The IBBP was established to provide backup storage for biological resources utilized in individual research endeavors, to ensure the continued vitality of life sciences in Japan from its inception. This initiative is informed by the experiences of the loss of numerous biological resources in the Great East Japan Earthquake. The IBBP has established the IBBP Center at the National Institute for Basic Biology in Okazaki, Aichi, Japan, to provide a centralized storage facility for biological resources. The storage facility houses a range of biological materials, including sperm, fertilized eggs, microorganisms, libraries, proteins, nucleic acids, and plant seeds. The storage of sperm, fertilized eggs, microorganisms, libraries, proteins, and nucleic acids is conducted using liquid nitrogen. Plant seeds can be stored at 4°C and 30% humidity. In principle, any researcher affiliated with a research institute and/or university in Japan is eligible to use the facility, and there is no distribution to third parties. As of May 31, 2024, the IBBP had received 863 applications and stored a total of 37,929 items. Furthermore, the IBBP engages in collaborative research programs to develop long-term preservation techniques for biological resources for which such techniques have not yet been established. Additionally, it holds workshops to disseminate the developed preservation techniques to the research community. Moreover, the Cryopreservation Conference is held annually to facilitate the exchange of information on long-term preservation technologies for various types of research resources.

During the decoding of the triplet code of nucleotides, known as a codon, the preference for certain synonymous codons affects the efficiency and accuracy of protein translation. Therefore, identifying codon usage bias provides insights into the gene expression system of a particular organism. The unicellular red alga Cyanidioschyzon merolae features a remarkably simple genome structure and a small number of genes for a eukaryotic organism, yet its codon usage code remains unclear. Here we report the synonymous codon usage frequencies for protein-coding genes in C. merolae. By comparing codon usage frequencies, we discovered that not only the wobble position—the third nucleotide of the codon—but also the first nucleotide contributes to codon bias. The overall difference in the frequency of codon usage among genes is attributed to the selectivity for the G/C base, particularly evident in highly expressed genes. The extremely narrow range of the codon adaptation index for protein-coding genes suggests that C. merolae has not undergone frequent gene uptake from extracellular sources to date. We found that not only highly expressed genes but also many functional genes have been optimized for a specific set of codon usage patterns. In contrast, codon bias was very low in genes thought to be newly created de novo in the genome. These results suggest that the evolution of genes has progressed through replacing to G/C base-containing synonymous codons, and that codon substitutions would continue until the codon usage frequency has adjusted to the ideal ratio for gene function or necessity.

Polyploidy, the condition of having multiple sets of genome, has been analyzed in 200 species from Kinnaur district of Himachal Pradesh, India. Among presently studied species, 50 species have been recorded at different polyploid levels. Out of different polyploid cytotypes, the tetraploid cytotype is more frequently found (68.0%) while the higher levels like 8x and 10x are rather less represented. Unreduced gametes might be the first cause of polyploidy which impacts the species distribution, morphological characteristics, plant habit, chromosome pairing, meiotic course, and pollen fertility. Three species, Spergularia diandra (2x, 4x), Indigofera heterantha (2x, 6x), and Veronica anagallis-aquatica (2x, 4x) with intraspecific diploid and polyploid cytotypes showed the variation in the morphological characters and distribution pattern. Four polyploids Erigeron annuus (2n=27; 3x), Carduus nutans (2n=40; 4x), Geranium pratense (2n=56; 4x), and Taraxacum officinale (2n=32; 4x) showed nonhomologous chromosome pairing and went through a disturbed course of cell division. Overall, 38% of polyploid species exhibited irregular events during meiosis, resulting in low fertility in gametes. The production of 2n gametes through meiotic aberrations might be responsible for the origin of polyploid taxa and also due to the tendency of harsh environmental conditions prevailing in the area. Finally, these species adopt the alternate mode of reproduction to produce new offsprings for the next generations.

Gloriosa superba is a highly valued vegetatively propagating rhizomatous medicinal plant. Unfortunately, unrestricted overexploitation from its natural habitat has made the species endangered. Intra-specific variations have been reported but, detailed genetic diversity analysis at the chromosomal level is unavailable. This study has standardized an enzymatic maceration and air drying (EMA) protocol followed by sequential staining with Giemsa, 4′-6-diamidino-2-phenylindole (DAPI), and chromomycin A₃ (CMA) in three Indian germplasm of G. superba. Chromosomal analysis on cytoplasm-free metaphase plates with distinct chromosomal configurations has revealed that two wild populations (I and II) are diploid with 2n=22 chromosomes, and the horticulture population (III) has 2n=22–80 plus chromosomes. Two pairs of interstitial secondary constrictions in two wild diploid populations are confirmed through Giemsa, DAPI, and CMA bandings. However, the horticulture population shows terminal secondary constrictions. The DAPI-positive banding pattern in two wild populations generates four and 10 DAPI-positive bands resulting in a differential karyotype formula for population I (2A+4B+16D) and population II (10A+4C+8D). Meiotic investigation of populations I and II has confirmed their diploid nature with 11 bivalents. This repeatable protocol may be useful for applying to any species/population of Gloriosa for conservation, phylogenetic analysis, and future crop improvement programs.

