Bagley, Stuart
(2021)
Characterisation of fungicidal and non-fungicidal effects of Inatreq™ active.
PhD thesis, University of Nottingham.
Abstract
With growing demand for increased crop yields, mitigating losses due to abiotic and biotic stresses is of paramount importance. A new fungicide with a novel mode of action effective in wheat against the pathogen responsible for Septoria tritici blotch (Zymoseptoria tritici), has recently been released by Corteva Agriscience. Inatreq™ active (active ingredient fenpicoxamid) is the first commercially available picolinamide fungicide. Preliminary observations of this fungicide suggest that it may also have biostimulant-like properties, unrelated to its fungicidal activity. The aim of this study is to further characterise the fungicidal activity of Inatreq when applied as a curative application, using traditional and image-based assessment techniques. This work also aims to characterise the beneficial non-fungicidal effects associated with the application of Inatreq, and to begin to understand the mechanisms underlying this activity.
It was found that when the curative efficacy of Inatreq was compared to a panel of commercially available fungicides also used to manage Septoria tritici blotch, it performed excellently, outperforming all alternatives. This work was also used to validate an imagebased assessment tool against traditional manual scoring methods. This tool aims to eliminate the influence of bias from the process of scoring disease severity and was found to be reliable and accurate, providing more consistent scores, that were more specific in the mid-range of disease severity, and closer to the accepted ground truths than traditional methods.
Inatreq application was associated with improvements in biomass accumulation, a reduction in stomatal conductance and improvement of water use efficiency, in both wellwatered plants and plants experiencing drought. These effects were observed in controlled environment growth room conditions, as well as in a large-scale glasshouse trial, across multiple wheat varieties. These effects were also observed in the model plant species A. thaliana. However, this conserved response was not observed in A. thaliana plants that had mutations in their abscisic acid (ABA) signalling and biosynthesis pathways. RNA sequencing data revealed an array of biological processes and genes that were upregulated following the application of Inatreq, with many related to ABA, stomatal regulation, and a variety of other stress responses, providing targets for future research.
The findings of this project highlight the amenability of Inatreq to a variety of crop protection strategies, as well as characterising its biostimulant-like activity. This research utilised a range of phenotyping technologies, as well as developing some bespoke tools, with a particular emphasis on low-cost phenotyping approaches with wider applicability.
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