Changes in Carotenoids and Polyphenols during the Growth Stages of Orange-Fleshed Sweet Potato (Ipomoea batatas (L.) Lam.)

The storage roots of orange-fleshed sweet potato contain high levels of polyphenols and carotenoids. Little information is available on changes in the content and composition of these secondary metabolites during the growth stages of the root system. We investigated changes in carotenoids, polyphenols, and anthocyanins in the root system of the orange-fleshed sweet potato ‘Tamaakane’ from the post-planting stage. Carotenoids and polyphenols accumulated immediately after root-system formation at 15 days after transplanting (DAT). The levels of carotenoids increased by 45 DAT and decreased once the storage root enlargement began, but increased rapidly thereafter. After 90 DAT, β-carotene accounted for >90% of the total carotenoids, and the frequency remained stable until maturity. Total polyphenol content increased significantly towards 45 DAT and then gradually decreased as the storage roots began to thicken. No anthocyanin was detected in the root systems of ‘Tamaakane’ at any stage. The content and composition of these secondary metabolites are discussed in terms of agronomic aspects, as they might contribute to a strategy to protect storage roots while engaging with each other against biotic or abiotic stresses at the growth stage of the root system.Citation: Setoguchi, Y.; Narasako, Y.; Hirano, T.; Otani, M.; Kunitake, H. Changes in Carotenoids and Polyphenols during the Growth Stages of Orange-Fleshed Sweet Potato (Ipomoea batatas (L.) Lam.). Horticulturae 2024, 10, 629. https://doi.org/10.3390/horticulturae1006062

Distinctive development of embryo and endosperm caused by male gametes irradiated with carbon-ion beam

Pollen irradiation with ionizing radiations has been applied in plant breeding and genetic research, and haploid plant induction has mainly been performed by male inactivation with high-dose irradiation. However, the fertilization process of irradiated male gametes and the early development of embryo and endosperm have not received much attention. Heavy-ion beams, a type of radiation, have been widely applied as effective mutagens for plants and show a high mutation rate even at low-dose irradiation. In this study, we analyzed the effects of male gametes of Cyrtanthus mackenii irradiated with a carbon-ion beam at low doses on fertilization. In immature seeds derived from the pollination of irradiated pollen grains, two types of embryo sacs were observed: embryo sac with a normally developed embryo and endosperm and embryo sac with an egg cell or an undivided zygote and an endosperm. Abnormalities in chromosome segregation, such as chromosomal bridges, were observed only in the endosperm nuclei, irrespective of the presence or absence of embryogenesis. Therefore, in Cyrtanthus, embryogenesis is strongly affected by DNA damage or mutations in male gametes. Moreover, various DNA contents were detected in the embryo and endosperm nuclei, and endoreduplication may have occurred in the endosperm nuclei. As carbon-ion irradiation causes chromosomal rearrangements even at low doses, pollen irradiation can be an interesting tool for studying double fertilization and mutation heritability.Citation: Hirano, T., Murata, M., Watarikawa, Y. et al. Distinctive development of embryo and endosperm caused by male gametes irradiated with carbon-ion beam. Plant Reprod (2024). https://doi.org/10.1007/s00497-024-00496-

Seasonal Variation and Mean Degree of Polymerization of Proanthocyanidin in Leaves and Branches of Rabbiteye Blueberry (Vaccinium virgatum Aiton)

The leaves and branches of rabbiteye blueberry are rich in proanthocyanidins, which are thought to have different physiological activities depending on their structure and degree of polymerization. In this study, we analyzed the constituents of the leaves and branches of rabbiteye blueberry to determine the seasonal variations in polyphenol and proanthocyanidin (PAC) contents as well as their mean degrees of polymerization (mDP). Total PAC content was determined using two methods: The p-dimethylaminocinnamaldehyde (DMACA) method, which measures monomeric PAC, showed an increase from spring to summer in both leaves and branches. On the other hand, using the butanol/HCl method, which measures only polymerized PAC, the PAC content of leaves increased from spring to summer but those of branches remained low throughout the year, showing no significant increase or decrease. Furthermore, analysis of the mDP of PAC showed increases from spring to summer in the leaves of ‘Kunisato 35 gou’. Although the highest value (8.0) was observed in October, values around 4 remained throughout the year in the branches. Since differences in polymerization degree affect absorption in the body and physiological properties such as antioxidant capacity, selecting the appropriate harvest time and plant organs for each purpose is expected to ensure the quality of processed blueberry foods.Citation: Koga, Y.; Setoguchi, Y.; Sugamoto, K.; Goto, Y.; Hirano, T.; Kunitake, H. Seasonal Variation and Mean Degree of Polymerization of Proanthocyanidin in Leaves and Branches of Rabbiteye Blueberry (Vaccinium virgatum Aiton). Plants 2024, 13, 1864. https://doi.org/10.3390/plants1313186

