Biology subjects

Schwechheimer, C.

Publications and source records attributed to Schwechheimer, C..

6 recordsLinked to original sources

bioRxiv2025

MIK2 clade receptor function in perception of a Fusarium-derived elicitor is conserved among different plant families

Plants continuously monitor their environment to adapt to threats affecting health and fitness. Cell-surface receptors detect conserved microbe-associated molecular patterns (MAMPs) or endogenous immunogenic signals to activate signaling pathways that induce broad-spectrum disease resistance, known as pattern-triggered immunity (PTI). In Arabidopsis thaliana, the leucine-rich repeat receptor kinase MIK2 emerged as a versatile receptor involved in perceiving endogenous SCOOP peptides as well as potential MAMPs derived from Fusarium and related fungi. While SCOOP perception appears restricted to Brassicales, the Fusarium-derived elicitor triggers PTI-responses across different plant lineages. Here, we demonstrate that Fusarium elicitor-responsiveness and MIK2-clade proteins are conserved among seed plants. We identified a tomato MIK2-clade receptor that shares AtMIK2 properties in perceiving the Fusarium elicitor, but not SCOOPs. Tomato mutants lacking the receptor show compromised PTI-responses to the fungal elicitor and increased susceptibility to Fusarium oxysporum. By integrating AI-assisted structural prediction with experimental data, we identify conserved and variable residues in Arabidopsis and tomato MIK2-clade receptors that may underlie shared and lineage-specific recognition specificities. Together, these findings establish MIK2-clade receptors as immune surveillance modules that have undergone lineage-specific diversification, supporting a model in which endogenous danger perception might have evolved from an ancestral role in microbial pattern recognition.

plant biology↗

bioRxiv2024

KIPK and KIPK-LIKE1 suppress overbending during negative hypocotyl gravitropic growth

Plants use environmental cues, such as the direction of gravity or the direction, quantity and quality of light, to orientate organ and plant growth. During germination of angiosperm seeds in the soil, hypocotyl elongation is directed by negative gravitropism responses such that the seedling can reach the light for photosynthesis and autotrophic growth. Hypocotyl elongation in the soil, however, also requires mechanisms to efficiently grow around obstacles such as soil particles. Here, we identify KIPK (KINESIN-LIKE CALMODULIN-BINDING PROTEIN INTERACTING PROTEIN KINASE) and the paralogous KIPKL1 (KIPK-LIKE1) as genetically redundant regulators of hypocotyl bending, in that KIPK and KIPKL1 are required to efficiently align hypocotyl growth with the gravity vector after obstacle avoidance. At the same time, we find that the highly homologous KIPKL2 (KIPK-LIKE2) must be functionally distinct. We further find that KIPK, and likely also KIPKL1, phosphorylate BRXL2 (BREVIS RADIX LIKE2) and ARKs (ARMADILLO REPEAT KINESINs), that mutants of both KIPK phosphorylation substrates share the overbending phenotype with kipk kipkl1 mutants, and that KIPK and KIPKL1 act synergistically with the ARK-regulatory NEK6 (NIMA-RELATED PROTEIN KINASE6). We propose that KIPK and KIPKL1 regulate ARK kinesins and thereby cortical microtubules for efficient gravitropic hypocotyl bending.

plant biology↗

bioRxiv2024

Cross-family transfer of the Arabidopsis cell-surface immune receptor LORE to tomato confers sensing of 3-hydroxylated fatty acids and enhanced disease resistance

Plant pathogens pose a high risk of yield losses and threaten food security. Technological and scientific advances have improved our understanding of the molecular processes underlying host-pathogen interactions, which paves the way for new strategies in crop disease management beyond the limits of conventional breeding. Cross-family transfer of immune receptor genes is one such strategy that takes advantage of common plant immune signaling pathways to improve disease resistance in crops. Sensing of microbe- or host damage-associated molecular patterns (MAMPs/DAMPs) by plasma membrane-resident pattern recognition receptors (PRR) activates pattern-triggered immunity (PTI) and restricts the spread of a broad spectrum of pathogens in the host plant. In the model plant Arabidopsis thaliana, the S-domain receptor-like kinase LIPOOLIGOSACCHARIDE-SPECIFIC REDUCED ELICITATION (AtLORE, SD1-29) functions as PRR, which senses medium chain-length 3-hydroxylated fatty acids (mc-3-OH-FAs), such as 3-OH-C10:0, and 3-hydroxyalkanoates (HAAs) of microbial origin to activate PTI. In this study, we show that ectopic expression of the Brassicaceae-specific PRR AtLORE in the solanaceous crop species Solanum lycopersicum cv. M82 leads to the gain of 3-OH-C10:0 immune sensing without altering plant development. AtLORE-transgenic tomato shows enhanced resistance against Pseudomonas syringae pv. tomato DC3000 and Alternaria solani NL03003. Applying 3-OH-C10:0 to the soil before infection induces resistance against the oomycete pathogen Phytophthora infestans Pi100 and further enhances resistance to A. solani NL03003. Our study proposes a potential application of AtLORE-transgenic crop plants and mc-3-OH-FAs as resistance-inducing bio-stimulants in disease management.

