Zinc (Zn) is an essential micronutrient for the growth and development of all organisms. Zinc deficiency is a widespread micronutrient disorder worldwide, which reduces crop yields and the nutritive value of the grain. Understanding the process of zinc absorption and translocation in crop is essential for this purpose. Zinc is taken up by plants and translocated within plants through high-affinity zinc transporter proteins embedded in the plasma membrane. The Zn transporters are induced under Zn deficiency, and it is speculated that the expression levels of some of zinc transporters are critical for improved tolerance to low zinc. A number of Zn transporters have been cloned from higher plants including rice and Arabidopsis, but little has been done in barley and wheat. This project aims to investigate genes involveld in zinc efficiency mechanism by complementation analysis in yeast, which is double mutant of zinc-transporters, using cDNA expression library from a most zinc efficient barley cultivar, Tokak-157.

Yellow rust disease is one of the most important problems in wheat production. It causes substantial yield losses throughout the world. There are resistant and susceptible wheat varieties to various yellow rust pathotypes. In this thesis genes that are induced in wheat, in virulence and avirulence conditions upon yellow rust inoculations were investigated. Consequently, it was aimed to identify genes that may be playing critical roles in the disease resistance mechanism. The strategy was to construct subtracted cDNA libraries from resistant and susceptible plants and analyse the sequences obtained from these libraries. The subtraction approach in this study differs from the common subtraction designs implicated in plant-pathogen interactions / instead of comparing a compatible or an incompatible interaction with a control, one of the subtractions in this study is done taking a compatible interaction as the tester and an incompatible one as the driver, and the second subtraction, vice versa. Therefore, it was intended to compare the transcriptomes from compatible and incompatible plant-pathogen interactions directly. Suppression Subtractive Hybridization method was used to construct subtracted cDNA libraries. Two subtractions were performed / SSH1 (D-R), taking a compatible interaction as the tester sample and an incompatible one as the driver sample, and SSH2 (R-D), taking an incompatible interaction as the tester sample and a compatible one as the driver. In the end, two subtracted cDNA libraries, SSH1 (D-R) library (1536 clones) and SSH2 (R-D) library (1152 clones) were obtained and the libraries were sequenced. Sequence results were subjected to BlastN and BlastX analysis. We looked for a group of genes that were frequently emphasized in plant disease related studies when we searched within the Blast N homology results of the two libraries. We found out that 19 such genes are present in our libraries. We discussed supposed induction of these genes in the interactions investigated in our study. The fact that these genes were found to be present in our libraries enhances the reliability of our results suggesting that the gene sequences we found indeed belong to genes differentially expressed in the respective comparisons investigated in our study. As such, it also implies that other sequences that were found similar to genes of known functions may represent candidate genes as subjects of further studies investigating wheat-yellow rust interactions.

Verticillium wilt is a serious disease in a wide range of economic crops worldwide. Verticillium wilt of potato is caused, primarily, by the fungus Verticillium dahliae. Disease management requires understanding of V. dahliae pathogenesis and interactions with potato, which was the main objective of this study. A differential potato-V. dahliae pathosystem was established where pathogenicity of four V. dahliae isolates with different levels of aggressiveness was evaluated on two potato cultivars, Kennebec (susceptible) and Ranger Russet (moderately resistant). External and internal symptoms and growth measurements revealed that isolates Vd1396-9 and Vs06-14 are highly and weakly aggressive, respectively. These two isolates were selected for transcriptomics and proteomics investigations to identify pathogenicity-related factors. Transciptomics analysis was conducted in both isolates after elicitation by root extracts from either Kennebec or Ranger Russet using a combinational approach involving subtractive hybridization and cDNA-AFLP. A total of 573 differentially expressed transcripts were detected in one or the other isolate. Among them, 185 transcripts of interest were recovered, re-amplified, sequenced and searched against NCBI and the Broad Institute V. dahliae genome databases for identification. The two contrasting-aggressiveness isolates were used for a comparative proteomics investigation. The first proteomic map of V. dahliae was established. The proteomics analysis was carried out using 2-Dimentional electrophoresis and mass spectrometry. Twenty five proteins were differentially expressed and identified in one or the other isolate. Many of the identified genes/proteins showed potential involvement in pathogenesis of V. dahliae or other fungi. Genes of stress response regulator A (oxidative stress tolerance factor), isochorismatase hydrolase (potential plant defense suppressor) and tetrahydroxynaphthalene reductase (involved in melanin and microsclerotia formation) were isolated from both isolates and cloned. Sequence analysis of these genes showed many differences that may explain their differential expression in the two isolates. Given that some of the identified genes/proteins are potentially involved in overcoming and suppressing plant defense, phenolics were profiled in Kennebec-inoculated with Vd1396-9 or Vs06-14 isolate. Chlorogenic, caffeic, ferulic acids, cis-jasmone and rutin accumulation showed variations after inoculation. The results obtained from this study will help understanding the V. dahliae-potato interactions and develop efficient strategies to control Verticillium wilt disease.

