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Okuda S.,Kagoshima University | Okuda M.,Chiyoda Corporation | Sugiyama M.,National Institute of Vegetable and Tea Science | Sakata Y.,National Agriculture Research Center for Kyushu Okinawa Region | And 2 more authors.
European Journal of Plant Pathology | Year: 2013

Fifty-one melon (Cucumis melo) accessions that originated from India, Pakistan and Bangladesh were evaluated for resistance to Cucurbit chlorotic yellows virus (CCYV), a newly emerged species in the genus Crinivirus. CCYV was inoculated using sweet potato whitefly (Bemisia tabaci) biotype Q. Accessions, JP 138332, JP 216154, JP 216155, JP 216751 and JP 91204, showed no or faint symptoms, although CCYV was detected from the non-inoculated upper leaves by reverse transcription-polymerase chain reaction (RT-PCR). The five accessions were subjected to quantitative RT-PCR to analyze relative accumulation of CCYV RNA. All accessions except JP 138332 had levels of CCYV RNA accumulation comparable to the commercial variety, 'Earl's Seine', which was used as a control. JP 138332 showed a much lower CCYV RNA accumulation. Numbers of B. tabaci biotype Q on JP 138332 did not differ from 'Earl's Seine', in antixenosis tests, and the result suggested the resistance to CCYV was not due to antixenosis. Consequently, five accessions are of interest for development of resistant varieties. In particular, JP 138332 possesses a promising resistant trait for CCYV, which might be associated with inhibition of virus multiplication. © 2012 KNPV.

Toju H.,Kyoto University | Abe H.,Tohoku University | Ueno S.,Japan Forestry and Forest Products Research Institute | Miyazawa Y.,Kyushu University | And 3 more authors.
American Naturalist | Year: 2011

In nature, spatiotemporally dynamic coevolutionary processes play major roles in the foundation and maintenance of biodiversity. Here, we examined the arms race coevolution involving a seed-eating weevil with a long snout and its camellia plant host with a thick fruit coat (pericarp) throughout the marked climatic gradient observed across the Japanese islands. Results demonstrated that female weevils, which bored holes through camellia pericarps to lay eggs into seeds, had evolved much longer snouts than males, especially in areas in which Japanese camellia pericarps were very thick. The thickness of the plant pericarp was heritable, and the camellia plant evolved a significantly thicker pericarp on islands with the weevil than on islands without it. Across populations with weevils, resource allocation to plant defense increased with increasing annual mean temperature or annual precipitation, thereby geographically differentiating the evolutionary and ecological interactions between the two species. Given that the coevolutionary relationship exhibited appreciable variation across a relatively small range of annual mean temperatures, ongoing global climatic change can dramatically alter the coevolutionary process, thereby changing the ecological interaction between these species. © 2011 by The University of Chicago.

Kunihisa M.,National Institute of Vegetable and Tea Science
Journal of the Japanese Society for Horticultural Science | Year: 2011

The cultivated strawberry, Fragaria × ananassa (2n = 8x = 56), is an economically important crop in many regions of the world, and many breeding programs are competing to produce new, high-value cultivars. Despite this level of interest, marker-assisted selection of strawberry based on QTL analysis has lagged behind that of diploid crops because of its complex polyploidy and unclear genomic construction. During the past decade, great progress in the development of DNA markers has begun to overcome these difficulties, and the study of inheritance, mapping, and phylogeny is proceeding rapidly. Meanwhile, strawberry breeders have become much more aware of their rights with respect to the cultivars they have developed, as the volumes of harvested fruits that are transported globally have increased. To address the need to identify illegally grown strawberry fruits, genomics researchers have been required to develop simple and reproducible techniques for cultivar identification. This review summarizes the recent development of DNA marker studies in F. × ananassa, with a focus on the genome-specific markers we have developed. JSHS © 2011.

Tarutani Y.,Nara Institute of Science and Technology | Tarutani Y.,National Institute of Genetics | Shiba H.,Nara Institute of Science and Technology | Iwano M.,Nara Institute of Science and Technology | And 6 more authors.
Nature | Year: 2010

A diploid organism has two copies of each gene, one inherited from each parent. The expression of two inherited alleles is sometimes biased by the effects known as dominant/recessive relationships, which determine the final phenotype of the organism. To explore the mechanisms underlying these relationships, we have examined the monoallelic expression of S-locus protein 11 genes (SP11), which encode the male determinants of self-incompatibility in Brassica. We previously reported that SP11 expression was monoallelic in some S heterozygotes, and that the promoter regions of recessive SP11 alleles were specifically methylated in the anther tapetum. Here we show that this methylation is controlled by trans-acting small non-coding RNA (sRNA). We identified inverted genomic sequences that were similar to the recessive SP11 promoters in the flanking regions of dominant SP11 alleles. These sequences were specifically expressed in the anther tapetum and processed into 24-nucleotide sRNA, named SP11 methylation inducer (Smi). Introduction of the Smi genomic region into the recessive S homozygotes triggered the methylation of the promoter of recessive SP11 alleles and repressed their transcription. This is an example showing sRNA encoded in the flanking region of a dominant allele acts in trans to induce transcriptional silencing of the recessive allele. Our finding may provide new insights into the widespread monoallelic gene expression systems. © 2010 Macmillan Publishers Limited. All rights reserved.

Hirono H.,National Institute of Vegetable and Tea Science
Food Science and Technology Research | Year: 2016

We examined the dynamics of water-soluble pectin (WSP), specifically the content and molecular weight distribution, in tea leaves and tea infusions in relation to steaming time during unrefined tea processing. It was revealed that the fraction of higher-molecular weight (MW) WSP in tea leaves was infused at the beginning of unrefined tea processing at all steaming times, and lower-MW WSP was not infused during any processing steps. Moreover, by increasing steaming time, the increase of higher-MW WSP content in tea leaves was reflected by the increase in WSP content of corresponding size in the tea infusions. © 2016, Japanese Society for Food Science and Technology.

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