no desenvolvimento radicular ocasionando baixa absorção de água e nutrientes levando a pouca produtividade e desenvolvimento das plantas. Os microRNAs tem sido descritos como um dos fatores responsáveis pela regulação gênica e a descoberta dessas moléculas abre um novo caminho para a elucidação da tolerância e adaptação das plantas aos estresses abióticos. Este estudo visou avaliar em duas cultivares de cana-de-açúcar (CTC-2 e RB855453) a expressão dos microRNAs miR159, miR164 e miR168, associados à resposta ao alumínio em espécies como Arabidopsis thaliana, arroz (Oriza sativa) e tabaco (Nicotiana tabacum). Algumas características foram avaliadas, como densidade de raízes (DS), área foliar (AR), produção de massa seca (MS) e teor de prolina nas folhas, em quatro cultivares de cana-de-açúcar submetidas a diferentes concentrações de alumínio. A cultivar CTC 2 foi classificada como tolerante e a RB855453 como sensível ao estresse. Ambas foram selecionadas e em sistema de hidroponia submetidas novamente ao estresse pela toxidez de alumínio na concentração de 221 μmol L -1 . Parâmetros fisiológicos foram mensurados (área foliar, potencial osmótico, taxa de fotossíntese, transpiração, condutância estomát... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The sugarcane is currently one of the main crops of global agribusiness. Due to the wide expansion of its plantation is constantly subjected unproductive soils. The presence of toxic molecules in the soil, such as aluminum (Al3+), directly affects root development, leading to poor absorption of nutrients and water leading to low productivity and development of plants. Studies of the interactions of plants with the environment are being conducted to clarify the resistance or susceptibility of various cultures, favoring the discovery of important mechanisms that participate in physiological and molecular responses to environmental stresses. MicroRNAs have been described as one of the factors responsible for gene regulation and the discovery of these molecules opens a new path for the elucidation of tolerance and adaptation of plants to abiotic stresses. This study evaluated in two sugarcane varieties the expression of microRNA miR159, miR164 and miR168, associated with the response to the aluminum species such as Arabidopsis thaliana, rice (Oryza sativa) and tobacco (Nicotiana tabacum). Some characteristics were evaluated, such as density (DS), area (AR), dry mass production (DM) and proline content, in four sugarcane cultivars submitted to different concentrations of aluminum. CTC 2 cultivar was classified as tolerant and RB855453 as stress sensitive. Both were selected and in a hydroponics system again submitted to stress by the aluminum toxicity in the conc... (Complete abstract click electronic access below) / Mestre

Orientador: Regiane Cristina Oliveira de Freitas Bueno / Banca: Thiago Assis Rodrigues Nogueira / Banca: Marcelo de Almeida Silva / Banca: Simone de Souza Prado / Resumo: As mudanças climáticas previstas para os próximos anos indicam incremento na temperatura em 1,4°C a 5,8°C em decorrência, principalmente, do aumento da concentração dos gases de efeito estufa, além de alterações na umidade relativa e taxas de CO2 da atmosfera terrestre. Essa mudança influenciará diretamente nos regimes de chuvas, promovendo veranicos e/ou excessos em determinadas regiões. Dessa forma, o objetivo da dissertação foi avaliar os efeitos do estresse hídrico em plantas de milho Bt sob situações de estresse frente ao ataque de S. frugiperda. O delineamento experimental utilizado foi em esquema fatorial triplo em blocos casualizados com quatro lâminas de irrigação (estimadas a partir da tensão do solo): L1- 50% da capacidade de campo (CC) considerada estresse severo, L2- 75% CC estresse moderado, L3- 100% CC controle e L4-125% CC excesso de água; três eventos de milho: PowerCore® (Cry1A.105 Cry2Ab2 Cry1F PAT CP4-ESPS), Herculex ® (Cry1F PAT) e Optimum® Intrasect® (Cry1Ab Cry1F PAT CP4-EPSPS) e três infestações (sem infestação, população S. frugiperda suscetível ao milho Bt e população S. frugiperda resistente ao Bt). Quando as plantas atingiram o estádio fenológico de V8 (fase considerada mais suscetível ao ataque de S. frugiperda e de maior atuação dos mecanismos de ativação de sistema enzimático) foram infestadas artificialmente, por 24h e após este período folhas do terço médio da planta foram coletas para análise enzimática. Os híbridos que ficaram sob estresses... / Abstract: The climate changes foreseen for the next years show an increase in temperature of 1.4°C to 5.8°C, mainly due to the increase in the concentration of greenhouse gases, besides relative humidity alterations and CO2 rates changes of the Earth's atmosphere. This change will