Verticillium wilt is a serious disease in a wide range of economic crops worldwide. Verticillium wilt of potato is caused, primarily, by the fungus Verticillium dahliae. Disease management requires understanding of V. dahliae pathogenesis and interactions with potato, which was the main objective of this study. A differential potato-V. dahliae pathosystem was established where pathogenicity of four V. dahliae isolates with different levels of aggressiveness was evaluated on two potato cultivars, Kennebec (susceptible) and Ranger Russet (moderately resistant). External and internal symptoms and growth measurements revealed that isolates Vd1396-9 and Vs06-14 are highly and weakly aggressive, respectively. These two isolates were selected for transcriptomics and proteomics investigations to identify pathogenicity-related factors. Transciptomics analysis was conducted in both isolates after elicitation by root extracts from either Kennebec or Ranger Russet using a combinational approach involving subtractive hybridization and cDNA-AFLP. A total of 573 differentially expressed transcripts were detected in one or the other isolate. Among them, 185 transcripts of interest were recovered, re-amplified, sequenced and searched against NCBI and the Broad Institute V. dahliae genome databases for identification. The two contrasting-aggressiveness isolates were used for a comparative proteomics investigation. The first proteomic map of V. dahliae was established. The proteomics analysis was carried out using 2-Dimentional electrophoresis and mass spectrometry. Twenty five proteins were differentially expressed and identified in one or the other isolate. Many of the identified genes/proteins showed potential involvement in pathogenesis of V. dahliae or other fungi. Genes of stress response regulator A (oxidative stress tolerance factor), isochorismatase hydrolase (potential plant defense suppressor) and tetrahydroxynaphthalene reductase (involved in melanin and microsclerotia formation) were isolated from both isolates and cloned. Sequence analysis of these genes showed many differences that may explain their differential expression in the two isolates. Given that some of the identified genes/proteins are potentially involved in overcoming and suppressing plant defense, phenolics were profiled in Kennebec-inoculated with Vd1396-9 or Vs06-14 isolate. Chlorogenic, caffeic, ferulic acids, cis-jasmone and rutin accumulation showed variations after inoculation. The results obtained from this study will help understanding the V. dahliae-potato interactions and develop efficient strategies to control Verticillium wilt disease.

Aspergillus fumigatus is a foodborne and airborne human pathogen which produces mycotoxins such as gliotoxin, helvolic acid, fumigallin, and fumigaclavin. The most common disease caused by A. fumigatus is aspergillosis, which is often fatal, especially among AIDS, cancer, and organ-transplant patients. In this study, random cDNA cloning was performed from a cDNA library of A. fumigatus (IMI 385708) constructed on &amp / #955 / ZAP Express. Some of these clones were selected according to their insert sizes and were further subjected to sequence analysis. The sequences were then analyzed by a BLAST search (NCBI Genome Database) to determine the possible functions of these genes. Two of the clones were identified as the primase and 60S ribosomal protein L1-b genes. These genes and a third gene corresponding to the antigenic cell wall galactomannoprotein gene of A. fumigatus were used for the design of three distinct primer pairs. For the primer design, a software was written to differentiate nonconserved regions by multiple sequence alignment. Designed primers were employed in PCR experiments against genomic DNAs of different Aspergillus species. Unique bands were obtained only against A. fumigatus genomic DNA. It was concluded that this PCR-based detection method can be further developed for the rapid detection of A. fumigatus spores from air and food samples.

No description available.

