Biology subjects

Kawamitsu, M.

Publications and source records attributed to Kawamitsu, M..

3 recordsLinked to original sources

bioRxiv2025

De novo genome assembly of an interspecific hybrid grapevine 'Maeve'

The grapevine is one of the most ancient and economically important horticultural crops in the world. The grapevine species Vitis vinifera is cultivated globally; however, due to its susceptibility to pathogens and environmental stresses, wild Vitis species and their hybrids are often used as rootstocks in vineyards. Here, we report the genome analysis of a Vitis strain named Maeve, which was identified in a vineyard in Japan, though its genetic origin remains unclear. We performed haplotype-resolved de novo assembly of the Maeve genome using PacBio HiFi sequencing and Hi-C assembly. Our genome analysis revealed that Maeve has originated from an interspecific hybridization between an unknown V. vinifera cultivar and the V. riparia Gloire cultivar, likely arising through breeding or natural pollination. This novel cultivar has a potential to expand wine grape production across a wider range of environmental conditions where conventional cultivars are unsuitable for viticulture.

plant biology↗

bioRxiv2023

A genome and tissue-specific transcriptomes of the large-polyp coral, Fimbriaphyllia (Euphyllia) ancora: Recipe for a coral polyp

Coral "polyps" are composed of several tissues; however, their characteristics are largely unexplored. Here we report biological characteristics of the four tissues that comprise polyps: tentacle (Te), mesenterial filament (Me), body wall (Bo), and mouth with pharynx (MP), using comparative genomic, morpho-histological, and transcriptomic analyses of the large-polyp coral, Fimbriaphyllia ancora. A draft F. ancora genome assembly of 434 Mbp was created. Morpho-histological and transcriptomic characterization of the four tissues showed that they have distinct differences in structure, primary cellular composition, and transcriptional profiles. Tissue-specific, highly expressed genes (HEGs) of Te are related to biological defense, predation, and coral-algal symbiosis. Me expresses multiple digestive enzymes, whereas Bo expresses innate immunity and biomineralization-related molecules. Many receptors for neuropeptides and neurotransmitters are expressed in MP. The established dataset and new insights into tissue functions will facilitate a deeper understanding of coral biology.

genomics↗

bioRxiv2020

Color morphs of the coral, Acropora tenuis, show different responses to environmental stress and different expression profiles of fluorescent-protein genes

Corals of the family Acroporidae are key structural components of reefs that support the most diverse marine ecosystems. Due to increasing anthropogenic stresses, coral reefs are in decline. Along the coast of Okinawa, Japan, three different color morphs of Acropora tenuis have been recognized for decades. These include brown (N morph), yellow-green (G) and purple (P) forms. The tips of axial coral polyps exhibit specific fluorescence spectra. This attribute is inherited asexually, and color morphs do not change seasonally. In Okinawa Prefecture, during the summer of 2017, the N and P morphs experienced bleaching, in which some N morphs died while P morphs recovered. In contrast, G morphs successfully withstood the stress. Symbiotic dinoflagellates are essential symbiotic partners of scleractinian corals. Photosynthetic activity of symbionts was reduced in July in N and P morphs; however, the three color-morphs host similar sets of Clade-C zoothanthellae, suggesting that beaching of N and P morphs cannot be attributed to differences in symbiont clades. The decoded Acropora tenuis genome includes five genes for green fluorescent proteins (GFP), two for cyan fluorescent proteins (CFP), three for red fluorescent proteins (RFP), and seven genes for chromoprotein (ChrP). A summer survey of gene expression profiles demonstrated that (a) expression of CFP and REP was quite low in all three morphs, (b) P morphs expressed higher levels of ChrP, (c) both N and G morphs expressed GFP highly, and (d) GFP expression was reduced in N morphs, compared to G morphs, which maintained higher levels of GFP expression throughout the summer. Although further studies are required to understand the biological significance of these color morphs of Acropora tenuis, our results suggest that thermal stress resistance is modified by genetic mechanisms that coincidentally lead to diversification of color morphs.

evolutionary biology↗