Plant Foraging Strategies Driven by Distinct Genetic Modules: Cross-Ecosystem Transcriptomics Approach.

Plants have evolved diverse strategies for foraging, e.g., mycorrhizae, modification of root system architecture, and secretion of phosphatase. Despite extensive molecular/physiological studies on individual strategies under laboratory/greenhouse conditions, there is little information about how plants orchestrate these strategies in the field. We hypothesized that individual strategies are independently driven by corresponding genetic modules in response to deficiency/unbalance in nutrients. Roots colonized by mycorrhizal fungi, leaves, and root-zone soils were collected from 251 maize plants grown across the United States Corn Belt and Japan, which provided a large gradient of soil characteristics/agricultural practice and thus gene expression for foraging. RNA was extracted from the roots, sequenced, and subjected to gene coexpression network analysis. Nineteen genetic modules were defined and functionally characterized, from which three genetic modules, mycorrhiza formation, phosphate starvation response (PSR), and root development, were selected as those directly involved in foraging. The mycorrhizal module consists of genes responsible for mycorrhiza formation and was upregulated by both phosphorus and nitrogen deficiencies. The PSR module that consists of genes encoding phosphate transporter, secreted acid phosphatase, and enzymes involved in internal-phosphate recycling was regulated independent of the mycorrhizal module and strongly upregulated by phosphorus deficiency relative to nitrogen. The root development module that consists of regulatory genes for root development and cellulose biogenesis was upregulated by phosphorus and nitrogen enrichment. The expression of this module was negatively correlated with that of the mycorrhizal module, suggesting that root development is intrinsically an opposite strategy of mycorrhizae. Our approach provides new insights into understanding plant foraging strategies in complex environments at the molecular level.

Identification and characterization of bacteriocin biosynthetic gene clusters found in multiple bacteriocins producing Lactiplantibacillus plantarum PUK6.

The multiple bacteriocins produced by Lactiplantibacillus plantarum PUK6 isolated from misozuke-tofu (tofu pickled in miso) were identified as plantaricins A, EF, and NC8. The pln locus (21,847 bp) containing the three plantaricin structural genes and another newly found putative bacteriocin structural genes (orf1 and orf2) were determined, and a biosynthesis mechanism was proposed. Reverse transcription-PCR analysis revealed that orf1 and orf2, the putative two-peptide bacteriocin structural genes, were expressed after 8 h (logarithmic growth phase) and 20 h (stationary growth phase) of cultivation of the PUK6 strain. Additionally, the growth inhibition profile obtained using the chemically synthesized mature peptides of Orf1 and Orf2 (referred to as mOrf1 and mOrf2) showed that the equimolar mixture of mOrf1 and mOrf2 exhibited bactericidal effect against the indicator strain Latilactobacillus sakei subsp. sakei JCM 1157T. Furthermore, fluorescence microscopic analysis revealed disruption of the cell membranes. These findings indicate that orf1 and orf2 are structural genes encoding class IIb bacteriocins consisting of two peptides. Therefore, the novel bacteriocin encoded by plnPUK6α (orf1) and plnPUK6ß (orf2) genes was named plantaricin PUK6. Since the PUK6 strain produces multiple bacteriocins, when used as a starter culture, it could contribute to improving the shelf life of fermented foods and preventing the appearance of bacteriocin-resistant bacteria.

Post-transplant food anaphylaxis in an adult cord blood transplant recipient (Ms. No. IJHM-D-20-01037R1).

Transplant acquired food allergy (TAFA) is a well-known complication following pediatric liver transplantation, but post-cord blood transplantation (post-CBT) TAFA has rarely been reported. Here, we describe a case of new-onset food anaphylaxis after CBT in an adult patient that demonstrates that post-CBT allergen-challenge is not a risk for long-term allergic sensitization even in adult recipients. The patient was a 39-year-old Japanese man with aggressive NK cell leukemia. He had no previous history of allergies. After receiving CBT, the patient had an unbalanced diet with high preference for bread, bananas, miso-soup, cow's milk, cheese, egg, sesame and buckwheat soba noodles, and experienced repeated diarrhea. Six months later, he developed symptoms such as vomiting, epigastric pain, diarrhea, high fever and hypotension. The condition was initially diagnosed as enterocolitis, but symptoms recurred after consumption of buckwheat. Anaphylaxis induced by buckwheat was confirmed with serum radioallergosorbent tests (RAST), showing allergen-specific IgE for buckwheat (greater than 100 U/mL, Class 6) and egg ovomucoid (Class 4). Nineteen months after a buckwheat and egg-free diet, serum RAST for buckwheat and egg significantly improved. As a result, the patient acquired a tolerance and was able to consume buckwheat and egg without allergic symptoms.

