Hunting for sources of durable resistance in crop cultivar evaluation data: The case of wheat yellow rust in France

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Hunting for sources of durable resistance in crop cultivar evaluation data: The case of wheat yellow rust in France

Trajectories of field adult plant resistance ratings to yellow rust in 719 French wheat cultivars between 1963 and 2018 suggest the presence of effector-triggered and/or quantitative resistance.


Abstract

Cultivar resistance is a major asset for the management of crop diseases and can play an important role in agroecological transition. However, the wide deployment of a reduced number of resistance genes can lead to a rapid adaptation of pathogen populations and to a loss of resistance efficiency. The objective of this study was to characterize and discuss different trajectories of adult plant ratings for resistance to yellow rust in French wheat cultivars between 1963 and 2018. Among 719 cultivars assessed for at least 2 years, 590 cultivars showed no variation in their resistance scores, despite a mean of 4.3 years and up to 33 years of assessment. A set of descriptive variables was computed in order to compare the evolution of resistance score of 129 cultivars that experienced resistance variation. We applied a principal component analysis and a hierarchical clustering on principal components to this subdataset to constitute clusters corresponding to different cultivar profiles. Clusters C1 and C2 had small resistance variations (1–2 points on a 1–9 scale); Cluster C3 had long assessment durations and several small drops in resistance score and could be associated with quantitative resistance erosion; Cluster C4 included major drops in resistance score (4–5 points), often associated with known breakdowns of major resistance genes. Cases of limited drops in resistance score as a known resistance gene was broken down suggest the presence of efficient adult plant resistance. We discuss the use of information extracted from this dataset and methods to further explore sources of resistance to yellow rust present in French cultivars.

Ergot of cereals: Toxins, pathogens and management

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Ergot of cereals: Toxins, pathogens and management

This review article focuses on recent progress in understanding the toxins, pathogens and management of ergot, an important disease of cereals that affects food safety.


Abstract

Ergot is a fungal disease of many plants but is perhaps most commonly associated with domesticated grasses or cereals, such as rye, wheat, barley, oat, sorghum, millet, maize and rice. Ergot is of historical significance, having been reported for several millennia, but is also of concern in modern agricultural production systems. Caused by many different species within the genus Claviceps, the fungi cause the production of sclerotia, which are typically dark in colour, in place of healthy grain. The sclerotia contain toxins that can make the grain unsafe for consumption by humans or livestock. Ergot can be managed both preharvest as well as postharvest to minimize the presence of sclerotia and their associated toxins in food and feed systems. In this review, we provide a detailed update on our current knowledge of ergot on cereals, with a focus on recent advances in our understanding of fungal toxins and their regulation, pathogen biology and disease management.

An old mission revealed for BZRs

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Nature Plants, Published online: 11 April 2024; doi:10.1038/s41477-024-01671-6

BZR/BES transcription factors are widely recognized as mediators of brassinosteroid (BR)-responsive gene expression in seed plants, but details of how they act in species that lack BR perception are unclear. A study now uncovers an ancient mission of a BZR/BES transcription factor in sexual organ development in the liverwort Marchantia polymorpha.

Structure of intact α-carboxysome specifies role of CsoS2 in shell assembly

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Nature Plants, Published online: 11 April 2024; doi:10.1038/s41477-024-01667-2

The carbon fixation machinery α-carboxysome of the marine cyanobacterium Prochlorococcus is composed of an icosahedral-like proteinaceous shell that encapsulates the enzymes RuBisCO and carbonic anhydrase. Our cryo-EM structure reveals how thousands of protein components self-assemble into the α-carboxysome and characterizes the multivalent interactions by which the scaffolding protein CsoS2 crosslinks the shell with internal RuBisCO molecules.