Plant Biotechnology最新文献

Ditylenchus destructor is a plant-parasitic nematode that severely damages garlic (Allium sativum L.) in Japan. D. destructor is detected in roots, bulbs, and outer bulb skins of garlic at harvest; however, the resistance of garlic to D. destructor infection is not well understood. Here, we investigated the propagation of D. destructor in storage organs and roots using in vitro plantlets of six Japanese garlic varieties to exclude the effects of microbes and to uniform growing conditions. In vitro inoculation can proceed simultaneously with vegetative growth, storage organ formation of garlic plantlets, and D. destructor infection. In 'Fukuchi-white', a variety susceptible to D. destructor, nematodes successfully propagated in storage organs and roots. Furthermore, the nematodes invaded and propagated in the newly formed storage organs. By contrast, 'Kirishima', 'Hirado', and 'Shishimaru' substantially suppressed more the propagation of the nematodes in storage organs and roots than 'Fukuchi-white'. Additionally, the propagation of nematodes in newly formed storage organs was inhibited in these three varieties. 'Shishimaru' showed unique responses to D. destructor infection: nematode propagation was the lowest among six varieties in inoculation tests and the nematode-inoculated cloves turned brown. Our results suggest that several garlic varieties have resistance mechanisms that suppress the propagation of D. destructor in storage organs and roots, and that in vitro inoculation methods are useful for selecting resistant garlic varieties. These findings will help developing novel D. destructor-resistant garlic varieties and our further understanding of garlic-nematode interactions.

The sustainable production and utilization of lignocellulose biomass are indispensable for establishing sustainable societies. Trees and large-sized grasses are the major sources of lignocellulose biomass, while large-sized grasses greatly surpass trees in terms of lignocellulose biomass productivity. With an overall aim to improve lignocellulose usability, it is important to increase the lignin content and simplify lignin structures in biomass plants via lignin metabolic engineering. Rice (Oryza sativa) is not only a representative and important grass crop, but also is a model for large-sized grasses in biotechnology. This review outlines progress in lignin metabolic engineering in grasses, mainly rice, including characterization of the lignocellulose properties, the augmentation of lignin content and the simplification of lignin structures. These findings have broad applicability for the metabolic engineering of lignin in large-sized grass biomass plants.

The members of glutathione S-transferase (GST) belonging to the Phi class of the GST family are known to play a role in anthocyanin transport to the vacuole. We isolated a GST orthologue from the torenia petal cDNA library. Transgenic plants transcribing GST double stranded RNA were generated from a torenia cultivar having blue flowers. These plants exhibited a range of flower colors, from blue to almost white. Quantitative RT-PCR confirmed the downregulation of the GST transcript, accompanied by a decrease in anthocyanin levels in the petals of the transgenic plants, whereas flavone levels remained unchanged. These results suggest that GST is involved in anthocyanin transport in torenia petals, and that anthocyanins and flavones are likely transported to the vacuole through different mechanisms.

Cell division is important for organisms to grow and repair damaged tissues. A mutant screen in rice has identified dwarf korpokkur (kor) mutants that code for a novel protein potentially involved in mitosis including cytokinesis in rice. The KOR gene is expressed during the mitotic phase and a defect in the KOR gene induces cells with two nuclei. Analysis of kor mutants suggests that the KOR gene promotes cell division in the rice leaf primordia for a period after initiation, and maintains proper cell morphology especially in non-meristematic tissues. Additionally, kor mutants showed a delayed transition from juvenile phase to adult phase. Future research will shed light on the relationship between the mitotic defect and other features observed in the kor mutants.

Initial light reception after germination is a dramatic life event when a seedling starts proper morphogenesis. Blue light contains a range of light wavelengths that plants can perceive. A previous report suggested that the chemical compound 3-bromo-7-nitroindazole (3B7N) inhibits blue light-mediated suppression of hypocotyl elongation by physically interacting with the blue light receptor Cryptochrome 1 (CRY1). We previously examined changes of genome-wide gene expression in Arabidopsis seedlings germinated in the dark and then exposed to blue light by RNA-seq and Ribo-seq analyses. The expression of ribosome-related genes was translationally upregulated in response to the initial blue light exposure, depending on signals from both the nucleus and chloroplasts. Here, we re-analyzed our previous data and examined the effect of 3B7N treatment on changes in gene expression upon blue light exposure. The results showed that 3B7N negatively affected translation of ribosome-related genes and, interestingly, the effects were similar to not only those in cry1cry2 mutants but also plants under suppression of photosynthesis. We propose an apparent crosstalk between chloroplast function and blue light signaling.