Thesis (MSc (Plant Biotechnology))--University of Stellenbosch, 2010. / Includes bibliography. / Title page: Dept. of Genetics, Faculty of Science / ENGLISH ABSTRACT: Recent advances in medical pharmacology have identified the immune-potentiating effects of β-1,3-glucans on mammalian immune systems. Extensive research has identified and described the mechanisms of action and receptor binding specificity of different β-1,3-glucans as well as their structural and functional relationships. Molecular mass, solubility, structural order, degree of branching as well as chemical modification all determine the effectiveness of the β-1,3-glucan immune-modulating activities, which typically include; macrophage activation, antibody adjuvant activities, reduction of LDL-cholesterol, leukocyte mitogenic activities, cytokine and chemokine production as well as antiviral and antitumor activities. Currently β-1,3-glucans have been sold commercially under the name β-glucan, mostly in the form of Betafectin, a genetically modified yeast derived β-1,3-glucan. Recent studies of different β-1,3-glucans have identified the pharmacological activities of paramylon, a Euglena derived β-1,3-glucan. Although paramylon has relatively low immune-stimulating activities, chemical modification of the paramylon granule increased immune-potentiation with specific antimicrobial and anti-HIV activities. Due to these specific immune-potentiating activities, paramylon is novel in terms of both structure as well as functional activity. In terms of biotechnological application, paramylon is greatly favoured as it is synthesized as an insoluble membrane bound granule in the cytosol of Euglena where most plant and fungal β-1,3-glucan synthases are cell membrane bound highly regulated multifunctional complexes, synthesizing β-1,3-glucan as cell wall components. Due to the novel granular nature of paramylon, expression in other systems with genetic modification could potentially further increase immuno-potentiating activities. In this study, different approaches were attempted in order to identify the genes involved in paramylon synthesis including; constructing and screening a Euglena gracilis cDNA library, sequence analysis of the purified proteins as well as transcription analysis of the sequenced transcriptome and genome of E. gracilis. Putative candidates that encode subunits of the paramylon synthase complex have been identified. / AFRIKAANSE OPSOMMING: Onlangse vordering in mediese farmakologie het die immuun-stimulerende effek van β-1,3-glukane op die soogdier immuunsisteem geïdentifiseer. Intensiewe navorsing het die meganisme van die werking en reseptor bindingspesifisiteit van verskillende β-1,3-glukane, asook hulle struktuur en funksionele verhoudings, geïdentifiseer. Die molekulêre massa, oplosbaarheid, strukturele orientasie, mate van vertakking asook chemiese modifikasies bepaal almal die effektiwiteit van die β-1,3-glukaan immuun-modulerende aktiwiteite. Tipiese immuno-moduleringsaktiwiteite sluit makrofaag aktivering, teenliggaampie adjuvant aktiwiteite, verlaging van LDL-cholesterol, leukosiet mitogeniese aktiwiteite, sitokien en chemokien produksie asook anti-virale en antitumor aktiwiteite in. Huidiglik word β-1,3-glukane onder die naam β-glukaan verkoop meestal in die vorm van Betafectin, ‘n geneties gemodifiseerde gis wat van β-1,3-glukaan afkomstig is. Onlangse studies van verskillende β-1,3-glukane het die farmakologiese aktiwiteit van paramylon, ‘n Euglena afkomstige β-1,3-glukaan geïdentifiseer. Alhoewel paramylon relatiewe lae immuun-stimulerende aktiweite toon, verhoog chemiese modifikasies van die paramylon granules immuun-stimulering, spesifiek die anti-mikrobiese en anti-MIV aktiwiteite. Weens hierdie spesifieke immuun-stimulerende aktiweite, word paramylon as nuut beskou veral in terme van beide struktuur asook funksionele aktiwiteit. In terme van biotegnologiese toepassing, verkry paramylon voorkeur aangesien dit as ‘n onoplosbare membraangebonde granule in die sitosol van Euglena gesintetiseer word terwyl meeste plant en fungus β-1,3-glukaan sintases hoogs gereguleerde multifunksionele selmembraan gebonde komplekse is wat β-1,3-glukaan asook ander selwand komponente sintetiseer. Weens die unieke granulêre natuur van paramylon, sal uitdrukking in ander sisteme ‘n moontlike industrie skep waar deur die transgeniese uitdrukking van granulêre paramylon verdere verbetering van die immuun-stimulerings aktiwiteite kan lei. In hierdie studie is verskillende benaderings aangewend om die gene wat by paramylon sintese betrokke is te identifiseer, dit sluit in die konstruksie en sifting van ‘n E. gracilis cDNS biblioteek, aminosuur volgorde analise van gesuiwerde proteiene asook die transkripsionele analise van die volgorde van die transkriptoom en genoom van E. gracilis. Moontelike kandidate wat vir die subeenhede van die paramylon syntase kompleks kodeer is geïdentifiseer.