著者

Daiki Matsumoto Ryohei Yamazaki Misato Kasai Satoshi Taira Ryutaro Tao

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-087, (Released:2023-07-19)

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Prunus fruit trees of the Rosaceae family exhibit S-RNase-based gametophytic self-incompatibility (GSI), which enables pistils to reject self-pollen by suppressing pollen tube elongation. In other plant species with S-RNase-based GSI, it has been shown that this suppression consists of two steps: first, slowing down of pollen tube elongation in the middle part of the style and second, complete arrest involving programmed cell death. To characterize the suppression pattern of incompatible pollen tubes in Prunus, we observed pollen tube elongation of ‘Satonishiki’ sweet cherry (Prunus avium) in ‘Satonishiki’ and ‘Rainier’ pistils on agar plates and ‘Satonishiki’ and ‘Rainier’ pollen tube growth in pistils on ‘Satonishiki’ cut branches. Incompatible selfed pollen tubes delayed penetration into the stigma in both experiments. Observation of pollen tubes in pistils on agar plates was difficult 24 h after pollination (HAP) due to wilting of the styles, while observing them on cut branches was possible up to 72 HAP. In the pistils on cut branches, ‘Satonishiki’ pollen tubes barely elongated in self pistils from 32 to 48 HAP when compatible ‘Rainier’ pollen tubes reached the base of a style, but resumed growth after 48 HAP and reached the base of the style. An RNase activity staining indicated that S-RNase was inactive 48 HAP. Finally, we observed pollen tube elongation in the style-grafted pistils on the cut branches. ‘Satonishiki’ pollen tube elongation was accelerated when the upper one-third of the self-pollinated styles was grafted onto compatible ‘Taishonishiki’ pistils. These results indicated that the suppression of incompatible pollen tube elongation in P. avium was consistently reversible. We discuss the suppression mechanism of incompatible pollen tube growth and the possibility of artificial control of Prunus self-incompatibility.

著者

Yutaro Osako Hisayo Yamane Ryunhee Kim Hisashi Miyagawa Ryutaro Tao

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-352, (Released:2022-05-19)

被引用文献数

1

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Seed size affects the edible portion rate of lychee fruit and is therefore an important trait for fruit quality in lychee (Litchi chinensis). Lychee fruits can be classified into four categories in terms of seed properties: normal, small, aborted seed and seedless. ‘Salathiel’ is known to bear a relatively high rate of aborted-seeded (pseudo-parthenocarpy, stenospermocarpy) and seedless (parthenocarpy) fruit regardless of environmental and cultivation conditions. In other horticultural fruit crops, such as tomato, auxin metabolism and signaling is critical for parthenocarpy, although auxin metabolism has not been characterized in relation to (pseudo) parthenocarpy in lychee. The purpose of this study was to characterize the physiological and morphological properties of maternal reproductive organs in ‘Salathiel’ female flowers, with a specific focus on the associated auxin metabolism. Microscopic observations of the internal structures of the ‘Salathiel’ embryo revealed that ‘Salathiel’ reproductive organ differentiation is similar to that of normal-seeded cultivars. However, the obturator was significantly smaller in ‘Salathiel’ than in other normal-seeded cultivars, suggesting that specific developmental characteristics may exist in the maternal reproductive organs of ‘Salathiel’. Our investigation of indole acetic acid (IAA) contents revealed that IAA levels were significantly higher in ‘Salathiel’ than in other cultivars. Moreover, the IAA metabolite contents also differed significantly between ‘Salathiel’ and the normal-seeded and small-seeded cultivars. Specifically, N-3-hydroxy-2-oxindole-3-acetyl glutamic acid contents were significantly higher in ‘Salathiel’ than in ‘Yu Her Pau’ and ‘Hei Ye’. 3-hydroxy-2-oxindole-3-acetic acid was lower in ‘Yu Her Pau’ and ‘Salathiel’ than in ‘Hei Ye’, while indole-acetylaspartic acid was significantly lower in ‘Salathiel’ compared to ‘Hei Ye’. Expression analyses of the genes related to auxin biosynthesis, catabolism, transport, and signaling indicated that the IAA influx-related and efflux-related gene expression levels were respectively higher and lower in ‘Salathiel’ than in the other cultivars, which is consistent with the increased IAA accumulation in the ‘Salathiel’ ovary. The possible involvement of auxin metabolism in the aborted-seeded and seedless fruit production in ‘Salathiel’ is discussed herein.

