小原 均

Abstract 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 portion of ¹³C-photosynthates in the grapevine clusters that were fed ¹³CO₂; compared to the portion in the cluster in the untreated control. Fructose and glucose concentrations and the expressions of VvSWEET10, VvSUC11, and VvSUS4 in blue LED-irradiated berries were increased. The blue LED-irradiated berries’ sucrose concentrations were significantly lower than the untreated control at 14 days after treatment. We speculated that the blue LED-treated berries’ decreased sucrose was associated with the increased Sugars Will Eventually be Exported Transporter (VvSWEET10), sucrose transporter (VvSUC11), and sucrose synthase (VvSUS4) expressions and promoted the translocation of ¹³C-photosynthates from the leaves that were fed ¹³CO₂. Blue-LED irradiation increased the expressions of SNF1-related protein kinases (VvSnRK2.6) and ABA responding element binding transcription factor (VvABF1), while decreasing the expression of protein phosphateses 2C9 (VvPP2C9) genes, which are related to ABA signaling. Blue-LED irradiation increased the expressions of cryptochrome (VvCRYa) and phototropin (VvPHOT2), which are photoreceptor genes. The application of the pyrabactin resistance-like (PYL)-PP2C ABA receptor interaction antagonist AS6 did not affect endogenous ABA concentrations in the grape berries, but it decreased sucrose concentrations at harvest. The application of ABA did not affect sucrose, glucose, or fructose concentrations or the expressions of VvSnRK2.6 and VvPP2C9. The application of nordihydroguaiaretic acid (NDGA, an inhibitor of 9-cis-epoxycarotenoid dioxygenase activity in ABA biosynthesis) did not affect sugar concentrations at harvest. These results suggest that upregulation of photoreceptor gene expressions and ABA signaling are associated with sugar concentrations in grape berries.

Abstract 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 recognize prolonged chilling during the initial stage of bud dormancy. The vegetative axillary buds of the ‘Fuji’ apple, which shows typical low temperature-dependent, but not photoperiod, dormancy induction, were used for the chromatin structure and transcriptional change analyses. The results were integrated using a deep-learning model and interpreted using statistical models, including Bayesian estimation. Although our model was constructed using a small dataset of two time points, chromatin remodelling due to random changes was excluded. The involvement of most nucleosome structural changes in transcriptional changes and the pivotal contribution of cold-driven circadian rhythm-dependent pathways regulated by the mobility of cis-regulatory elements were predicted. These findings may help to develop potential genetic targets for breeding species with less bud dormancy to overcome the effects of short winters during global warming. Our artificial intelligence concept can improve epigenetic analysis using a small dataset, especially in non-model plants with immature genome databases.

The functions of l-isoleucine (Ile) in anthocyanin biosynthesis were investigated in apple fruit. Whole trees (Malus x 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 treatment (DAT). The expressions of MdUF3GT and MdMYB1 genes under the Ile and PDJ treatments were higher than those in the untreated control at 19 and 30 DAT. Endogenous JA and jasmonoyl-l-isoleucine (JA-Ile) concentrations in Ile- and PDJ- treated fruit were increased at 19 and 30 DAT. At 30 DAT, the Ile and PDJ treatments stimulated the expressions of MdJAR1, which is related to the conjugation of JA to Ile, and MdMYC2, which is a transcription factor in the JA response. Our study suggests that Ile can induce anthocyanin formation depending on the increase of JA-Ile production and the up-regulation of MdJAR1 and MdMYC2 in apples.