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2018-04-03T17:06:06Z No. of bitstreams: 1 texto completo.pdf: 2556158 bytes, checksum: 27b067863ed5da400bb343a3468852f4 (MD5) / Made available in DSpace on 2018-04-03T17:06:06Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2556158 bytes, checksum: 27b067863ed5da400bb343a3468852f4 (MD5) Previous issue date: 2005-04-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Meloidogyne incognita é um nematóide endoparasita sedentário que induz a formação de galhas nas raízes das plantas suscetíveis. Em tomateiros com o gene Mi-1, as células próximas ao estilete dos juvenis de segundo estágio exibem reação de hipersensibilidade (HR) a partir de oito a doze horas após a inoculação. Esse trabalho objetivou identificar e caracterizar parcialmente genes envolvidos nas vias de transdução de sinais e nas respostas de defesa do tomateiro a Meloidogyne incógnita mediadas pelo gene Mi-1 utilizando a técnica de hibridização subtrativa seguida de amplificação por PCR (suppressive subtractive hybridization, SSH). A partir dos cultivares quase isogênicas de tomateiros Moneymaker (suscetível) e Motelle (resistente) inoculados com M. incognita foram construídas duas bibliotecas subtrativas enriquecidas para genes diferencialmente expressos na interação incompatível (MoI 24h e MoI 72h) e uma biblioteca para a interação compatível (MMI 24h). Foram seqüenciados 81 clones da biblioteca MoI 72h, 26 da MMI 24h e 620 da MoI 24h. As análises subseqüentes se concentraram nesta última porque as outras duas apresentaram elevada redundância ou muitos ESTs (Expressed Sequence Tags) com similaridade a genes não caracterizados. Na análise de expressão por macroarranjo, 126 (41%) entre os 307 clones não redundantes de cDNAs apresentaram expressão diferencial. A análise de Northern blot não apresentou sensibilidade suficiente para evidenciar diferenças nos níveis de expressão. Vinte e um genes foram submetidos à análise de expressão por PCR quantitativa e, entre estes, oito apresentaram indução duas horas após a inoculação. A classificação dos ESTs em categorias funcionais em potencial mostrou que 31% deles têm relação com resposta de resistência, resposta a patógenos, proteção à célula, sinalização celular ou a estresse abiótico. Os ESTs classificados como não caracterizados corresponderam a 26%. Entre os ESTs com similaridade a genes induzidos nessa interação relatados previamente, estão inibidores de proteases, quitinase, aquaporina, fenilalanina amônia liase, Ki1 e peroxidase. Entre os ESTs relacionados com defesa relatados em outros patossistemas estão os similares a genes que codificam para MAPK4, defensinas, proteínas de transferência de lipídios, PR10 e proteína 14-3-3. Os genes semelhantes a MtN19, D13F MYB ST1 e cinase dependente de cálcio parecem apresentar mais de uma cópia no genoma e os genes semelhantes a Myb1, gene relacionado à resposta de resistência, gene envolvido com a resistência sistêmica adquirida, Ki1 e a defensina parecem estar presentes em cópia única no genoma. Os transcritos dos genes correspondentes aos clones SSH08D08 (MtN19), SSH09A10 (peroxidase 10), SSH10H09 (semelhante a Ki1) e SSH09D04 (defensina) possuem cerca de 2,5 kb, 1,2 kb, 1,8 kb e 0,5 kb, respectivamente. A presença de muitos genes relacionados com defesa e a ausência de genes do patógeno na biblioteca demonstra que a subtração foi eficiente para enriquecer para genes diferencialmente expressos. A grande quantidade de genes identificados e parcialmente caracterizados fornece subsídios para o estudo funcional visando caracterizar as vias de respostas de defesa mediadas pelo gene Mi-1. / In the compatible interaction between tomato and root-knot nematode Meloidogyne incognita, galls are formed on the roots. The tomato gene Mi-1 confers resistance to M. incognita accompanied by a hypersensitive response. To elucidate the mechanisms underlying these interactions, three cDNA libraries enriched for transcripts differentially expressed in susceptible (MMI 24h) and in resistant (MoI 24h and MoI 72h) plants, respectively, were generated by suppressive subtractive hybridization (SSH). Twenty-six ESTs were generated from MMI 24h, 81 from MoI 72h and 620 from MoI 24h library. The