著者

Takuya Morimoto Takashi Akagi Ryutaro Tao

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-060, (Released:2015-04-04)

被引用文献数

14 24

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Flowering plants have developed a genetically determined self-incompatibility (SI) system to maintain genetic diversity within a species. The Solanaceae, the Rosaceae, and the Plantaginaceae have the S-RNase-based gametophytic SI (GSI) system, which uses S-RNase and F-box proteins as the pistil S and pollen S determinants, respectively. SI is associated with culture and breeding difficulties in rosaceous fruit trees, such as apple, pear, and stone fruit species; therefore, researchers in the pomology field have long studied the mechanism and genetics of SI in order to obtain clues to overcome these difficulties. Here, we investigated the evolutionary paths of the S-RNase genes by tracking their duplication patterns. Phylogenetic analysis and estimation of proxy ages for the establishment of S-RNase and its homologs in several rosaceous species showed that the divergence of S-RNase in the subtribe Malinae and the genus Prunus predated the gene in most recent common ancestors of Rosaceae species. Furthermore, the duplicated S-RNase-like genes were accompanied by duplicated pollen S-like F-box genes, suggesting segmental duplications of the S locus. Analysis of the expression patterns and evolutionary speeds of duplicated S-RNase-like genes in Prunus suggested that these genes have lost the SI recognition function, resulting in a single S locus. Furthermore, the S loci in the current Rosaceae species might have evolved independently from the duplicated S loci, which could explain the presence of genus-specific SI recognition mechanisms in the Rosaceae. The results of the present study should be valuable for the future development of artificial SI control and for self-compatible breeding in rosaceous horticultural plant species.

著者

Masafumi Omori Yosuke Fujiwara Hisayo Yamane Kenji Miura Ryutaro Tao

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-062, (Released:2023-06-14)

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Evaluating the function of genes expressed in fruit tissues of fruit tree species using a genetic transformation approach is a long process because the trees are generally recalcitrant to genetic transformation and cannot bear fruit during their long juvenile phases. Transient gene expression in fruit enables the functional analysis of genes associated with fruit traits, which may accelerate the study of fruit physiology. Here, by using the recently developed “Tsukuba system”, we successfully established an efficient transient expression system in harvested fruit tissues. The “Tsukuba system” utilizes a combination of the geminiviral replication system and a double terminator, which ensures sufficient levels of transgene expression. We used blueberry fruit as a model to characterize the applicability of this system for transient expression in fruit tissue. The pTKB3-EGFP vector was introduced by agroinfiltration into the fruit tissues of several blueberry cultivars. We found that transient GFP fluorescence in fruit peaked 4–6 days after agroinfiltration. Agrobacterium suspensions were easily injected into soft, mature fruit, and GFP was strongly expressed; however, hard, immature fruit were not penetrable by Agrobacterium suspensions, and GFP was rarely detected. We then tested the applicability of the developed system to other fruit tree species: six families, 17 species, and 26 cultivars. GFP fluorescence was detected in all species, except for Japanese apricot. In blueberry, bilberry, sweet cherry, apricot, and satsuma mandarin, GFP was highly expressed and observed in a large proportion of the flesh. In kiwifruit, hardy kiwifruits, persimmon, peach, apple, European pear, and grape, GFP fluorescence was limited to certain parts of the fruits. Finally, transient VcMYBA1 overexpression in blueberry was tested as a model for gene functional analysis in fruit. Transient VcMYBA1 overexpression induced red pigmentation in the flesh, suggesting that VcMYBA1 expression caused anthocyanin accumulation. This study provides a technical basis for the rapid evaluation of genes expressed in fruit, which will be useful for gene function evaluation studies in fruit crops with long juvenile phases.

著者

Kentaro Ono Kaho Masui Ryutaro Tao

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-002, (Released:2022-08-09)

被引用文献数

3

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Prunus (Rosaceae) includes many commercially important fruit crop species that exhibit self-incompatibility (SI), including sweet cherry (P. avium L.), Japanese apricot (P. mume Sieb. et Zucc.), Japanese plum (P. salicina Lindl.), apricot (P. armeniaca L.), and almond (P. dulcis [Mill.] D. A. Webb.). These species exhibit S-ribonuclease-based gametophytic SI, which prevents self-pollen tube growth in the pistil. The successful production of self-fertilized progeny accomplished by artificially overcoming the SI barrier has not been reported in Prunus, but self-compatible (SC) Prunus mutants with mutated pollen S determinant S haplotype–specific F-box (SFB) or pollen modifier M-locus encoded glutathione S-transferase-like (MGST) genes have been identified and used as SC cultivars and breeding stocks. In this study, we suppressed translation of SFB or MGST mRNA in self-pollen using antisense oligonucleotides to overcome the SI barrier in P. avium, P. mume, and P. salicina. Over the three years of the study, we obtained self-fertilized progeny of SI Japanese plum ‘Sordum’ only when SFB or MGST was knocked down. We also found that the average length of the self-pollinated pollen tube in the pistil of ‘Sordum’ was increased following treatment with an antisense oligonucleotide against SFB. This is the first report regarding the successful production of selfed progeny of Prunus obtained by disrupting SI. Our findings also provide evidence that the loss of function of SFB or MGST in Prunus pollen leads to SC.

