Biology subjects

Pruitt, R. N.

Publications and source records attributed to Pruitt, R. N..

3 recordsLinked to original sources

bioRxiv2021

Genotyping-by-sequencing-based identification of Arabidopsis pattern recognition receptor RLP32 recognizing proteobacterial translation initiation factor IF1

Pattern-triggered immunity (PTI) is a central component of plant immunity. Activation of PTI relies on the recognition of microbe-derived structures, termed patterns, through plant encoded surface-resident pattern recognition receptors (PRRs). We have identified proteobacterial translation initiation factor 1 (IF1) as an immunogenic pattern that triggers PTI in Arabidopsis thaliana and some related Brassicaceae species. Unlike most other immunogenic patterns identified, IF1 elicitor activity cannot be assigned to a small peptide epitope, suggesting that tertiary fold features are required for IF1 receptor activation. We have deployed natural variation in IF1 sensitivity to identify leucine-rich repeat (LRR) receptor-like protein 32 (RLP32) as the corresponding Arabidopsis receptor using a restriction site-associated DNA sequencing (RAD-seq) approach. Transgenic expression of RLP32 confers IF1 sensitivity to rlp32 mutants, IF1-insensitive Arabidopsis accessions and IF1-insensitive Nicotiana benthamiana. RLP32 binds IF1 specifically and forms complexes with LRR receptor kinases SOBIR1 and BAK1 to mediate signaling. Similar to previously identified PRRs RLP32 confers resistance to Pseudomonas syringae infection, highlighting an unexpectedly complex array of bacterial pattern sensors within a single plant species.

plant biology↗

bioRxiv2020

Arabidopsis cell surface LRR immune receptor signaling through the EDS1-PAD4-ADR1 node

Plants use both cell surface and intracellular immune receptors with leucine rich-repeat (LRRs) to detect pathogens. LRR receptor kinases (LRR-RKs) and LRR receptor-like proteins (LRR-RPs) recognize extracellular microbe-derived molecules to confer pattern-triggered immunity (PTI), while nucleotide-binding LRR (NLR) proteins detect microbial effectors inside the cell to confer effector-triggered immunity (ETI). Despite PTI and ETI signaling being initiated in different compartments, both rely on the transcriptional activation of similar sets of genes, suggesting convergence in signaling upstream of nuclear events. Here we report that two sets of molecules, helper NLRs from the ADR1 (ACTIVATED DISEASE RESISTANCE 1) family as well as lipase-like proteins EDS1 (ENHANCED DISEASE SUSCEPTIBILITY 1) and PAD4 (PHYTOALEXIN DEFICIENT 4), are required not only for ETI, but also for PTI. A further similarity is seen in the evolutionary patterns of some PTI and ETI receptor genes, with both often being highly polymorphic, and with nevertheless distinct roles of LRR-RK and LRR-RP receptors in immunity. We find that the LRR-RK SOBIR1 directly links LRR-RPs with the ADR1 helper NLR as well as EDS1 and PAD4, suggesting the formation of constitutive supramolecular signalosome complexes at the inner side of the plasma membrane. We propose that the EDS1-PAD4-ADR1 node is an essential component and convergence point for immune signaling cascades activated by both surface-resident LRR-RP receptors and intracellular NLR receptors.

plant biology↗

bioRxiv2017

A microbially derived tyrosine sulfated peptide mimics a plant peptide hormone

O_LIThe biotrophic pathogen Xanthomonas oryzae pv. oryzae (Xoo) produces a sulfated peptide named RaxX, which shares similarity to peptides in the PSY (plant peptide containing sulfated tyrosine) family. We hypothesize that RaxX functionally mimics the growth stimulating activity of PSY peptides.\nC_LIO_LIRoot length was measured in Arabidopsis and rice treated with synthetic RaxX peptides. We also used comparative genomic analysis and Reactive Oxygen Species (ROS) burst assay to evaluate the activity of RaxX and PSY peptides.\nC_LIO_LIHere we found that a synthetic sulfated RaxX derivative comprising 13 residues (RaxX13-sY), highly conserved between RaxX and PSY, induces root growth in Arabidopsis and rice in a manner similar to that triggered by PSY. We identified residues that are required for activation of immunity mediated by the rice XA21 receptor but that are not essential for root growth induced by PSY. Finally, we showed that a Xanthomonas strain lacking raxX is impaired in virulence.\nC_LIO_LIThese findings suggest that RaxX serves as a molecular mimic of PSY peptides to facilitate Xoo infection and that XA21 has evolved the ability to recognize and respond specifically to the microbial form of the peptide.\nC_LI

plant biology↗