Persimmon Calyx is a crude drug derived from the persistent calyx of mature fruit of Diospyros kaki Thunberg (Ebenaceae) and is used for the treatment of intractable hiccups. Although there are several reports on the isolation of constituents from Persimmon Calyx, its active constituents have not been elucidated. In this study, by focusing on the medicinal part of Persimmon Calyx, calyx on mature fruit of D. kaki, we examined the changes in the extraction amounts of 3 cultivars of D. kaki ('Hiratanenashi', 'Jiro', and 'Tonewase') to identify and quantify seasonally variable constituents during the maturation process by analysing their chemical compositions. We found that the extraction weight of the calyx, fruit of persimmons, and total tannin content in calyxes were significantly increased during maturation. Lupeol (1), betulinic acid (2), pomolic acid (3), ursolic acid (4), beta-sitosterol (5), rotungenic acid (6), barbinervic acid (7), catechin (8), gallocatechin (9), and sucrose (10) were identified in the calyx of D. kaki. Compounds 1, 6, and 7 were isolated from Persimmon Calyx for the first time. Moreover, the isolated compounds (1-7) and their analogue (oleanolic acid) were quantitatively analysed, and the results showed that the amounts of 4 and oleanolic acid were reduced during maturation, whereas that of 2, 3, 6, and 7 were increased.

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 labruscaL. x Vitis viniferaL.) were sprayed with 100 mu M of Abz-E3M and subjected to water deficit conditions at the stage when their first leaves fully expanded. The physiological and morphological changes in the leaves and basal portions of the cuttings were determined. In Abz-E3M-treated leaves, lower ABA metabolite and higher ABA and indole-3-acetic acid (IAA) concentrations were observed. Compared to the untreated control leaves, higher water potential was significantly maintained in Abz-E3M-treated leaves. Abz-E3M applications resulted in lower proline accumulation and 2,2-diphenyl-2-picrylhydrazyl radical scavenging activity in the leaves and led to enhanced dehydration tolerance. In addition, the percentage of rooted cuttings was significantly increased by Abz-E3M application. In the basal portion of Abz-E3M-treated cuttings, endogenous IAA concentrations and the gene expressions ofVvARF6andVvARF8, which are positive regulators of adventitious root formation, were significantly increased. Moreover, the expression levels of the negative regulator,VvARF17,were significantly lower. These results suggested that the inhibition of ABA 8 '-hydroxylase enhanced dehydration tolerance and adventitious rooting and may be an effective strategy for achieving drought stress tolerance in grape cuttings.

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-apical shoot and gene expression in the apices of terminal shoots. Evident responses to PBZ were observed a fortnight after treatment, as the shoot and internode lengths were suppressed significantly. Endogenous indole-3-acetic acid increased in the PBZ treatment, and the polar auxin transporter genes MdPIN1 and MdLAX1 and the biosynthesis gene MdYUCCA10a were upregulated along with the MdARF2 gene. Additionally, PBZ increased the abscisic acid (ABA) concentration and the biosynthesis-related gene MdNCED1 but repressed the degradation gene MdCYP707A1. The ABA transporter gene MdAITb-like was upregulated by PBZ. The concentrations of the gibberellins (GAs) GA(1) and GA(4) decreased in the PBZ-treated rootstocks. The GA transporter gene MdNFP3.1-like and the signaling gene MdGID1b-like were strongly downregulated by PBZ, whereas the catabolic gene MdGA2OX2 was upregulated. PBZ treatment significantly reduced trans-zeatin (tZ) levels and downregulated the cytokinin biosynthesis gene MdIPT6 but upregulated the MdCKX7 degradation gene. Additionally, PBZ upregulated the cytokinin-related transporter genes MdPUP7-like and MdPUP9-like. Collectively, our results show that the physiological and molecular effect of PBZ was observed within two weeks, and this was indicated by the modulation of phytohormonal levels as well as transporter and other gene expression in Marubakaido apple rootstocks.

© 2019 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, and retarded the degradation of chlorophyll and the accumulation of carotenoids including β-carotene and lycopene through the expression of PmCHL (coding for chlorophyllase), PmGGPPS (coding for geranylgeranyl diphosphate synthase), PmPDS (coding for phytoene desaturase), PmPSY (coding for phytoene synthases), and PmLCYB (coding for lycopene beta-cyclase). NDGA inhibited the ABA synthesis through PmNCED1 and these results show that ABA may affect the ripening of the Japanese apricot by influencing ethylene production and the expression of PmACS (coding for ACC synthase), PmACO (ACC oxidase) and the ethylene-responsive gene PmERF (ethylene-responsive transcription factor), and thus that ethylene and ABA may interact during fruit ripening in climacteric fruit.

