Development of retrotransposon-based markers IRAP and REMAP for cassava (Manihot esculenta)

Retrotransposons are abundant in the genomes of plants. In the present study, inter-retrotransposon amplified polymorphism (IRAP) and retrotransposon-microsatellite amplified polymorphism (REMAP) markers were developed for the cassava genome (Manihot esculenta Crantz). Four cassava cultivars (Fécula Branca, IPR-União, Olho Junto, and Tamboara, two samples per cultivar) were used to obtain IRAP and REMAP fingerprints. Twelve designed primers were amplified alone and in combinations. The 42 IRAP/REMAP primer combinations amplified 431 DNA segments (bands; markers) of which 36 (8.36%) were polymorphic. The largest number of informative markers (16) was detected using the primers AYF2 and AYF2xAYF4. The number of bands for each primer varied from 3 to 16, with an average of 10.26 amplified segments per primer. The size of the amplified products ranged between 100 and 7000 bp. The AYF2 primer generated the highest number of amplified segments and showed the highest number of polymorphic bands (68.75%). Two samples of each cassava cultivar were used to illustrate the usefulness and the polymorphism of IRAP/REMAP markers. IRAP and REMAP markers produced a high number of reproducible bands, and might be informative and reliable for investigation of genetic diversity and relationships among cassava cultivars

Genetic and chemical diversity in seeds of cactus mandacaru (Cereus sp.) from two edaphoclimatic regions contrasting

ABSTRACT The purpose of this study was to evaluate the chemical, physiological and genetic differences in seeds of cactus of the Cereus genus (mandacaru) cultivated in the Northeast (Picos, State of Piauí) and Southern (Maringá, State of Paraná) regions of Brazil. Over a period of eight days, temperatures of 25°C and 30°C were equally efficient for the germination of all the seeds. Oleic acid (C18:1) was the most common fatty acid found in the seeds collected in the Southern (41%) and Northeast (45.5%) regions. The analysis of lipases indicated that seeds from Maringá have high mean observed and expected heterozygosities and that seeds from Picos have a higher number of alleles per loci. Therefore, the seeds of mandacaru from the semiarid region of Northeast as well as the seeds from the South (the two contrasting regions of Brazil) are promising with regards to the preservation of the biodiversity in the genome of mandacaru. The low genetic identity between mandacaru seeds from Maringá and Picos at Lipase-5 locus analysis (I = 0.77) suggests that the mandacaru plants from Maringá and Picos may correspond to two species: C. peruvianus and C. jamacaru, respectively

Controle de podridão peduncular do mamão utilizando irradiação UVC.

Resumo: A podridão peduncular compromete a quantidade e a qualidade fitossanitária de mamões podendo provocar grandes perdas. O uso da irradiação ultravioleta C (UVC) vem ganhando reconhecimento, por atuar diretamente sobre o fitopatógeno e induzir o fruto a criar mecanismos de defesa ao ataque de agentes infecciosos. O objetivo do presente trabalho foi definir as doses de UVC que inibem a germinação de esporos dos fungos do complexo causador da podridão peduncular em mamão: Alternaria alternata, Colletotrichum gloeo sporioides, Fusarium solani e Lasiodiplodia theobromae, e avaliar doses de UVC no controle da doença em mamão papaya. Preparou-se, para cada fungo, uma suspensão de esporos na concentração 105 esporos mL-1, que foi irradiada com diferentes doses de UVC, variando de 0,25 kJ m-2 a 3,00 kJ m-2. As suspensões irradiadas foram plaqueadas e após 72 h avaliou-se a inibição na germinação de esporos pela contagem de Unidade Formadora de Colônias (UFC). Irradiou-se a região peduncular do fruto nas seguintes doses: 0,5; 1,0; 1,5 e 2,0 kJ m-2. Após irradiados os mamões foram armazenados durante 7 dias em câmara fria (10ºC ) e 8 dias em temperatura ambiente (22ºC ), avaliando-se diariamente a severidade da doença utilizando uma escala de notas. A dose letal de UVC variou em função da sensibilidade da espécie fúngica: 0,6 kJ m-2 para F. solani, 1,5 kJ m-2 para L. theobromae e 2,0 kJ m-2 para C. gloeosoporioides e A. alternata. No controle da podridão peduncular obteve-se o melhor resultado com a dose de 0,5 kJ m-2. Abstract: Stem-end rot compromises the quantity and quality of papaya and can cause great losses. The use of ultraviolet C (U VC) irradiation has gained recognition, as it acts directly on the phytopathogen and induces mechanisms of defense in fruit against the attack of infectious agents. The objective of the present work was to define the doses of UVC, which inhibit spore germination of fungi of the complex causing stem-end rot in papaya: Alternaria alternata, Colletotrichum gloeosporioides, Fusarium solani and Lasiodiplodia theobromae, and to evaluate doses of UVC in the control of the disease. Spore suspension at the concentration of 105 spores mL-1, was prepared for each fungus which was irradiated with different doses of UVC ranging from 0.25 kJ m-2 to 3,0 kJ m-2. The irradiated suspension was plated and after 72 h the inhibition on spore germination was evaluated by the Colony Forming Unit (CFU) count. Peduncle region of the fruit was irradiated by the following doses: 0.5, 1.0, 1.5 and 2.0 kJ m- 2. After irradiation, papayas were stored for 7 days in a cold chamber (10ºC) and 8 additional days at room temperature (22ºC), evaluating daily the evolution of disease severity using a scale of notes. The lethal dose of UVC varied according to the fungal species sensibility: 0.6 kJ m-2 for F. solani, 1.5 kJ m-2 for L. theobromae, 2.0 kJ m-2 for C. gloeosoporioides and A. alternata. The best control of stem-end rot was obtained with the dose of 0.5 kJ m-2

