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Molecular Plant-Microbe Interactions® (MPMI)
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MPMI, a gold Open Access journal from The American Phytopathological Society and the International Society for Molecular Plant-Microbe Interactions, features research on plant interactions with microbes, insects, nematodes, and parasitic plants.
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Molecular Plant-Microbe Interactions® (MPMI) @mpmijournal.bsky.social · Sep 8
Deadline extended: Submit to the forthcoming MPMI focus issue by November 1, 2025! 🚨
mpmijournal.bsky.social Molecular Plant-Microbe Interactions® (MPMI) @mpmijournal.bsky.social · May 8
New call for papers alert 🚨🌱🦠 Submit to the "Symbiotic and Pathogenic Interactions in the Rhizosphere" focus issue by September 1, 2025!

Focus Issue Guest Editors: Tarek Hewezi, Hari Krishnan, Kevin Garcia, and Mina Ohtsu

Learn more: apsjournals.apsnet.org/mpmirhizosph...
Call for Papers! Symbiotic and Pathogenic Interactions in the Rhizosphere—a Molecular Plant-Microbe Interactions Focus Issue
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Contrary to expectations, K. K. Pennerman et al. found that #Macrophomina phaseolina should be considered a single species with both specialist and generalist populations in which meiosis can maintain genetic diversity. Learn more: https://doi.org/10.1094/MPMI-03-25-0032-R
Fig. 4. Geographic distribution of Macrophomina spp. genotype clusters. A, Isolates without a known state, province, or locality were assigned longitudes and latitudes at the midpoints of their respective sub-country region (Supplementary Table S1). Pie charts scaled to the number of isolates recovered are shown for locations that had multiple isolates. The color code for the pie charts is the same as provided for panel B of this figure. Minimum spanning trees for isolates in this study colored by B, genotype cluster or C, the country of origin.
February 9, 2026 at 5:15 PM
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Nicolas Lapalu et al. developed a new method to improve the prediction of eukaryotic genes and demonstrate its utility using the genome of the fungal wheat pathogen #Zymoseptoria tritici. Learn more: https://doi.org/10.1094/MPMI-07-25-0077-TA
Fig. 4. Single gene and polycistronic transcripts shown for reannotated gene models (RGMs) ZtIPO323_010430 and ZtIPO323_010440. RGMs ZtIPO323_010430 and ZtIPO323_010440, located at chr_1: 2692944...2694593 and chr_1: 2694544...2697087, respectively, were transcribed on the same strand with overlapping 3′ untranslated region (UTR) and 5′ UTR (red rectangle).
February 6, 2026 at 11:38 PM
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Editor’s Pick: “Non-Nitrogen-Fixing Sinorhizobium meliloti Can Escape Sanctions in Indeterminate Alfalfa Nodules, Exhibiting Parasitic Growth,” by Amanpreet K. Brar et al. Learn more: https://doi.org/10.1094/MPMI-06-25-0074-R
Fig. 1. Schematic of the organization of an indeterminate nodule. The persistent meristem in indeterminate nodules produces a cylindrical shape with distinct zones (Vasse et al. 1990).
February 4, 2026 at 4:54 PM
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Editor’s Pick: "Interactions of Wheat Powdery Mildew Effectors Involved in Recognition by the Wheat NLR PM3," by Jonatan Isaksson et al. Learn more: https://doi.org/10.1094/MPMI-05-25-0050-SC
Fig. 3. A single L91Y amino acid substitution in AVRPM3a2/f2-A leads to recognition by the non-corresponding PM3b.
February 2, 2026 at 4:54 PM
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NEW H. H. Flor Distinguished Review: "The Extended Plant Immune System," by Corné M. J. Pieterse. Read the open access review in MPMI: https://doi.org/10.1094/MPMI-10-25-0144-HH
Fig. 1. The extended plant immune system. Schematic overview integrating key elements of classical plant immunity with microbiome-mediated protection, as discussed in this review. PTI, pattern-triggered immunity; ETI, effector-triggered immunity; SAR, systemic acquired resistance; ISR, induced systemic resistance; PGPR, plant growth-promoting rhizobacteria.