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-harvest applications of either n-propyl dihydrojasmonate (PDJ) (a JA analog) or KODA stimulated ethylene production and 1-aminocyclopropane-1-carboxylate (ACC) concentrations in fruit that were harvested at 88 and 102 DAFB. KODA application significantly increased levels of ACC oxidase (PpACO1) expression at 5 and 8 days after treatment (DAT) in 88-DAFB-harvested fruit, and at 1 DAT in 102-DAFB-harvested fruit. Expression levels of ethylene response factors (PpERS1) were not influenced by either PDJ or KODA applications at 88 or 102 DAFB. In contrast, levels of ethylene-receptor-coding genes (PpETR1) expression in 88-DAFB KODA-treated fruit increased at 8 and 14 DAT. Expression levels of constitutive triple response (PpCTR1) in the untreated control fruit decreased with DAT in both 88- and 102-DAFB-harvested fruit. These results suggest that certain oxylipins may promote ethylene production in peach fruit, and that PpETR1 and PpCTR1 may be associated with the autocatalytic system of ethylene production.

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 G family member-, NO VEIN-, and Auxin transporter-like protein 2-like genes, which are known to be associated with cellular auxin distribution and maintenance of root meristem niche, before the appearance of the first visible adventitious root formation in Marubakaido was revealed by quantitative RT-PCR. In addition, we conducted comprehensive co-expression network and MAPMAN analysis, and found a relationship between adventitious root formation and phytohormones such as cytokinin and abscisic acid (ABA). Finally, we also found the genes encoding receptor of plant peptide hormone, such as Barely any meristem 3-like gene (a receptor of plant peptide hormone CLAVATA45) and phloem intercalated with xylem-like gene (a receptor of the plant peptide hormone known as tracheary element differentiation inhibitory factor or TDIF), assuming the association of plant peptide hormone with adventitious root formation in Marubakaido apple rootstock. CLAVATA and TDIF are known as plant peptide hormones related to root stem cell and vascular differentiation, respectively. Therefore, we conclude that the process of adventitious root formation such as the maintenance of stem cell and vascular differentiation in Marubakaido apple rootstock was controlled by complex plant hormone signalling, including auxin, cytokinin, ABA, and plant peptide hormone.

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 mu M PDJ solution and then inoculated with B. cinerea. The fruit were stored at 25 degrees C and 95% relative humidity for 16 days after PDJ treatment. The inoculation without PDJ application (PDJ(-) Ino(+)) showed larger B. cinerea lesion diameters compared to the PDJ application with inoculation (PDJ(-) Ino(+)) and the untreated controls. In contrast, the PDJ(-) Ino(+) group showed a higher ethylene production rate, higher 1-aminocyclo-propane-1-carboxylic acid (ACC) concentration, and greater expressions of ethylene-related genes [MdACS1 (ACC synthase), MdACO1 (ACC oxidase), MdETR1 (Ethylene receptor 1), MdERS1 (Ethylene response sensor 1), and MdCTR1 (Constitutive triple response 1)], and endogenous JA, MdAOS1 (Allene oxide synthase 1) gene. However, the abscisic acid concentrations were decreased in the PDJ(-) Ino(+) group. The results suggest that PDJ application induces ethylene production through ethylene-related genes and endogenous JA, resulting in B. cinerea infection inhibition.

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. Transcriptional profiling revealed that 2218 genes in the grapes treated with IPT and 2270 genes in those treated with NDGA were differentially expressed compared to the untreated control grapes at 70days after full bloom (DAFB). IPT or NDGA application regulated the expression of genes involved in ABA, auxin, and ethylene metabolism. MapMan analysis and qRT-PCR validation showed that the expression levels of VvNCED1, VvCYP707A1, VvAAO4, and VvGEM-like genes in the ABA metabolic pathway were negatively regulated by IPT and NDGA treatment at 70 DAFB. Moreover, IPT and NDGA treatment inhibited glucose accumulation via the VvSUS, VvAI, VvHT genes in the sugar metabolic pathway. In addition, IPT and NDGA treatment delayed (E)-2-hexenal and hexanol productions, and down-regulated aroma metabolic pathway genes such as VvLOX, VvADH, VvGPPS, and VvTPS. These results suggest that IPT and NDGA influence chlorophyll degradation, ABA accumulation, and sugar and aroma volatile syntheses in the maturation process.

