Zygnematophytes are the closest algal relatives of land plants. They hold key information to infer how the earliest land plants overcame the barrage of terrestrial stressors, the prime of which is osmotic stress. Here, we apply two osmotic stressors on a unicellular and a multicellular representative of zygnematophytes and study their responses over a 25-hour time course, generating 130, 60, and 30 transcriptomic, proteomic, and metabolomic samples combined with photophysiology, sugar analysis, immunocytochemical glycoprotein analysis, and microscopy. Our data highlight a shared protein chassis that shows divergent responses with the same outcome: successful acclimation to osmotic challenges. We establish a model of how the algal sisters of land plants can overcome a prime stressor in the terrestrial habitat and highlight components of the plant terrestrialization toolkit.

ABSTRACT Land plants possess a unique system for responding to environmental stressors. How this system evolved during plant terrestrialization remains one of the major questions in plant evolutionary biology. To retrace this process, it is essential to study both land plants and their closest algal relatives, the zygnematophytes. Using the single-celled zygnematophyte Mesotaenium , we integrated physiological stress experiments with phosphoproteomics, genome-wide transcription factor binding analyses, and protein–protein interaction studies to investigate the architecture of a key stress response pathway: the signaling cascade homologous to the plant abscisic acid (ABA)-mediated pathway. Our results highlight the roles of histidine kinases (HKs) and calcium-dependent protein kinases (CDPKs) in osmotic stress signaling. Focusing on SnRK2 and ABF, key components at the downstream end of the canonical ABA signaling pathway, we provide evidence that ABF plays a central role in osmotic stress responses even in the absence of ABA. Together, our data reveal the coordinated action of parallel functional modules that were likely integrated into the ABA response cascade during plant terrestrialization.

Introduction:Lysin motif domain-containing glycosylphosphatidyl inositol-anchored protein 2 (LYM2) is a GPI-anchored LysM receptor-like protein (LysM-RLP) that harbors three extracellular LysM-domains and a GPI moiety at the C- terminus. In rice, the LYM2 homolog CEBiP is part of the canonical chitin receptor complex mediating chitin triggered MAPK activation and ROS burst. In the annual plant Arabidopsis thaliana, AtLYM2 is specifically involved in chitin-mediated plasmodesmal flux regulation. The aim of this study is to analyse components of chitin perception in the perennial plant poplar and to explore if LYM2 proteins in dicots are generally involved in chitin mediated PD closure. Methods:A BLAST search identified LYM2 orthologs in the genomes of Populus trichocarpa and Populus x canescens. The poplar paralogs PcLYM2-1 and PcLYM2-2 were subsequently characterized on the molecular and functional level using chitin affinity purification and protein-tagging with fluorescent labels. The chitin response of knockout lines generated via the CRISPR/Cas9 approach was examined with particle bombardment assays. Results:PcLYM2-2 exhibits tissue-specific alternative splicing, resulting in variants that differ exclusively at the first exon encoding the three LysM domains. Chitin-binding assays showed that all identified PcLYM2 proteins bind chitin. Subcellular localization studies in Nicotiana benthamiana indicated that all identified PcLYM2 proteins localize at plasmodesmata, suggesting a specific subcellular function of these proteins. Plasmodesmal flux analysis of wildtype poplar and Pclym2-1 Pclym2-2 double knockout lines demonstrated that PcLYM2 proteins mediate chitin-triggered PD closure. Loss-of-function of PcLYM2-1 is sufficient to abolish chitin-induced PD closure, suggesting that PcLYM2-1 is an essential LysM-RLP involved in this process. Conclusion:Poplar regulates plasmodesmal flux after chitin detection through LYM2 orthologs. The expression of LYM2 variants may modify chitin perception and signaling in different tissues of poplar.

