Estudo de métodos naturais para redução de doenças fúngicas em sementes nativas da região Amazônica / Study of natural methods for reducing fungal diseases in native seeds in the Amazon region

Existe uma preocupação na produção de alimentos com a segurança sanitária desde o processo de cultivo até a sua expedição aos centros comerciais. Uma das maiores contaminações em sementes por suas características físicas e químicas, é a contaminação fúngica devida à acidez e umidade dos frutos. As doenças fúngicas entre elas, antracnose, vassoura de bruxa e podridão parda são consideradas importante doenças em pós colheita, ocorrendo, principalmente, sob condições de alta umidade relativa do ar e temperaturas elevadas (26ºC a 28ºC). Dentre as sementes da região Amazônica, destacam-se sementes de (cacau- Theobroma cacao L., pupunha- Bactris gasipaes, tucumã da Amazonas-Astrocaryum aculeatum), que apresentam problemas de contaminação fúngica durante o sistema de cultivo. Métodos de biocontroles com ação antimicrobiana: bactérias endofíticas, rizobactérias e fungo Trichoderma ssp, entre outros estão sendo estudados para a redução destas contaminações fúngicas em estudos in vitro e no campo. O objetivo deste trabalho é apresentar uma revisão bibliográfica sobre a utilização de métodos de biocontrole como uma alternativa promissora no manejo de doenças de plantas na fase de pós-colheita, com excelentes resultados em culturas de grande importância econômica. Assim novas alternativas ecologicamente sustentáveis demonstram a possibilidade de os produtos estudados serem utilizados no manejo da antracnose na pós-colheita.(AU)

There is a concern in food production with health security from cultivation process to its dispatch to redistribution centers. One of the biggest contaminations in seeds due to their physical and chemical characteristics, is the fungal contamination due to the acidity and humidity of the fruits. Fungal diseases including anthracnose, bruca's broom and brownrot are considered important diseases in post-harvest, occurring mainly under conditions of high relative humidity and high temperatures (26ºC to 28ºC). Among the seeds of the Amazon region, seeds of de (cacau- Theobroma cacao L., pupunha- Bactris gasipaes, tucumã da Amazonas- Astrocaryum aculeatum ), that present problems fungals contamination during in their growing cultures sistems. Biocontrol methods with antimicrobial action: endophytic bacteria, rhizobacteria and the fungus Trichoderma ssp, among others, are being studied to reduce these fungal contaminations in in vitro and field studies. The objective of this work is to present a bibliographic review on the use of biocontrol methods as an alternative that is promising in the management of plant diseases in the post-harvest phase, with excellent results in crops of great economic importance. Thus, new ecologically sustainable alternatives demonstrate the possibility of the studied products to be used in the management of anthracnose in the post-harvest period.(AU)

Elaboração e análise microbiológica de geleia de polpa de Mauritia flexuosa / Elaboration and microbiological analysis of Mauritia flexuosa polar jelly

A região dos cerrados é muito rica em espécies frutíferas nativas, oferecendo grande quantidade de frutas comestíveis, e dentre elas encontra-se o Buriti. Diante disso, objetivou-se com esta pesquisa elaborar e avaliar as características microbiológicas de geleia de polpa de buriti após 90 dias de estocagem a 25 ºC. Para a elaboração da geleia foi utilizada a proporção de 60 partes da mistura da polpa de buriti para 40 partes de açúcar. Foram realizadas as determinações de Coliformes totais e termotolerantes, Salmonella spp., mesófilos, bolores e leveduras após 1, 15, 30, 45, 60 e 90 dias de estocagem a 25 ºC. Os resultados indicaram que a geleia elaborada não apresentaram contaminação por bolores e leveduras, Salmonella spp., coliformes e mesófilos estando em consonância com os parâmetros exigidos pela legislação para geleias.

Screening the antifungal activity of essential oils against decay fungi from palmyrah leaf handicrafts

