Satoru Kondo

Chiba University · Graduate School of Horticulture

Various attempts have been made to use abscisic acid (ABA) as a plant bioregulator (PBR). Recently, a new ABA formulation, produced through microbial fermentation, has been commercialized in Japan as a PBR for improving grape peel color. Nonetheless, the horticultural application of ABA remains limited compared to other plant hormones. Generally, t...

The effects of blue-light irradiation on abscisic acid (ABA) signaling, sugar metabolism and translocation, and photoreceptors and gene expressions were investigated to clarify the mechanism by which blue-LED irradiation increases sugar concentrations in grape berries (Vitis labruscana L.). Blue light-emitting diode (LED) irradiation increased the...

Epigenetic changes serve as a cellular memory for cumulative cold recognition in both herbaceous and tree species, including bud dormancy. However, most studies have discussed predicted chromatin structure with respect to histone marks. In the present study, we investigated the structural dynamics of bona fide chromatin to determine how plants reco...

To elucidate the inhibitory effect of ethephon on the occurrence of water-soaked disorder in Japanese pear ‘Akizuki’ (Pyrus pyrifolia Nakai) fruit, we sprayed fruits with 100 mg·L⁻¹ ethephon solution approximately 120 DAFB in the 2012, 2014, 2015, 2016, and 2017 seasons. Ethephon treatment reduced the incidence and degree of water-soaked disorder a...

We have previously reported that the application of- used as isoprothiolane (IPT), a fungicide against rice blast- 20 to 30 days before harvest improved peel color in satsuma mandarin fruit (Citrus unshiu Marcow). However, the mechanism by which IPT improves peel coloration is not yet fully understood. This study examined the effects of IPT on plan...

Artificial pollination is essential in pears (Pyrus spp.) for stable fruit set and the production of high-quality fruit. Low temperatures in the early spring before bud flowering can damage pear pollen and pose a special risk to pollen production for artificial pollination. In this study, we sought to identify, in pears, the flower bud stage most s...

The functions of isoprothiolane (IPT), which is a fungicide against rice blast, in carotenoid accumulation were examined in satsuma mandarin fruit ( Citrus unshiu Marc). Whole trees were treated with IPT at 25 days before harvest. Concentrations of gibberellic acid-1 (GA 1 ) and GA 4 in the flavedo of IPT-treated trees were significantly decreased...

Plant hormones are associated with many physiological aspects in fruit tree growth and fruit production. Since jasmonates (jasmonic acid (JA) and methyl ester of JA (MeJA)), which are oxylipins from linolenic acid, were found in plants including fruits, many physiological and molecular actions of jasmonates to regulate fruit development and stress...

The accumulation of abscisic acid (ABA) is considered a crucial signal for the onset of berry maturation in grape berry, including ‘Kyoho’ (Vitis labruscana L.). Therefore, the delay of grape berry maturation, especially of peel coloration, by applying an ABA inhibitor (nordihydroguaiaretic acid, NDGA) to berry clusters has been investigated in var...

Green mold caused by Penicillium digitatum is an important factor limiting the shelf life of mandarin fruit. In this study, the effect of ultraviolet-C (UV-C) irradiation on cellular structure, endogenous jasmonic acid (JA), and development of P. digitatum in satsuma mandarin fruit was investigated. UV-C treatments included 0 (untreated control), 3...

The functions of l-isoleucine (Ile) in anthocyanin biosynthesis were investigated in apple fruit. Whole trees (Malus × domestica Bokh.) were treated with Ile or n-propyl dihydrojasmonate (PDJ), which is a jasmonic acid (JA) analog, 20 and 30 days before harvest. Both Ile and PDJ treatments stimulated anthocyanin formation at 30 and 35 days after tr...

The effects of an inhibitor (Abz-E3M) of abscisic acid (ABA) 8′-hydroxylase, which is a primary enzyme of ABA catabolism, on dehydration tolerance and root formation in grape cuttings under drought conditions were investigated. Cuttings of ‘Kyoho’ grape (Vitis labrusca L. × Vitis vinifera L.) were sprayed with 100 μM of Abz-E3M and subjected to wat...

