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Dive into the research topics where Masaki Yahata is active.

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Featured researches published by Masaki Yahata.


Plant Physiology | 2013

Enzymatic formation of β-Citraurin from β-Cryptoxanthin and Zeaxanthin by Carotenoid Cleavage Dioxygenase4 in the Flavedo of Citrus Fruit

Gang Ma; Lancui Zhang; Asami Matsuta; Kazuki Matsutani; Kazuki Yamawaki; Masaki Yahata; Anung Wahyudi; Reiko Motohashi; Masaya Kato

The biosynthesis of β-citraurin from β-cryptoxanthin and zeaxanthin contribute to the reddish peel color of citrus fruits. In this study, the pathway of β-citraurin biosynthesis, carotenoid contents and the expression of genes related to carotenoid metabolism were investigated in two varieties of Satsuma mandarin (Citrus unshiu), Yamashitabeni-wase, which accumulates β-citraurin predominantly, and Miyagawa-wase, which does not accumulate β-citraurin. The results suggested that CitCCD4 (for Carotenoid Cleavage Dioxygenase4) was a key gene contributing to the biosynthesis of β-citraurin. In the flavedo of Yamashitabeni-wase, the expression of CitCCD4 increased rapidly from September, which was consistent with the accumulation of β-citraurin. In the flavedo of Miyagawa-wase, the expression of CitCCD4 remained at an extremely low level during the ripening process, which was consistent with the absence of β-citraurin. Functional analysis showed that the CitCCD4 enzyme exhibited substrate specificity. It cleaved β-cryptoxanthin and zeaxanthin at the 7,8 or 7′,8′ position. But other carotenoids tested in this study (lycopene, α-carotene, β-carotene, all-trans-violaxanthin, and 9-cis-violaxanthin) were not cleaved by the CitCCD4 enzyme. The cleavage of β-cryptoxanthin and zeaxanthin by CitCCD4 led to the formation of β-citraurin. Additionally, with ethylene and red light-emitting diode light treatments, the gene expression of CitCCD4 was up-regulated in the flavedo of Yamashitabeni-wase. These increases in the expression of CitCCD4 were consistent with the accumulation of β-citraurin in the two treatments. These results might provide new strategies to improve the carotenoid contents and compositions of citrus fruits.


Journal of Agricultural and Food Chemistry | 2012

Effect of Blue and Red LED Light Irradiation on β-Cryptoxanthin Accumulation in the Flavedo of Citrus Fruits

Gang Ma; Lancui Zhang; Masaya Kato; Kazuki Yamawaki; Yoshikazu Kiriiwa; Masaki Yahata; Yoshinori Ikoma; Hikaru Matsumoto

β-Cryptoxanthin (β-cry), an antioxidant abundant in citrus fruits, plays an important role in the prevention and treatment of certain diseases, especially cancers. In the present study, to increase the content of β-cry in citrus flavedo, the effects of blue (470 nm) and red (660 nm) light-emitting diode (LED) lights on the accumulation of carotenoids and expression of genes related to carotenoid biosynthesis were investigated in the flavedo of Satsuma mandarin. The results showed that accumulation of β-cry was induced by red light, while it was not affected by blue light. The accumulation of β-cry under red light was attributed to simultaneous increases in the expression of CitPSY, CitPDS, CitZDS, CitLCYb1, CitLCYb2, CitHYb, and CitZEP. The results presented herein might provide new strategies to enhance the commercial and nutritional value of citrus fruits.


BMC Plant Biology | 2016

Expression and functional analysis of citrus carotene hydroxylases: unravelling the xanthophyll biosynthesis in citrus fruits

Gang Ma; Lancui Zhang; Witchulada Yungyuen; Issei Tsukamoto; Natsumi Iijima; Michiru Oikawa; Kazuki Yamawaki; Masaki Yahata; Masaya Kato