© 2018 International Society for Horticultural Science. All rights reserved. There is evidence that abscisic acid (ABA) and ethylene both play important roles in the physiological processes of grape maturation. However, the interaction between ABA and ethylene metabolism in grape maturation is unclear. We applied 50 μM (±) abscinazole-E3 (Abz, ABA 8'-hydroxylase inhibitor) or 500 μM ethephon to grape berries at 44 DAFB (days after full bloom). Grape berries were sampled at 44, 48, 54, 64, 94 DAFB. The ABA, ethylene concentrations and related gene expressions were analyzed. The results showed that Abz or ethephon treatment decreased the firmness and titratable acid concentration. Abz treatment inhibited VvCYP707A1 gene expression levels at 48 DAFB and increased endogenous ABA accumulation at 54 DAFB. Ethephon treatment significantly up-regulated VvNCED1 gene expression levels at 48 DAFB and VvCYP707A1 at 54 DAFB, but had no effect on ABA concentration. Ethylene and gene expression levels of VvACO1 and VvERF2 in Abz- and ethephon-treated berries at 48 DAFB were up-regulated. Abz or ethephon treatment also accelerated chlorophyll breakdown in berry skin with the up-regulation of VvPPH and VvRCCR gene expression levels. The total sugar concentrations slightly increased in both Abz- and ethephon-treated berries. These results suggest that Abz treatment before veraison can stimulate grape maturation by increasing endogenous ABA and the ethephon treatment can promote grape maturation similarly to Abz, through VvACO1 and VvERF2.

© 2018 International Society for Horticultural Science. All rights reserved. Salinity imposes stress on plant tissues that can lead to water deficits or ionspecific stresses resulting from altered ion ratios. The effect of exogenous ABA on 'Fuji' apple seedlings exposed to sodium chloride (NaCl) was analyzed by measuring parameters such as water potential, stomata aperture, sodium (Na+) concentration, endogenous abscisic acid (ABA), and total polyamines as well as genes related to their metabolism. The results show that damage to the leaf surface such as sunburn, yellowing and hardening of the leaves became more prominent compared to untreated controls (no ABA or NaCl) as treatment progressed. Regarding endogenous ABA levels, there was a significant difference at 5 days between the ABA+NaCl and NaCl groups. At the end of the treatment, the NaCl group showed higher levels of chlorophyll when compared to the untreated control and ABA+NaCl group. The stomata of the groups under stress showed recovery at the end of the treatment; however, the ABA+NaCl group response more closely resembled the status of the untreated, non-stressed control. Water potential levels dropped and stomata closure was apparent at 5 days for groups under stress; however, while the ABA+NaCl group displayed recovery as treatment continued, the NaCl group remained low even when the plants had recovered from the initial shock. Total polyamine levels were higher for the ABA+NaCl group after ABA application and then decreased with time, whereas that for the NaCl group was higher after stress began, peaking at 5 and 10 days. Taken together, ABA, PA and gene activations suggest that the early response to stress induced by ABA might have helped the seedlings overcome it more efficiently.

© 2018 Elsevier B.V. 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 generation sequencing to assemble RNA-seq data. Anthocyanin accumulation in ABA- and Abz-treated berry peels increased compared with the untreated control. ABA and Abz application affected anthocyanin biosynthesis genes in different ways. At 15 DAT, ABA application significantly upregulated MYB113-like, bZIP42-like, and UGT85A2-like genes, while Abz application significantly induced bZIP42-like gene expression only. Additionally, significant induction of DNA methylation levels of the MYB113-like gene was found in ABA application, which was correlated with heightened accumulation of anthocyanin concentrations in ABA-treated berry peels. Moreover, ABA application decreased the chlorophyll a/b ratio and suppressed the expressions of LHCA1-like and LHCB3-like genes, while Abz application did not affect these genes. The results suggest that exogenous ABA and endogenous ABA influence grape coloration via different pathways.

