ABSTRACT. The reduced longevity of coffee seeds has been attributed to their sensitivity to desiccation. Studies related to gene expression and enzyme activity in coffee seeds under drying are important for understanding the effects of drying on their physiological quality. The aim of this study was to investigate the molecular aspects of seeds under different drying methods and associate them with physiological quality. Coffee seeds with different water contents were dried both slowly and rapidly. Enzymatic activity was analysed, as well as the expression of genes that encode the enzymes superoxide dismutase, catalase, peroxiredoxins, isocitrate lyase, and endo-ß-mannanase. There was a significant effect of drying speed and final water content on enzyme activity and on the expression of the different genes analysed. In seeds under rapid drying, there was greater expression of the genes that encode the enzymes catalase and endo-ß-mannanase. Greater expression of the 1 CYS PRX and SOD genes and greater activity of the ICL isoenzymes were found in seeds with superior physiological quality, but greater activity of the endo-β-mannanase and CAT enzymes occurred in seeds with lower physiological quality.

Resumo: A patologia de sementes é uma área de estudos que se iniciou no século passado e vem se desenvolvendo desde então, com crescente contribuição especialmente aos sistemas de produção agrícola. Contudo, na área ambiental os estudos se iniciaram muito tempo depois, mas demonstraram igual importância, especialmente para os programas de restauração vegetal e de conservação de germoplasma. Nesta revisão são apresentadas informações acerca do conhecimento em patologia de sementes de espécies não domesticadas de ecossistemas tropicais e são discutidos os benefícios e as lacunas desses estudos.

Abstract: Seed pathology is an area of study that began in the last century and has been developing since then, with increasing contribution especially to agricultural production systems. However, in the environmental area, studies began much later, but showed equal importance, especially for plant restoration and germplasm conservation programs. In this review, information about the knowledge on the pathology of seeds of non-domesticated species from tropical ecosystems is presented and the benefits and gaps of these studies are discussed.

Sclerotinia sclerotiorum causador do "mofo branco" na cultura da soja, é responsável por redução da produção e contaminação do solo. A introdução e disseminação da doença podem se dar pelo uso de sementes contaminadas com escleródios e por sementes infectadas pelo micélio. A qualidade das sementes deve ser monitorada por testes de sanidade antes da semeadura. Neste estudo foram utilizadas técnicas de PCR convencional e quantitativo para avaliar a viabilidade de uso das mesmas para a detecção de S. sclerotiorum em amostras de sementes de soja artificialmente e naturalmente infectadas. Para isso, as sementes foram inoculadas usando a técnica do condicionamento osmótico por 0, 24, 48 e 72 horas de contato das sementes com a colônia do fungo e misturadas à sementes sadias gerando incidência de 1, 2, 10, 20 e 100% para cada tempo de incubação. A técnica de cPCR foi sensível para detectar S. sclerotiorum em amostras com, no mínimo, incidência de 1% inoculadas por 72 horas, enquanto que com o qPCR foi possível detectar o patógeno em todas as combinações incidência/potencial de inóculo. A PCR convencional foi capaz de detectar 0,25% de incidência de S. sclerotiorum em lotes de sementes de soja naturalmente infectados adicionando-se uma etapa de pré-incubação das sementes.

Sclerotinia sclerotiorum, the etiological agent of the "white mould" in soybean, is responsible for severe losses in this crop and soil contamination. The introduction and dissemination of the disease can made through the use of seed lots contaminated with sclerotia and by seeds infected by mycelium. Therefore, seed health quality is one aspect to be monitored by means of health testing before to sowing time. In this study conventional and quantitative PCR techniques were used to assess their viability to detect S. sclerotiorum in artificially and naturally infected soybean seed samples. For that, seeds were inoculated by osmotic conditioning technique for 0, 24, 48 and 72 hours of contact of the seed with the fungal colony and mixed with healthy seeds generating incidence levels of 1, 2, 10, 20 and 100% for each incubation time. The cPCR was sensitive to detect S. sclerotiorum in samples with at least incidence 1% inoculated for 72 hours while the qPCR detected the pathogen in all incidence/inoculum potential combinations. The conventional PCR was able to detect 0.25% of the incidence of S. sclerotiorum in soybean seed lots naturally infected added a preincubation step.