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The New Phytologist Jun 2024
PubMed: 38837388
DOI: 10.1111/nph.19879 -
International Journal of Systematic and... Jun 2024During a study on the diversity of culturable actinobacteria from coastal halophytes in Thailand, strain LSe6-5 was isolated from leaves of sea purslane ( L.), and a...
During a study on the diversity of culturable actinobacteria from coastal halophytes in Thailand, strain LSe6-5 was isolated from leaves of sea purslane ( L.), and a polyphasic approach was employed to determine its taxonomic position. The 16S rRNA gene sequences analysis indicated that the strain was most closely related to Tu 6233 (99.2 %), YIM M13156 (99.1 %), and PB261 (98.7 %). The genome of strain LSe6-5 was estimated to be 4.33 Mbp in size, with DNA G+C contents of 74.3%. A phylogenomic tree based on whole-genome sequences revealed that strain LSe6-5 formed a clade with DSM 45722, indicating their close relationship. However, the average nucleotide identity (ANI)-blast, ANI-MUMmer, and dDDH values between strain LSe6-5 with DSM 45722 (87.1, 88.9, and 33.0 %) were below the thresholds of 95-96 % ANI and 70 % dDDH for identifying a novel species. Furthermore, strain LSe6-5 showed morphological and chemotaxonomic characteristics of the genus . Cells were motile, rod-shaped, and Gram-stain-positive. Optimal growth of strain LSe6-5 occurred at 28 °C, pH 7.0, and 0-3 % NaCl. The whole-cell hydrolysates contained -diaminopimelic acid as the diagnostic diamino acid, with galactose, glucose, mannose, and ribose as whole-cell sugars. The predominant menaquinones were MK-9(H) and MK-9(H). The polar lipid profile was composed of diphosphatidylglycerol, hydroxyphosphatidylethanolamine, phosphatidylinositol, glycophosphatidylinositol, an unidentified phospholipid, and an unidentified lipid. Major cellular fatty acids were -C, -C, and -C. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, it is supported that strain LSe6-5 represents a novel species of the genus , for which the name sp. nov. is proposed. The type strain is strain LSe6-5 (=TBRC 16417= NBRC 115929).
Topics: Phylogeny; Base Composition; RNA, Ribosomal, 16S; Fatty Acids; Plant Leaves; Thailand; Salt-Tolerant Plants; DNA, Bacterial; Bacterial Typing Techniques; Sequence Analysis, DNA; Vitamin K 2; Phospholipids; Whole Genome Sequencing; Genome, Bacterial
PubMed: 38832855
DOI: 10.1099/ijsem.0.006410 -
The New Phytologist Aug 2024Plant secreted peptides RAPID ALKALINISATION FACTORs (RALFs), which act through the receptor FERONIA (FER), play important roles in plant growth. However, it remains...
Plant secreted peptides RAPID ALKALINISATION FACTORs (RALFs), which act through the receptor FERONIA (FER), play important roles in plant growth. However, it remains unclear whether and how RALF-FER contributes to the trade-off of plant growth-defense. Here, we used a variety of techniques such as CRISPR/Cas9, protein-protein interaction and transcriptional regulation methods to investigate the role of RALF2 and its receptor FER in regulating lignin deposition, root growth, and defense against Fusarium oxysporum f. sp. lycopersici (Fol) in tomato (Solanum lycopersicum). The ralf2 and fer mutants show reduced primary root length, elevated lignin accumulation, and enhanced resistance against Fol than the wild-type. FER interacts with and phosphorylates MYB63 to promote its degradation. MYB63 serves as an activator of lignin deposition by regulating the transcription of dirigent protein gene DIR19. Mutation of DIR19 suppresses lignin accumulation, and reverses the short root phenotype and Fol resistance in ralf2 or fer mutant. Collectively, our results demonstrate that the RALF2-FER-MYB63 module fine-tunes root growth and resistance against Fol through regulating the deposition of lignin in tomato roots. The study sheds new light on how plants maintain the growth-defense balance via RALF-FER.