Aromatic compounds play essential roles in plant physiology and various industries because of their unique fragrances and beneficial properties. In this study, we investigated the transport and biosynthesis of eugenol, a prominent aromatic compound, within the Ocimum genus, using grafting experiments. Grafting sweet basil (Ocimum basilicum) scions onto diverse rootstocks, including tobacco (Nicotiana benthamiana) and thyme (Thymus vulgaris), revealed that eugenol is transported from the shoot to the root across distinct plant species. Furthermore, grafting within the Ocimum genus, which includes O. basilicum, O. tenuiflorum, and O. americanum, resulted in variations in eugenol transport and accumulation. The eugenol content in the shoots remained constant across all combinations, whereas the root eugenol levels varied depending on the scion-rootstock pair. To elucidate the biosynthetic capabilities of eugenol in Ocimum roots, we performed in vitro enzyme assays using crude protein extracts from roots, which revealed that eugenol can be synthesized in roots in addition to being transported. Expression analysis of eugenol synthase (EGSs) genes showed that EGS4 expression was influenced by grafting in O. basilicum roots, suggesting compensation by other EGSs. Our results suggest that eugenol transport and biosynthesis are multifaceted processes influenced by the interactions between different species and tissues. The potential to engineer eugenol levels in rootstocks lacking biosynthetic capacity has potential applications in agriculture and industry. This study reveals the dynamic interplay between eugenol transport and biosynthesis in the Ocimum genus, providing insights into the manipulation of aromatic compound production in plants.

Thermostable α-amylase from germinating Sword bean (Canavalia gladiata (Jacq.) DC.) seeds has been successfully immobilized on DEAE-cellulose (ICgAmy1) and chitosan bead (ICgAmy2) support materials. Optimum conditions of immobilization for DEAE-cellulose and chitosan bead revealed 97% and 96% immobilization yield, respectively. The optimum pH and temperature of both DEAE-cellulose and chitosan bead immobilized α-amylases were pH 7 and 70°C. Both ICgAmy1 and ICgAmy2 were high stability over a wide pH range of pH 5-9 and a temperature range of 70-90°C. In addition, ICgAmy1 and ICgAmy2 led to an operationally stable biocatalyst with above 74% and 76% residual activity after 10 reuses, respectively. Immobilized α-amylases showed high storage stability with 81% (ICgAmy1) and 85% (ICgAmy2) residual activity after 120 days of storage. The easy immobilization process on low-cost, biodegradable, and renewable support materials exhibited an increase in the enzyme operation range and storage stability which reduces production costs. This makes immobilized amylases an effective biocatalyst in various industrial applications especially a potential candidate for bioethanol production, a key renewable energy source.

Floral scents play important ecological roles because they attract pollinators and seed-dispersers. Historically, humans have used plant volatiles, including floral scents, as food additives, cosmetic products, and medicines. Floral scent formation and emissions are sometimes considerably affected by environmental and climatic conditions. Both enzymes and genes involved in floral scent biosynthesis have been consistently identified, and have provided insights into the potential of metabolic engineering of floral scents. This review summarizes recent studies on various aspects of floral scent biosynthesis and emission, including biosynthetic enzymes and genetic engineering. The findings ultimately show that the metabolic pathways of floral volatiles may be regulated by a more complex system than previously thought.

The tissue culture process is usually involved in gene transfer and genome editing in plants. Like other species, there is enormous variation among wheat genotypes in tissue culture response. In the rapidly advancing system of CRISPR/Cas9 for genome editing, particle bombardment has received increasing attention as a delivery method for a large amount of nucleic acids and RNA-protein complexes. However, the efficiency of transformation by particle bombardment has been low in wheat, and only a limited number of varieties have been transformed. In this study, replacement of maltose with trehalose as an osmolyte for high osmotic treatment for the protection of tissues from physical impacts improved callus formation in immature wheat embryos and efficiency of transformation and genome editing in varieties that are relatively poor in tissue culture response. The range of varieties amenable to biolistic transformation and genome editing may be expanded by this modification.

Papaya (Carica papaya L.) is a herbaceous plant belonging to the family Caricaceae in the order Brassicales. The shape of papaya fruit was linked to sex, and the fruit of female plants is round, whereas that of hermaphrodites is pyriform. Although fruit shape preferences vary by region, differences in their functionalities have not been investigated. Since unripe fruit, also called green papaya, is known for its nutritional and therapeutic benefits, we performed a metabolome analysis of unripe papaya using liquid chromatography coupled with quadrupole/time of flight mass spectrometry. We first focused on capraine derivatives, major piperidine alkaloids, and bioactive compounds with significant antiplasmodial activity. Interestingly, carpaine derivatives tended to be altered in the peel and pulp but not in the seed. Multivariate analyses indicated little difference or minor differences to the extent that they can be caused by individual differences in metabolite profiling between the two sexes. Conversely, total polyphenol content and proteolytic activity were also investigated, but there were no differences between females and hermaphrodites for total polyphenol content and proteolytic activity. In conclusion, the metabolome and major functionalities were similar between hermaphrodites and female unripe fruit. However, it would be worth considering the sex of the material fruit, especially when focusing on the functional properties of carpaine derivatives.