著者

Nobuhiro Kotoda Satoshi Matsuo Ichiro Honda Kanako Yano Tokurou Shimizu

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-085, (Released:2015-11-28)

被引用文献数

13

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Satsuma mandarin (Citrus unshiu Marc.) has two GA 20-oxidase genes, CuGA20ox1 and CuGA20ox2, and the genomic sequence for CuGA20ox1 is shorter than that for CuGA20ox2, although the coding region of cDNA for CuGA20ox1 is slightly longer than that for CuGA20ox2. Southern blot analysis revealed that 12 Citrus cultivars examined and trifoliate orange [Poncirus trifoliata (L.) Raf.] have at least two types of GA 20-oxidase genes, such as CuGA20ox1 and CuGA20ox2 genes. CuGA20ox1 and CuGA20ox2 were differentially expressed in various tissues. CuGA20ox1 was expressed in almost all of the tissues investigated with relatively higher expression in vegetative than in reproductive tissues, whereas CuGA20ox2 was specifically expressed in flower buds just before anthesis. These distinct expression patterns of CuGA20ox1 and CuGA20ox2 imply that function of these two genes diverged in the process of evolution. The specific and relatively higher expression of CuGA20ox2 in flower buds would explain why GA-like activity was higher in Satsuma mandarin’s ovaries at anthesis. Transgenic Arabidopsis [Arabidopsis thaliana (L.) Heynh] plants ectopically expressing CuGA20ox1 or CuGA20ox2 were examined to elucidate the function of these two Satsuma mandarin genes. Phenotypic analysis revealed that both CuGA20ox1 and CuGA20ox2 caused elongated inflorescence but did not affect the timing of flowering in transgenic Arabidopsis as compared with wild-type controls. Ectopic expression of CuGA20ox1 and CuGA20ox2 significantly affected the levels of GA24 and GA34 on the non-13-hydroxylation pathway; GA24 decreased and GA34 increased. This observation indicates that both CuGA20ox1 and CuGA20ox2 accelerated the conversion of GA24, a substrate of a GA 20-oxidase, to GA9, a precursor of an active form of GA4. Likewise, on the early-13-hydroxylation pathway, ectopic expression of CuGA20ox1 significantly decreased GA19 and increased GA29 and GA8, inactive metabolites of 2-hydroxylation of GA20 and GA1, respectively, suggesting the activation of this biosynthetic pathway. CuGA20ox2 also had a tendency to activate the early-13-hydroxylation pathway although it increased only GA20 with a statistically significant difference. Taken together, we concluded that CuGA20ox1 and/or CuGA20ox2 activated both the early-13- and non-13-hydroxylation pathways for increasing active GAs, resulting in elongated inflorescences in transgenic Arabidopsis.

著者

Inna Martha Rumainum Kanjana Worarad Yoshikazu Yamaki Kenji Yamane

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-077, (Released:2015-11-21)

被引用文献数

6

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A red-fleshed peach (Prunus persica L. Batsch ‘Tenshin Suimitsuto’; ‘Tianjinshuimi’ in Chinese) was used to study the mechanisms of skin and flesh pigmentation. Anthocyanin accumulation was detected at the pre-endocarp-hardening and maturation stages in skin, while it appeared from maturation stage in flesh. The flesh at harvest stage contained approximately 1.1 mg·g−1 FW of anthocyanin. In contrast, flavonoid and phenolic compounds were found in all stages. The final phenolics concentration was 1.6 mg·g−1 FW. To study the effects of light, fruits were on-tree bagged in double-layered paper bags. The total anthocyanin content in the skin was significantly lowered by bagging, but not in the flesh. This suggested that flesh tissue pigmentation was less sensitive to light intensity than that of skin tissue, and thus, anthocyanin accumulation in flesh occurred even under low light conditions. Dark treatments, such as triple-layered paper bagging, significantly reduced anthocyanin and phenolic concentrations in the skin and flesh. A combined treatment of darkness and an auxin polar transport inhibitor, 2,3,5-triiodobenzoic acid (TIBA), had no effect on anthocyanin concentration in skin and flesh. However, total flavonoids in the skin was increased by TIBA treatments under darkness. Factors affecting anthocyanin accumulation in the flesh tissue are discussed.

著者

Yuka Takatori Keiichi Shimizu Jun Ogata Hiroki Endo Kanji Ishimaru Shigehisa Okamoto Fumio Hashimoto

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-029, (Released:2015-03-07)

被引用文献数

3 7

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A full-length cDNA of a putative flavonoid 3'-hydroxylase (F3'H) gene encoding a key enzyme in the production of cyanidin was cloned from a lisianthus (Eustoma grandiflorum) petal. Lisianthus F3'H (EgF3'H) shares 75.1, 73.8, and 68.2% amino acid identity with Arabidopsis thaliana, Ipomoea nil, and Petunia hybrida, respectively. RT-PCR revealed that wild-type lisianthus flowers accumulated higher levels of F3'H mRNA during the early stages of development than in the late stages. The accumulated F3'H transcript levels in leaves were similar to those in flowers in the early stages of development. Overexpression of lisianthus F3'H cDNA altered flower color from red to blue in the I. nil cultivar ‘Violet’, which lacks a functional F3'H gene. In addition, the transgenic ‘Violet’ plants accumulated cyanidin and peonidin at similar levels to wild-type I. nil. Taking these findings together, this study demonstrates that EgF3'H functions as a flavonoid 3'-hydroxylase with a role in the synthesis of cyanidin and peonidin pigments.

