Wheat drought-responsive WXPL transcription factors regulate cuticle biosynthesis genes

Published online: 4 February 2017The cuticle forms a hydrophobic waxy layer that covers plant organs and provides protection from biotic and abiotic stresses. Transcription of genes responsible for cuticle formation is regulated by several types of transcription factors (TFs). Five orthologous to WAX PRODUCTION (WXP1 and WXP2) genes from Medicago truncatula were isolated from a cDNA library prepared from flag leaves and spikes of drought tolerant wheat (Triticum aestivum, breeding line RAC875) and designated TaWXP-like (TaWXPL) genes. Tissue-specific and drought-responsive expression of TaWXPL1D and TaWXPL2B was investigated by quantitative RT-PCR in two Australian wheat genotypes, RAC875 and Kukri, with contrasting glaucousness and drought tolerance. Rapid dehydration and/or slowly developing cyclic drought induced specific expression patterns of WXPL genes in flag leaves of the two cultivars RAC875 and Kukri. TaWXPL1D and TaWXPL2B proteins acted as transcriptional activators in yeast and in wheat cell cultures, and conserved sequences in their activation domains were localised at their C-termini. The involvement of wheat WXPL TFs in regulation of cuticle biosynthesis was confirmed by transient expression in wheat cells, using the promoters of wheat genes encoding two cuticle biosynthetic enzymes, the 3-ketoacyl-CoA-synthetase and the cytochrome P450 monooxygenase. Using the yeast 1-hybrid (Y1H) assay we also demonstrated the differential binding preferences of TaWXPL1D and TaWXPL2B towards three stress-related DNA cis-elements. Protein structural determinants underlying binding selectivity were revealed using comparative 3D molecular modelling of AP2 domains in complex with cis-elements. A scheme is proposed, which links the roles of WXPL and cuticle-related MYB TFs in regulation of genes responsible for the synthesis of cuticle components.Huihui Bi, Sukanya Luang, Yuan Li, Natalia Bazanova, Nikolai Borisjuk, Maria Hrmova, Sergiy Lopat

Generation of drought-resistant transgenic cereals using transcription factors isolated from wheat grain

Tese de doutoramento em Ciências da Saúde, ramo de Medicina, na especialidade de Medicina Interna (Cardiologia), apresentada à Faculdade de Medicina da Universidade de Coimbr

Molecular interaction of the gamma-clade homeodomain-leucine zipper class I transcription factors during the wheat response to water deficit

The ᵧ-clade of class I homeodomain-leucine zipper (HD-Zip I) transcription factors (TFs) constitute members which play a role in adapting plant growth to conditions of water deficit. Given the importance of wheat (Triticum aestivum L.) as a global food crop and the impact of water deficit upon grain yield, we focused on functional aspects of wheat drought responsive HD-Zip I TFs. While the wheat ᵧ-clade HD-Zip I TFs share significant sequence similarities with homologous genes from other plants, the clade-specific features in transcriptional response to abiotic stress were detected. We demonstrate that wheat TaHDZipI- 3, TaHDZipI-4, and TaHDZipI-5 genes respond differentially to a variety of abiotic stresses, and that proteins encoded by these genes exhibit pronounced differences in oligomerisation, strength of DNA binding, and trans-activation of an artificial promoter. Three-dimensional molecular modelling of the protein-DNA interface was conducted to address the ambiguity at the central nucleotide in the pseudo-palindromic cis-element CAATNATTG that is recognised by all three HD-Zip I proteins. The coexpression of these genes in the same plant tissues together with the ability of HD-Zip I TFs of the ᵧ -clade to heterodimerise suggests a role in the regulatory mechanisms of HD-Zip I dependent transcription. Our findings highlight the complexity of TF networks involved in plant responses to water deficit. A better understanding of the molecular complexity at the protein level during crop responses to drought will enable adoption of efficient strategies for production of cereal plants with enhanced drought tolerance.John C. Harris, Pradeep Sornaraj, Mathew Taylor, Natalia Bazanova, Ute Baumann, Ben Lovell, Peter Langridge, Sergiy Lopato, Maria Hrmov

Complex regulation by Apetala2 domain-containing transcription factors revealed through analysis of the stress-responsive TdCor410b promoter from durum wheat

Expression of the wheat dehydrin gene Cor410b is induced several fold above its non-stressed levels upon exposure to stresses such as cold, drought and wounding. Deletion analysis of the TdCor410b promoter revealed a single functional C-repeat (CRT) element. Seven transcription factors (TFs) were shown to bind to this CRT element using yeast one-hybrid screens of wheat and barley cDNA libraries, of which only one belonged to the DREB class of TFs. The remaining six encoded ethylene response factors (ERFs) belong to three separate subfamilies. Analysis of binding selectivity of these TFs indicated that all seven could bind to the CRT element (GCCGAC), and that three of the six ERFs could bind both to the CRT element and the ethylene-responsive GCC-box (GCCGCC). The TaERF4 subfamily members specifically bound the CRT element, and did not bind either the GCC-box or DRE element (ACCGAC). Molecular modeling and site-directed mutagenesis identified a single residue Pro42 in the Apetala2 (AP2) domain of TaERF4-like proteins that is conserved in monocotyledonous plants and is responsible for the recognition selectivity of this subfamily. We suggest that both DREB and ERF proteins regulate expression of the Cor410b gene through a single, critical CRT element. Members of the TaERF4 subfamily are specific, positive regulators of Cor410b gene expression.Omid Eini, Nannan Yang, Tatiana Pyvovarenko, Katherine Pillman, Natalia Bazanova, Natalia Tikhomirov, Serik Eliby, Neil Shirley, Shoba Sivasankar, Scott Tingey, Peter Langridge, Maria Hrmova, Sergiy Lopat