Formation of functional innexin hemichannels, as well as gap junctional channels, in an insect cell line, NIAs-AeAl-2, derived from Asian tiger mosquito Aedes albopictus (Diptera: Culicidae): A partial but significant contribution of innexin 2.

In vertebrates, gap junctions and hemichannels consisting of connexins are important cell surface structures for communication with neighboring cells and for the regulation of various cell functions. To date, various gap-junction-related proteins have been found, including innexins in invertebrates and pannexins in vertebrates. Significant contributions of gap junctions by innexins and (hemi-)channels by pannexins to numerous functions have been reported. Verification of the presence and functional significance of innexin hemichannels, however, remains a gap in our knowledge in innexin physiology. In this study, we revealed the localization of an innexin protein (innexin 2) on the cell surface in mosquito tissues and cultured cells. Furthermore, we demonstrated the presence of functional hemichannels, as well as gap junctions, in mosquito cells using dye transfer assays. The inward uptake of fluorescent dye was inhibited by anti-innexin 2 antibody. These results suggest that innexin hemichannels are formed to function in cultured mosquito cells, in at least a partially innexin 2-dependent manner. Although only a few studies on insect hemichannels have been published, innexin-based hemichannels, as well as innexin gap junctions, could also significantly contribute to insect intercellular signal transduction.

Nestedness in Arbuscular Mycorrhizal Fungal Communities along Soil pH Gradients in Early Primary Succession: Acid-Tolerant Fungi Are pH Generalists.

Soil acidity is a major constraint on plant productivity. Arbuscular mycorrhizal (AM) fungi support plant colonization in acidic soil, but soil acidity also constrains fungal growth and diversity. Fungi in extreme environments generally evolve towards specialists, suggesting that AM fungi in acidic soil are acidic-soil specialists. In our previous surveys, however, some AM fungi detected in strongly acidic soils could also be detected in a soil with moderate pH, which raised a hypothesis that the fungi in acidic soils are pH generalists. To test the hypothesis, we conducted a pH-manipulation experiment and also analyzed AM fungal distribution along a pH gradient in the field using a synthesized dataset of the previous and recent surveys. Rhizosphere soils of the generalist plant Miscanthus sinensis were collected both from a neutral soil and an acidic soil, and M. sinensis seedlings were grown at three different pH. For the analysis of field communities, rhizosphere soils of M. sinensis were collected from six field sites across Japan, which covered a soil pH range of 3.0-7.4, and subjected to soil trap culture. AM fungal community compositions were determined based on LSU rDNA sequences. In the pH-manipulation experiment the acidification of medium had a significant impact on the compositions of the community from the neutral soil, but the neutralization of the medium had no effect on those of the community from the acidic soil. Furthermore, the communities in lower -pH soils were subsets of (nested in) those in higher-pH soils. In the field communities a significant nestedness pattern was observed along the pH gradient. These observations suggest that the fungi in strongly acidic soils are pH generalists that occur not only in acidic soil but also in wide ranges of soil pH. Nestedness in AM fungal community along pH gradients may have important implications for plant community resilience and early primary succession after disturbance in acidic soils.

Reversible methotrexate-associated lymphoma of the liver in rheumatoid arthritis: a unique case of primary hepatic lymphoma.

