Molecular Plant-Microbe Interactions® (MPMI)
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Molecular Plant-Microbe Interactions® (MPMI)
@mpmijournal.bsky.social
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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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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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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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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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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
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Just Published: "Early Activation of RNAi Reveals Genomic Regions of Grapevine Red Blotch Virus Targeted for Silencing in Grapevine," by Christian Mandelli and Laurent G. Deluc 🍇 Read the full article to learn more: https://doi.org/10.1094/MPMI-04-25-0038-R
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).
October 14, 2025 at 6:57 PM
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Beet mosaic virus (BtMV), once managed via neonicotinoid seed treatments, is now being targeted with RNA-based resistance. Dennis Rahenbrock et al. report dsRNA designed from small RNA sequencing effectively reduced BtMV in sugar beet and N. benthamiana in the greenhouse: doi.org/10.1094/MPMI...
Fig. 5. Detection of beet mosaic virus (BtMV)-derived A, nuclear inclusion body b double-stranded RNA (dsNIb) and B, P1 double-stranded RNA (dsP1) after mechanical application on Beta vulgaris in treated (local) and untreated (systemic) leaves at different time points (1 h after application [hpi], 2 and 7 days after application [dpi]) by RT-PCR. Mock-inoculated plants were treated only with carborundum and water. M, DNA marker (GeneRuler 100 bp DNA Ladder, Thermo Fisher Scientific).
September 22, 2025 at 3:57 PM
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New interactions review on Verticillium longisporum, the cause of stripe disease in Brassica crops. Rafiei, Dixelius & Tzelepis outline the pathogenicity factors, host immune responses, knowledge gaps, and molecular tools for studying this threat.
Read the full article here: doi.org/10.1094/MPMI...
Life cycle of Verticillium longisporum-infected oilseed rape. When Brassica napus plants start to senesce, microsclerotia protrude from the stem tissue, become visible, and begin to fall to the ground. Commonly, microsclerotia are observed or spotted on the stubble and leaf debris after harvest and become mixed into the soil, following the next soil management step. The microsclerotia are resistant structures and can survive in the soil for many years under adverse conditions. Upon germination, fungal hyphae enter openings or wounds in the root, and the fungus progresses into the xylem tissue. V. longisporum can remain in the vascular tissue for a long time, making it invisible during field plant inspections. Upon plant maturation, grayish stripes appear on the ripening stems by densely formed microsclerotia. They can start dropping to the ground and will be ready to initiate a new round of infections when the conditions become favorable.
September 3, 2025 at 6:12 PM
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In Sinorhizobium meliloti, loss of the carbon metabolism blocks symbiosis with alfalfa. Kaur et al. demonstrate that disrupting the key metabolic enzyme transketolase (tktA) in S. meliloti completely impairs its ability to engage in nitrogen-fixing symbiosis with alfalfa: doi.org/10.1094/MPMI...
Fig. 1. Visual symbiotic phenotypes. Strains were inoculated onto alfalfa plants grown under nitrogen-deficient conditions. Representative pictures were taken of A, plant growth and B, their representative nodules after 28 days of growth. Strains used are as follows: wild type (wt), Rm1021; tktA::Tn5, SRmD397; stkR1, SRmD410. Scale bar in Panel B represents 1 mm.
August 29, 2025 at 4:05 PM
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Crops often lack diverse resistance genes, making them vulnerable to rapidly evolving pathogens. Xiaoxiao Zhang et al. used DNA shuffling on barley Mla7 and Mla13 genes to create MLA variants, some gaining the ability to recognize the powdery mildew effector AVRA13: doi.org/10.1094/MPMI...
Representative images showing the outcome of cell death assays for MLA7L902S in Nicotiana benthamiana. Agrobacterium strains carrying Mla13, Mla7, or Mla7L902S were co-infiltrated with Agrobacterium strains carrying AVRA13-V2, AVRA13-1, or AVRA7-2 into N. benthamiana leaves. Images were taken 5 days after infiltration. Cell death is indicated by yellow to dark spots on the leaves. The numbers indicate the numbers of leaves showing cell death phenotypes as a proportion of the total number of leaves infiltrated.
