One of the most economically important fruit trees in Mediterranean countries is the olive tree (Olea europaea L.). Foliar and fruit fungal pathogens are responsible for economically important diseases in most olive-growing areas. Within these pathogens, we highlight Colletotrichum spp., the causal agent of the serious anthracnose disease. Under favourable conditions, the disease can devastate entire production fields. Symptoms typically occur in fruits at maturation under wet autumn conditions, causing severe quantitative and qualitative yield losses of olive oil and fruits. The best control strategy currently relies on the use of synthetic fungicides, but there is regulatory pressure in agriculture worldwide to limit their use.
In search of a sustainable approach to disease management, the present study reports the transcriptional changes of genes that encode enzymes actively involved in the olive tree's defence response to C. nymphaeae infection. ‘Galega vulgar’, an olive cultivar known to be highly susceptible to the disease, was selected for the studies. The plants used in the experiments were grown in vitro to ensure their health status, transplanted into pots, and grown under controlled conditions. Leaf samples were collected before fungi inoculation, and in different timepoints after inoculation with a spore suspension of C. nymphaeae. Transcriptomic studies revealed a general upregulation of the selected target genes, but only Endochitinase_EP3-like (CHI) presented a significant upregulation in response to C. nymphaeae infection. CHI is a promising candidate to be used in functional analysis. We stress the importance of this study for the incorporation of new sources of resistance of olive trees to anthracnose for the promotion of sustainable management strategies.
Acknowledgements and Funding:
- Patanita and J.A. Ribeiro are supported by Portuguese National Funds through FCT/MCTES under the PhD scholarships 2022.13638.BD and SFRH/BD/145321/2019, respectively. This work is also funded by National Funds through FCT under the Project UIDB/05183/2020 and under the project INOVCIRCOLIVE PRR-C05-i03-I-000208.