Topics: Solanum lycopersicum; Plant Proteins; Plant Roots; Lignin; Gene Expression Regulation, Plant; Fusarium; Mutation; Disease Resistance; Transcription Factors; Plant Diseases; Phosphorylation
PubMed: 38831656
DOI: 10.1111/nph.19865 -
The New Phytologist Aug 2024Glycosyltransferases (GTs) are enzymes that transfer sugars to various targets. They play important roles in diverse biological processes, including photosynthesis, cell...
Glycosyltransferases (GTs) are enzymes that transfer sugars to various targets. They play important roles in diverse biological processes, including photosynthesis, cell motility, exopolysaccharide biosynthesis, and lipid metabolism; however, their involvement in regulating carbon metabolism in Synechocystis sp. PCC 6803 has not been reported. We identified a novel GT protein, Slr1064, involved in carbon metabolism. The effect of slr1064 deletion on the growth of Synechocystis cells and functional mechanisms of Slr1064 on carbon metabolism were thoroughly investigated through physiological, biochemistry, proteomic, and metabolic analyses. We found that this GT, which is mainly distributed in the membrane compartment, is essential for the growth of Synechocystis under heterotrophic and mixotrophic conditions, but not under autotrophic conditions. The deletion of slr1064 hampers the turnover rate of Gap2 under mixotrophic conditions and disrupts the assembly of the PRK/GAPDH/CP12 complex under dark culture conditions. Additionally, UDP-GlcNAc, the pivotal metabolite responsible for the O-GlcNAc modification of GAPDH, is downregulated in the Δslr1064. Our work provides new insights into the role of GTs in carbon metabolism in Synechocystis and elucidate the mechanism by which carbon metabolism is regulated in this important model organism.
Topics: Synechocystis; Carbon; Glycosyltransferases; Bacterial Proteins; Uridine Diphosphate N-Acetylglucosamine; Gene Expression Regulation, Bacterial; Gene Deletion
PubMed: 38831647
DOI: 10.1111/nph.19872 -
The New Phytologist Jul 2024In the early 1900s, Erwin Baur established Antirrhinum majus as a model system, identifying and characterising numerous flower colour variants. This included...
In the early 1900s, Erwin Baur established Antirrhinum majus as a model system, identifying and characterising numerous flower colour variants. This included Picturatum/Eluta, which restricts the accumulation of magenta anthocyanin pigments, forming bullseye markings on the flower face. We identified the gene underlying the Eluta locus by transposon-tagging, using an Antirrhinum line that spontaneously lost the nonsuppressive el phenotype. A candidate MYB repressor gene at this locus contained a CACTA transposable element. We subsequently identified plants where this element excised, reverting to a suppressive Eluta phenotype. El alleles inhibit expression of anthocyanin biosynthetic genes, confirming it to be a regulatory locus. The modes of action of Eluta were investigated by generating stable transgenic tobacco lines, biolistic transformation of Antirrhinum petals and promoter activation/repression assays. Eluta competes with MYB activators for promoter cis-elements, and also by titrating essential cofactors (bHLH proteins) to reduce transcription of target genes. Eluta restricts the pigmentation established by the R2R3-MYB factors, Rosea and Venosa, with the greatest repression on those parts of the petals where Eluta is most highly expressed. Baur questioned the origin of heredity units determining flower colour variation in cultivated A. majus. Our findings support introgression from wild species into cultivated varieties.
Topics: Antirrhinum; Flowers; Pigmentation; Plant Proteins; Gene Expression Regulation, Plant; Anthocyanins; Phenotype; Plants, Genetically Modified; Genes, Plant; Nicotiana; Promoter Regions, Genetic; DNA Transposable Elements; Alleles
PubMed: 38822654
DOI: 10.1111/nph.19866 -
The New Phytologist Aug 2024Cross-kingdom RNA interference (RNAi) is a crucial mechanism in host-pathogen interactions, with RNA-dependent RNA polymerase (RdRP) playing a vital role in signal...