Highly polymerized proanthocyanidins (PAC) components from blueberry leaf and stem significantly inhibit SARS-CoV-2 infection via inhibition of ACE2 and viral 3CLpro enzymes

With the current worldwide pandemic of COVID-19, there is an urgent need to develop effective treatment and prevention methods against SARS-CoV-2 infection. We have previously reported that the proanthocyanidin （PAC） fraction in blueberry （BB） leaves has strong antiviral activity against hepatitis C virus （HCV） and human T-lymphocytic leukemia virus type 1 （HTLV-1）. In this study, we used Kunisato 35 Gou （K35） derived from the rabbit eye blueberry （Vaccinium virgatum Aiton）, which has a high PAC content in the leaves and stems. The mean of polymerization （mDP） of PAC in K35 was the highest of 7.88 in Fraction 8 （Fr8） from the stems and 12.28 of Fraction 7 （Fr7） in the leaves. The composition of BB-PAC in K35 is that most are B-type bonds with a small number of A-type bonds and cinchonain I as extension units. A strong antiviral effect was observed in Fr7, with a high polymerized PAC content in both the leaves and stems. Furthermore, when we examined the difference in the action of BB-PAC before and after SARS-CoV-2 infection, we found a stronger inhibitory effect in the pre-infection period. Moreover, BB-PAC Fr7 inhibited the activity of angiotensin II converting enzyme （ACE2）, although no effect was observed in a neutralization test of pseudotyped SARS-CoV-2. The viral chymotrypsin-like cysteine protease （3CLpro） of SARS-CoV-2 was also inhibited by BB-PAC Fr7 in leaves and stems. These results indicate that BB-PAC has at least two different inhibitory effects, and that it is effective in suppressing SARS-CoV-2 infection regardless of the time of infection

Allelopathic activity in barbados nut (Jatropha curcas L.)

Allelopathic activities of the leaves and cultivating soil in barbados nut during the cultivating season were investigated to clarify the impact on the surrounding environment into cultivation of this plant. Allelopathic activities of the raw, artificially dried and naturally dried young or adult leaves in barbados nut were assessed to the initial growth of lettuce. Their lengths in hypocotyl and radicle of lettuce seedlings were shorter than those on control from June to December by leachate from the artificially dried young and adult and naturally dried adult leaves. The soil cultivating barbados nut was investigated for assessment of allelopathic activities. Their lengths in hypocotyl and radicle of lettuce seedlings were shorter than those on non-transplanted soil under the soils collected in September from the base of barbados nut tree, and under the soils collected in July and October from between the trees, respectively. From the results of these experiments, it was found that the dried leaves of barbados nut have the highest allelopathic activities with the initial growth of lettuce of the year, and was thought that they might be affected on their surrounding plants. On the other hand, the initial growth of lettuce have affected under the cultivating soils of barbados nut tree on the periods of flowering or active assimilation. Therefore, it was suggested that the allelopathic activities in root of barbados nut tree might varied depending on the season to the growth of surrounding plants.ナンヨウアブラギリを栽培する上で周辺環境に対する影響を明らかにするために, 生育期間中の葉および栽培土壌についてそれらのアレロパシー活性を検討した. 1. ナンヨウアブラギリの様々な様態の葉を用いてレタスに対するアレロパシー活性を評価したが, 6月～12月の間で乾燥葉, 枯死葉あるいは乾燥幼葉においてレタスの幼根伸長を強く阻害する傾向が見られた. 2. ナンヨウアブラギリの栽培土壌を用いてレタスに対するアレロパシー活性を評価したが, 9月では株元において, 7月および10月では株間においてレタスの下胚軸長および幼根長が対照土壌と比較して有意に短かった.departmental bulletin pape

Partial Transfer of Citrus genome to Fortunella species using cell engineering techniques