library MoI 24 was further characterized because the first two were highly redundant or had many ESTs similar to unknown genes. The cDNA macroarray analysis of 307 nonredundant clones revealed that 126 (41%) corresponded to differentially expressed transcripts. Northern blot analysis did not show enough sensitivity to detect differential expression. Quantitative PCR was performed to investigate the expression patterns of 21 selected genes. Transcript accumulation occurred for eight out of the 21 genes two hours after M. incognita challenge in resistant plants. Classification of the ESTs into several putative functional categories showed that 31% of these ESTs represented genes involved in resistance response, pathogen and stress response, cell protection or signaling. Twenty-six percent of ESTs corresponded to genes with unknown functions. Among ESTs similar to genes known to be involved in plant- nematode interactions were trypsin-alpha amylase inhibitor, chitinase, aquaporin, phenylalanine ammonia-lyase, Ki1 and peroxidase. Among ESTs similar to genes reported in other pathosystems were MAPK4, defensins, lipid transfer proteins, PR10 and 14-3-3 proteins. The genes similar to MtN19, to D13F MYB ST1 and to calcium-dependent protein kinase 3 apparently are present in more than one copy in the tomato genome and the genes similar to Myb1, to disease resistance response protein, to systemic acquired resistance- related protein, to Ki1 and to plant defensin apparently have only one copy. The transcripts corresponding to SSH08D08 (MtN19), SSH09A10 (peroxidase 10), SSH10H09 (similar to Ki1) and SSH09D04 (plant defensin) clones have approximately 2,5 kb, 1,2 kb, 1,8 kb and 0,5 kb, respectively. The presence of various defense related genes and the absence of pathogen genes in the libraries give evidence of successfully subtraction for genes differentially expressed. The identification and partial characterization of these cDNAs will assist functional analysis aimed to elucidate the pathways activated by the Mi-1 gene.

Made available in DSpace on 2014-06-11T19:26:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-09Bitstream added on 2014-06-13T20:54:10Z : No. of bitstreams: 1 moraes_fe_me_jabo.pdf: 1680634 bytes, checksum: 35809b1bab51b8d182c7d496667f751f (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A cana-de-açúcar (Saccharum spp.) é uma das gramíneas cultivadas mais importantes do mundo e o Brasil é hoje o maior produtor e exportador mundial de cana, de açúcar de cana e etanol de cana, com o estado de São Paulo sendo o maior produtor. Entretanto, esta cultura é ameaçada por várias pragas e doenças. Dentre essas pragas, uma das mais importantes na região centro-sul é a cigarrinha-das-raízes (Mahanarva fimbriolata), que assumiu este posto devido ao aumento da colheita mecanizada. Por meio da técnica de cDNA-AFLP este trabalho teve como objetivo identificar genes possivelmente envolvidos na resistência a ninfas de Mahanarva fimbriolata em cana-de-açúcar. Para isso, foi utilizada uma variedade suscetível (SP80-1816) e uma resistente (SP83-5073). Ambas foram infestadas com ninfas da cigarrinha 77 dias após o plantio e amostras de raízes foram coletadas antes da infestação (controle) e 1, 2 e 7 dias após a infestação, posteriormente foi feita a extração de RNA, síntese de cDNA e o cDNA-AFLP. Após a análise dos fragmentos foram encontrados 16 fragmentos expressos somente na variedade resistente. Nove fragmentos foram encontrados no 2º dia de infestação e sete no 7º dia. Dentre os 16 fragmentos, sete foram recuperados e sequenciados. Seis fragmentos não apresentaram homologia com proteínas já descritas e um fragmento, de 129 pb, apresentou homologia com uma proteína putativa associada à senescência. Todos os fragmentos podem representar genes relacionados com a resistência da planta contra o inseto / The sugarcane (Saccharum spp.) is the most important grass cultivated in the world and Brazil is now the world’s largest producer and exporter of sugarcane, sugarcane sugar and sugarcane ethanol, with the São Paulo state being the largest producer. However, this culture is threatened by several pests and diseases. Among these pests, one of the most important in south-central region is the froghopper-roots (Mahanarva fimbriolata), that took this position because of increased mechanization. Through cDNA-AFLP technique this study aimed to identify genes possibly involved in resistance to nymphs of Mahanarva fimbriolata in sugarcane. Therefore we used a susceptible variety (SP80-1816) and a resistant (SP83-5073). Both were infested with spitlebugs 77 days after planting and root samples were collected before infestation (control) and 1, 2 and 7 days after infestation, was later made the extraction of RNA, cDNA synthesis and cDNA-AFLP. After fragments analyses were found 16 fragments expressed only in the resistant variety. Nine fragments were found on day 2 of infection and seven on day 7. Among the 16 fragments, seven were recovered and sequenced. Six fragments showed no homology to described proteins and a fragment of 129 bp showed homology to a putative protein associated with senescence. All fragments could represent genes related to the plant resistance against the insect