Cross-kingdom RNA interference (RNAi) is a crucial mechanism in host-pathogen interactions, with RNA-dependent RNA polymerase (RdRP) playing a vital role in signal amplification during RNAi. However, the role of pathogenic fungal RdRP in siRNAs generation and the regulation of plant-pathogen interactions remains elusive. Using deep sequencing, molecular, genetic, and biochemical approaches, this study revealed that VmRDR2 of Valsa mali regulates VmR2-siR1 to suppress the disease resistance-related gene MdLRP14 in apple. Both VmRDR1 and VmRDR2 are essential for the pathogenicity of V. mali in apple, with VmRDR2 mediating the generation of endogenous siRNAs, including an infection-related siRNA, VmR2-siR1. This siRNA specifically degrades the apple intracellular LRR-RI protein gene MdLRP14 in a sequence-specific manner, and overexpression of MdLRP14 enhances apple resistance against V. mali, which can be suppressed by VmR2-siR1. Conversely, MdLRP14 knockdown reduces resistance. In summary, this study demonstrates that VmRDR2 contributes to the generation of VmR2-siR1, which silences the host's intracellular LRR protein gene, thereby inhibiting host resistance. These findings offer novel insights into the fungi-mediated pathogenicity mechanism through RNAi.
Topics: Malus; RNA Interference; Disease Resistance; Plant Diseases; Plant Proteins; Gene Expression Regulation, Plant; Fungal Proteins; RNA, Small Interfering; Genes, Plant
PubMed: 38822646
DOI: 10.1111/nph.19867 -
The New Phytologist Jul 2024During arbuscular mycorrhizal (AM) symbiosis, plant innate immunity is modulated to a prime state to allow for fungal colonization. The underlying mechanisms remain to...
During arbuscular mycorrhizal (AM) symbiosis, plant innate immunity is modulated to a prime state to allow for fungal colonization. The underlying mechanisms remain to be further explored. In this study, two rice genes encoding LysM extracellular (LysMe) proteins were investigated. By obtaining OsLysMepro:GUS transgenic plants and generating oslysme1, oslysme2 and oslysme1oslysme2 mutants via CRISPR/Cas9 technique, OsLysMe genes were revealed to be specifically induced in the arbusculated cells and mutations in either gene caused significantly reduced root colonization rate by AM fungus Rhizophagus irregularis. Overexpression of OsLysMe1 or OsLysMe2 dramatically increased the colonization rates in rice and Medicago truncatula. The electrophoretic mobility shift assay and dual-luciferase reporter assay supported that OsLysMe genes are regulated by OsWRI5a. Either OsLysMe1 or OsLysMe2 can efficiently rescue the impaired AM phenotype of the mtlysme2 mutant, supporting a conserved function of LysMe across monocotyledonous and dicotyledonous plants. The co-localization of OsLysMe proteins with the apoplast marker SP-OsRAmy3A implies their probable localization to the periarbuscular space (PAS) during symbiosis. Relative to the fungal biomass marker RiTEF, some defense-related genes showed disproportionately high expression levels in the oslysme mutants. These data support that rice plants deploy two OsLysMe proteins to facilitate AM symbiosis, likely by diminishing plant defense responses.
Topics: Mycorrhizae; Oryza; Symbiosis; Plant Proteins; Gene Expression Regulation, Plant; Mutation; Plants, Genetically Modified; Medicago truncatula; Amino Acid Motifs; Extracellular Space; Plant Roots; Fungi
PubMed: 38812277
DOI: 10.1111/nph.19873 -
The New Phytologist Jul 2024Aerosols could significantly influence ecosystem carbon and water fluxes, potentially altering their interconnected dynamics, typically characterized by water-use...