Tissue specific promoters from rice and wheat for modifying grain characteristics

Trabalho final do 6º Ano Médico com vista à atribuição do grau de mestre no âmbito do ciclo de estudos de Mestrado Integrado em Medicina, apresentada à Faculdade de Medicina da Universidade de CoimbraA tiroidite, inflamação da glândula tiroideia, é, juntamente com o bócio, a afecção endócrina mais frequente, sendo comummente encontrada em medicina ambulatória. Associada a uma função tiroideia normal, aumentada ou diminuída (frequentemente com evolução de uma condição para outra), as circunstâncias da sua descoberta podem ser variadas e a distinção dos seus vários tipos baseia-se, essencialmente, no panorama clínico, rapidez de instalação sintomática, história familiar e presença ou ausência de sintomas prodrómicos e dor no pescoço. Vários critérios podem ser utilizados para a sua classificação, nomeadamente histológicos e clínicos (acompanhada ou não de dor tiroideia), sendo, contudo, a evolução da doença o critério classicamente utilizado. Assim, de acordo com este último, os diferentes subtipos de tiroidite podem ser agrupados em: tiroidite aguda, tiroidite subaguda ou tiroidite crónica. A primeira é uma forma dolorosa de tiroidite extremamente rara causada por uma infecção bacteriana, fúngica ou parasitária da tiróide e surgindo, sobretudo, na criança/adolescente e adulto jovem. Nas tiroidites subagudas, podemos encontrar a tiroidite subaguda granulomatosa ou de De Quervain – causa mais frequente de dor tiroideia, eventualmente, de origem viral – e as tiroidites subagudas linfocíticas – tiroidites esporádica indolor, do pós-parto, iatrogénica (interferão, interleucina-2, lítio), tóxica (amiodarona), por irradiação (iodo 131, irradiação externa) ou traumática (cirurgia, punção, traumatismo externo). Finalmente, nas tiroidites crónicas, caracterizadas, portanto, por um maior tempo de evolução, podemos destacar a tiroidite de Riedel, de natureza fibrótica e fisiopatologia desconhecida, e a tiroidite de Hashimoto, a tiroidite mais frequente e causa mais comum de hipotiroidismo nas regiões com aporte suficiente de iodo e da qual as tiroidites esporádica indolor e do pós-parto se aproximam pelo seu carácter autoimune. O diagnóstico destas afecções é feito pelo contexto e achados clínicos, incluindo a presença ou ausência de dor, textura e autoanticorpos. Adicionalmente, o grau de absorção de iodo radioactivo pela iii glândula é reduzido na maioria dos pacientes com inflamação viral, induzida por radiação, traumática, autoimune ou induzida por drogas. O tratamento é, primeiramente, dirigido ao alívio sintomático da dor tiroideia e restabelecimento do eutiroidismo.Thyroiditis, inflammation of the thyroid gland, is, along with goiter, the most frequent endocrine pathology, being commonly found in ambulatory medicine. Associated with normal, elevated or depressed thyroid function (often with evolution from one condition to another), the circumstances of its discovery are varied and the distinction of its several types is based primarily on the clinical setting, rapidity of symptom onset, family history and presence or absence of prodromal symptoms and neck pain. Different criteria can be used to its classification, namely histological and clinical (with thyroid pain or not). Nevertheless, the evolution of the disease is the classically used criterion. Thus, accordingly with this one, the several subtypes of thyroiditis can be divided into: acute thyroiditis, subacute thyroiditis and chronic thyroiditis. The first one is an extremely rare painful form of thyroiditis cause by a bacterial, fungic or parasitic infection of the thyroid and it in children/adolescents and young adults. In subacute thyroiditis, we can have the subacute granulomatous or de De Quervain thyroiditis – most common cause of thyroid pain, eventually of viral original – and the subacute lymphocytic thyroiditis – sporadic painless, postpartum, iatrogenic (interferon, interleukin-2, lithium), toxic (amiodarone), by irradiation (iodine 131 and external irradiation) or traumatic (surgery, puncture or external traumatism) thyroiditis. Finally, in chronic thyroiditis, characterized, therefore, by a longer time of evolution, we can mention Riedel’s thyroiditis, of fibrotic nature and unknown physiopathology, and Hashimoto’s thyroiditis, the most frequent thyroiditis and the most common cause of hypothyroidism in the regions with an adequate iodine supply, from which the sporadic painful and postpartum thyroiditis are close by their autoimune character. Diagnosis is by clinical context and findings, including the presence or absence of pain, tenderness and autoantibodies. In addition, the degree of radioactive iodine uptake by the gland is reduced in most patients with viral, radiation-induced, traumatic, autoimmune, or drug-induced inflammation of the thyroid. Treatment primarily is directed at symptomatic relief of the thyroid pain and restoration of euthyroidism

Механизм формирования пленок SnS химическим осаждением из водных растворов

The results of investigation of the growth mechanism of SnS thin films prepared by hydrochemical deposition by means of a scanning probe microscopy are presented. According to the results of a comparative analysis of layers morphology at different growth stages and the use of fractal formalism growth model of SnS films by clustercluster aggregation with elements of self-organization is proposed. It is shown that there is a solid layer, which again are deposited particles of the solution. The process has expressed periodic self-organizing nature. The study showed that the proposed model of film growth SnS when hydrochemical deposition agrees well with ex-periments and proves difficult coagulation mechanism of the formation of hard phase of the saturated aqueous solution.В работе представлены результаты исследования механизма роста пленок сульфида олова при химическом осаждении из водных растворов с использованием сканирующей зондовой микроскопии. По результатам сравнительного анализа морфологии слоев на различных этапах роста и использования фрактального формализма предложена модель роста пленок SnS путем кластер-кластерной агрегации с элементами самоорганизации