Hyphal fusion and sexual development in filamentous fungi rely on coordinated signaling of numerous conserved nodes such as the striatin-interacting phosphatase and kinase (STRIPAK) complex or the pheromone response (PR) MAP kinase cascade (MIK2, MEK2, MAK2, HAM5). Here, we used the homothallic ascomycete Sordaria macrospora (Sm) to screen for putative protein interactors of the SmSTRIPAK complex. Using the STRIPAK complex interactor 1 (SCI1) subunit of the complex as bait, we enriched and identified canonical SmSTRIPAK components and a determinant of communication (DOC) protein. The DOC proteins were previously described in the closely related and heterothallic species Neurospora crassa, functioning in allorecognition of germlings and hyphal fusions. We generated ΔSmdoc1, ΔSmdoc2 single-deletion strains and the double deletion mutant ΔSmdoc1ΔSmdoc2 in S. macrospora. Deletion phenotypes were paradoxical: single knockouts (ΔSmdoc1 or ΔSmdoc2) were nearly sterile, and sexual development was impaired, yet the double mutant (ΔSmdoc1ΔSmdoc2) exhibited wild-type fertility and development, demonstrating non-redundant and mutually antagonistic roles. Using gene tagging at the native locus, we performed TurboID-based proximity mapping with SmDOC1 and SmDOC2 as bait proteins. This proximity mapping demonstrated close ties of SmDOC1/2 to components of the PR MAP kinase pathway and revealed mutual SmDOC1 - SmDOC2 proximity. Yeast two-hybrid experiments with SmDOC1 confirmed the direct interaction with the MAP kinases MEK2 and MAK2. Fluorescence microscopy revealed that SmDOC1-TagRFP-T localized to structures near septal pores. Our results demonstrate that the DOC system is not restricted to heterothallic N. crassa but also plays an essential role in the development of fruiting bodies in the homothallic fungus S. macrospora. These findings suggest the DOC1/2 proteins as a novel system that integrates STRIPAK and PR pathways, providing a possible mechanistic explanation for their non-additive deletion strain phenotypes.

Abstract Ubiquitin is a posttranslational modifier that is conserved among eukaryotes. Ubiquitination alters stability and folding of cellular proteins. Deubiquitinases (DUBs) reverse ubiquitination and often function as part of protein complexes. There are 32 predicted DUB-encoding genes present in the soil-borne phytopathogenic fungus Verticillium dahliae . Nuclear ubiquitin-specific protease 3 (Usp3) is a member of the S pt– A da– G cn5 a cetyltransferase (SAGA) complex, whereas Usp1 is predicted to associate with the C OP9 s ig n alosome (CSN), which controls specificities of cellular E3 ubiquitin ligase activities. A proteomics approach using bio tin capture and id entification (BioID) supports that Usp3 regulates gene expression beyond the transcription level. Western experiments showed a dysregulation in ubiquitinated cellular proteins in corresponding deletion strains. Usp3 and Usp1 are both required for fungal development. They regulate microsclerotia formation based on different environmental cues and provide redundant functions in controlling conidiation. Absence of both corresponding genes resulted in significant impairment of conidiospore formation, which is required for fungal propagation within the plant vascular system. This paralysed spreading ability reduced virulence on tomato plants ( Solanum lycopersicum ). In summary, V. dahliae responds to environmental cues by Usp3- and Usp1-mediated adjustment of gene expression and protein stability. This is important for key developmental processes of the V. dahliae disease cycle and its virulence towards the host plant. Author summary Ubiquitination and deubiquitination of proteins enable cells to rapidly react to environmental cues and adjust protein stabilities and subsequently transcriptomic profiles. Usp3 is a nuclear deubiquitinase subunit of the S pt– A da– G cn5 a cetyltransferase (SAGA) transcriptional coactivator complex. Usp1 is predicted to be associated with the COP9 signalosome that regulates substrate specificities of the ubiquitin-proteasome system. BioID experiments suggest that other SAGA complex subunits, histone proteins, spliceosomal proteins, ribosomal proteins, a protein that tackles transcriptionally stalled RNAPII, and a protein that degrades mRNA with premature stop codons locate proximal to Usp3 within the cell. Deletion of USP3 led to the dysregulation of protein ubiquitination. A single deletion of USP1 did not significantly change ubiquitination profiles, however, a double deletion of USP1/3 significantly affected the ubiquitin-proteasome system. The altered ubiquitination profile correlated with a dysregulation of key developmental processes. Microsclerotia formation was decoupled from environmental cues in the Δ USP3 strain, whereas an additional deletion of USP1 reconnected it in a media-dependent manner. USP3 and USP1 contribute to a common governing process in conidiation, and the defect in spreading of the Δ USP1/3 strain is reflected by a significant reduction in plant pathogenicity.

