Biology subjects

Hou, L.-Y.

Publications and source records attributed to Hou, L.-Y..

6 recordsLinked to original sources

bioRxiv2026

Conserved core and dynamic periphery NRC helper NLRs underpin immune receptor network evolution across Solanaceae

Plant nucleotide-binding leucine-rich repeat (NLR) proteins function as intracellular immune receptors that detect pathogen-derived signals and activate defense responses. The NRC (NLR required for cell death) receptor network plays central roles in immunity of solanaceous crops, yet its evolutionary diversification across Solanaceae remains poorly understood. Here, we combined comparative phylogenomics and comprehensive functional complementation assays to investigate the evolution and functional diversification of NRC helper NLRs across nine representative species from diverse genera within the Solanaceae. Phylogenetic analyses resolved 11 NRC helper subfamilies with distinct evolutionary trajectories, revealing a conserved core and dynamic periphery within the NLR receptor network. NRC2, NRC3, and NRC4 were broadly conserved across all examined species, whereas other NRC lineages exhibited degrees of presence-absence polymorphisms, lineage-specific expansion, and rapid diversification. Comparative genomic analyses revealed highly dynamic helper-sensor NLR cluster organization, indicating substantial genomic restructuring during Solanaceae evolution. Functional assays further showed that some NRC subfamilies retained broad compatibility with multiple sensor NLRs despite extensive sequence and genomic divergence, whereas other helpers displayed lineage-specific gains and losses of compatibility, revealing extensive rewiring of helper-sensor functional connections. Together, our study provides a cross-Solanaceae evolutionary and functional atlas of the NRC immune receptor network and demonstrates how a conserved core and dynamic periphery of NRC helper NLRs underpin the evolution of immune signaling specificity across Solanaceae.

plant biology↗

bioRxiv2025

A plant pathogen effector blocks stepwise assembly of a helper NLR resistosome

Helper NLRs function as central nodes in plant immune networks. Upon activation, they oligomerize into inflammasome-like resistosomes to initiate immune signaling, yet the dynamics of resistosome assembly remain poorly understood. Here, we show that the virulence effector AVRcap1b from the Irish potato famine pathogen Phytophthora infestans suppresses immune activation by directly engaging oligomerization intermediates of the tomato helper NLR SlNRC3. Cryo-EM structures of SlNRC3 in AVRcap1b-bound and unbound states reveal that AVRcap1b bridges multiple protomers, stabilizing a stalled intermediate and preventing formation of a functional resistosome. Leveraging AVRcap1b as a molecular tool, we also capture an additional SlNRC3 resistosome intermediate showing that assembly proceeds in a stepwise manner from dissociated monomers. These findings uncover a previously unrecognized vulnerability in NLR activation and reveal a pathogen strategy that disrupts immune complex assembly. This work advances mechanistic understanding of resistosome formation and uncovers a previously unrecognized facet of pathogen-plant coevolution.

plant biology↗

bioRxiv2025

Virus-induced upregulation of mitochondrial metabolism modulates cytosolic redox balance and defense responses

Plants possess a remarkable capacity to reprogram their metabolism in response to pathogen attacks. However, the mechanisms by which metabolic reprogramming modulates defense signaling remain poorly understood. In this study, we leverage a multifaceted omics approach to investigate the metabolic shifts induced by the Bamboo mosaic virus (BaMV), a positive-sense single-stranded RNA virus that depends on host factors from multiple organelles for its replication. Metabolic profiling revealed an accumulation of hexose phosphates and Krebs cycle intermediates in Nicotiana benthamiana plants following BaMV infection. Fluxomic analysis uncovered an orchestrated redirection of metabolic flux toward glycolysis and the Krebs cycle during infection. Proteomic data further highlighted a concerted upregulation of mitochondrial enzymes, with three mitochondrial proteins showing markedly increased accumulation in BaMV-infected tissues. These integrated omics results suggest that BaMV infection triggers a metabolic shift toward energy-generating pathways. Notably, functional analysis revealed that silencing mitochondrial NAD+-dependent malic enzyme 1 significantly enhanced BaMV accumulation, accompanied by alterations in cytoplasmic NADH-to-NAD+ ratio and changes in the landscape of defense gene expression. Collectively, our findings underscore the pivotal role of mitochondrial metabolism in governing cytoplasmic redox balance, finely tuning defense responses to viral infection. One sentence summaryBaMV infection enhances mitochondrial metabolism to regulate cytoplasmic redox balance and promote antiviral defense.

plant biology↗

bioRxiv2025

Single-cell-resolved calcium and organelle dynamics in resistosome-mediated cell death