Made available in DSpace on 2014-06-11T19:26:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-04-19Bitstream added on 2014-06-13T18:54:10Z : No. of bitstreams: 1 dedemo_gc_me_jabo.pdf: 1096079 bytes, checksum: 9710fc882b784efd70e97e20b286cf3e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A cultura da cana-de-açúcar é de grande importância econômica nas regiões tropicais e subtropicais, especialmente para alguns países da América, como o Brasil, que é atualmente o maior produtor mundial. Estresses abióticos, como a seca, podem reduzir os rendimentos das lavouras. Sendo assim, a identificação e a compreensão dos mecanismos de tolerância à seca são fundamentais no desenvolvimento de novas cultivares comerciais mais tolerantes ao déficit hídrico. O objetivo deste trabalho foi identificar, através da técnica de macroarranjos de cDNA, o perfil de expressão de genes pertencentes a diferentes vias metabólicas em folhas de duas cultivares de cana-de-açúcar (Saccharum spp), uma tolerante ao estresse por déficit hídrico (SP83-2847) e outra sensível (SP90-1638) submetidas a dois períodos de restrição no fornecimento de água, ocasionando um estresse por déficit hídrico leve (T1) e severo (T2). Por meio das análises dos resultados foi possível identificar, na cultivar tolerante, a indução de ESTs (etiquetas de seqüências expressas) com similaridade a genes de enzimas de síntese de osmoprotetores, tais como prolina, hidroxiprolina e GABA (ácido g-aminobutírico); de hormônios vegetais como o ácido abscísico (ABA) e o ácido jasmônico (JA) e repressão de ESTs similares aos genes das enzimas de biossíntese de amido, de glicina betaína e de algumas enzimas do sistema de defesa antioxidante. Ao passo que, na cultivar sensível foram induzidas ESTs similares aos genes de enzimas de síntese dos osmoprotetores trealose e glicina betaína; do sistema de defesa antioxidante e reprimidas ESTs com similaridade a genes das enzimas de síntese de prolina, hidroxiprolina e GABA e envolvidas na biossíntese de ABA e de jasmonatos. Em ambas as cultivares, ESTs similares a genes de diferentes enzimas fotossintéticas foram reprimidas. / Sugarcane crop is of large economic importance in the tropical and subtropical regions, especially in some countries of Central and South America as Brazil, which is actually the major worldwide producer. Abiotic stress, such as drought, can reduce yield of the farmings. Thus, identification and understanding of the drought tolerance mechanisms is crucial to the development of new commercials cultivars more tolerant to water deficit. The aim of this study was to identify, using cDNA macroarrays technique, expression profile of genes involved in distinct metabolic pathways in leaves of two sugarcane (Saccharum spp) cultivars, one water stress tolerant (SP83-2847) and another water stress sensitive (SP90-1638) which were submitted to periods of withhold watering occasioning a mild (T1) and severe (T2) water deficit stress. Through the analysis of the results, it was identified in the tolerant cultivar up-regulated ESTs similar to genes of enzymes involved in the synthesis of osmoprotectants, such as proline, hydroxyproline, GABA (g-amino butyric acid), of synthesis of plant hormones as abscisic acid (ABA) and jasmonic acid (JA); and down-regulated ESTs similar to genes of enzymes of the biosynthesis of starch, glycine betaine and of some enzymes involved antioxidant defense system. In the other hand, ESTs similar to genes of enzymes involved in the biosynthesis of the osmoprotectants as trehalose and glycine betaine and enzymes from the antioxidant defense system were induced as well as were down-regulated ESTs similar to genes of enzymes of synthesis of proline, hydroxyproline and GABA and involved in biosynthesis of ABA and jasmonates, for the sensitive cultivar. In both cultivars, ESTs with similarity to genes of different photosynthetic enzymes were repressed.