BACKGROUND: The whitish tender leaves of Palmyrah are used for making handicrafts. The problem with these articles is discolouration with time and become more brittle due to fungal attack. This could be prevented by some protective coating. Instead of expensive and harmful chemicals we decided to test natural plant essential oils to control fungal attack. Palmyrah leaf article decay fungi were isolated from two different sites of Jaffna peninsula. In this investigation Antifungal Activity of different plant essential oils from neem (Azadirachta indica), castor (Ricinus communis), citronella (Cymbopogon sp) and camphor (Cinnamomum camphora) obtained from local market have been evaluated against isolated fungi. For screening of Antifungal activity, tests and controls were set to determine minimum inhibitory concentration (MIC) and Percentage of Growth Inhibition. RESULTS: Morphologically three different types of Palmyrah leaf decay fungi were isolated and characterized asAspergillus niger, Aspergillus flavus and Penicillium sp. Neem and castor oils have recorded no significant (0.05 > P) antifungal activity while citronella and camphor oils showed significantly different antifungal activity compared with control. Camphor oil and Citronella oil showed 100, 58.13% of average growth inhibition for A. niger. 96.38, 51.32% for A.flavus and 84.99, 72.76% forPenicillium sp respectively. Camphor oil showed highest percentage of growth inhibition at lowest minimum inhibitory concentration compared with citronella oil. Camphor oil was found to be highly antifungal and most effective against A niger, and A. flavus, compared with Penicillium sp and gave 100 percentage of growth inhibitions at 5, 1 and 15 ml/dl minimum inhibitory concentration respectively. CONCLUSION: Significantly higher broad-spectrum of antifungal activity was observed in camphor oil than other tested oils because it showed highest percentage of growth inhibition at lowest inhibitory concentration. Therefore it could be used for the development of new environmental friendly antifungal agent for the preservation of leafy handicrafts. Further formulation, field experiments are necessary to achieve this target.

Morphological and molecular characterization of Fusarium. solani and F. oxysporum associated with crown disease of oil palm

Crown disease (CD) is infecting oil palm in the early stages of the crop development. Previous studies showed that Fusarium species were commonly associated with CD. However, the identity of the species has not been resolved. This study was carried out to identify and characterize through morphological approaches and to determine the genetic diversity of the Fusarium species. 51 isolates (39%) of Fusarium solani and 40 isolates (31%) of Fusarium oxysporum were recovered from oil palm with typical CD symptoms collected from nine states in Malaysia, together with samples from Padang and Medan, Indonesia. Based on morphological characteristics, isolates in both Fusarium species were classified into two distinct morphotypes; Morphotypes I and II. Molecular characterization based on IGS-RFLP analysis produced 27 haplotypes among the F. solani isolates and 33 haplotypes for F. oxysporum isolates, which indicated high levels of intraspecific variations. From UPGMA cluster analysis, the isolates in both Fusarium species were divided into two main clusters with the percentage of similarity from 87% to 100% for F. solani, and 89% to 100% for F. oxysporum isolates, which was in accordance with the Morphotypes I and II. The results of the present study indicated that F. solani and F. oxysporum associated with CD of oil palm in Malaysia and Indonesia were highly variable.

Impact of solar dehydration on composition and antioxidant properties of acai (Euterpe oleracea Mart.)

Commercial products derived from the acai fruit (Euterpe oleracea Mart.) are available in Brazil, but in Venezuela, it is only known by ethnic indigenous groups of the Amazon. In this study, acai flour was made by solar dehydration and the effect of processing on the composition, microbiological quality, and antioxidant properties of such flour were evaluated. The fruit was purchased in Puerto Ayacucho, Venezuela, and a portion was manually pulped. Microbiological quality, proximal composition, minerals, polyphenols, tannins, anthocyanins, and antioxidant capacity were evaluated. The remaining portion of fruit was blanched in a solution of ascorbic acid and citric acid at 98ºC for 1min in the same manner, manually pulped, dried by solar dehydration and the acai flour was also analysed. From the composition of the acai flour, its high content of fat (22.9%), protein (13.7%), dietary fibre (20.5%), total polyphenols (1.60 g/kg) and antioxidant capacity (79.97%) stood out. The blanching of the fruit and the solar dehydrating of the acai pulp did not modify the composition, but they improved its microbiological quality and reduced phenolic compounds and antioxidant capacity. The flour obtained is stable and innocuous and could be used to diversify the diet of the indigenous people of the Amazon region.

Los productos comerciales derivados del fruto del acai (Euterpe oleracea Mart) están disponibles en Brasil, no así en Venezuela donde sólo los grupos indígenas del Amazonas lo conocen y consumen. En este estudio se elaboró una harina de acai mediante deshidratación solar y se evaluó el efecto del procesamiento en la composición, calidad microbiológica y propiedades antioxidantes de dicha harina. Los frutos fueron adquiridos en Puerto Ayacucho, Venezuela y una porción de ellos se despulpó manualmente y se le determinó calidad microbiológica, composición proximal, contenido de minerales, contenido de polifenoles, taninos, antocianinas y la capacidad antioxidante. La otra porción del fruto se escaldó en una solución de ácido ascórbico y ácido cítrico a 98ºC por 1min, se despulpó manualmente y se eliminó su humedad por deshidratación solar; a la harina de acai obtenida se le hicieron los mismos análisis que a la pulpa. De la composición del acai resaltó su alto contenido de grasa (22.9%), proteína (13.7%), fibra dietética (20.5%), polifenoles totales (1.60 g/kg-1) y su capacidad antioxidante (79.97%). El lavado y escaldado de los frutos y la posterior deshidratación solar de la pulpa del acai no modificó significativamente su composición, pero si mejoró la calidad microbiológica y redujo los compuestos fenólicos y la capacidad antioxidante. La harina obtenida es estable e inocua y se podría utilizar para diversificar la dieta de los indígenas de la región del Amazonas.