January 30, 2026 at 11:39 PM
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Maniraj Rathinam et al. found the CpMSRB1 gene in a wild pigeonpea acts as a molecular "repairman," protecting a key enzyme to ramp up antioxidants and defense chemicals against the devastating pod borer. Future pest resistance starts here. Learn more: https://doi.org/10.1094/MPMI-11-24-0149-R
Fig. 6. Characterization of transgenic tomato plants (Pusa Ruby) overexpressing CpMSRB1.
January 13, 2026 at 5:05 PM
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Jacob R. Botkin and Shaun J. Curtin engineered Medicago plants using CRISPR-Cas9 and gene overexpression and reported enhanced resistance (up to 80%) to the devastating Spring Black Stem fungus. This research paves the way for resistant alfalfa. Learn more: https://doi.org/10.1094/MPMI-05-25-0053-R
Fig. 1. Putative candidate genes involved in spring black stem and leaf spot (SBS) disease resistance in Medicago truncatula.
January 6, 2026 at 4:51 PM
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Lina Yang et al. cracked the signal pathways used by peach shoot blight fungus, Diaporthe amygdali. Targeting the Pmk1 and Mps1 cascades cripples the pathogen’s growth and ability to infect. This is a key step for new disease control! Learn more: https://doi.org/10.1094/MPMI-06-25-0071-R
Fig. 4. Proteins in the Pmk1 and Mps1 mitogen-activated protein kinase (MAPK) cascades were required for Diaporthe amygdali virulence.
December 29, 2025 at 4:50 PM
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Rune Hansen et al. reported that the substomatal cavity is a crucial check point where the devastating Septoria blotch (Zymoseptoria tritici) infection is stopped. Understanding this mechanism is key to future wheat immunity. Learn more: https://doi.org/10.1094/MPMI-11-24-0147-R
Fig. 1. Confocal laser scanning microscopy (CLSM) images of Aegilops cylindrica leaves infected with IPO323 (incompatible) and Zt469 (compatible) Zymoseptoria tritici isolates. Microscopic images from CLSM analysis using maximum projections of image z-stacks. Cell nuclei and plant tissue are visible in purple, and fungal hyphae are in green. Except for the 4 days postinfection (dpi) sample of the incompatible interaction, only fungal hyphae growing within the plant tissue are shown. Letters indicate which infection stage is represented by the images. Time points listed in purple were chosen for RNA sequencing analysis
December 22, 2025 at 4:55 PM
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Research by Aidan C. Shands et al. on Phytophthora root rot in California avocados revealed that the pathogen, P. cinnamomi, likely migrated from Mexico. Learn more: https://bit.ly/4hxxsdA
Fig. 1. Population structure of Phytophthora cinnamomi observed on avocado in California and Mexico.
December 16, 2025 at 4:45 PM
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Melanie Mendel et al. developed a new Type 3 Secretion System (T3SS) tool to study how Pseudomonas syringae effectors invade spinach. They identified AvrE1 and HopM1 as key virulence factors. This is a vital step for breeding disease-resistant leafy greens. Learn more: https://bit.ly/4nrvqgn
Fig. 1. Pseudomonas syringae pv. tomato DC3000 polymutant D36E is a suitable candidate for effector screens in spinach.
December 9, 2025 at 5:11 PM
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Rikky Rai and Nian Wang report that Xanthomonas effector PthA4 indirectly triggers the disease by activating a host gene, which then switches on plant genes (CsEXP2 and CsEG1) that lead to the destructive canker symptoms. This pinpoints new targets for breeding resistance: https://bit.ly/47FUg6C
Fig. 3. Confirmation of the expression of putative CsLOB1 target genes driven by designer transcription activator-like effectors (dTALEs).
December 2, 2025 at 4:52 PM
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Jana Sperschneider et al. reported a new, high-quality genome assembly of the flax rust fungus (Melampsora lini) resolved complex effector loci and confirmed 2 unusually large effector proteins, AvrM3 and AvrN. This challenges the standard idea that effectors must be small: https://bit.ly/3Jpr37O
Fig. 2. Structural variation at avirulence (Avr) loci in CH5. The figure shows synteny plots between the C and H haplotypes at the AvrM, AvrL567, AvrL2, and AvrP123 loci. Genes are labeled with their identifiers, and NA stands for “not annotated” in the gene annotation. Repetitive elements are shown in green boxes. Separate scale bars are shown to the left of each locus. Shaded boxes connect haplotype regions of conserved sequence. Effector genes are marked with a black star.