plant biology↗

bioRxiv2024

Transport properties of canonical PIN-FORMED proteins and the role of the loop domain in auxin transport

Indole-3-acetic acid (IAA), the most abundant endogenous auxin is transported in plants in a polar fashion by PIN-FORMED (PIN) transporters and controls virtually all plant growth and developmental processes. Canonical PINs possess a long and largely disordered cytosolic loop domain which is shorter in non-canonical PINs. Auxin transport by canonical PINs is activated loop phosphorylation by kinases. While the structure of the transmembrane domains of these transporters was recently solved, their transport properties remained poorly characterized and particularly the relative roles of the transmembrane and loop domain therein. In this study we used flux studies to obtain quantitative kinetic parameters of IAA transport mediated by canonical PINs as well as of chimeras between transmembrane and loop domains of different PINs upon their activation by D6 PROTEIN KINASE or PINOID. We found that the transporters possess distinct transport properties that are due to both the transmembrane and loop domain. To demonstrate the physiological relevance of these distinct transport properties, we modelled root tip IAA distribution patterns and investigated the potential of different PINs to complement the agravitropic root growth phenotype of the pin2 mutant when expressed in the PIN2 domain. We found a strong correlation between transport parameters and physiological output indicating that in addition to PIN polarity a low transport rate in the PIN2 expression domain is required for gravitropic growth. Overall, the data show that the loop domain is not only required for activation of PIN-mediated auxin transport but has an additional role in the transport cycle by a currently unknown mechanism.

plant biology↗

bioRxiv2023

Monitoring single root hairs using a micro-chambered hydroponics system MiCHy reveals a new mode of action of the aminosteroid U73122

When using chemical probes and inhibitors for cell biological studies, the uniform and rapid access of the chemical to the sample is key for the accuracy of the analysis. Until now, however, this could only be accomplished by using expensive equipment and labor-intensive and often lengthy procedures. Here, we introduce MiCHy, a micro-chambered hydroponics system, as an accessible and versatile method for chemical treatments and demonstrate its use for imaging roots of Arabidopsis thaliana, the major model system for plant cell biological research. Using lipid biosensors in combination with established chemicals, such as the phosphoinositol 4-kinase (PI4K) inhibitor phenylarsine oxide and the phosphoinositide-specific phospholipase C (PI-PLC) inhibitor U73122, we demonstrate the suitability of MiCHy for studying the relationship between growth and lipid dynamics in root hairs. We further reveal novel effects of U73122 on the plasma membrane localization of phosphatidylinositol-4-phosphate 5-kinase 3 (PIP5K3), which is the first evidence demonstrating a role for U73122 besides its role as a PI-PLC inhibitor in plants.

plant biology↗

bioRxiv2017

A set of Columbia-0-specific single nucleotide polymorphism markers for the genetic analysis of natural variation in Arabidopsis thaliana

Genetic markers are important tools for the study of natural and induced genetic variation. Due to the strong increase in the number of genome sequences, an overview of the genomic diversity of many natural strains from individual species could be gained. This allows for the design of markers for flexible use and cost-efficient small scale genetic studies requiring minimal laboratory and bioinformatics effort. Here, we describe 140 single nucleotide polymorphism (SNP) markers with genome-wide distribution that discriminate between the genotype of the common Arabidopsis thaliana reference accession Columbia-0 (Col-0) and the majority of Arabidopsis thaliana accessions that have been sequenced to date. We designed, generated and validated the markers using the kompetitive allele-specific PCR (KASP) technology and made all 140SNPvCol marker assays publicly available through a service provider. Through the integration of available genomic SNP allele information of 1,135 accessions, we found that 120 of these 140 markers could detect non-reference alleles in 647 accessions and more than 100 markers showed non-reference alleles in 1,094 accessions. We further show that the marker set can be used for the verification or identification of accessions of unknown identity. As the KASP methodology is very flexible, an optimal marker subset can be easily selected among the available 140SNPvCol markers presented here to analyze genetic combinations of Col-0 with any other accession.

genetics↗