Changes in nitrogen (N) availability in the soil trigger transcriptional responses in plants to optimize N acquisition, allocation, and remobilization. In roots of N-starved Arabidopsis (Arabidopsis thaliana) plants, transcriptional activation of genes encoding, for example, low-affinity nitrate transporters, depends on 4 related C-TERMINALLY ENCODED PEPTIDE DOWNSTREAM (CEPD) proteins, also known as ROXY6, ROXY7, ROXY8, and ROXY9. All 21 ROXYs found in A. thaliana interact with members of the TGACG-binding (TGA) family of transcription factors. Here, we demonstrate that 2 Clade I TGAs (TGA1, TGA4) serve as molecular links between CEPDs and their target promoters in roots. In the roxy6 roxy7 roxy8 roxy9 quadruple mutant (named cepd in this manuscript), transcriptional activation of N-starvation-inducible genes is impaired, most likely due to the association of Clade I TGAs with a repressive complex at their target promoters. In wild-type plants, this repressive complex is nonfunctional, and gene expression may be regulated by the N supply-regulated ratio of CEPDs over opposing ROXYs containing the TOPLESS-interacting ALWL motif. Although CEPDs resemble glutaredoxins with glutathione-dependent oxidoreductase activity, a ROXY9 variant with a mutation in the catalytic cysteine in its putative active site can confer wild-type-like regulation of target genes. This finding demonstrates that ROXY9 does not function through redox-dependent mechanisms.

Fungi possess several transcription factors with a characteristic velvet domain for DNA binding and homo- or heterodimerization, which is structurally similar to the mammalian NF-κB Rel homology domain. Velvet dimers control fungal development, virulence, and mycotoxin formation. VelB is the only regulator, which carries an intrinsically disordered domain (IDD) within the velvet domain. The IDD, as well as the positioning within VelB, is conserved in the fungal kingdom. Intrinsically disordered regions contribute to transcription activation and DNA binding and frequently appear in eukaryotic transcription factors. The VelB IDD provides selective heterodimerization and protein stability control. The IDD is not required for the formation of the VelB-VeA heterodimer of Aspergillus nidulans or Verticillium dahliae, but promotes the formation of the VelB-VosA heterodimer. The IDD destabilizes VelB single molecules and also balances its distribution and ratio between both velvet heterodimers. These balances contribute to control appropriate mycotoxin production and sexual development. Herewith, the VelB IDD represents a novel control mechanism of velvet protein stability and heterodimer formation for precise priming of fungal development.