November 25, 2025 at 4:45 PM
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Nicholas Rhoades et al. identified an RGAE homolog in Fusarium graminearum that is critical for the initial infection and DON mycotoxin accumulation in wheat and barley. Targeting this single effector gene, FgRGAE, offers a powerful new strategy to protect cereal crops: https://bit.ly/4oilO96
Fig. 2. Deletion of FgRGAE reduces wheat infection at early time points. A, FgRGAE::HygR mutants M27 and M36 both significantly reduced disease severity at 4 days postinfection (dpi) in wheat cultivar Alsen. At 7 dpi, the difference was not statistically significant. B, Toxin deoxynivalenol (DON) was not significantly different at 7 dpi. C, Representative pictures showing less severe Fusarium head blight symptoms observed on Alsen heads infected with FgRGAE::HygR M27 mutant than the wild type. Bars represent the average and standard error of 24 inoculated wheat heads with each strain. Different letters indicate a significant difference at the P < 0.05 level by one-way analysis of variance.
November 18, 2025 at 5:06 PM
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Mandelli & Deluc identified 9 "hotspots" on the Grapevine Red Blotch Virus genome that are highly targeted by the grapevine's defense system. Delivering double-stranded RNA from these sites significantly reduced viral expression, paving the way for targeted RNAi biopesticides: https://bit.ly/3Jvwr9e
Fig. 3. Mapping of the most significantly represented viral small-interfering RNAs (vsiRNAs) to the grapevine red blotch virus (GRBV) genome (NY358 to JQ901105.2). A, Linear representation of the GRBV genomic features (open reading frames [ORFs] and intergenic regions) and the location of RNA interference (RNAi) hotspots (HSs). The genomic features are labeled as follows: long intergenic region (LIR), coat protein (V1 or CP), short intergenic region (SIR), and replication-associated protein (C1 or RepA). B, Predicted secondary structures for each HS. The color coding on these structures, generated by RNAfold, reflects the entropy at each position, indicating the binding stability between base pairs (red = high stability, green/blue = low stability).
November 11, 2025 at 5:11 PM
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Xiaoxiao Zhang et al. reports that flax rust effectors are secreted into a space outside the host cell, but only AvrM has the key signal for delivery into the host cell cytoplasm. Translocation is a separate process! Learn more: https://bit.ly/47BTl6Z

Read the commentary: https://bit.ly/4oO50Xj
Fig. 6. Localization of signal peptide (SP)-yellow fluorescent protein (YFP) and AvrM1-105-YFP in flax leaves infected with the respective transgenic Melampsora lini strains. Representative confocal images showing localization of A, SP-YFP; B, cyan fluorescent protein (CFP); and C and D, AvrM1-105-YFP. YFP fluorescence is shown in yellow, chloroplast autofluorescence in red, and CFP fluorescence in cyan. Scale bars indicate 10 µm. Hy, hyphae; Ha, haustorium; Cy, flax cytoplasm; Nu, flax nucleus.
November 4, 2025 at 4:48 PM
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Po-Yuan Shih et al. found that the pea aphid's specialized salivary effector protein, Ap4, interacts directly with key pea proteins (PsBPL1/2) involved in plant immunity. When expressed, Ap4 enhances aphid performance: https://bit.ly/3Ww9pCg

Read the commentary: https://bit.ly/3JytiFH
Fig. 4. Ap4 and PsBPL1 or PsBPL2 colocalize in Nicotiana benthamiana. sGFP-Ap4 was co-expressed with A, PsBPL1-mRFP (n = 7) or B, PsBPL2-mRFP (n = 17). White scale bars represent 50 μm, and arrows indicate the colocalized signals. Synthetic green fluorescent protein (sGFP) and monomeric red fluorescent protein (mRFP) signals are shown in green and red, respectively, and a bright-field image is shown for each observation. Similar localization patterns were confirmed in at least three different parts of N. benthamiana leaves, and only a representative image is shown for each experiment.