August 19, 2025 at 5:53 PM
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Editor’s Pick! The cassava pathogen Xanthomonas phaseoli pv. manihotis (Xpm) causes severe disease, but its effector functions are not well understood. ‪‪Diana Gómez De La Cruz‬ et al. show that the Xpm effector XopAE suppresses plant defenses. Learn more: doi.org/10.1094/MPMI...
Representative images of callose deposition. EV, empty vector.
July 28, 2025 at 1:42 PM
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A breakthrough for potatoes: Samodya K. Jayasinghe et al. identify salicylic acid as a key defense hormone against Spongospora subterranea f. sp. subterranea, a persistent soilborne protist threatening yields around the world. 🥔

Read the press release to learn more: www.apsnet.org/about/newsro...
Infection of Spongospora subterranea f. sp. subterranea (Sss) in a hairy root culture system. A, Healthy potato hairy roots 21 days after induction with Rhizobium rhizogenes. B, Formation of gall-like structures on hairy roots. C, Sss sporangia stained with trypan blue observed in root hairs 4 weeks post-inoculation. D, Sss sporangia stained with trypan blue observed in the cortex of hairy roots 8 weeks post-inoculation.
July 23, 2025 at 8:02 PM
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Haider Ali, Megan C. McDonald, and Graeme J. Kettles developed a rapid forward genetics methodology to identify genes that enable Zymoseptoria tritici to gain virulence on previously resistant wheat varieties. Learn more: doi.org/10.1094/MPMI...
Co-inoculation of Zymoseptoria tritici strains IPO323 and IPO88004. Co-inoculation experiments were performed with the avirulent strain IPO323 and the virulent strain IPO88004. Disease severity was evaluated across a series of virulent-to-avirulent ratios ranging from 1:10 to 1:1,000. Disease symptoms were recorded 21 days postinfection (dpi).
June 12, 2025 at 9:46 PM
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Eliza P. I. Loo et al. discuss gaps in information acquisition and transfer between the field and laboratory and indicate that collaboration among stakeholders, scientists, farmers, and policymakers could enhance the development of pathogen-resistant crops. doi.org/10.1094/MPMI...
Disease symptoms for bacterial blight (BB)-susceptible and -resistant rice varieties based on Kauffman's leaf-clipping assay.
May 19, 2025 at 7:31 PM
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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
May 8, 2025 at 9:13 PM
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Just published! Barbara Valent honors H. H. Flor by exploring how rice blast fungus evades plant resistance via AVR gene changes—driving boom–bust cycles—and warns of rising wheat and ryegrass blast threats from similar shifts and crossbreeding. Read the article: doi.org/10.1094/MPMI...
B, Sporulating lesion on a rice leaf. C, Sporulating lesions on a wheat leaf. D, Rice panicle neck infections block all grain filling above the infection points (red arrows). E, Wheat spike blast with individual directly infected spikelets. F, Wheat rachis infections kill all spikelets above the infection points. Removed spikelets show stem infection points (red arrows) with gray sporulation. G, Finger millet neck infection (red arrow) kills all fingers on the seed head. H, Leaf lesions on perennial ryegrass showing white lesion centers after spore release.
April 25, 2025 at 4:15 PM
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Alissar Cheaib and Nabil Killiny review how pathogens disrupt photosynthesis, from tissue destruction to chlorosis, and how plants adapt. Understanding these interactions is essential for #sustainableagriculture and ecosystem health. ☀️🌱 Learn more: doi.org/10.1094/MPMI... @alissarcheaib.bsky.social
Types of phytopathogens (viruses, bacteria, and fungi) invade plant organs. Pathogens can invade the aboveground organs, the phyllosphere (leaves, stems, branches, and fruits), the roots or rhizosphere, the vascular system (phloem and xylem), or the endosphere. Phytopathogens can be biotrophic feeding on living host cells, necrotrophic feeding on dying host cells, and hemibiotrophic with an initial biotrophic phase and a later necrotrophic stage.
