Biology subjects

Chanclud, E.

Publications and source records attributed to Chanclud, E..

3 recordsLinked to original sources

bioRxiv2024

Cytokinin-induced immunity enhances rice blast resistance

Plant cytokinins (CKs) affect the outcome of plant-pathogen interactions. However, despite many examples their role remains ambiguous. In rice, CKs act synergistically with salicylic acid (SA) to induce defense genes in vitro but no effect on resistance against the blast fungus, Magnaporthe oryzae, was further observed in planta. Here, we demonstrate that exogenous CKs treatment triggers rice blast resistance in a molecule-, dose- and time-dependent manner by affecting defense- and CK-responsive genes. Similar enhanced resistance and gene expression patterns were confirmed in rice insertion mutant lines impaired for a gene that encodes a putative CK inactivation enzyme, supporting that endogenous CKs affect rice immunity. Together, our work brings insights on the CK-induced resistance of rice to M. oryzae.

plant biology↗

bioRxiv2020

Population-level deep sequencing reveals the interplay of clonal and sexual reproduction in the fungal wheat pathogen Zymoseptoria tritici

Pathogens can rapidly surmount crop resistance challenging global food security. On annual crops, pathogens must re-infect from environmental sources at the beginning of every growing season. Fungal pathogens evolved mixed reproductive strategies to cope with the distinct life cycle challenges of colonizing plants, spreading within fields and ultimately producing propagules for survival in winter. However, how genotypic diversity evolves over this period remains largely unknown. Here, we performed a deep hierarchical sampling in a single experimental wheat field infected by the major fungal pathogen Zymoseptoria tritici. We analyzed whole genome sequences of 177 isolates collected from twelve distinct cultivars replicated in space at three time points of the growing season. The field population was highly diverse with 37 SNPs per kilobase and a linkage disequilibrium decay within 200-700 bp. We found that ~20% of the individual isolates were grouping into 15 clonal groups. Pairs of clones were disproportionally found at short distance (<5m) but a low degree of dispersal occurred also at the scale of the entire field consistent with a predominant leaf-to-leaf dispersal. We found no association of wheat cultivars and clonal genotypes with the exception of one cultivar. Surprisingly, levels of clonality did not increase over time in the field although reproduction is thought to be exclusively asexual during the growing season. Our study shows that the pathogen establishes vast and stable gene pools in single fields over the growing season. Monitoring short-term evolutionary changes in crop pathogens will inform more durable strategies to contain diseases.Competing Interest StatementThe authors have declared no competing interest.View Full Text

genomics↗

bioRxiv2017

Lessons in effector and NLR biology of plant-microbe systems

A diversity of plant-associated organisms secrete effectors--proteins and metabolites that modulate plant physiology to favor host infection and colonization. However, effectors can also activate plant immune receptors, notably nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins, enabling plants to fight off invading organisms. This interplay between effectors, their host targets, and the matching immune receptors is shaped by intricate molecular mechanisms and exceptionally dynamic coevolution. In this article, we focus on three effectors, AVR-Pik, AVR-Pia, and AVR-Pii, from the rice blast fungus Magnaporthe oryzae (syn. Pyricularia oryzae), and their corresponding rice NLR immune receptors, Pik, Pia, and Pii, to highlight general concepts of plant-microbe interactions. We draw 12 lessons in effector and NLR biology that have emerged from studying these three little effectors and are broadly applicable to other plant-microbe systems.

plant biology↗