directly influence rainfall regimes, promoting summer and / or excess in certain regions. Thus, the objective of the dissertation was to evaluate the effects of water stress in Bt maize plants under stress situations facing the attack of S. frugiperda. The experimental design used was a randomized triple block design with four irrigation slides (estimated from soil tension): L1- 50% of field capacity (CC) severe stress, L2-75% CC moderate stress, L3 -100% CC control and L4-125% CC water excess; (Cry1A.10 Cry1A PAT C4-EPSPS), Herculex® (Cry1F PAT) and Optimum® Intrasect® (Cry1Ab Cry1F PAT CP4-EPSPS) and three infestations (non-infestation, susceptible S. frugiperda population to Bt maize and Bt resistant S. frugiperda population). When plants reached the phenological stage of V8 (phase considered more susceptible to S. frugiperda attack and of greater performance of the mechanisms of activation of enzymatic system), they were infested artificially for 24 hours. After this period, leaves of the middle third of the plant were collected for enzymatic analysis. The development of the hybrids that were under water stresse was slower than other hybrid studied. On the other hand, the analyzes and determinations of e ... / Mestre

Orientador: Sonia Marli Zingaretti / Banca: Tiago Antunes Paz / Banca: Janete Apparecida Desiderio / Resumo: A cana-de-açúcar é acometida por uma doença conhecida por "escaldadura das folhas" causada pela bactéria colonizadora do xilema Xanthomonas albilineans, considerada uma das principais doenças que atingem a cultura da canade-açúcar. A sintomatologia na fase crônica se caracteriza, principalmente, pelo aparecimento de uma faixa branca ao lado da nervura central da folha, a qual evolui para clorose total causando a morte da planta. Uma vez que o patógeno pode ser transmitido de várias maneiras, o seu controle demanda altos custos. Desta maneira, o desenvolvimento de cultivares tolerantes é uma boa opção para o controle efetivo da doença. A tolerância e sensibilidade das plantas aos fatores bióticos está relacionada com a expressão de genes, e dentre estes, os miRNAs (incluindo o miR397 e o miR319) têm sido relatados como importantes reguladores em vários mecanismos de resposta das plantas. O objetivo deste trabalho foi analisar a expressão de dois miRNAs (miR319 e miR397) em duas cultivares de cana-de-açúcar (RB86-7515 - tolerante e SP78-4467 - suscetível), infectadas por uma linhagem de X. albilineans (IACXa11), considerada a mais virulenta do Brasil. Para isto, as plantas foram cultivadas em vasos, inoculadas com X. albilineans e mantidas em casa de vegetação. Amostras de folhas e colmos foram coletadas em cinco períodos (24, 72, 144, 360 e 720 h) e a expressão dos miRNAs foi analisada pela técnica de Stem-loop RT-qPCR. Os miR397 e miR319 apresentaram-se diferencialmente expre... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Sugarcane is affected by a disease known as "leaf scald" caused by the bacterium Xanthomonas albilineans, which colonizes the xylem. This disease is one of the most important for sugarcane culture. The chronic phase is mainly characterized by the white band emergence along the central leaf vein, which causes total chlorosis of the leaf and plant death. Since the pathogen can be transmitted in many ways, his control demands high costs, and the development of tolerant cultivars is a good option for disease control. The plant tolerance and sensitivity to biotic factors is related to gene expression, and among these, the miRNAs (including miR397 and miR319), have been reported as important regulators in various plant response mechanisms. The aim of this work was to analyze the expression of two miRNAs (miR319 and miR397) in two sugarcane cultivars (RB86-7515 - tolerant, and SP78- 4467 - susceptible), infected by a strain of X. albilineans (IACXa11), the most virulent in Brazil. The plants were grown in vases, inoculated with X. albilineans and kept in a greenhouse. Samples of leaves and stems were collected in five periods (24, 72, 144, 360, and 720 h), and the miRNA expression was analyzed by Stem-loop RT-qPCR. The miR397 and miR319 expression were different between cultivars and tissues. In the susceptible cultivar (SP78-4467), during the first infection periods (24, 72 and 144 h), there was a late defense response when compared to the tolerant cultivar (RB86-7515). The miR319 presented the same expression profile in leaves and stems of the cultivar RB86-7515 (tolerant), suggesting that the pathogen recognition and defense mechanisms activation were modulated in both tissues. In general, miRNAs analyzes demonstrated that miR397 expression is lower when compared to miR319. The sa... (Complete abstract click electronic access below) / Mestre