Browsing by Author "Peixe, A."
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- Identification of candidate genes involved in olive response to anthracnose for a sustainable disease managementPublication . Inácio, Diogo; Félix, M.R.; Campos, Catarina; Patanita, Mariana; Ribeiro, Joana A.; Varanda, Carla; Materatski, Patrick; Albuquerque, André; Osa, Nicolás; Peixe, A.; Campos, Maria DoroteiaAnthracnose is a disease that affect the olive tree caused by fungi of the genus Colletotrichum. These fungi are responsible to premature fruit drop and a consequent decrease in the oil quality, and also cause defoliation of trees compromising the production of the following years. Currently the best control strategy is based on application of synthetic fungicides, with a regulatory pressure in agriculture worldwide to limit its use. Looking for a sustainable disease management, the present study reports the transcriptional changes of olive genes that encode enzymes directly associated with the maintenance of the balance of oxidative oxygen species (ROS), in response to Colletotrichum sp. infection. The cultivar selected for the studies was ‘Galega vulgar’, known to be extremely susceptible to this disease. Plants used in the experiments were from in vitro culture (to warranty their healthy status), transplanted to pots and maintained under controlled conditions. Leaves of the olive plants were inoculated with a spore suspension of Colletotrichum sp., and leaf samples were collected before fungi inoculation (T0) and at 10 days (T1) and 35 days (T2) after inoculation. Confirmation of the presence of the fungi in inoculated plants was performed following a real-time qPCR approach. The selected target genes for expression analysis were Superoxide dismutase (SOD), Endochitinase_EP3-like (CHI2), Glutathione S-transferase L3-like (TransFL3), Glutathione peroxidase 2 (PEROX2), Glutathione S-transferase THETA 1 (THETA), Glutathione S-transferase DHAR2-like (TransfDHAR), Glutathione peroxidase 5 (PEROX5) and Glutathione peroxidase 8 (PEROX8). Following a qPCR approach, a general up-regulation of the target genes was detected, but only CHI2 revealed a significantly up-regulation (p<0.005) between T0 and T2 in response to Colletotrichum sp. infection, being a promising candidate to be later used in functional analysis. We emphasize the importance of this study for the identification of candidate genes to incorporate new sources of resistance of olive trees to anthracnose with the promotion of the development of sustainable management strategies.
- Resultados preliminares sobre o estudo da fase de enraizamento, em nogueira (Juglans nigra L.) propagada in vitroPublication . Jacob, Ana Paula; Peixe, A.; Grego, José; Böhm, J.Foram efectuados ensaios para o estudo da indução da formação de raízes adventícias em estacas de nogueira (Juglans nigra L.) micropropagada. Foi utilizado o protocolo de enraizamento proposto por Ripetti et al. (1994) tendo sido estudada a duração do período de indução da rizogénese (entre três a sete dias) para concentração de 3 mg l-1 de IBA, o efeito de várias concentrações de fluoroglucinol (PG) (0,5; 1,5 e 2 mg l-1) como co-factor da acção do IBA e ainda o efeito da administração líquida (contacto por imersão com a base da estaca) de diferentes concentrações de IBA (de 8 a 140 mg l-1). Os resultados obtidos mostram que a adição de 3 mg l-1 de IBA ao meio de cultura, conduziu à obtenção de taxas de enraizamento na ordem dos 40% para 3 e 4 dias de indução; a administração líquida de IBA não induziu rizogénese para qualquer das concentrações utilizadas. Obtiveram-se taxas de enraizamento de 100% para cinco dias de indução, na presença de 3 mg l-1 de IBA e 2 mg l-1 de PG incorporados no meio de indução.