Biology subjects

Lozano-Torres, J. L.

Publications and source records attributed to Lozano-Torres, J. L..

4 recordsLinked to original sources

bioRxiv2023

From root to shoot; Quantifying nematode tolerance in Arabidopsis thaliana by high-throughput phenotyping of plant development

Nematode migration, feeding site formation, withdrawal of plant assimilates, and activation of plant defence responses have a significant impact on plant growth and development. Plants display intraspecific variation in tolerance limits for root-feeding nematodes. Although disease tolerance has been recognised as a distinct trait in biotic interactions of mainly crops, we lack mechanistic insights. Progress is hampered by difficulties in quantification and laborious screening methods. We turned to the model plant Arabidopsis thaliana, since it offers extensive resources to study the molecular and cellular mechanisms underlying nematode-plant interactions. Through imaging of tolerance-related parameters the green canopy area was identified as an accessible and robust measure for assessing damage due to cyst nematode infection. Subsequently, a high-throughput phenotyping platform simultaneously measuring the green canopy area growth of 960 A. thaliana plants was developed. This platform can accurately measure cyst- and root-knot nematode tolerance limits in A. thaliana through classical modelling of tolerance limits. Furthermore, real-time monitoring provided data for a novel view of tolerance, identifying a compensatory growth response. These findings show that our phenotyping platform will enable further studies into a mechanistic understanding of tolerance to below-ground biotic stress. HighlightThe mechanisms of tolerance to root-parasitic nematodes remain unknown. We developed a high-throughput phenotyping system that enables unravelling the underlying mechanisms of tolerance to nematodes.

plant biology↗

bioRxiv2022

Root architecture plasticity in response to endoparasitic cyst nematodes is mediated by damage signaling

O_LIPlant root architecture plasticity in response to biotic stresses has not been thoroughly investigated. Infection by the endoparasitic cyst nematodes induces root architectural changes that involve the formation of secondary roots at infection sites. However, the molecular mechanisms regulating secondary root formation in response to cyst nematode infection remain largely unknown. C_LIO_LIWe first assessed whether secondary roots form in a nematode-density dependent manner by challenging wild type Arabidopsis plants with increasing numbers of cyst nematodes (Heterodera schachtii). Next, by using jasmonate-related reporter lines and knock-out mutants, we tested if tissue damage by nematodes triggers secondary root formation. Finally, we verified whether damage-induced secondary root formation depends on local auxin biosynthesis at nematode infection sites. C_LIO_LIIntracellular host invasion by H. schachtii triggers a transient local increase in jasmonates, which activates the expression of ERF109 in a COI1-dependent manner. Knock-out mutations in COI1 and ERF109 disrupt the nematode-density dependent increase of secondary roots observed in wildtype plants. Furthermore, ERF109 regulates secondary root formation upon H. schachtii infection via local auxin biosynthesis. C_LIO_LIHost invasion by H. schachtii triggers secondary root formation via the damage-induced jasmonate-dependent ERF109 pathway. This points at a novel mechanism underlying plant root plasticity in response to biotic stress. C_LI

plant biology↗

bioRxiv2021

Comparative genomics among three cyst nematode species reveals distinct evolutionary histories among effector families and an irregular distribution of effector-associated promoter motifs

Potato cyst nematodes (PCNs), an umbrella term used for two species, Globodera pallida and G. rostochiensis, belong worldwide to the most harmful pathogens of potato. Pathotype-specific host plant resistances are an essential handle for PCN control. However, the poor delineation of G. pallida pathotypes hampers the efficient use of available host plant resistances. Long-read sequencing technology allowed us to generate a new reference genome of G. pallida population D383 and, as compared to the current reference, the new genome assembly is 42 times less fragmented. For comparison of diversification patterns of six effector families between G. pallida and G. rostochiensis, an additional reference genome was generated for an outgroup, the beet cyst nematode Heterodera schachtii (IRS population). Large evolutionary contrasts in effector family topologies were observed. While VAPs diversified before the split between the three cyst nematode species, the families GLAND5 and GLAND13 only expanded in PCN after their separation from the genus Heterodera. Although DNA motifs in the promoter regions thought to be involved in the orchestration of effector expression ( DOG boxes) were present in all three cyst nematode species, their presence is not a necessity for dorsal gland-produced effectors. Notably, DOG box dosage was only loosely correlated with expression level of individual effector variants. Comparison of the G. pallida genome with those of two other cyst nematodes underlined the fundamental differences in evolutionary history between effector families. Re-sequencing of PCN populations with deviant virulence characteristics will allow for the linking of these characteristics with the composition of the effector repertoire as well as for the mapping of PCN diversification patterns resulting from extreme anthropogenic range expansion.

genomics↗

bioRxiv2021

The genome and lifestage-specific transcriptomes of a plant-parasitic nematode and its host reveal susceptibility genes involved in trans-kingdom synthesis of vitamin B.

Plant-parasitic nematodes are a major, and in some cases a dominant, threat to crop production in all agricultural systems. The relative scarcity of classical resistance genes highlights a pressing need to identify new ways to develop nematode-resistant germplasm. Here, we sequence and assemble a high-quality genome of the model cyst nematode Heterodera schachtii to provide a platform for the first system-wide dual analysis of host and parasite gene expression over time, covering all major stages of the interaction. This novel approach enabled the analysis of the hologenome of the infection site, to identify metabolic pathways that were incomplete in the parasite but complemented by the host. Using a combination of bioinformatic, genetic, and biochemical approaches, we show that the highly atypical completion of vitamin B5 biosynthesis by the parasitic animal, putatively enabled by a horizontal gene transfer from a bacterium, is critically important for parasitism. Knockout of either the plant-encoded or the now nematode-encoded steps in the pathway blocks parasitism. Our experiments establish a reference for cyst nematodes, use this platform to further our fundamental understanding of the evolution of plant-parasitism by nematodes, and show that understanding congruent differential expression of metabolic pathways represents a new way to find nematode susceptibility genes, and thereby, targets for future genome editing-mediated generation of nematode-resistant crops.

genetics↗