Tratamento hidrotérmico no controle de podridão peduncular em mamão papaya.

Resumo: Doenças pós-colheita são fatores importantes que reduzem o rendimento e a qualidade do fruto, as quais ocorrem principalmente durante o transporte e armazenamento. O tratamento hidrotérmico é conhecido por controlar doenças pós-colheita, e por manter a qualidade do fruto durante o armazenamento, além de induzir resistência contra infecções e lesões na casca. O presente trabalho objetivou avaliar um método alternativo ao uso de fungicidas no tratamento pós-colheita de mamão para controlar a podridão peduncular, por meio de tratamento hidro térmico. Para avaliar este tratamento hidro térmico, a região peduncular da fruta foi imersa em água nas temperaturas, 55ºC, 60ºC, 65ºC, 70ºC e 75ºC, durante 15s, e em seguida imersa em água fria a 15ºC, por 2 minutos, para interromper o processo térmico. Após o tratamento, os frutos foram armazenados durante 7 dias em câmara fria (10ºC ) e 8 dias em temperatura ambiente (22ºC ), avaliando-se diariamente a evolução da severidade da doença utilizando uma escala de notas. Analisando-se os resultados, verificou-se que todas as temperaturas avaliadas diferiram estatisticamente da testemunha, comprovando que o tratamento hidrotérmico proposto é eficiente no controle da podridão peduncular do mamão, sendo que, o tratamento que proporcionou o melhor controle de severidade da doença foi a imersão do pedúnculo por 15 segundos a 70ºC. Portanto, o tratamento hidrotérmico do pedúnculo é uma alternativa sustentável e viável ao uso de fungicidas no tratamento pós-colheita de mamão. ? Abstract: Postharvest disease is an important factor that reduces fruit yield and quality, which occur mainly during transportation and storage. Hydrothermal treatment is known to be efficient in control ling postharvest diseases, and to maintain fruit quality during storage, in addition to induce fruit resistance against infections and peel lesions. The present work aimed to evaluate an alternative method to fungicides use in postharvest treatment of papaya, to control stem-end rot, using hydrothermal treatment. In order to evaluate this hydrothermal treatment, the peduncle region of the fruit was immersed in water at temperatures of 55° C, 60° C, 65° C, 70° C and 75° C for 15 s, and then immersed in cold water at 15°C for 2 minutes to stop the thermal process. After the treatment, papayas were stored for 7 days in a cold room (10ºC) and 8 days at room temperature (22ºC), evaluating daily disease severity using a scale of notes. Analyzing the results, it was verified that all the evaluated temperatures differed statistically from the control, proving that the hydrothermal treatment is efficient to control of stem-end rot of papaya, and the treatment that provided the best control of the disease severity was the immersion of the peduncle by 15 seconds at 70°C. Therefore, the hydrothermal treatment of the peduncle is a sustainable and viable alternative to the fungicides application in the pos tharvest treatment of papaya