Codonopsis pilosula (Franch.) Nannf. is used as root organ medicine, and ploidy breeding is conducive to its resource development and utilization. The autotetraploid of C. pilosula was induced by colchicine with seeds and sterile stem tips as materials and identified by flow cytometry and chromosome counting. At the same time, based on the diploid proliferation medium, the L₉ (3⁴) orthogonal experiment was carried out with 6-benzylaminopurine (6-BA), α-naphthaleneacetic acid (NAA), and kinetin (KT) as factors to optimize the autotetraploid proliferation medium and realize rooting outside the bottle. Finally, the morphological cell analysis of the autotetraploid was carried out. The results showed that stem tips were more suitable for inducing tetraploid than the seeds. The chromosome number of diploid was 2n=2x=16, and that of tetraploid was 2n=4x=32. Adventitious buds were identified by three consecutive generations, and no ploidy variation appeared. The callus induction and adventitious bud proliferation of the tetraploid stem tip were synchronized in Murashige and Skoog (MS) medium with 60 mL L⁻¹ coconut juice, 1.0 mg L⁻¹ 6-BA, 0.5 mg L⁻¹ NAA, and 0.1 mg L⁻¹ KT, and the proliferation coefficient was up to 39.69. The rooting rate of tetraploid-regenerated buds outside the bottle was 85.97%, and the survival rate after transplanting was 98.26%. Tetraploid plants exhibited superior characteristics in terms of leaf size, stem diameter, number of branches and leaves, and floral organ size when compared to diploid plants. In addition, the induction method of diploid stem tips soaked in a colchicine sterile solution and then cultured in the colchicine-containing medium greatly improved the induction rate of tetraploid. In this study, the autotetraploid of C. pilosula was successfully induced, and the artificial efficient regeneration system of tetraploid C. pilosula was established, which provided an effective way for the optimization of C. pilosula germplasm resources.

The genus Ocimum (Lamiaceae) comprises approximately 65 aromatic species. The taxonomic classification of Ocimum is often very complicated due to centuries of selection and breeding, as well as spontaneous events, such as speciation, hybridization, and polyploidy. Our previous studies identified a ploidy-stable series of Ocimum species sharing the chromosome base number x=13 from Thailand: diploid O. americanum (2n=26), tetraploid O. basilicum (2n=52) and hexaploid O. africanum (2n=78). In this study, we measured and analyzed the sizes of viable pollen with the aim of characterizing the gametophytic features of this polyploid series. Samples were collected from three Ocimum species originating from two geographically distant locations in Thailand, Chiang Mai (northern) and Prachuab Khiri Khan (southwestern) provinces. A total of 29,418 pollen grains were analyzed. The results revealed positive and significant correlations between pollen size and ploidy level in O. americanum (43.9–63.5 µm), O. basilicum (52.9–73.6 µm), and O. africanum (57.7–80.8 µm) (Spearman’s rho=0.900, n=28,431, p＜0.001). An overlapping size distribution between nonviable and viable pollen grains was observed for all three species, probably indicating aneuploid viable pollen. Notably, polyploid pollen was also detected in the diploid species O. americanum, possibly because the pollen contains unreduced gametes, which can drive polyploidization. Despite the existence of polyploid and supposed aneuploid pollen grains, the viability of the pollen that formed in these species was exceptionally high: O. americanum (97.6–99.5%), O. basilicum (87.6–98.5%) and O. africanum (90.4–99.4%). These viable, unbalanced pollen grains should be capable of fertilization, resulting in aneuploidy and polyploidy.