Hyphal fusion and sexual development in filamentous fungi rely on coordinated signaling of numerous conserved nodes such as the striatin interacting phosphatase and kinase (STRIPAK) complex or the pheromone response (PR) MAP kinase cascade (MIK2, MEK2, MAK2, HAM5). Here we used the homothallic ascomycete Sordaria macrospora (Sm) to screen for putative protein interactors of the SmSTRIPAK complex. Using the STRIPAK complex interactor 1 (SCI1) subunit of the complex as bait, we enriched and identified canonical SmSTRIPAK components and a determinant of communication (DOC) protein. The DOC proteins were previously described in the closely related and heterothallic species Neurospora crassa , functioning in allorecognition of germlings and hyphal fusions. We generated ΔSmdoc1, ΔSmdoc2 single deletion strains and the double deletion mutant ΔSmdoc1ΔSmdoc2 in S. macrospora . Deletion phenotypes were paradoxical: single knockouts (ΔSmdoc1 or ΔSmdoc2) were nearly sterile and sexual development was impaired, yet the double mutant (ΔSmdoc1ΔSmdoc2) exhibited wild-type fertility and development, demonstrating non-redundant and mutually antagonistic roles. Similarly, we demonstrated an impairment of the N. crassa Δ doc-2 mutant in sexual development. Using gene tagging at the native locus, we performed TurboID-based proximity mapping with SmDOC1 and SmDOC2 as bait proteins. This proximity mapping demonstrated close ties of SmDOC1/2 to components of the PR MAP kinase pathway and revealed mutual SmDOC1 - SmDOC2 proximity. Yeast Two-Hybrid experiments with SmDOC1 confirmed the direct interaction with the MAP kinases MEK2 and MAK2. Fluorescence microscopy revealed that SmDOC1-TagRFP-T localized to ring-like structures around septal pores. Our results demonstrate that the DOC system is not restricted to heterothallic N. crassa , but also plays an essential role in the development of fruiting bodies in the homothallic fungus S. macrospora . These findings suggest the DOC1/2 proteins as a novel system that integrates STRIPAK and PR pathways, providing a possible mechanistic explanation for their non-additive deletion strain phenotypes. ### Competing Interest Statement The authors have declared no competing interest. Deutsche Forschungsgemeinschaft, PO 523/10-1 project number 538832008, INST 186/1230-1 FUGG, INST 186/1465-1

Climate change-enforced drought stress conditions and diseases caused by pathogens often co-occur and represent one of the greatest challenges in plant science. Wilt pathogens that colonize water-conducting plant tissues can aggravate the problem and affect a wide range of agricultural crops. However, whilst fungal infections with the vascular pathogen Verticillium dahliae are typically associated with wilt symptoms due to occlusion of xylem tissues, the related V. longisporum induces de novo formation of tracheary elements. This promotes not only its virulence but also enables elevated water storage capacity of the infected host plant and resilience against drought stress conditions. Here, we identified a secreted Verticillium protein, TRANSDIFFERENTIATION EFFECTOR (TRADE), which triggers cell identity switches of bundle sheath cells into tracheary elements. We show that TRADE interacts with the intracellular plant protein VARICOSE (VCS), a conserved component of the mRNA turnover machinery and ortholog of the metazoan protein ENHANCER OF DECAPPING 4 (EDC4/HEDLS/Ge-1). The TRADE-VCS interaction induces SUCROSE NON-FERMENTING 1 (SNF1)-related protein kinase (SRK)-dependent phosphorylation and thus dysfunction of VCS. This affects the abundance of mRNAs encoding master regulators of xylem differentiation and demonstrates how a single pathogen effector protein triggers complex tissue-specific developmental reprogramming and thus promotes abiotic stress resilience. ### Competing Interest Statement The authors have declared no competing interest.

Fungi possess several transcription factors with a characteristic velvet domain for DNA-binding and homo- or heterodimerization, which is structurally similar to the mammalian NF-ᴋB Rel homology domain. Velvet dimers control fungal development, virulence and mycotoxin formation. VelB is the only regulator, which carries an intrinsically disordered domain (IDD) within the velvet domain. The IDD as well as the positioning within VelB is conserved in the fungal kingdom. Intrinsically disordered regions contribute to transcription activation and DNA binding and frequently appear in eukaryotic transcription factors. The VelB IDD provides selective heterodimerization as well as protein stability control. The IDD is not required for the formation of the VelB-VeA heterodimer of Aspergillus nidulans or Verticillium dahliae , but promotes the formation of the VelB-VosA heterodimer. The IDD destabilizes VelB single molecules and also balances its distribution and ratio between both velvet heterodimers. These balances contribute to control appropriate mycotoxin production and sexual development. Herewith, the VelB IDD represents a novel control mechanism of velvet protein stability and heterodimer formation for precise priming of fungal development. ### Competing Interest Statement The authors have declared no competing interest.