April 14, 2025 at 7:15 PM
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New research by K. M. Martin et al. expands our knowledge of tomato spotted wilt virus infection and elaborates on the intricate relationships between viral proteins, cellular dynamics, and host responses.
Learn more: doi.org/10.1094/MPMI...
Localization of tomato spotted wilt virus (TSWV) proteins with infected and healthy plant cells. Left: TSWV proteins expressed in agroinfiltrated plant cells. Column 1, green fluorescent protein (GFP) tagged to TSWV protein; column 2, unfused red fluorescent protein (RFP); and column 3, overlay of columns 1 and 2. Rows are as follows: I to III, TSWV-N:GFP; IV to VI, TSWV-NSs:GFP; VII to IX, TSWV-GFP:NSm; X to XII, TSWV-GN:GFP; and XIII to XV, TSWV-GC:GFP. Right: TSWV proteins expressed in TSWV-infected plant cells. Column 1, GFP tagged to TSWV protein; column 2, unfused RFP; and column 3, overlay of columns 1 and 2. Rows are as follows: XVI to XVIII, TSWV-N:GFP; XIX to XXI, TSWV-NSs:GFP; XXII to XXIV, TSWV-GFP:NSm; XXV to XXVII, TSWV-GN:GFP; and XXVIII to XXX, TSWV-GC:GFP. Scale bar is equal to 20 μm.
April 3, 2025 at 7:06 PM
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Selin Ozdemir et al. investigated the differential regulation and function of lncRNAs during two different stages of tomato infection by the root-knot #nematode Meloidogyne incognita. 🍅🪱 Learn more: apsjournals.apsnet.org/doi/10.1094/...
Differentially expressed long noncoding RNAs (lncRNAs) contain putative mimic binding sites for microRNAs (miRNAs). Schematic representations showing base-pairing between A, TCONS_00160362 and miR47; B, TCONS_00188971 and miR156e-5p; C, TCONS_00041366 and miR403-5p; D, TCONS_00084313 and miR184; and E, TCONS_00146883 and miR698.
April 1, 2025 at 7:20 PM
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Iron's redox states (Fe2+/Fe3+) are critical in fungal pathogenesis, influencing ROS production during plant-pathogen interactions. Aliyeva-Schnorr et al. developed p-TEMPO and MPNBD dyes to visualize Fe2+/Fe3+ distribution in #Colletotrichumgraminicola hyphae. Learn more: doi.org/10.1094/MPMI...
Colletotrichum graminicola conidia/appressoria were fluorescence-labeled for Fe2+/Fe3+ with/without carpropamid. MPNBD/p-TEMPO stained Fe2+/Fe3+ (A-C). MPNBD/DAPI showed Fe3+ in nuclei (D-G). p-TEMPO/GelRed stained Fe2+, not in nuclei (I-L). Quantification of Fe2+/Fe3+ in hyphae/appressoria (H). Asterisk: conidium, arrowhead: appressorium. Scale: 10μm.
March 31, 2025 at 4:52 PM
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New research by Joydeep Chakraborty et al. elucidates the tomato PP2C-immunity associated candidate 6 (Pic6) as a negative regulator of MAPK signaling and its pivotal role in modulating tomato immunity against bacterial pathogens. 🍅🦠

Learn more: doi.org/10.1094/MPMI...
March 26, 2025 at 5:22 AM
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Tan et al. developed efficient base editing vectors, achieving high A-to-G conversion rates in Arabidopsis thaliana and successfully targeting multiple genes, including NLRs, to modify protein function, demonstrating the potential of base editing 🧬
Learn more: doi.org/10.1094/MPMI...
March 25, 2025 at 4:19 PM
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Editor's Pick! Amelia Lovelace et al. examined the transcriptomic landscape of ‘Candidatus Liberibacter asiaticus’ in citrus seed coat vasculatures, revealing unique gene expression patterns vs. previous midrib studies and new insights into citrus #huanglongbing. 🍊🦠 doi.org/10.1094/MPMI...
Two ‘Candidatus Liberibacter asiaticus’ (Las) virulence proteins inhibited bacterial infection-triggered callose deposition when expressed in Nicotiana benthamiana.
March 21, 2025 at 6:00 PM