Linking pine cell wall composition and structure to pinewood nematode resistance under climate change

Pine-related goods and activities make up a substantial share of the Portuguese forestry sector, and more generally, of the Portuguese Economy. Therefore, it is vital for this resource to be protected, especially as uncertain economic times lie ahead. The pinewood nematode (PWN), Bursaphelenchus xylophilus, is a major threat to this sector, as it causes the pine wilt disease (PWD), leading to high losses in conifer forests. The PWN infects various Pinus spp., namely the maritime pine (P. pinaster), which is widely distributed in Portugal and is one of the most susceptible species. Other Pinus spp., such as the stone (P. pinea) and Aleppo (P. halepensis) pines are less, or even non-susceptible to the PWN. However, the reasons for these differences in susceptibility to PWN are not well understood. In recent years, members of our research team have independently worked on furthering our knowledge about PWN pathogenicity mechanisms and on host defence mechanisms. With this preliminary database at our disposal, we have now conceived the PineWALL project. This will be an innovative transdisciplinary approach focused on an often-overlooked aspect, which is how the pine cell wall (CW) composition and structure can influence the host susceptibility/resistance to PWN infection under a climate change scenario. The PWN uses its stylet to mechanically breach host CW, while releasing hydrolytic enzymes against all groups of plant CW glycans. These enzymes act by softening the CW, facilitating PWN migration within the plant. Nonetheless, there is a lack of studies focused on CW characterisation in function of PWN infection. With PineWALL we aim at addressing this gap in our knowledge. This project will focus on how Pinus spp. traits are linked to PWN susceptibility/resistance. Our main premise is that CW composition and structure are associated to varying degrees of susceptibility to PWN. Moreover, as drier and warmer conditions are likely to exacerbate vulnerability to PWN, we need to better understand the effects of varying environmental conditions on host susceptibility/resistance to PWN infection. With this in mind, we have defined seven interconnected tasks that will make up the workplan for PineWALL. Susceptible and non-susceptible pine species (P. pinaster, P. pinea, P. halepensis) and P. pinaster genotypes with different susceptibilities to PWN will be inoculated with the nematodes and disease progression will be monitored while plants are grown under controlled temperatures and soil water contents. The morphology/anatomy of susceptible and less susceptible Pinus spp. will be compared, in order to understand whether anatomical features have implications on disease progression. High-throughput vibrational spectroscopy methods will be used for an overall characterisation of the Pinus spp. CW. Chemical analytical methods will be used to perform a targeted characterisation of different CW fractions. Moreover, two immunological approaches will be employed to unveil the glycome profile of Pinus spp. CW, and to reveal in muro glycan distributions by in situ immunolabelling. Thus, helping to understand how CW glycans are linked to PWN susceptibility/resistance. Data modelling will be performed to integrate all collected data, allowing the identification of biomarkers which would be used to predict PWN susceptibility/resistance, ultimately contributing to the modelling of a P. pinaster ideotype, better adapted to changing climatic and phytopathological conditions. PineWALL will highly benefit from the Research and Higher Education platforms at the Universities of Coimbra and Porto, which are the two main institutions of the project. Furthermore, the multidisciplinary nature of PineWALL is the result of careful planning to include diverse but complementary skills within the team. Thus, each team member will uniquely contribute to the project, while relying on the skills of others, towards a shared purpose. This purpose being of producing a comprehensive picture of Pinus spp. CW in the context of PWN infection under a changing climate scenario. These studies will provide a wider understanding of PWN infection and host defence responses, and will be a valuable resource for researchers working with this detrimental plant pathogen. Lastly, as PineWALL aims at having a positive impact on society, we will interact directly with stakeholders in the forestry sector, promoting joint discussions to find solutions for problems affecting the Portuguese pine sector.

State
Ongoing
Period
2021 to 2024
Funding
239.781,74 €
Project code
PTDC/ASP-SIL/3142/2020
Funding entity
Portuguese Foundation for Science and Technology (FCT)

Members
Ricardo da Costa (Investigador Responsável)
Luís Fonseca
Hugo Silva
Filipe Campelo
Carmen Diniz
Isabel Abrantes
Joana Marques
Joana Cardoso
João Martins
Jorge Canhoto
Luís Batista de Carvalho
Maria Paula Marques
Maria João Ferreira
Sílvia Coimbra