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 MdBCAT1) during ripening of 'Orin' apple. ABA application also promoted the production of ethylene, and caused ethylene peak shifts correlated with the expression of ethylene synthesis genes (MdACS1/3 and MdACO1), suggesting that ABA may act jointly with ethylene as a positive regulator at the ripening stage of 'Orin' apple. Additionally, endogenous levels and expression of biosynthesis (MdNCED1) and signal transduction genes (MdABF2-like) of ABA increased towards ripening. Finally, the localization of the putative MdABF2-like protein binding element, AREB/ABF, was observed in the 5'-upstream region of MdACS1/3 and MdACO1.

In deciduous trees, including apples (Malus x domestica Borkh.), lipid accumulation in the meristem region towards endodormancy induction has been thought to be an important process for the acquisition of cold tolerance. In this study, we conducted histological staining of crude lipids in the meristem region of 'Fuji' apples and found that lipid accumulation coincided with endodormancy induction. Since a major component of lipid bodies (triacylglycerol) is esterified fatty acids, we analysed fatty acid-derived volatile compounds and genes encoding fatty acid-modifying enzymes (MdLOX1A and MdHPL2A); the reduction of lipid breakdown also coincided with endodormancy induction. We then characterised the expression patterns of lipid body-regulatory genes MdOLE1 and MdLIP2A during endodormancy induction and found that the expression of MdLIP2A correlated well with lipid accumulation towards endodormancy induction. Based on these results, we conducted chromatin remodelling studies and localized the cis-element in the 5'-upstream region of MdLIP2A to clarify its regulatory mechanism. Finally, we revealed that chromatin was concentrated - 764 to - 862 bp of the 5'-upstream region of MdLIP2A, which harbours the GARE [gibberellin responsive MYB transcription factor binding site] and CArG [MADS-box transcription factor binding site] motifs-meristem development-related protein-binding sites.

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 (MdCYP707A) genes. Water potential and stomatal aperture in the leaves treated with Abz-E2B and NaCl (Abz-E2B(+)NaCl(+) group) were lower than those in the untreated controls, but remained higher than those in the leaves treated with NaCl alone (Abz-E2B(-)NaCl(+) group). Endogenous ABA levels were higher in the Abz-E2B(+)NaCl(+) leaves at 4 days after treatment, whereas those in the Abz-E2B(-)NaCl(+) leaves increased with time and peaked at 12 days after treatment. Expressions of the MdNCED1 and MdNCED2 genes remained lower in Abz-E2B(+)NaCl(+) compared with Abz-E2B(-)NaCl(+) leaves, especially at 12 days after treatment. Proline levels increased sharply at 100-mM NaCl, and Na+ levels increased with time. The Na+ concentrations in the Abz-E2B(-)NaCl(+) leaves increased fourfold compared to those in the Abz-E2B(+)NaCl(+) leaves. The expressions of MdCYP707A1 and MdCYP707A2 were higher in Abz-E2B(+)NaCl(+) at 4 days, but declined at 12 days. The present data suggest that the increased endogenous ABA during the early stages of Fuji apple cultivation under salinity-stress conditions might be a good approach to prevent long-lasting damage and allow plants to recover.

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 mu L.L(-1)ethephon or 100 mu mol.L-1 ABA, and the expression levels of chlorophyll synthase (AcCLS), chlorophyllase1 (AcCLH1), polygalacturonase (AcPG), expansin (AcEXP), beta-amylase (Ac beta-AM), sucrose synthase (AcSUSY), MADS-box SEPALLATA4/RIPENING INHIBITOR-like (AcSEP4/RIN) and FRUITFUL-like (AcTDR4/FUL) genes were analyzed. The expression levels of AcPG, AcEXP, Ac beta-AM, and AcSUSY increased in the ethephon-treated fruit, but those of AcCLH1 at 6 and 9 days after treatment and AcCLS decreased. Moreover, the expression levels of AcSEP4/RIN and AcTDR4/FUL, the latter of which is associated with ethylene biosynthesis, were higher in the ethephon-treated fruit. The expression level of each gene in ABA-treated fruit was not significantly different from that of the untreated control. The results suggest that ethephon application increases the expression levels of AcPG, AcEXP, Ac beta-AM, AcSUSY, AcSEP4/RIN, and AcTDR4/FUL in 'Kohi' kiwifruit on the vine.