To examine the dwarfing mechanism in apples, one-year-old Marubakaido (Malus prunifolia Borkh.) (invigorating) apple rootstock stools were foliar-sprayed with 860 mg L⁻¹ of paclobutrazol (PBZ) as a single application or without. M.9 apple rootstock (dwarf) was used as a positive control. The phytohormones were estimated in the shoot bark and sub-ap...

Great progress has been made during the last decade in clarifying the molecular details of aroma accumulation in grape berries. However, the multigene complex controlling monoterpene accumulation in grape is not well understood. To shed light on this issue, the grapes of 149 F1 progenies from the cross 87-1 (Vitis vinifera L.) × 9-22 (Vitis vinifer...

Red pulp color of Tubtim-Siam pummelo (Citrus maxima Burm.) is a distinct specific characteristic, which is the preferred in the international market. This present study aimed to determine (1) the influence of tree age on carotenoid accumulation during fruit development, and (2) the carotenoid profile and related biosynthesis gene expression in “Tu...

The effects of bagging-induced light reductions on lycopene synthesis and the expression of related genes, antioxidant activity, and sugar composition of ‘Tubtim Siam’ pummelo ( Citrus maxima ) were investigated. Glucose, ascorbic acid, and flavonoid concentrations and 2, 2-diphenyl-1-picryhydrazyl scavenging activity were decreased in fruit covere...

In this study, changes in gene transcription during adventitious root formation in hardwood cuttings of Marubakaido apple rootstock were examined by RNA-seq analysis. In line with above, 11 genes related to root development were identified as candidate genes for modulator of adventitious root formation. Among them, the induction of ABC transporter...

The Japanese apricot (Prunus mume Sieb. et Zucc.) is a typical climacteric fruit which loses commercial value during processing when the surface color turns yellow. In our study, treatment with nordihydroguaiaretic acid (NDGA), an abscisic acid (ABA) synthesis inhibitor, delayed the increase of ethylene and decrease of firmness towards ripening, an...

Considering the economic importance of grape (Vitis spp.), breeding for downy mildew (P. viticola) resistance has made great progress in the last two decades. However, the genetic and genomic information of resistance against grape downy mildew remain largely unknown. In this study, we described the quantitative trait loci (QTL) and candidate genes...

The effects of isoprothiolane (IPT: a fungicide used to control rice blast) and nordihydroguaiaretic acid (NDGA: an inhibitor of the phytohormone abscisic acid (ABA) biosynthesis) on the maturation of “Shine Muscat” grape berries were investigated. The results showed that IPT and NDGA retarded chlorophyll degradation in the berry skin. Transcriptio...

The effects of the jasmonic acid derivative n-propyl dihydrojasmonate (PDJ) on ethylene signal transduction and endogenous jasmonic acid (JA) in apples infected with Botrytis cinerea (gray mold) were investigated. Apples were dipped into 400 μM PDJ solution and then inoculated with B. cinerea. The fruit were stored at 25°C and 95% relative humidity...

Physico-chemical and quality changes in 72 sugar apple (Annona squamosa Linn.) fruits subjected to pre-harvest drought stress were analyzed at harvest and during storage at 10 °C or 15 °C, with 90–95% relative humidity. At harvest, the ascorbic acid, sugar and endogenous abscisic acid concentrations increased while the concentration of the substrat...

Abscisic acid (ABA) or Abscinazole (Abz), which is the specific inhibitor of CYP707A and induces endogenous ABA, was applied to ‘Kyoho’ grape berries at 30 days after full bloom (DAFB), and 37 DAFB (veraison). The RNAs were extracted from the grape berry peels, which were sampled at 15 and 45 days after treatment (DAT), and analyzed using next gene...