Aerosols could significantly influence ecosystem carbon and water fluxes, potentially altering their interconnected dynamics, typically characterized by water-use efficiency (WUE). However, our understanding of the underlying ecophysiological mechanisms remains limited due to insufficient field observations. We conducted 4-yr measurements of leaf photosynthesis and transpiration, as well as 3-yr measurements of stem growth (SG) and sap flow of poplar trees exposed to natural aerosol fluctuation, to elucidate aerosol's impact on plant WUE. We found that aerosol improved sun leaf WUE mainly because a sharp decline in photosynthetically active radiation (PAR) inhibited its transpiration, while photosynthesis was less affected, as the negative effect induced by declined PAR was offset by the positive effect induced by low leaf vapor pressure deficit (VPD). Conversely, diffuse radiation fertilization (DRF) effect stimulated shade leaf photosynthesis with minimal impact on transpiration, leading to an improved WUE. The responses were further verified by a strong DRF on SG and a decrease in sap flow due to the suppresses in total radiation and VPD. Our field observations indicate that, contrary to the commonly assumed coupling response, carbon uptake and water use exhibited dissimilar reactions to aerosol pollution, ultimately enhancing WUE at the leaf and canopy level.
Topics: Water; Aerosols; Photosynthesis; Carbon; Plant Leaves; Plant Transpiration; Populus; Plant Stems
PubMed: 38812270
DOI: 10.1111/nph.19877 -
The New Phytologist Jul 2024In natural systems, different plant species have been shown to modulate specific nitrogen (N) cycling processes so as to meet their N demand, thereby potentially...
In natural systems, different plant species have been shown to modulate specific nitrogen (N) cycling processes so as to meet their N demand, thereby potentially influencing their own niche. This phenomenon might go beyond plant interactions with symbiotic microorganisms and affect the much less explored plant interactions with free-living microorganisms involved in soil N cycling, such as nitrifiers and denitrifiers. Here, we investigated variability in the modulation of soil nitrifying and denitrifying enzyme activities (NEA and DEA, respectively), and their ratio (NEA : DEA), across 193 Arabidopsis thaliana accessions. We studied the genetic and environmental determinants of such plant-soil interactions, and effects on plant biomass production in the next generation. We found that NEA, DEA, and NEA : DEA varied c. 30-, 15- and 60-fold, respectively, among A. thaliana genotypes and were related to genes linked with stress response, flowering, and nitrate nutrition, as well as to soil parameters at the geographic origin of the analysed genotypes. Moreover, plant-mediated N cycling activities correlated with the aboveground biomass of next-generation plants in home vs away nonautoclaved soil, suggesting a transgenerational impact of soil biotic conditioning on plant performance. Altogether, these findings suggest that nutrient-based plant niche construction may be much more widespread than previously thought.
Topics: Arabidopsis; Nitrogen Cycle; Soil Microbiology; Biomass; Nitrogen; Soil; Genotype; Nitrification; Denitrification; Ecosystem
PubMed: 38812269
DOI: 10.1111/nph.19870 -
Carbon isotope trends across a century of herbarium specimens suggest CO fertilization of C grasses.The New Phytologist Jul 2024Increasing atmospheric CO is changing the dynamics of tropical savanna vegetation. C trees and grasses are known to experience CO fertilization, whereas responses to CO...
Increasing atmospheric CO is changing the dynamics of tropical savanna vegetation. C trees and grasses are known to experience CO fertilization, whereas responses to CO by C grasses are more ambiguous. Here, we sample stable carbon isotope trends in herbarium collections of South African C and C grasses to reconstruct C discrimination. We found that C grasses showed no trends in C discrimination over the past century but that C grasses increased their C discrimination through time, especially since 1950. These changes were most strongly linked to changes in atmospheric CO rather than to trends in rainfall climatology or temperature. Combined with previously published evidence that grass biomass has increased in C-dominated savannas, these trends suggest that increasing water-use efficiency due to CO fertilization may be changing C plant-water relations. CO fertilization of C grasses may thus be a neglected pathway for anthropogenic global change in tropical savanna ecosystems.
Topics: Carbon Dioxide; Poaceae; Carbon Isotopes; Rain
PubMed: 38812264
DOI: 10.1111/nph.19868