October 30, 2025 at 9:03 PM
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Get a First Look 🔍: "STT3A Is Required for Recognition of Pathogen-Derived Sphingolipids in Arabidopsis," by Seowon Choi et al. https://doi.org/10.1094/MPMI-05-25-0061-R
STT3A Is Required for Recognition of Pathogen-Derived Sphingolipids in Arabidopsis | Molecular Plant-Microbe Interactions®
Plants recognize pathogen-associated molecular patterns (PAMPs) via pattern recognition receptors, leading to the activation of pattern-triggered immunity in response to pathogen attack. Phytophthora infestans ceramide D (Pi-Cer D) is a sphingolipid fro...
doi.org
October 29, 2025 at 4:47 PM
Reposted by Molecular Plant-Microbe Interactions® (MPMI)
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The Pea Aphid's Secret Weapon Uncovered! 🤫 Our Commentary highlights the discovery of aphid effector Ap4—a single salivary protein—that manipulates the plant's defense system to boost pest's reproductive success.
apsjournals.apsnet.org/doi/10.1094/...
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October 27, 2025 at 10:00 PM
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Just Published: "The TALE PthA4 of Xanthomonas citri subsp. citri Indirectly Activates an Expansin Gene CsEXP2 and an Endoglucanase CsEG1 via CsLOB1 to Cause Citrus Canker Symptoms," by Rikky Rai and Nian Wang. Learn more: https://doi.org/10.1094/MPMI-03-25-0030-R
Fig. 5. Virulence assay with constructed designer transcription activator-like effectors (dTALEs) in sweet orange leaves: Xanthomonas citri subsp. citri (Xcc) strains wild type (WT), XccpthA4::Tn5, XccpthA4::Tn5 dTALECsLOB1, and XccpthA4::Tn5 dTALEs for putative CsLOB1 target genes were infiltrated into fully expanded young leaves of Valencia sweet orange, which were evaluated for the symptoms at 14 and 21 days postinoculation (dpi). Representative results were chosen from three independent experiments. Inoculation of leaves with different strains was conducted as illustrated in Figure 3A.
October 27, 2025 at 5:08 PM
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Get a First Look 🔍: "Structural Insights into WY Domain-SLiM Containing Conserved RxLR Effectors: A Case Study of Five Important Phytophthora Species," by B. C. Salasini et al. https://doi.org/10.1094/MPMI-11-24-0144-R
Structural Insights into WY Domain-SLiM Containing Conserved RxLR Effectors: A Case Study of Five Important Phytophthora Species | Molecular Plant-Microbe Interactions®
Pathogenicity in Phytophthora species is in part underpinned by a sophisticated arsenal of RxLR effectors, which function as molecular determinants of host immune manipulation. Among these, Conserved RxLR Effectors (CREs) represent an evolutionarily con...
doi.org
October 23, 2025 at 9:22 PM
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Just Published: "A Chromosome-Scale Genome Assembly of the Flax Rust Fungus Reveals the Two Unusually Large Effector Proteins, AvrM3 and AvrN," by Jana Sperschneider et al. Learn more: https://doi.org/10.1094/MPMI-04-25-0047-R
Fig. 3. AvrM3 sequence alignment and agroinfiltration assays.
October 21, 2025 at 4:47 PM
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Get a First Look 🔍: "Conservation of Genes Required for Arbuscular Mycorrhizal Symbiosis," by Ellen Krall et al. https://doi.org/10.1094/MPMI-05-25-0065-CR
Conservation of Genes Required for Arbuscular Mycorrhizal Symbiosis | Molecular Plant-Microbe Interactions®
Arbuscular mycorrhizal (AM) symbiosis is an ancient association that played a key role in the adaptation of plants to terrestrial environments. Originating over 400 million years ago at the dawn of land plants, this interaction depends on a core set of ...
doi.org
October 17, 2025 at 7:46 PM
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Just Published: "An RGAE Homolog in Fusarium graminearum Is Critical for Initial Infection in Wheat and Barley," by Nicholas Rhoades et al. 🌾

Read the full article to learn more: https://doi.org/10.1094/MPMI-03-25-0027-R
Fig. 3. Deletion of FgRGAE reduces infection and toxin accumulation in barley.
October 16, 2025 at 9:29 PM
Reposted by Molecular Plant-Microbe Interactions® (MPMI)
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On this #WorldFoodDay, we celebrate the efforts of those who nourish our communities, protect our planet, and shape a better future through better food for all. Explore resources to learn more about food security and sustainability. #FAO80

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October 16, 2025 at 2:14 PM