平成14年度～平成16年度科学研究費補助金 (基盤研究(C)) 研究成果報告書research repor

カンキツ類における倍数性周縁キメラ植物体の発生起源の解明と育種的利用に関する研究

平成17年度～平成19年度 科学研究費補助金 (基盤研究(C)) 研究成果報告書research repor

ブルーベリー葉からRNAを効率的に抽出する方法

The isolation of high-quality RNA from blueberry leaves is difficult due to the presence of many organic acids and polyphenols in the leaves. We established an efficient method for isolating RNA from rabbit-eye blueberry (Vaccinium virgatum Aiton) leaves using a modified cetyl trimethyl ammonium bromide (CTAB) method. More than 200 μg of RNA from 1 g of blueberry leaves was obtained with a HEPES or a MOPS buffer changed from a Tris-HCl buffer. The quality and quantity of the total RNA was sufficient for the cDNA synthesis. We succeeded in the amplification of cDNAs using polymerase chain reaction (PCR).ブルーベリー葉には有機酸やポリフェノールが大量に含まれるため,高品質なRNAを抽出することが難しい.我々は,改良した臭化セチルトリメチルアンモニウム法を用いることにより,ラビットアイブルーベリー (Vaccimium virgatum Aiton) の葉から,RNAを効率的に抽出する手法を確立した. トリス緩衝液をHEPES緩衝液若しくはMOPS緩衝液に変えることで,1gのブルーベリー葉から200μg以上の全RNAを得ることができた.cDNA合成を行うのに十分な質と量であった.また,我々は,RT-PCRによるcDNAの増幅にも成功した.departmental bulletin pape

Triploid and aneuploid hybrids from diploid-diploid intergeneric crosses between Citrus cultivar 'Kiyomi' tangor and Meiwa kumquat (Fortunella crassifolia swingle) for seedless breeding of kumquats

In order to produce new seedless kumquat cultivars, we carried out an intergeneric cross between'Kiyomi' tangor [Citrus unshiu Marcow. x C. sinensis （L.） Osbeck] and Meiwa kumquat （Fortunella crassifolia Swingle）, obtaining 2 normal seeds and 7 undeveloped seeds. These seeds were cultivated on Murashige and Tucker medium, and the 2 normal seeds germinated and developed. The results of genome size analysis by flow cytometry revealed that both seedlings were triploids and that the difference in genome size corresponded to more than one chromosome in the 2 seedlings. Chromosome observation confirmed diploid （2n = 2x = 18） in both parents, aneuploid with 28 chromosomes （2n=28） for one of the seedlings, and triploid （2n=3x=27） for the other seedling. Random amplified polymorphic DNA （RAPD） and cleaved amplified polymorphic sequence （CAPS） analyses proved that the seedlings were intergeneric hybrids between 'Kiyomi' tangor and Meiwa kumquat, with the maternal organelle genome. These hybrids have the potential to be released as a cultivar after further tree and fruit evaluations, and for use as cross-parents in seedless kumquat breeding

DNA多型に基づいたキンカン属植物の系統発生と分類

Fortunella are classified into the subfamily Aurantioideae (family Rutaceae). The taxonomy and phylogeny of this genus are complicated and controversial. Therefore, we carried out an estimation based on RAPD and cytoplasmic CAPS analyses in order to understand the relationship and phylogeny of the genus Fortunella. Among the 6 Fortunella species examined, F. hindsii showed the most distant position on the dendrogram based on RAPD analysis. On the other hand, close relationships were found among the 3 species F. margarila, F. japonica and F. crassifolia. F. obovata was separated into the same cluster as C. madurensis, which was reported to be an intergeneric hybrid between Fortunella and Citrus, and the band patterns on CAPS analysis for the cpDNA regions were similar to other Fortunella species than Citrus. We concluded that there are only two true species for the genus Forlunella F. hindsii and F. margarita complex, moreover, F. obovata should be provided a taxonomic rank as natural or horticultural intergeneric hybrids.キンカン属植物(Fortunella) は, ミカン科ミカン亜科植物に分類されているが, この属における分類と系統発生は, 未だ混乱している. そこで,我々は, キンカン属の類縁関係と系統発生を理解するために, RAPD分析とオルガネラDNA領域のCAPS分析に基づいて評価を行った. 試験に用いられたキンカン属6種のうち, マメキンカンは,RAPD分析により作成した系統樹において最も離れた位置を示した. 一方, ナガキンカン, マルキンカンおよびニンポウキンカンの3種は, 近い類縁関係を有していた. フクシュウキンカンは, キンカン属植物とカンキツ属植物との属間雑種と報告されているシキキツと同じクラスターに分類され, オルガネラDNA領域のCAPS分析におけるバンドパターンは, カンキツ属植物よりも他のキンカン属植物に類似していた. 本研究の結果より,我々は, キンカン属の種が, マメキンカンとナガキンカンコンプレックス(ナガキンカン, マルキンカンおよびニンポウキンカン) の2つのみであり, フクシュウキンカンは自然的もしくは園芸的に派生した属間雑種として分類すべきであると結論付けた.departmental bulletin pape