Job Opening: Precision detection and control of plant pathogens: the case study of Erwinia amylovora and Stemphylium vesicarium sp. in apple/pear
Brief Description:
Italy is the second largest EU producer of apples (2.2 Mt/year). In 2021, Italy was the 4th EU largest pear producer (273,450 t/year), but lost its leadership due to the high losses caused by pathogens like S. vesicarium and climate change. The World Apple and Pear Association (WAPA) forecasts for 2024 that EU apples and pear will reach ~11.4 Mtons and ~1.7 Mtons respectively, below 3.3% and 12.8%, the values of 2022. This decrease is mainly due to prolonged heat/drought episodes and extreme out-season storms (e.g., Portugal/Spain had during 2023 a severe prolonged drought, and the northern/eastern EU had a drought period in June/July). Italy was mostly affected by extreme storms and heat/drought, which, according to WAPA. Climate change impacts are aggravated by the increasing number of hectares infected with pathogens, whose behavior under climate change remains unquantified. The main pathogens are:
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Erwinia amylovora causes sudden and severe disease in Rosaceae and may lead to the tree death. Primary infection occurs at blooming, when pathogen control is very challenging and the risk of phytotoxicity high. Furthermore, secondary infections may occur from May to late October posing serious difficulty for a seasonal-long control of this disease. In addition, no efficient treatments are available (only sanitary pruning and use of Cu-based compounds). Finally, no in-site, fast and reliable diagnostic methods exists to precisely tailor control inputs and minimize pesticide use.
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Stemphylium vesicarium causes a critical fungal disease in pear, with a devastating incidence in specific pear cultivars such as Abbé Fétel. The first symptoms of fruit are observed at the fruit set. Identification of S. vesicarium conidia and P. allii ascospores is normally accomplished through spore trap devices and optical microscope observations. Molecular markers and specific metabolites can also be used for distinguishing S. vesicarium isolates. Identification of risk factors (e.g., levels of inoculum, Tª, wetness, host cultivar) are being used to predict brown spots in pear (an advisory system to reduce fungicide inputs is BSPcast
AIMS:
Test Early detection and informatic/SA tools to better manage pathogen dispersal and outbreaks – The research will be based on samples from field-orchards (or Italian pilot orchards) and the RCP8.5-mesocosms. Primarily, VOC-based diagnosis for early pathogen detection under different environmental conditions will be performed. The compiled information of climatic data and of lab/mesocosms/field detection will be integrated considering the cultivar, region, pathogen, microbiome, RCP 8.5.
Develop Precision Control tools under RCP8.5 – This task will be based on two parallel approaches: the selection of biocontrol agents (BCAs) and the entering of synthetic communities SynComs.
BCAs isolation and characterization – In parallel to the microbiota characterization by NGS, we will isolate bacterial and fungal strains (including pathogens) from the field/pilot orchards and the RCP8.5-mesocosms patho/microbiomes using culturing methods. Isolates characterized for fitness will be tested at normal temperature and at up to 48ºC (also used in RCP8.5 mesocosm). Temperature and drought resistant taxa/strains including E. amylovora, S. vesicarium, and candidate BCA strains like Trichoderma spp., Bacillus spp. will be selected. The effect of temperature will be assessed on E. amylovora survival and biology (e.g., growth, virulence-determinants, motility, quorum-sensing), and S. vesicarium survival and biology (e.g., growth, virulence factors, sporulation, hsp, etc.). Resistant candidate BCAs will be sequenced and key genes enabling growth at RCP8.5 identified. Most RCP8.5 resistant and bioactive BCAs will be characterized for compatibility traits, and bioactive compounds (e.g, AMPs).
Engineering SynComs – Most compatible tolerant BCAs will be tested to build SynComs. For that, candidate strains physicochemical/biological traits metadata will be in silico analyzed (e.g., Biolog, pH, IAA-production, ACC-deaminase) to sort the most compatible/stable combinations of SynCom (against E. amylovora or S. vesicarium) at high Tª. The above smart algorithms will learn with the increasing number of strains and temperatures. Engineering and delivery (formulations) methods will be optimized for each SynCom combination, and their stability tested for ~20 generations in vitro and later in planta (assessing colonization ability and persistence of SynCom by qPCR) at normal vs. an RCP8.5 scenarios. SynComs effects on pathobiome will be profiled (physiology, omics).
Applicants should have a background in plant molecular biology and/or plant physiology and/or plant pathology/plant-microbe interactions.
Research involves laboratory and field trials. The selected candidate will assist the program leader with all aspects of the planning, implementation and management of the research program. The main duties will be collecting and analyzing data, preparing presentations and scientific publications, and supervision of students.
For more information, please consult the website: https://bandi.unibo.it/ricerca/assegni-ricerca?id_bando=68152