Bacteria are major pathogens causing plant diseases and important economic losses in agricultural crops. We are mainly working in two bacterial genera which concern worldwide: Xanthomonas and Liberibacter.
Xanthomonas is a bacterial genus characterized by its diversity and host specialization and has been studied for a long time because of its phytopathological interest but also to be an interesting microbiological model. Liberibacter are non-culturable bacteria causing severe diseases like citrus Huanglongbing (HLB) and potato `zebra chip´.
We have worked and currently work largely in two species of Xanthomonas: Xanthomonas citri subsp. citri (Xcc), causal agent of citrus bacterial canker which is not present in Spain or any European or Mediterranean basin country, and Xanthomonas arboricola pv. pruni (Xap), which causes bacterial spot of stone fruits and almond, a disease recently described in Spain.
Our group has contributed to the knowledge on the bacterial mechanisms of infection. In X. citri, por example, we have been profusely working about its ability to form biofilm and its relationship with the host range of the different types of Xcc. In addition, to learn about the biofilm forming ability on plant surface and interior, we have identified elements involved in bacterial aggregate matrix that might be targets for chemical control in future approaches.
In X. arboricola, we work to elucidate those factors involved in the pathogen characteristics of these bacteria, for that, pathogenic and non-pathogenic bacteria from the same host are compared. We approach genomic analysis, trying to connect the results with phenotypic characters, for instance, assessing aggregation and motility in different environments. Moreover, we are very interested and work about biofilm composition matrix and chemotaxis and their link to host range
Results on Xcc and Xap have allowed us to develop hypotheses about the different host infection modes as it is reflected in an article recently published by our group.
Finally, in these two Xanthomonas models we work in developing new detection methods based many times on results from bacterial genetic analysis.
In Candidatus Liberibacter spp. our group works developing detection protocols for these bacteria either to be applied in plant material or for insect vectors.
In the last few years, we have been involved in international and national projects addressed to evaluate detection techniques, and for instance, for HLB, of great interest for UE, and consider a priority pest which introduction must be avoided, we have published a manuscript lately.
We have been working in characterization of those Candidatus Liberibacter solanacearum (CLso) detected in different crops in Spain through sequencing approaches and phylogenetic analysis. Our effort has been directed mainly on CLso detected from potatoes and to do so we have been cooperating with plant protection services from the different Autonomous Communities in Spain.
Our final goal is pathogen control on plant diseases, following two approaches: pathogen exclusion, avoiding bacteria introduction, especially those qurantinable species, in a free area. For that, it Is necessary to have a perfect pathogen identification through rapid and precise techniques of detection, identification and characterization. On the other hand, our work tries to lay the ground for new control approaches based in blocking any of the essential factors involved in virulence. To do so, it is crucial a deep knowledge of bacteria-plant interaction.