The effects of two oxylipins – jasmonic acid (JA) and 9, 10-ketol-octadecadienoic acid (KODA) – on ethylene metabolism and ethylene receptor genes were examined in peach fruit (Prunus persica L.) harvested at 88 days after full bloom (DAFB), in the pre-climacteric stage, and at 102 DAFB, at the beginning of the climacteric stage. Immediate post-har...

The production of aromatic volatiles such as esters during the ripening process in climacteric fruits is known to be controlled by ethylene. However, we here show that abscisic acid (ABA) application accelerated the onset of short-chain ester production (hexyl propionate, ethyl-2-methyl butyrate) and the expression of biosynthesis genes (MdAAT2 and...

Key message: We found that lipid accumulation in the meristem region and the expression of MdLIP2A, which appears to be regulated by chromatin remodeling, coincided with endodormancy induction in the 'Fuji' apple. In deciduous trees, including apples (Malus × domestica Borkh.), lipid accumulation in the meristem region towards endodormancy inducti...

The effects of applying abscisic acid (ABA), Abz (abscinazole, an inhibitor of CYP707A), and nordihydroguaiaretic acid ((NDGA), an inhibitor of 9-cis-epoxycarotenoid dioxygenase (NCED)) on fruit firmness, anthocyanin biosynthesis, aroma volatiles, and their related genes were investigated in grape berries (Vitis vinifera L. × Vitis labrusca L. cv....

The effects of an ABA 8′-hydroxylase inhibitor, (±)abscinazole-E2B (Abz-E2B), were examined in “Fuji” apple seedlings exposed to sodium chloride (NaCl). Water potential, stomata aperture, and endogenous ABA, proline, and sodium (Na⁺) levels were analyzed, along with expression of the 9-cis-epoxycarotenoid dioxigenase (MdNCED) and ABA 8′-hydroxylase...

The effects of ethephon and abscisic acid (ABA) application on ripening-related genes of pre-harvest ‘Kohi’ kiwifruit (Actinidia chinensis) were studied to clarify the possibility of the fruit ripening on the vine. The fruits were treated on the vine at mature stage with 250 µL⋅L⁻¹ ethephon or 100 µmol⋅L⁻¹ ABA, and the expression levels of chloroph...

Apples are rich source of phenolic compounds exhibiting a strong antioxidant activity. Although type 2 red-fleshed apples highly accumulate health-promoting anthocyanins, accumulation profiles of other phenolic compounds had not been investigated. The objective of this study was to characterize the accumulation profiles of eight phenolic compounds...

The effects of ethephon, abscisic acid (ABA), and nordihydroguaiaretic acid (NDGA) application on the ripening of pre-harvest ‘Kohi’ kiwifruit (Actinidia chinensis) were studied. The fruits were treated on-vine at 155 days after full bloom (DAFB) (mature stage) with 250 μL/L ethephon, 100 μmol ABA, or 100 μmol NDGA. The fruits were sampled at 0, 3,...

Introduction. Anthocyanins are a group of flavonoids, and their synthesis is influenced by external and internal factors such as light, temperature, phytohormones and sugar concentration. A high anthocyanin concentration, which is related to redder coloration, is one of the factors of high-quality fruit. The effects of LED irradiation on the anthoc...

The effects of blue- and red-light irradiation at night on abscisic acid (ABA) synthesis, anthocyanin and sugar concentrations were examined in delayed-start cultured grapes under a double-cropping cultivation system. ABA and anthocyanin concentrations increased in skin treated with blue and red light-emitting diodes (LED) and the expressions of Vl...

Effects of α-ketol linolenic acid (KODA) application on endogenous abscisic acid (ABA), jasmonic acid (JA), and aromatic volatiles were investigated in ‘Kyoho’ grapes (Vitis labrusca × V. Vinifera) infected by a pathogen (Glomerella cingulata). The expressions of 9-cis epoxycarotenoid dioxygenase (VvNCED1), ABA 8′-hydroxylase (VvCYP707A1), lipoxyge...

