Browsing by Author "Santos, Miguel G."
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- Assessing the effectiveness of different Pseudomonas syringae pv. actinidiae pre-inoculation procedures to promoting disease visual symptoms in adult kiwifruit plantsPublication . Santos, Miguel G.; Silva, Marta Nunes da; Gallego, Pedro P.; Vasconcelos, Marta W.; Carvalho, Susana M. P.
- Effect of different pre-inoculation procedures on leaf spotting appearance in adult kiwifruit plants artificially inoculated with Pseudomonas syringae pv. actinidiaePublication . Santos, Miguel G.; Silva, Marta Nunes da; Gallego, Pedro P.; Vasconcelos, Marta W.; Carvalho, Susana M. P.Phytopathology studies most often rely on laboratory, greenhouse or field experiments in which plants are artificially inoculated using a variety of pre-inoculation procedures that aim to improve plant infection success. Concerning the Kiwifruit Bacterial Canker (KBC), whose aetiological agent is the bacterium Pseudomonas syringae pv. actinidiae (Psa), the pre-inoculation procedures most often target leaf tissues, promoting bacterial colonization through natural (e.g., stomata) or artificial openings (e.g., leaf wounds). However, the variability in pre-inoculation methods can influence the infection dynamics, making pathogenicity analysis amongst different research studies very complex. Here, four pre-inoculation procedures were tested in adult kiwifruit plants (Actinidia chinensis var. deliciosa ‘Tomuri’; lignified 15-month-old plants grown in pots) for their effect on leaf spotting appearance at 21 days after inoculation. These procedures consisted of: (i) plant enclosure in a plastic bag (maintained 24 h before and 24 h after inoculation; BAG), (ii) leaf wounding with three superficial cuts (CUTS), (iii) plant maintenance at 5 ℃ for 24 h (COLD) and (iv) a combination of all these procedures (ALL). Plants mock-inoculated with Ringer’s solution were included in the experiment as control. Results showed that BAG was the treatment with highest efficacy in causing appearance of leaf spots, since plants showed 7.1, 15 and 40 times more leaf spots than plants from ALL, CUTS and COLD, respectively. Furthermore, treatments ALL, CUTS and COLD did not appear to be suitable pre-inoculation procedures for promoting KBC foliar symptoms. This study highlights the importance of following precise pre-inoculation procedures in plant artificial inoculation with Actinidia chinensis – Psa, where leaf symptoms appearance is commonly utilized in disease severity analysis.
- Mitigation of emergent bacterial pathogens using pseudomonas syringae pv. Actinidiae as a case study - from orchard to gene and everything in betweenPublication . Silva, Marta Nunes da; Santos, Miguel G.; Vasconcelos, Marta W.; Carvalho, Susana M. P.Globalization propelled human migration and commercial exchanges at the global level, but woefully led to the introduction of non-indigenous organisms into several agroecological systems. These include pathogenic bacteria with devastating consequences for numerous crops of agronomical importance for food production worldwide. In the last decade, research efforts have focused on these noxious organisms, aiming to understand their evolutionary processes, degree of pathogenicity, and mitigation strategies, which have allowed stakeholders and policymakers to develop evidence-based regulatory norms to improve management practices and minimize production losses. One of these cases is the bacterium Pseudomonas syringae pv. actinidiae (Psa), the causal agent of the kiwifruit bacterial canker, which has been causing drastic production losses and added costs related to orchard management in the kiwifruit industry. Although Psa is presently considered a pandemic pathogen and far from being eradicated, the implementation of strict regulatory norms and the efforts employed by the scientific community allowed the mitigation, to some extent, of its negative impacts through an integrated pest management approach. This included implementing directive guidelines, modifying cultural practices, and searching for sources of plant resistance. However, bacterial pathogens often have high spatial and temporal variability, with new strains constantly arising through mutation, recombination, and gene flow, posing constant pressure to agroecosystems. This review aims to critically appraise the efforts developed to mitigate bacterial pathogens of agronomical impact, from orchard management to genome analysis, using Psa as a case study, which could allow a prompter response against emerging pathogens in agroecosystems worldwide.
- Scientific and technological advances in the development of sustainable disease management tools: a case study on kiwifruit bacterial cankerPublication . Santos, Miguel G.; Silva, Marta Nunes da; Vasconcelos, Marta W.; Carvalho, Susana M. P.Plant disease outbreaks are increasing in a world facing climate change and globalized markets, representing a serious threat to food security. Kiwifruit Bacterial Canker (KBC), caused by the bacterium Pseudomonas syringae pv. actinidiae (Psa), was selected as a case study for being an example of a pandemic disease that severely impacted crop production, leading to huge economic losses, and for the effort that has been made to control this disease. This review provides an in-depth and critical analysis on the scientific progress made for developing alternative tools for sustainable KBC management. Their status in terms of technological maturity is discussed and a set of opportunities and threats are also presented. The gradual replacement of susceptible kiwifruit cultivars, with more tolerant ones, significantly reduced KBC incidence and was a major milestone for Psa containment – which highlights the importance of plant breeding. Nonetheless, this is a very laborious process. Moreover, the potential threat of Psa evolving to more virulent biovars, or resistant lineages to existing control methods, strengthens the need of keep on exploring effective and more environmentally friendly tools for KBC management. Currently, plant elicitors and beneficial fungi and bacteria are already being used in the field with some degree of success. Precision agriculture technologies, for improving early disease detection and preventing pathogen dispersal, are also being developed and optimized. These include hyperspectral technologies and forecast models for Psa risk assessment, with the latter being slightly more advanced in terms of technological maturity. Additionally, plant protection products based on innovative formulations with molecules with antibacterial activity against Psa (e.g., essential oils, phages and antimicrobial peptides) have been validated primarily in laboratory trials and with few compounds already reaching field application. The lessons learned with this pandemic disease, and the acquired scientific and technological knowledge, can be of importance for sustainably managing other plant diseases and handling future pandemic outbreaks.