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 mu L/L ethephon, 100 mu mol ABA, or 100 mu mol NDGA. The fruits were sampled at 0, 3, 6, 9, and 12 days after treatment (DAT), and the following were analyzed at each time point: ethylene production, 1-aminocyclopropane-1-carboxylate (ACC) and ABA concentrations, ACC synthase (ACS) and ACC oxidase (ACO) activities, volatile compounds (n-hexanal and (E)-2-hexexnal), and the expressions of AcACS1, AcACO1, and 9-cis-epoxycarotenoid dioxygenase 1 (AcNCED1) genes. ABA concentrations and AcNCED1 gene expression increased in ABA-treated fruit. Malic acid concentrations and fruit firmness decreased in ethephon-treated fruit, but soluble solids concentrations (SSC), ethylene biosynthesis, and both AcACS1 and AcACO1 gene expressions increased. The accumulated fruit drop rate in ethephon-treated fruit was 4% at the edible stage at 9 DAT. Moreover, the production of n-hexanal and (E)-2-hexexnal decreased in ethephon-treated fruit. These results suggest that 'Kohi' kiwifruit may be ripened by on-vine ethephon application at 9 DAT, thus obviating ripening treatment after harvest. (C) 2016 Elsevier B.V. All rights reserved.

© 2015, Springer Science+Business Media Dordrecht. 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 grapes cultivated in the ordinary growing season were highest in red-LED-treated skin. The expressions of 9-cis-epoxycarotenoid dioxygenase (VvNCED1) and ABA 8′-hydroxylase (VvCYP707A1) were high in each treatment at veraison regardless of the growing season. In both seasons, anthocyanin concentrations were highest under the blue-LED treatment, followed by the red-LED treatment. The expressions of VlMYBA1-2, VlMYBA2, and VvUFGT coincided with anthocyanin concentrations. Sugar concentrations were increased by the blue-or red-LED treatment dependent on the growing season. The results suggest that blue- or red-LED irradiation at night may influence the ABA and anthocyanin metabolism including VvNCED1, VlMYBA1-2, and VlMYBA2 and sugar synthesis in grape berries, although the degree of the effects differs with the growing season.

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 VlMYBA1-2 and VlMYBA2 at veraison were higher in blue- and red-LED- treated skin. Therefore, the expressions of VlMYBA1-2 and VlMYBA2 at veraison may significantly influence the anthocyanin productions. An increase in sugars was also observed in blue- and red-LED-treated skin. The results suggest that the blue and red LED irradiation at night may be effective at increasing anthocyanin and sugar concentrations in delayed-start cultured grapes under a double-cropping cultivation system. The results also suggest interactions among ABA, anthocyanin and sugar syntheses.

Effects of alpha-ketol linolenic acid (KODA) application on endogenous abscisic acid (ABA), jasmonic acid (JA), and aromatic volatiles were investigated in 'Kyoho' grapes (Vitis labrusca x Vitis vinifera) infected by a pathogen (Glomerella cingulata). The expressions of 9-cis-epoxycarotenoid dioxygenase (VvNCED1), ABA 8'-hydroxylase (VvCYP707A1), lipoxygenase (VvLOX), and allene oxide synthase (VvAOS) were also examined. The grape berries were dipped in 0.1 mM KODA solution before inoculation with the pathogen and stored at 25 degrees C for 12 days. The development of infection was significantly suppressed upon KODA treatment. Endogenous ABA, JA and phaseic acid (PA) were induced in inoculated berries. KODA application before inoculation increased endogenous ABA, PA and JA through the activation of VvNCED1, VvCYP707A1 and VvAOS genes, respectively. In addition, terpenes, methyl salicylate (Me-SA) and C-6-aldehydes such as (E)-2-hexenal and cis-3-hexenal associated with fungal resistance also increased in KODA-treated berries during storage. These results suggest that the synergistic effect of JA, ABA, and some aromatic volatiles induced by KODA application may provide resistance to pathogen infection in grape berries. (C) 2016 Elsevier GmbH. All rights reserved.