Establishment of Desmoncus orthacanthos Martius (Arecaceae): effect of inoculation with arbuscular mycorrhizae

Inoculation with arbuscular mycorrhizal (AM) fungi has often promoted increased growth of plants but very little work has been done in the tropics to evaluate the effects of inoculation on the establishment and development of seedlings in forests. Desmoncus orthacanthos Martius is a scandent palm present both in early and late succession, and consequently can be used in restoration processes. A test was conducted to determine the effect of AM on the establishment of Desmoncus orthacanthos in tropical forest in the Yucatan Peninsula, Mexico. Thirty inoculated and 30 non-inoculated seedlings were introduced in two sites of different successional age, a mature forest and an eight-year old abandoned cornfield (acahual).Survival and growth parameters were evaluated after 12 months. Leaf area and phosphorus, but not height, were greater in inoculated than non-inoculated plants in the forest but not in the acahual. However, mycorrhizae had a clear effect on plant survival in both sites, with a threefold increase in survival of inoculated compared with non-inoculated plants bassed on an odds ratio. The results suggest that inoculation will be important to increase the establishment of this commercially important palm.

La inoculación con hongos micorrizógenos arbusculares (AM)promueve un incremento en el crecimiento de las plantas, sin embargo poco trabajo se ha realizado en los trópicos para evaluar el efecto de la inoculación en el proceso de establecimiento de plántulas. Desmoncus orthacanthos Martius es una palmera trepadora que se distribuye tanto en etapas tempranas y tardías de la sucesión, por lo tanto puede ser empleada en procesos de restauración. Se realizó una prueba de establecimiento de D. orthacanthos en una selva tropical de la península de Yucatán, México. Treinta plántulas inoculadas y 30 no inoculadas se establecieron en dos sitios con diferentes etapas sucesionales: selva madura y un campo abandonado de maíz (acahual). Después de 12 meses el valor de área foliar y contenido de fósforo fue mayor en el tratamiento con micorrizas en la selva pero no en el acahual, sin embargo, el tratamiento con micorrizas mostró un claro efecto en la supervivencia de las palmeras en ambos sitios con un incremento tres veces mayor en la probabilidad de supervivencia de palmeras inoculadas comparadas con las no inoculadas de acuerdo al análisis de razón de disparidad (odds ratio). La inoculación podría ser importante para incrementar el establecimiento de esta palmera.

Immature embryo: a useful tool for oil palm (Elaeis guineensis Jacq. ) genetic transformation studies

Oil palm (Elaeis guineensis Jacq.) is the highest yielding oil-bearing crop. However, being a perennial crop, genetic improvement of oil palm is extremely slow. Indeed, compared to other annual oil crops such as soybean and rapeseed, genetic manipulations remained less important. Therefore, to remain competitive, oil palm growers and breeders need new and novel approaches. In this report, the potential of immature embryos (IE) as a useful tool for oil palm genetic transformation studies was evaluated. It was evident that IEs were amenable to both direct and Agrobacterium-mediated gene transfer. Due to the abundant supply of IE, optimization of biolistic and Agrobacterium-mediated gene transfer into IEs were easily carried out. Transient transformation frequencies were comparable to other plant systems reported, with as high as 97.4 percent recorded for biolistic and 64.4 percent for Agrobacterium-mediated gene transfer. Like most moncots, oil palm tissues were less sensitive to kanamycin, geneticin and chloramphenicol. Instead, both hygromycin and phosphinotrycin were toxic 20 mg/l, making both suitable candidates for selecting putative transformants. IEs were also more responsive to in vitro manipulations as compared to other explants such as leaf and root tissues. Rapid in vitro response to callusing and embryogenesis or rapid and highly efficient direct germination resulted in a shorter culture period. This would minimize the production of abnormal clonal palms, which has been associated to chromosomal aberration due to prolonged time in culture. In addition, IEs also allows rapid and direct introduction of elite genes into breeding programs and in biclonal seed production.