The effects of red- and blue-light irradiation at night on abscisic acid (ABA) synthesis and anthocyanin and sugar concentrations were examined in grape vines, which were grown in two different seasons. In grapes cultivated with early heating, the ABA concentrations were highest in blue-light-emitting diode (LED)-treated skin; however, those in gra...

The effects of an abscisic acid (ABA) 8'-hydroxylase inhibitor (ABAI) on ABA catabolism, stomatal aperture, and water potential were investigated in apple seedlings under dehydration conditions. In addition, 9-cis-epoxycarotenoid dioxygenase (MdNCED) and ABA 8'-hydroxylase (MdCYP707A) genes were isolated and their expressions were analyzed under de...

The effects of blue and red light irradiation at night on abscisic acid (ABA) metabolism and anthocyanin synthesis were examined in grape berries. The expressions of VlMYBA1-2, VlMYBA2, UDP-glucose-flavonoid 3-O-glucosyltransferase (VvUFGT), 9-cis-epoxycarotenoid dioxygenase (VvNCED1), and ABA 8′-hydroxylase (VvCYP707A1) were also investigated. End...

Fruit developmental changes in abscisic and jasmonic acid contents of dragon fruit (Hylocereous undatus) Abstract The changes in abscissic acid (ABA) and jasmonic acid (JA) contents during fruit development of dragon fruit (Hylocereus undaatus) were determined. Associated changes in respiration, 1-aminocyclopropane-1-carboxylic acid (ACC) contents,...

The changes in abscissic acid (ABA) and jasmonic acid (JA) contents during fruit development of dragon fruit (Hylocereus undaatus) were determined. Associated changes in respiration, 1-aminocyclopropane-1-carboxylic acid (ACC) contents, and sugar levels were also measured. ACC content and respiration rate were high at early fruit development stages...

Oxylipins are derived from lipoxygenase-dependent oxidation of fatty acid. We investigated the effects of two kinds of oxylipins such as 9,10-Ketoloctadecadienoic acid (KODA) and jasmonates on fruit maturation including ethylene production in pre-climacteric apple fruit. ACC oxidase activities and ethylene production in KODA-treated fruit were high...

We have succeeded in isolating an MdMYB110a_JP gene responsible for a red-fleshed trait from a fruit of apple cultivar ‘JPP35’ (‘Jonathan’ × ‘Pink Pearl’). The isolated MdMYB110a_JP gene was located on chromosome (ch.) 17, which was different from the location of known MdMYB1/10 gene of ch.9, and ‘JPP35’ and ‘Pink Pearl’ did not contain the known R...

Changes of endogenous 9, 10-ketol-octadecadienoic acid (KODA) concentrations, which is synthesized from linolenic acid by 9-lipoxygenase, were analyzed in apple [Malus xsylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] buds. In addition, the effects of 15, 16-chloro, hydroxy-9-hydroxy-10-oxo-12(Z)-octadecenoic acid (CKODA) application, which is...

Suppression subtractive hybridization (SSH) was employed to identify candidate genes involved in red coloration in apple peel with the UV-B-treated 'Mutsu'. After reverse Northern blotting verification, nearly 80 clones were successfully sequenced. Large portions of the ESTs are well-characterized anthocyanin biosynthesis-related genes, such as cha...

The relationship between internal browning (IB) and changes in endogenous abscisic acid (ABA), endogenous gibberellin (GA) [gibberellin A1 (GA1), gibberellin A3 (GA3) and gibberellin A4 (GA4)] concentrations were investigated using pineapples (Ananas comosus L. Merr; cv. Trad-see-thong and cv. Pattavia). The fruits were subjected to three different...

We investigated the effect of 9,10-ketol-octadecadienoic acid (KODA), which is synthesized from linolenic acid by 9-lipoxygenase, on 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase gene expression, their enzyme activities, and ethylene production in apple fruit [Malus sylvestris (L.) Mill. Var. domestica (Borkh.) Mansf.]. The fruit...