The effects of the application of the jasmonic acid (JA) derivative n-propyl dihydrojasmonate (PDJ) on lesion diameter, endogenous abscisic acid (ABA), phaseic acid (PA), JA, aroma volatiles, and antioxidant activity were investigated in grapes infected by the pathogen Glomerella cingulata. The berries were immersed in 0.4 mM PDJ solution before inoculation with the pathogen and stored at 25 degrees C for 12 days. Lesion diameters from the pathogen decreased upon PDJ application. Endogenous ABA and JA concentrations increased in inoculated 'Kyoho' grape berries (Vitis Iabrusca x Vitisvinifera). PDJ application before inoculation increased ABA and PA concentrations, perhaps through the activation of Vitis vinifera and VvCYP707A1 genes. The results suggest that the synergistic effect of JA and ABA may play a role in the defense mechanism against pathogen infection in grape berries. In addition, PDJ application generally increased the production of aldehydes, esters, and terpenes. These volatiles may also be associated with resistance to pathogen infection. (C) 2015 Elsevier B.V. All rights reserved.

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. Endogenous ABA, its metabolite phaseic acid (PA), and the expressions of VvNCED1 and VvCYP707A1 were highest in red light-emitting diode (LED)-treated skin. In contrast, anthocyanin concentrations were highest in blue LED-treated skin, followed by red LED treatment. However, the expressions of VlMYBA1-2, VlMYBA2, and VvUFGT did not necessarily coincide with anthocyanin concentrations. The quality of coloring may depend on the amount of malvidin-based anthocyanin, which increased toward harvest in blue and red LED-treated skin, unlike in untreated controls. An increase in sugars was also observed in blue and red LED-treated skin.These results suggest that blue LED irradiation at night may be effective in increasing anthocyanin and sugar concentrations in grape berries. However, there is evidence that another factor may influence anthocyanin concentrations in grape berry skin significantly more than endogenous ABA: ABA concentrations were highest in red LED-treated skin, which had lower anthocyanin concentrations than blue LED-treated skin. (C) 2014 Elsevier GmbH. All rights reserved.

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 an analog of KODA, on flower bud formation and the expression of MdTFL1 (terminal flower I) and MdFT1 (flowering locus t 1) genes in apple buds were investigated in heavy-crop treatment (HCT) and under shade. An increase of endogenous KODA in the buds. in the fruit-thinning treatment, which resulted in a higher proportion of flower bud formation than in HCT, was observed at 63 days after full bloom, but no such increase was found in HCT. In the shade-treated and heavy-crop trees, the expression of MdTFL1 in the buds to which CKODA was applied was lower than that in untreated buds. In contrast, under shade, the expression of MdFT1 in the CKODA-treated buds was higher than that in untreated buds. These results suggest that endogenous KODA may be associated with flower bud formation, and its application may be effective at improving the proportion of flower bud formation through its effect on MdTFL1 and MdFT1.

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 application did not influence endogenous gibberellic acid (GA) concentrations in apical buds. These results show that KODA may be related to flower bud formation through its influence on MdTFL1.