In oilseeds, energy-rich carbon is stored as triacylglycerols in organelles called lipid droplets (LDs). While several of the major biogenetic proteins involved in LD formation have been identified, the full repertoire of LD proteins and their functional roles remains incomplete. Here, we show that the low-abundance, seed-specific LD protein LIPID DROPLET PROTEIN OF SEEDS (LDPS) contains an amphipathic α-helix and proline hairpin motif that serves as an LD-targeting signal and a separate region that binds to the LD protein OLEOSIN 1 (OLEO1). Loss of LDPS function results in smaller LDs and less seed oil in comparison with wild type, while overexpression of LDPS results in an increase in LD size and seed oil content. Loss of LDPS function also results in an inability of LDs to undergo fusion during postgerminative seedling growth. Analysis of oleo1 and ldps single- and double-mutant seeds and freeze-thaw treatment of seeds revealed that OLEO1 suppresses the ability of LDPS to promote larger LDs. Collectively, our results identify LDPS as an important player in LD biology that functions together with OLEO1 to determine LD size in Arabidopsis (Arabidopsis thaliana) seeds and seedlings through a process that involves LD-LD fusion.

The Biotin Identification (BioID) method applies proximity-dependent labeling of co-localizing proteins to screen for protein-protein interactions in vivo. Therefore, the protein of interest (POI) is fused to a promiscuous biotin ligase. This ligase covalently biotinylates proximal proteins, which allows their specific enrichment and subsequent identification by mass spectrometry. In recent research, the BioID method was applied in the filamentous ascomycete Sordaria macrospora using a codon optimized TurboID ligase. In this study, we applied a smaller variant of the TurboID biotin ligase, named miniTurboID to perform BioID experiments in S. macrospora. Here, we provide a comprehensive and detailed guideline of experimental steps for the application of BioID in filamentous fungi. • The BioID method screens for protein-protein interactions via in vivo labeling of nearby proteins through a biotin ligase, which is fused to the POI • TurboID and miniTurboID ligases can be used for BioID experiments in the filamentous fungus Sordaria macrospora

Meningioma is the most common type of primary brain tumour, significantly impacting patients’ quality of life even after surgical intervention. While grade 1 meningiomas are classified as benign, some molecular sub- groups exhibit higher recurrence rates and resistance to conventional therapies. There is currently no effective systemic treatment for meningiomas. This study aims to investigate the role of a key glycolytic enzyme Hexok- inase 2 (HK2) in meningioma progression and assess its potential as a therapeutic target. We analysed the impact of HK2 knockdowns (KD) on meningioma cell proliferation and metabolic pathways. In vitro experiments examined the effects of HK2 KD on the gene expression of the androgen receptor (AR), Insulin Growth Factor Receptor 1 (IGF1R), glucose uptake, and lactate production. Additionally, higher-grade menin- gioma cells metabolic flexibility was evaluated under HK2 KD conditions. In vivo experiments were conducted using an NSG mouse model with HK2 KD cells to assess tumour growth, LDHA activity, and brain invasion. HK2 KD in lower-grade meningiomas reduced androgen receptor expression, inhibiting proliferation and low- ering IGF1R levels, glucose uptake, and lactate production. In higher-grade meningiomas, HK2 KD decreased LDHA activity and proliferation, triggering metabolic shifts. Some cells transitioned from glycolysis to oxidative phosphorylation, while others showed impaired oxidative phosphorylation. These adaptations influenced sen- sitivity to the AR inhibitor enzalutamide, with resistance overcome by increasing oxidative stress using hemin, which reduced HK2 expression. In vivo, HK2 KD significantly suppressed tumour growth, LDHA activity, and brain invasion in the NSG mouse model. Our findings reveal HK2’s key role in meningioma progression. In vitro and in vivo data show HK2 drives tumour growth through distinct adaptive mechanisms in different grades. Targeting HK2 offers therapeutic potential, providing insight into meningioma metabolism and highlighting HK2 and related pathways as promising targets for future treatments.