Plant nucleotide-binding domain leucine-rich repeat-containing (NLR) proteins act as intracellular immune receptors that assemble into resistosomes to execute immune responses. However, the subcellular processes during cell death following resistosome activation remain unclear. Here, we visualized the changes in calcium signaling and organelle behavior after activation of the NRC4 (NLR-required for cell death 4) resistosome. We found that NRC4 membrane enrichment coincided with calcium influx. This is followed by sequential mitochondria and plastid disruption, endoplasmic reticulum fragmentation and cytoskeleton depolymerization. Subsequent loss of plasma membrane integrity, nuclear shrinkage, and vacuolar collapse mark the terminal stage of cell death. Our findings reveal a spatiotemporally-resolved cascade of subcellular events downstream of resistosome activation, providing new mechanistic insight into the execution phase of plant immune cell death.

plant biology↗

bioRxiv2023

The impact of light and thioredoxins on the plant thiol-disulfide proteome

Thiol-based redox regulation is a crucial post-translational mechanism to acclimate plants to changing light availability. Here, we conduct a biotin-switch-based redox proteomics study to systematically investigate dynamics of the thiol-redox network in response to temporal changes in light availability and across genotypes lacking parts of the thioredoxin (Trx) or NADPH-Trx-reductase C (NTRC) systems in the chloroplast. Time-resolved dynamics revealed light leading to marked decreases in the oxidation states of many chloroplast proteins with photosynthetic functions during the first 10 min, followed by their partial re-oxidation after 2-6 hours into the photoperiod. This involved f, m and x-type Trx proteins showing similar light-induced reduction-oxidation dynamics, while NTRC, 2-Cys-Prx and Trx y2 showed an opposing pattern, being more oxidized in the light than the dark. In Arabidopsis trxf1f2, trxm1m2 or ntrc mutants, in the light most proteins showed increased oxidation states than wild type, suggesting their light-dependent dynamics being related to the NTRC/Trx networks. While NTRC deficiency had a strong influence in all light conditions, deficiencies in f- or m-type Trxs showed differential impacts on the thiol-redox proteome depending on the light environment, being higher in constant or fluctuating light, respectively. Results indicate plant redox proteomes to be subject to dynamic changes in reductive and oxidative pathways to cooperatively fine-tune photosynthetic and metabolic processes in the light. This involves f-type Trxs and NTRC to play a role in constant medium light, while both m-type Trxs and NTRC being important to balance changes in protein redox-pattern during dynamic alterations in fluctuating light intensities. One sentence summaryThe plant protein redoxome shows light-dependent reduction and reoxidation dynamics linked to Trxs f1/f2, m1/m2 and NTRC, being of different importance depending on the extent of light variability.

plant biology↗

bioRxiv2022

Simultaneous adjustments of major mitochondrial pathways through redox regulation of dihydrolipoamide dehydrogenase (mtLPD1)

Thioredoxins (TRX) are pivotal for the redox regulation of enzyme activities to adjust metabolic fluxes towards environmental changes. Previous reports demonstrated TRX o1 and h2 impact on mitochondrial metabolism including photorespiration and the tricarboxylic acid (TCA) cycle. Here, we aimed to unravel potential specificities between regulation modes of both TRXs, especially under conditions with short-term changes in photorespiration. Therefore, short-term metabolite responses of single TRX mutants were analyzed after exposure to altered CO2/O2 ratios during darkness and illumination. This approach was complemented by comprehensive characterization of multiple Arabidopsis mutants lacking either one or both TRX in the wild-type Arabidopsis or the glycine decarboxylase (GDC) T-protein knock down line (gldt1). The results provided evidence for additive effects of combined TRX o1 and h2 deficiency to suppress growth, photosynthesis and mitochondrial metabolism. Quantification of pyrimidine nucleotides in conjunction with metabolite and 13C-labelling approaches revealed a rather uniform impact on mitochondrial dihydrolipoamide dehydrogenase (mtLPD1) dependent pathways. Biochemical analysis of recombinant mtLPD1 demonstrated its inhibition by NADH, pointing at an additional measure to fine-tune its in vivo activity. Collectively, we propose that TRX o1 and h2 contribute to the communication of altered subcellular redox-states through direct and indirect regulation of mtLPD1. This regulation module might represent a common intercept for simultaneous adjustments in the operation of photorespiration, the TCA-cycle and the degradation of branched chain amino acids. One-sentence summaryRedox regulation of mitochondrial dihydrolipoamide dehydrogenase (mtLPD1) simultaneously modulates photorespiration, the tricarboxylic acid (TCA)-cycle and branched chain amino acid (BCAA) degradation in response to rapid environmental changes.

plant biology↗