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 investigated under dehydration and rehydration conditions. The stomatal aperture decreased up to 4 h after spraying with Abz-F1 and the stomatal aperture in the Abz-F1-treated leaves was generally lower than that in the untreated control-leaves during the dehydration condition. Although the water potential in untreated control-leaves decreased with the progress of dehydration, it was maintained at a higher level in the Abz-F1 treated-leaves than in the untreated control-leaves during dehydration. Endogenous ABA concentrations increased with dehydration in both the Abz-F1 treated- and untreated-control-leaves, but the ABA levels in the Abz-F1 treated-leaves were higher than those in the untreated control-leaves throughout dehydration. In contrast, the phaseic acid (PA) concentrations in the Abz-F1 treated-leaves were lower than those in the untreated control-leaves during dehydration. The expressions of MdNCEDs in the Abz-F1 treated-leaves were lower than those in the untreated control-leaves regardless of the higher endogenous ABA concentrations. Moreover, the expressions of MdCYP707As in the Abz-F1 treated-leaves were also lower than those in the untreated control-leaves. Higher 50% effective concentrations (EC50) and ascorbic acid concentrations were observed in the Abz-F1 treated-leaves, which show that the oxidative damage under dehydration may be reduced by Abz-F1 application.These results suggest that prompt stomata closure is required for survival under dehydration, and Abz-F1 application may therefore be of practical use. The increase of endogenous ABA, which induced prompt stomata closure in Abz-F1 treated-leaves may depend on inhibition of the expression of MdCYP707As. Furthermore, the results showed the close relationship between MdNCEDs and MdCYP707As on ABA catabolism. (C) 2011 Published by Elsevier GmbH.

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 PDJ solution before inoculation with the pathogen and stored at 25 C for 6 days. The inoculation induced an increase in 1-aminocyclopropane-1-carboxylic acid (ACC), ethylene, JA, and MeJA. In contrast, PDJ application reduced the endogenous JA, MeJA, and ethylene production and expression of the ACC oxidase gene (PmACO1) caused by the pathogen infection. The lesion diameter with C. gloeosporioides decreased upon PDJ application. The alcohol, ester, ketone, and lactone concentrations and alcohol acyltransferase (AAT) activity increased in the pathogen-infected fruit, but were decreased by PDJ application. These results suggest that PDJ application might influence ethylene production through PmACO1 and that aroma volatile emissions affected by pathogen infection can be correlated with the ethylene production, which is mediated by the levels of jasmonates.

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 the UV-C treated leaves were generally higher than those in the untreated control. Although the endogenous ABA concentrations were not significantly different between the untreated control and UV-C treatment, the endogenous jasmonic acid, putrescine, and spermine concentrations in the UV-C treated plants were higher than those in the untreated control. However, the application of PDJ before UV treatment inhibited the rise of endogenous jasmonate and putrescine concentrations. The increase of ascorbic acid was also inhibited by PDJ application before UV treatment. These facts suggest that the increase of jasmonates and polyamines may be associated with UV-C stimulation, and UV-C irradiation may be effective for increasing antioxidant activity in apple leaves. © 2010 Springer Science+Business Media B.V.

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 were higher than those in heavy crop treatment (HCT). In contrast, GA concentrations [the total of GA1 and GA4] in FTT were lower than those in HCT. The application of KODA increased the flower bud formation rate in 7-year-old trees, but not in 4-year-old and 18-year-old trees grafted onto M.9EMLA rootstock. These results are inconclusive but demonstrate that KODA may influence flower bud formation in apples.

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 higher than those in plants subjected to heavy crop treatment (HCT), under which the number of leaves per fruit was adjusted to 20 from 60 to 120 days after full bloom (DAFB). In contrast, the gibberellic acid concentrations [total of gibberellin A1 (GA1) and gibberellin A4 (GA4)] in FTT plants were low compared with those in HCT plants. The result suggests that KODA and JA in contrast to GAs may have opposite effects on flower bud formation which is significantly influenced by fruit load in apples and that KODA and JA may also be associated with flower bud formation in apples. © 2010 Elsevier B.V. All rights reserved.

The effect of diniconazole, an inhibitor of cytochrome P450, on drought tolerance was examined in 'Shiranui' [(Citrus unshiu Marc. x Citrus unshiu Osbeck) x Citrus reticulate Blanco] trees. Diniconazole treatment increased abscisic acid (ABA) concentration in leaves compared with untreated controls in water-stressed conditions after 20 days of water-stress treatment. Diniconazole significantly decreased the stomatal aperture at 9 h after application compared with untreated controls in water-stressed conditions. The photosynthetic rate decreased in water-stressed conditions; however, regardless of the earlier stomatal closure induced by diniconazole application, the decrease of photosynthetic rate was delayed by the application. (C) 2008 Elsevier B.V. All rights reserved.