Drosera genomes show variation in chromosome size. DNA sequences contributing to the size changes have not been fully characterized for Drosera species. This study aimed to identify DNA sequences that contribute to changes in chromosome size in a polyploid group of the genus Drosera using a random amplified polymorphic DNA (RAPD). RAPD fragment named DR-OPC01 was isolated from D. rotundifolia (2n=2x=20, 2C=2,333 Mbp, 45.4% GC ratio), which possessed 20 middle-sized chromosomes (m-chromosomes). The DNA fragment DR-OPC01 was also amplified in the allohexaploid D. tokaiensis (2n=6x=60, 2C=3,048 Mbp, 43.0% GC ratio), which has a hybrid origin between D. rotundifolia and D. spatulata (2n=4x=40, 2C=1,079 Mbp, 42.4% GC ratio). However, the fragment was not amplified in D. spatulata, which possessed 40 small chromosomes (s-chromosomes). The sequence length of DR-OPC01 was 669 bp with 10-bp palindromic repeat sequences of the RAPD primer OPC-01 at both ends. The GC ratio of the DR-OPC01 sequence was 49.6%, which was higher than that of the three Drosera species. In dot-blot hybridization, hybridized signals from the DR-OPC01 probe were clearly detected with dot-blots of genomic DNA from D. rotundifollia and D. tokaiensis, but not D. spatulata. Fluorescence in situ hybridization on the somatic chromosome of D. tokaiensis revealed that the DR-OPC01 probe hybridized to the entire m-chromosomes, but not to all s-chromosomes.

Endopolyploidy, the presence of cells with multiple sets of chromosomes, is a phenomenon observed in various insect tissues. These cells can arise through endoreplication or endomitosis, processes that lead to increased DNA content without cell division. In this study, we investigated, for the first time, the occurrence of endopolyploidy in the different developmental stages (larvae, young and old prepupae, pupae, and adults) of Solenopsis saevissima. Using flow cytometry, we measured the DNA ploidy levels and observed the presence of 2C, 4C, and 8C nuclei throughout the developmental stages. Our findings revealed dynamic changes in the mean number of 2C, 4C, and 8C nuclei during S. saevissima’s developmental stages, with a gradual decrease in endopolyploid cells (4C and 8C) over time. Cytogenetic analysis confirmed the presence of tetraploid cells alongside diploid cells in the cerebral ganglion, suggesting that endomitosis promotes endopolyploidy in the cerebral tissues of S. saevissima. These findings highlight the changes in endopolyploidy levels within cerebral ganglion cells throughout the developmental stages of S. saevissima and provide insights into its potential implications for the biology of fire ants. Further research is needed to fully understand the genetic and metabolic effects of endopolyploidy in these organisms.

Carex is the most species-rich group in the flowering plants in the temperate zones with more than 2,000 species worldwide. Coupled with the high species diversity, the genus possesses holocentric chromosomes, which miss constricted centromeres during cell divisions. Holocentric chromosomes are supposed to contribute to great variation in chromosome numbers by chromosome fragmentation (fission) and/or merging (fusion). Carex section Mitratae Kük. occurs mainly in East Asia and comprises about 80 taxa. Meiotic chromosome numbers of six taxa in the section were observed from 15 populations in South Korea: C. breviculmis R. Br. (n=32_II, 33_II, 34_II), C. brevispicula G. H. Nam & G. Y. Chung (n=34_II), C. candolleana H. Lév. & Vaniot (n=35_II), C. conica Boott (n=18_II, 19_II), C. fibrillosa Franch. & Sav. (n=34_II), and C. polyschoena H. Lév. & Vaniot (n=34_II, 36_II). All the chromosomes observed were very small (about 1–2 µm long) with diffuse centromeres (without constricted centromeres). Chromosome numbers vary in C. breviculmis, C. conica, and C. polyschoena. C. breviculmis and C. polyschoena show variation within a species (among populations), and C. conica exhibits two different numbers within a population. C. brevispicula, a Korean endemic, has a consistent chromosome number with previous counts, and C. fibrillosa shows the same chromosome number as the count from a Japanese population. For the first time, the chromosome number for C. candolleana is counted. Further investigations of chromosomes in Carex will help to understand the species diversity of the most species-rich group in flowering plants.

Chromosome numbers of five Strobilanthes species are reported here for the first time: S. austrosinensis (2n=90), S. labordei (2n=30), S. sarcorrhiza (2n=30), S. tetrasperma (2n=30), and S. wilsonii (2n=30). The chromosome number of S. oligantha is reiterated here as 2n=60. The results indicate that S. labordei, S. sarcorrhiza, S. tetrasperma, and S. wilsonii are diploid. Based on morphological and cytological data, it is inferred that S. oligantha and S. austrosinensis may be tetraploid and hexaploid, respectively. S. austrosinensis is morphologically similar to S. oligantha and S. tetrasperma with blurred distinctions, but their chromosome numbers are obviously different. Besides, we suspect that S. tetrasperma might potentially be the parent of both S. oligantha and S. austrosinensis.