Primary hepatic lymphoma (PHL) is an extremely rare disease, frequently associated with viruses such as hepatitis B virus (HBV), hepatitis C virus (HCV), and human immune deficiency virus (HIV). On the other hand, an increased risk of lymphoproliferative disorders (LPD) has been demonstrated in patients treated with immunosuppressive drugs such as methotrexate (MTX) for rheumatoid arthritis (RA). The role of Epstein-Barr virus (EBV) has been discussed in the pathogenesis of the immunodeficiency-associated LPDs. We here describe a RA patient, who developed PHL during RA treatment. The patient was a 64 year-old Japanese male with a 2-year history of RA, who had been treated with MTX at weekly dose of 8-14 mg for 2 years and infliximab (IFX) for 7 months. He presented with a 2 month history of generalized malaise, right hypochondrium pain and fever. Contrast-enhanced computed tomography (CECT) of the abdomen showed multiple irregular and nodular liver masses with a maximum of 13 cm in diameter on the right liver. Biopsy specimens demonstrated CD20-positve diffuse large B-cell lymphoma (DLBCL), but EBV was not identified by EBV-encoded RNA in situ hybridization. Serology for HBV, HCV, human T-cell leukemia virus I (HTLV-I), and HIV was negative. His symptoms disappeared following discontinuation of RA treatment including MTX. A drastic regression of the tumor masses was further obtained without cytotoxic chemotherapy. In addition, although the patient had no past history of liver dysfunction before MTX therapy, persistent elevation of liver enzymes has been observed during MTX treatment. These findings show a causative role of MTX in the development of reversible PHL in the patient.

Characterization of arbuscular mycorrhizal fungal communities with respect to zonal vegetation in a coastal dune ecosystem.

Coastal dune vegetation distributes zonally along the environmental gradients of, e.g., soil disturbance. In the preset study, arbuscular mycorrhizal fungal communities in a coastal dune ecosystem were characterized with respect to tolerance to soil disturbance. Two grass species, Elymus mollis and Miscanthus sinensis, are distributed zonally in the seaward and landward slopes, respectively, in the primary dunes in Ishikari, Japan. The seaward slope is severely disturbed by wind, while the landward slope is stabilized by the thick root system of M. sinensis. The roots and rhizosphere soils of the two grasses were collected from the slopes. The soils were sieved to destruct the fungal hyphal networks, and soil trap culture was conducted to assess tolerance of the communities to disturbance, with parallel analysis of the field communities using a molecular ecological tool. In the landward communities, large shifts in the composition and increases in diversity were observed in the trap culture compared with the field, but in the seaward communities, the impact of trap culture was minimal. The landward field community was significantly nested within the landward trap culture community, implying that most members in the field community did not disappear in the trap culture. No nestedness was observed in the seaward communities. These observations suggest that disturbance-tolerant fungi have been preferentially selected in the seaward slope due to severe disturbance in the habitat. Whereas a limited number of fungi, which are not necessarily disturbance-sensitive, dominate in the stable landward slope, but high-potential diversity has been maintained in the habitat.

Complete structure of nuclear rDNA of the obligate plant parasite Plasmodiophora brassicae: intraspecific polymorphisms in the exon and group I intron of the large subunit rDNA.

Plasmodiophora brassicae is a soil-borne obligate intracellular parasite in the phylum Cercozoa of the Rhizaria that causes clubroot disease of crucifer crops. To control the disease, understanding the distribution and infection routes of the pathogen is essential, and thus development of reliable molecular markers to discriminate geographic populations is required. In this study, the nuclear ribosomal RNA gene (rDNA) repeat unit of P. brassicae was determined, with particular emphasis on the structure of large subunit (LSU) rDNA, in which polymorphic regions were expected to be present. The complete rDNA complex was 9513bp long, which included the small subunit, 5.8S and LSU rDNAs as well as the internal transcribed spacer and intergenic spacer regions. Among eight field populations collected from throughout Honshu Island, Japan, a 1.1 kbp region of the LSU rDNA, including the divergent 8 domain, exhibited intraspecific polymorphisms that reflected geographic isolation of the populations. Two new group I introns were found in this region in six out of the eight populations, and the sequences also reflected their geographic isolation. The polymorphic region found in this study may have potential for the development of molecular markers for discrimination of field populations/isolates of this organism.