BackgroundXanthophylls are oxygenated carotenoids and fulfill critical roles in plant growth and development. In plants, two different types of carotene hydroxylases, non-heme di-iron and heme-containing cytochrome P450, were reported to be involved in the biosynthesis of xanthophyll. Citrus fruits accumulate a high amount of xanthophylls, especially β,β-xanthophylls. To date, however, the roles of carotene hydroxylases in regulating xanthophyll content and composition have not been elucidated.ResultsIn the present study, the roles of four carotene hydroxylase genes (CitHYb, CitCYP97A, CitCYP97B, and CitCYP97C) in the biosynthesis of xanthophyll in citrus fruits were investigated. Phylogenetic analysis showed that the four citrus carotene hydroxylases presented in four distinct clusters which have been identified in higher plants. CitHYb was a non-heme di-iron carotene hydroxylase, while CitCYP97A, CitCYP97B, and CitCYP97C were heme-containing cytochrome P450-type carotene hydroxylases. Gene expression results showed that the expression of CitHYb increased in the flavedo and juice sacs during the ripening process, which was well consistent with the accumulation of β,β-xanthophyll in citrus fruits. The expression of CitCYP97A and CitCYP97C increased with a peak in November, which might lead to an increase of lutein in the juice sacs during the ripening process. The expression level of CitCYP97B was much lower than that of CitHYb, CitCYP97A, and CitCYP97C in the juice sacs during the ripening process. Functional analysis showed that the CitHYb was able to catalyze the hydroxylation of the β-rings of β-carotene and α-carotene in Escherichia coli BL21 (DE3) cells. Meanwhile, when CitHYb was co-expressed with CitCYP97C, α-carotene was hydroxylated on the β-ring and ε-ring sequentially to produce lutein.ConclusionsCitHYb was a key gene for β,β-xanthophyll biosynthesis in citrus fruits. CitCYP97C functioned as an ε-ring hydroxylase to produce lutein using zeinoxanthin as a substrate. The results will contribute to elucidating xanthophyll biosynthesis in citrus fruits, and provide new strategies to improve the nutritional and commercial qualities of citrus fruits.


Journal of The American Society for Horticultural Science | 2005

Morphological Characterization and Molecular Verification of a Fertile Haploid Pummelo (Citrus grandis Osbeck)

Masaki Yahata; Seiichi Harusaki; Haruki Komatsu; Kayo Takami; Hisato Kunitake; Tsutomu Yabuya; Kensuke Yamashita; Pichit Toolapong


Postharvest Biology and Technology | 2015

Effect of the combination of ethylene and red LED light irradiation on carotenoid accumulation and carotenogenic gene expression in the flavedo of citrus fruit

Gang Ma; Lancui Zhang; Masaya Kato; Kazuki Yamawaki; Yoshikazu Kiriiwa; Masaki Yahata; Yoshinori Ikoma; Hikaru Matsumoto


Journal of The American Society for Horticultural Science | 2005

Production of a doubled haploid from a haploid pummelo using colchicine treatment of axillary shoot buds

Masaki Yahata; Hisato Kunitake; Tsutomu Yabuya; Kensuke Yamashita; Yukiko Kashihara; Haruki Komatsu


Journal of The Japanese Society for Horticultural Science | 2010

Production of haploid plant of 'Banpeiyu' pummelo [Citrus maxima (Burm.) Merr.] by pollination with soft X-ray-irradiated pollen.

Masaki Yahata; Kiichi Yasuda; Kohji Nagasawa; Seiichi Harusaki; Haruki Komatsu; Hisato Kunitake


Journal of The American Society for Horticultural Science | 2006

Production of Sexual Hybrid Progenies for Clarifying the Phylogenic Relationship between Citrus and Citropsis species

Masaki Yahata; Hisato Kunitake; Kiichi Yasuda; Kensuke Yamashita; Haruki Komatsu; Ryoji Matsumoto


Journal of The Japanese Society for Horticultural Science | 2005

Evaluation of Reproductive Functions in a Haploid Pummelo by Crossing with Several Diploid Citrus Cultivars

Masaki Yahata; Hironori Kurogi; Hisato Kunitake; Katsuya Nagano; Tsutomu Yabuya; Kensuke Yamashita; Haruki Komatsu


Horticultural Research (japan) | 2004

Effect of Colchicine and Oryzalin Treatments on Tetraploid Production of Nucellar Embryos in Meiwa Kumquat (Fortunella crassifolia Swingle)

Masaki Yahata; Yukiko Kashihara; Hironori Kurogi; Hisato Kunitake; Haruki Komatsu

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