著者

Soichiro Nishiyama Noriyuki Onoue Atsushi Kono Akihiko Sato Koichiro Ushijima Hisayo Yamane Ryutaro Tao Keizo Yonemori

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-140, (Released:2018-02-01)

被引用文献数

11

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Persimmon (Diospyros kaki) is a tree crop species that originated in East Asia, consists mainly of hexaploid individuals (2n = 6x = 90) with some nonaploid individuals. One of the unique characteristics of persimmon is the continuous accumulation of proanthocyanidins (PAs) in its fruit until the middle of fruit development, resulting in a strong astringent taste even at commercial fruit maturity. Among persimmon cultivars, pollination-constant and non-astringent (PCNA) types cease PA accumulation in early fruit development and become non-astringent at commercial maturity. PCNA is an allelic trait to non-PCNA and is controlled by a single locus called the ASTRINGENCY (AST) locus. Previous segregation analyses indicated that the AST locus shows hexasomic inheritance; a recessive allele, ast, at this locus confers PCNA. Here, we report a shuttle mapping approach to delimit the AST locus region in the hexaploid persimmon genome by using D. lotus, a diploid relative of D. kaki, as a reference. A D. lotus F1 population of 333 individuals and 296 D. kaki siblings segregating for the PCNA trait were used to map the AST region using haplotype-specific markers covering the AST region. This indicated that the AST locus is syntenic to an approximately 915-kb region of the D. lotus genome. In this 915-kb region, we found several candidates for AST that were revealed from the fruit transcriptome of a population segregating for the PCNA trait. These results could provide important clues for the isolation of AST in hexaploid persimmon.

著者

Daiki Matsumoto Ryutaro Tao

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-IR06, (Released:2016-04-27)

被引用文献数

2 44

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Prunus fruit tree species exhibit S-ribonuclease (S-RNase)-based gametophytic self-incompatibility (GSI). This system is also present in the families Plantaginaceae and Solanaceae and the tribe Maleae of the family Rosaceae. In S-RNase-based GSI, self/nonself-recognition between the pistil and pollen is controlled by the pistil S determinant S-ribonuclease gene (S-RNase) and the pollen S determinant F-box gene(s). Accumulated evidence indicates the Prunus pollen S locus contains a single F-box gene, while that of other plants consists of multiple F-box genes. The pollen S F-box genes are called S haplotype-specific F-box (SFB), S-locus F-box brothers (SFBB), and S-locus F-box (SLF) in Prunus, Maleae, and Solanaceae species, respectively. The consequences of pollen S gene mutations and heterodiallelic pollen production differ between Prunus species and other plants, suggesting there are different pollen S functions during self/nonself-recognition. The GSI systems of Prunus and other plants are believed to include the ubiquitin proteasome system for protein degradation. However, Prunus SFB is assumed to facilitate the S-RNase cytotoxic effects during self-recognition, while SLFs and SFBBs are thought to function collaboratively during nonself-recognition to avoid S-RNase cytotoxicity. This review summarizes the distinct features of the S-RNase-based GSI mechanism in Prunus species, with special references to the recent advances in our understanding of S-RNase-based GSI.

著者

Tsuyoshi Habu Hisayo Yamane Ippei Naito Soichiro Nishiyama Ayumi Nonaka Takashi Kawai Hisashi Yamada Ryutaro Tao

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-119, (Released:2016-02-09)

被引用文献数

8

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Japanese persimmon ‘Totsutanenashi’ (TTN) is a spontaneous small fruit mutant derived from ‘Hiratanenashi’ (HTN). To characterize the small fruit phenotype of TTN, we carried out a histological analysis, plant growth regulator treatments, and a transcriptome analysis using Illumina sequencing. The parenchymal cell number in TTN fruit was significantly less than in HTN fruit, and the parenchymal cell size in TTN fruit was also significantly smaller than that in HTN fruit at the later growing stage. However, the fruit size of TTN recovered by cytokinin treatments [50 or 200 ppm N-(2-chloro-4-pyridyl)-N′-phenylurea]. Thus, diminished cytokinin activity in TTN fruits may lead to less cell division in the early growing stage and less cell enlargement in the later growing stage. A large-scale transcriptome analysis was conducted using Illumina sequencing to determine the differences in gene expressions between TTN and HTN fruits. Illumina sequences were processed, resulting in 21,662,190 read pairs from HTN and 23,195,203 read pairs from TTN. After assembly of all sequences from HTN and TTN, 118,985 contigs (referred to as unigenes hereafter) ranging from 201 to 11,954 bases, with an average length of 915 bases, were obtained. Digital expression analyses revealed that the expression levels of 164 unigenes were significantly higher in HTN than in TTN, while the expression levels of 265 unigenes were significantly higher in TTN. A parametric analysis of gene set enrichment using the expression levels of unigenes showed that the biological process Gene Ontology categories of “cell cycle” and “regulation of cell cycle” were significantly down-regulated in TTN. The cell cycle-related differentially expressed genes included D3-type cyclin and Mitogen-Activated Protein Kinase Kinase Kinase. Based on the obtained results, the possible involvement of cell cycle-related genes in regulating the small fruit phenotype in TTN is discussed.