Plants must cope with a variety of stressors during their life cycle, and the adaptive responses to these environmental cues involve all cellular organelles. Among them, comparatively little is known about the contribution of cytosolic lipid droplets (LDs) and their core set of neutral lipids and associated surface proteins to the rewiring of cellular processes in response to stress. Here, we analyzed the changes that occur in the lipidome and proteome of Arabidopsis leaves after pathogen infection with Botrytis cinerea or Pseudomonas syringae , or after heat stress. Analyses were carried out in wild-type plants and the oil-rich double mutant tgd1-1 sdp1-4 that allowed for an allied study of the LD proteome in stressed leaves. Using liquid chromatography-tandem mass spectrometry-based methods, we show that a hyperaccumulation of the primary LD core lipid triacylglycerol is a general response to stress and that acyl chain and sterol composition are remodeled during cellular adaptation. Likewise, comparative analysis of the LD protein composition in stress-treated leaves highlighted the plasticity of the LD proteome as part of the general stress response. We further identified at least two additional LD-associated proteins, whose localization to LDs in leaves was confirmed by confocal microscopy of fluorescent protein fusions. Taken together, these results highlight LDs as dynamic contributors to the cellular adaptation processes that underlie how plants respond to environmental stress. One sentence summary Biotic and heat stress strongly alters the lipidome and proteome of Arabidopsis leaves including the proteome of lipid droplets.

The proximity-dependent biotin identification (BioID) method allows the in vivo examination of molecular environments of proteins. The methodology is based on the labeling of proteins with biotin that are proximal to a protein of interest, followed by affinity purification and identification via mass spectrometry. This article describes the application of BioID in fungi.

The conserved eight-subunit COP9 signalosome (CSN) is required for multicellular fungal development. The CSN deneddylase cooperates with the Cand1 exchange factor to control replacements of E3 ubiquitin cullin RING ligase receptors, providing specificity to eukaryotic protein degradation. Aspergillus nidulans CSN assembles through a heptameric pre-CSN, which is activated by integration of the catalytic CsnE deneddylase. Combined genetic and biochemical approaches provided the assembly choreography within a eukaryotic cell for native fungal CSN. Interactomes of functional GFP-Csn subunit fusions in pre-CSN deficient fungal strains were compared by affinity purifications and mass spectrometry. Two distinct heterotrimeric CSN subcomplexes were identified as pre-CSN assembly intermediates. CsnA-C-H and CsnD-F-G form independently of CsnB, which connects the heterotrimers to a heptamer and enables subsequent integration of CsnE to form the enzymatically active CSN complex. Surveillance mechanisms control accurate Csn subunit amounts and correct cellular localization for sequential assembly since deprivation of Csn subunits changes the abundance and location of remaining Csn subunits.

The vascular plant pathogenic fungus Verticillium dahliae has to adapt to environmental changes outside and inside its host. V. dahliae harbors homologs of Neurospora crassa clock genes. The molecular functions and interactions of Frequency (Frq) and Frq-interacting RNA helicase (Frh) in controlling conidia or microsclerotia development were investigated in V. dahliae JR2. Fungal mutant strains carrying clock gene deletions, an FRH point mutation, or GFP gene fusions were analyzed on transcript, protein, and phenotypic levels as well as in pathogenicity assays on tomato plants. Our results support that the Frq-Frh complex is formed and that it promotes conidiation, but also that it suppresses and therefore delays V. dahliae microsclerotia formation in response to light. We investigated a possible link between the negative element Frq and positive regulator Suppressor of flocculation 1 (Sfl1) in microsclerotia formation to elucidate the regulatory molecular mechanism. Both Frq and Sfl1 are mainly present during the onset of microsclerotia formation with decreasing protein levels during further development. Induction of microsclerotia formation requires Sfl1 and can be delayed at early time points in the light through the Frq-Frh complex. Gaining further molecular knowledge on V. dahliae development will improve control of fungal growth and Verticillium wilt disease.

