ABSTRACT
BACKGROUND: Pogoniopsis schenckii Cogn. is a mycoheterotrophic orchid that can be used as a model to understand the influence of mycoheterotrophy at different stages of the reproductive cycle. We aimed to verify the presence of endophytic and epiphytic fungi at each stage of the reproductive process and investigated how the breeding system may relate to genetic structure and diversity of populations. In this study we performed anatomical and ultrastructural analyses of the reproductive organs, field tests to confirm the breeding system, and molecular analysis to assess genetic diversity and structure of populations. RESULTS: During the development of the pollen grain, embryo sac and embryogenesis, no fungal infestation was observed. The presence of endophytic fungal hyphae was observed just within floral stems and indehiscent fruit. Beyond assuring the presence of fungus that promote seed germination, specific fungi hyphae in the fruit may affect other process, such as fruit ripening. As other mycoheterotrophic orchids, P. schenckii is autogamous, which may explain the low genetic diversity and high genetic structure in populations. CONCLUSIONS: We discuss an interesting interaction: fungal hyphae in the indehiscent fruit. These fungal hyphae seem to play different roles inside fruit tissues, such as acting in the fruit maturation process and increasing the proximity between fungi and plant seeds even before dispersion occurs. As other mycoheterotrophic orchids, P. schenckii is autogamous, which may explain the low genetic diversity and high genetic structure in populations. Altogether, our findings provide important novel information about the mechanisms shaping ecology and evolution of fragmented populations of mycoheterotrophic plant.
Subject(s)
Mycorrhizae/genetics , Orchidaceae/growth & development , Orchidaceae/genetics , Plant Roots/growth & development , Plant Roots/genetics , Reproduction/genetics , Symbiosis/genetics , Brazil , DNA, Fungal , Gene Expression Regulation, Fungal , Gene Expression Regulation, Plant , Orchidaceae/microbiology , Plant Roots/microbiologyABSTRACT
The number of integuments found in angiosperm ovules is variable. In orchids, most species show bitegmic ovules, except for some mycoheterotrophic species that show ovules with only one integument. Analysis of ovules and the development of the seed coat provide important information regarding functional aspects such as dispersal and seed germination. This study aimed to analyze the origin and development of the seed coat of the mycoheterotrophic orchid Pogoniopsis schenckii and to compare this development with that of other photosynthetic species of the family. Flowers and fruits at different stages of development were collected, and the usual methodology for performing anatomical studies, scanning microscopy, and transmission microscopy following established protocols. P. schenckii have ategmic ovules, while the other species are bitegmic. No evidence of integument formation at any stage of development was found through anatomical studies. The reduction of integuments found in the ovules could facilitate fertilization in this species. The seeds of P. schenckii, Vanilla planifolia, and V. palmarum have hard seed coats, while the other species have seed coats formed by the testa alone, making them thin and transparent. P. schenckii, in contrast to the other species analyzed, has a seed coat that originates from the nucellar epidermis, while in other species, the seed coat originates from the outer integument.
ABSTRACT
Biossurfactantes são compostos com características tensoativas, produzidos por diversas espécies de microrganismos. Nesse estudo, a composição de ácidos graxos de biossurfactantes produzidos por fungos filamentosos endofíticos foram analisados. Para a produção dos biossurfactantes, empregou-se fontes de carbono (óleo vegetal de milho) e nitrogênio (ureia) de baixo custo no meio de cultivo. A composição de ácidos graxos foi determinada a partir da cromatografia gasosa. Foram identificados seis picos de ésteres metílicos de ácidos graxos, com predominância do ácido linoleico (C18:2n-6c) e ácido oleico (C18:1n-9c). Tanto os ácidos graxos saturados quanto os insaturados foram encontrados na estrutura dos biossurfactantes. Estes resultados demonstraram a importância destes compostos para potenciais aplicações em várias áreas industriais.
Subject(s)
Fungi , Surface-Active Agents/isolation & purification , Surface-Active Agents/chemistry , Fatty Acids/analysis , Fatty Acids/chemistry , Chromatography, Gas , Urea , Corn OilABSTRACT
Estudos utilizando fungos endofíticos como produtores de metabólitos secundários de interesse biotecnológico vem sendo explorados. Assim, o presente trabalho objetivou avaliar a produção de enzimas por fungos filamentosos endofíticos, sendo escolhida a cepa 50 (C50), proveniente da coleção de cultura do Laboratório de Produtos Naturais e Biotecnologia (LPNBio) da UESB. A produção das enzimas amilase, celulase, invertase, lipase e poligalacturonase foi avaliada pelo o índice enzimático, atividade enzimática e verificado o tempo de fermentação de maior produtividade. Com exceção da invertase, a C50 apresentou atividade para as demais enzimas, destaque para lipase e poligalacturonase no tempo de 96 horas de fermentação. Estes resultados mostraram que a C50 tem potencial para ser explorada como produtora de enzimas.