著者

Kazuma Okada

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-IR04, (Released:2015-04-02)

被引用文献数

1 5

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Japanese pear (Pyrus pyrifolia Nakai) is an important Rosaceous fruit tree in Japan. This species exhibits gametophytic self-incompatibility (GSI), which is controlled by a single S-locus with multiple S-haplotypes. Although GSI is a genetic mechanism to prevent inbreeding and promote outcrossing to maintain genetic diversity, it can be problematic in fruit trees because it causes unstable fruit set. Therefore, orchardists interplant Japanese pear with other lines as pollinizers or conduct artificial pollination to ensure fruit set. To achieve stable fruit production and to reduce or eliminate the need for artificial pollination, research on the GSI of Japanese pear has been conducted by pollination experiments and by characterization of self-compatible (SC) mutants. Additionally, breeding programs have progressed to produce SC cultivars with high fruit quality. Recently, molecular analyses of GSI and SC mutants in Japanese pear have provided new information that is relevant to the stable fruit production and efficient breeding of Japanese pear. This review focuses on studies of the GSI of Japanese pear, and especially on the recent development of DNA markers for S-genotyping and marker-assisted selection of SC trees. In addition, the candidate genes controlling pollen S specificity and a model of the molecular mechanism of GSI in Japanese pear are described.

著者

So Sugiyama Shigeru Satoh

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-025, (Released:2015-02-21)

被引用文献数

7

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2,4-Pyridinedicarboxylic acid (2,4-PDCA) was shown to prolong the vase life of cut flowers of spray-type ‘Light Pink Barbara’ (LPB) carnation, mainly due to the reduced ethylene production caused by inhibition of 1-aminocyclopropane-1-carboxylate oxidase in the flowers. In addition, 2,4-PDCA has been suggested to accelerate flower opening in the flowers (Satoh et al., 2014). In the present study, we successfully developed a procedure to evaluate the activity of chemicals to accelerate flower (bud) opening by determining the shortened time (in days) to flower opening. Using this procedure, we could show the activities of several PDCA analogs to accelerate flower opening, in addition to their already-known activity to extend the vase life in cut flowers of ‘LPB’ carnation. Judging from their effectiveness in the acceleration of flower opening and extension of vase life, 2,3-PDCA and 2,4-PDCA were thought to be suitable agents for treatment of the flowers. The present study confirmed that PDCAs accelerate flower opening and retard senescence, which increase the number of open flowers, resulting in extension of the vase life of cut flowers of ‘LPB’ carnation.

著者

Tadahisa Higashide Ken-ichiro Yasuba Takeshi Kuroyanagi Akimasa Nakano

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-010, (Released:2015-02-21)

被引用文献数

3 24

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To investigate the mechanism of yield increase by elevated carbon dioxide (CO2) and fogging in Japanese tomato cultivars (Solanum lycopersicum), total above-ground dry matter (TDM), fraction of dry matter distribution to fruit (FDF), and photosynthetic characteristics were measured in 3 Japanese cultivars grown in elevated CO2 with fogging and ambient CO2 without fogging. Fresh fruit yield and TDM were improved by the elevated CO2 and fogging in the 3 Japanese cultivars. Light use efficiency (LUE) was also increased by the elevated CO2 and fogging. No significant decrease in FDF was observed by the elevated CO2 and fogging in 2 Japanese cultivars, ‘Asabiyori 10’ and ‘Junkei Aichi Fast’. Thus, the increase in TDM by higher LUE contributed directly to the yield increase in these 2 cultivars. However, FDF in ‘Momotaro York’ was decreased significantly by the elevated CO2 and fogging. Thereby, the yield increase by the elevated CO2 and fogging was diminished in ‘Momotaro York’ in spite of the increase in TDM. The number of trusses having immature fruit in ‘Momotaro York’ under elevated CO2 and fogging was significantly higher than those of the others, although no increase in the number of trusses having immature fruit was observed in the other 2 cultivars. Although vegetative growth characteristics such as leaf area, LAI, and fresh and dry weights of leaves and stem were increased by the elevated CO2 and fogging, no negative effects such as a change in light-extinction coefficient and a decrease in maximum photosynthetic rate were observed. The elevated CO2 and fogging increased the number of harvested fruit but decreased weight per fruit, namely, fruit size, in the 3 cultivars.

著者

Hiroshi Iwanami Yuki Moriya-Tanaka Chikako Honda Masato Wada

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.CH-112, (Released:2015-02-21)

被引用文献数

1 2

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The thinning of flowers or fruit is an essential part of the commercial production of quality apples. Although chemical thinners are generally used in apple orchards throughout the world, hand-thinning remains essential for controlling crop load to improve fruit quality and return bloom. The objectives of this study were to investigate factors that determine the time required for hand-thinning and to elucidate cultivar-related efficiency of hand-thinning. In all cultivars, the time taken for hand-thinning per cluster became shorter after petal fall, but the degree of this decrease differed among cultivars. The time taken for hand-thinning depended on both how much and when natural abscission of fruitlets occurred. The times required for hand-thinning were very similar among clusters with four, five, or six flowers/fruitlets, which was twice as long as that required for clusters with two or three flowers/fruitlets. This means that the time required for hand-thinning clusters is critically reduced when the number of flowers/fruitlets within a cluster is three or fewer. The time required for hand-thinning clusters of axillary buds became significantly longer from bloom to 7 days after bloom, and then decreased gradually from 7 to 25 days after bloom. When the proportion of clusters with three or fewer fruitlets is 50% at 15 days after bloom, the planting area of the cultivar that a person is able to hand-thin (six hours per day) from 10 to 30 days after bloom was 24.3 a, which was 40% larger than that of a cultivar in which the proportion of clusters with three or fewer fruitlets is 50% at 30 days after bloom (17.4 a). Therefore, the introduction of cultivars in which fruit abscission occurs at an early stage and on a large scale is a solution for reducing the labor costs of hand-thinning.