Plant terrestrialization brought forth the land plants (embryophytes). Embryophytes account for most of the biomass on land and evolved from streptophyte algae in a singular event. Recent advances have unravelled the first full genomes of the closest algal relatives of land plants; among the first such species was Mesotaenium endlicherianum . Here we used fine-combed RNA sequencing in tandem with a photophysiological assessment on Mesotaenium exposed to a continuous range of temperature and light cues. Our data establish a grid of 42 different conditions, resulting in 128 transcriptomes and ~1.5 Tbp (~9.9 billion reads) of data to study the combinatory effects of stress response using clustering along gradients. Mesotaenium shares with land plants major hubs in genetic networks underpinning stress response and acclimation. Our data suggest that lipid droplet formation and plastid and cell wall-derived signals have denominated molecular programmes since more than 600 million years of streptophyte evolution—before plants made their first steps on land.

The establishment of moss spores is considered a milestone in plant evolution. They harbor protein networks underpinning desiccation tolerance and accumulation of storage compounds that can be found already in algae and that are also utilized in seeds and pollen. Furthermore, germinating spores must produce proteins that drive the transition through heterotrophic growth to the autotrophic plant. To get insight into the plasticity of this proteome, we investigated it at five timepoints of moss (Physcomitrium patens) spore germination and in protonemata and gametophores. The comparison to previously published Arabidopsis proteome data of seedling establishment showed that not only the proteomes of spores and seeds are functionally related, but also the proteomes of germinating spores and young seedlings. We observed similarities with regard to desiccation tolerance, lipid droplet proteome composition, control of dormancy, and β-oxidation and the glyoxylate cycle. However, there were also striking differences. For example, spores lacked any obvious storage proteins. Furthermore, we did not detect homologs to the main triacylglycerol lipase in Arabidopsis seeds, SUGAR DEPENDENT1. Instead, we discovered a triacylglycerol lipase of the oil body lipase family and a lipoxygenase as being the overall most abundant proteins in spores. This finding indicates an alternative pathway for triacylglycerol degradation via oxylipin intermediates in the moss. The comparison of spores to Nicotiana tabacum pollen indicated similarities for example in regards to resistance to desiccation and hypoxia, but the overall developmental pattern did not align as in the case of seedling establishment and spore germination.

Verticillium transcription activator of adhesion 3 (Vta3) is required for plant root colonization and pathogenicity of the soil-borne vascular fungus Verticillium dahliae . RNA sequencing identified Vta3-dependent genetic networks required for growth in tomato xylem sap. Vta3 affects the expression of more than 1,000 transcripts, including candidates with predicted functions in virulence and morphogenesis such as Egh16-like virulence factor 1 (Elv1) and Master transcription factor 1 (Mtf1). The genes encoding Elv1 and Mtf1 were deleted and their functions in V . dahliae growth and virulence on tomato ( Solanum lycopersicum ) plants were investigated using genetics, plant infection experiments, gene expression studies and phytohormone analyses. Vta3 contributes to virulence by promoting ELV1 expression, which is dispensable for vegetative growth and conidiation. Vta3 decreases disease symptoms mediated by Mtf1 in advanced stages of tomato plant colonization, while Mtf1 induces the expression of fungal effector genes and tomato pathogenesis-related protein genes. The levels of pipecolic and salicylic acids functioning in tomato defense signaling against (hemi-) biotrophic pathogens depend on the presence of MTF1 , which promotes the formation of resting structures at the end of the infection cycle. In summary, the presence of VTA3 alters gene expression of virulence factors and tames the Mtf1 genetic subnetwork for late stages of plant disease progression and subsequent survival of the fungus in the soil.