The effects of a-ketol-octadecadienoic acid (KODA) application on the expression of MdTFL1 and MdFT1 genes were investigated in 'Fuji' apple trees (Malus domestica Borkh.). KODA application decreased the expression of MdTFL1 at 49 days after full bloom (DAFB), but it did not have a clear effect on the expression of MdFT1 from 21 to 91 DAFB. KODA ap...

The effects of an abscisic acid (ABA) 8′-hydroxylase inhibitor (Abz-F1) on ABA catabolism, stomatal aperture, and water potential were examined in apple seedlings under dehydration and rehydration conditions. In this study, 9-cis-epoxycarotenoid dioxigenase (MdNCED) and ABA 8′-hydroxylase (MdCYP707A) genes were isolated and their expressions were i...

The effects of the application of the jasmonic acid derivative n-propyl dihydrojasmonate (PDJ) on ethylene biosynthesis, volatile compounds, and endogenous jasmonic acid (JA) and methyl jasmonate (MeJA) were examined in Japanese apricot (Prunus mume Sieb.) infected by a pathogen (Colletotrichum gloeosporioides). The fruit were dipped into 0.4 mM PD...

The effect of UV-C irradiation on jasmonates, abscisic acid (ABA), polyamines and antioxidant activities was investigated in apple plants (Malus domestica Borkh.). The EC50 values of O2 –-scavenging activity in the UV-C treated leaves were lower than those in the untreated control. In addition, total ascorbic acid and polyphenolic concentrations in...

Jasmonates (jasmonic acid and methyl jasmonate) could regulate ethylene biosynthesis. The expression of the ACC synthase (ACS) 1 and ACC oxidase (ACO) 1 genes increased in pears (Pyrus communis L.) treated by n-propyl dihydrojasmonate (PDJ) at the preclimacteric stage. However, the accumulations of ACS1 mRNA decreased in the fruit treated by PDJ at...

We developed abscinazole-E1 (Abz-E1), a specific inhibitor of abscisic acid (ABA) 8'-hydroxylase (CYP707A). This inhibitor was designed and synthesized as an enlarged analogue of uniconazole (UNI), a well-known plant growth retardant, which inhibits a gibberellin biosynthetic enzyme (ent-kaurene oxidase, CYP701A) as well as CYP707A. Our results sho...

Jasmonates [jasmonic acid (JA) and methyl jasmonate (MeJA)] are linolenic acid-derived compounds. n-Propyl dihydrojasmonate (PDJ), a JA derivative, has been used to improve fruit quality in Japan. In apples (Malus sylvestris L.), PDJ application increased fruit coloration in the field by stimulating the anthocyanin biosynthetic gene MdUFGluT. Jasmo...

The relationship between the levels of 9,10-ketol octadecadienoic acid (KODA) and flower bud formation in apples (Malus domestica Borkh) was investigated. KODA and gibberellic acid (GA) had opposite changes during flower bud formation. KODA concentrations in the apical bud in flower thinning treatment (FTT) with a higher flower bud formation rate w...

The changes of xyloglucan and polyuronide during fruit development and storage in 'Khakdam' papayas (Carica papaya L.) were examined. Xyloglucan, water-soluble pectic substances (WSP), and hexametaphosphate-soluble pectic substance (HMP) did not change in the skin during fruit development, although fruit firmness decreased gradually toward the ripe...

The effects of fruit load, shading, and 9, 10-ketol-octadecadienoic acid (KODA) application on the expression of MdTFL1 and MdFT1 genes were investigated in apples (Malus domestica Borkh.). The expression of MdTFL1 in apical buds from 21 to 63days after full bloom (DAFB) in plants subjected to heavy crop treatment (HCT) was higher than that in plan...

The relationship between 9,10-ketol-octadecadienoic acid (KODA), GAs and jasmonic acid (JA) and flower bud formation influenced by fruit load in apples (Malus domestica Borkh.) was investigated. The endogenous KODA and JA concentrations in apical buds in plants subjected to flower thinning treatment (FTT), under which all flowers were removed were...