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- Alternaria alternata an emerging pathogen with great impact on olive grovesPublication . Carvalho, Teresa; Materatski, Patrick; Osa, Nicolás; Patanita, Mariana; Varanda, Carla; Ribeiro, Joana A.; Albuquerque, André; Campos, Maria Doroteia; Félix, M.R.Downy mildew, powdery mildew, grey mould, black rot, and grapevine trunk diseases are among the most important fungal or oomycete diseases affecting grapevine, with a high economic impact in all growing areas. In recent decades, extensive efforts have been made to reduce the use of agrochemicals in viticulture, turning the management of these diseases a major challenge. Given the urgent need to identify and develop new sustainable and effective protection strategies, a better understanding of plant defence mechanisms is essential to develop more tolerant plants and provide valuable insights for disease management. Although recent advances in molecular technologies have allowed the identification of several resistance genes, little is known about the complexity of the molecular mechanisms involved in grapevine-pathogen interactions. This chapter aims to bring together the most up-to-date findings on the regulation of grapevine defence mechanisms against major fungal and oomycete diseases by enumerating promising candidate genes that offer broad possibilities for inducing resistance to specific pathogens. We also focus on the use of functional genomics as a tool to study grapevine immunity to different pathogens, with particular emphasis on new emerging molecular technologies that will undoubtedly contribute to a sustainable plant breeding.
- 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.