LABORATORY OF BIOLOGICAL DIVERSITYHOSHINO Group
Assistant Professor:
Technical Assistant:

HOSHINO, Atsushi
TAKEUCHI, Tomoyo
ITO, Kazuyo
KAWADA, SakiFigure 1. The duskish mutant of I. nil shows variable flower phenotypes
and produces variegated, fully pigmented, and pale grayish-purple flowers.
It segregates offspring that only show fully pigmented or pale grayishpurple flowers, which can be stably inherited by further generations.

Genomic structures and their genetic information are stablytransmitted into daughter cells and future generations during
cell division; however, they can vary genetically and/orepigenetically. Such variability impacts gene expression andevolution. To understand these genomic dynamics in eukaryotes, particularly in plants, we are analyzing the flower
pigmentation of morning glories, including Ipomoea nil(Japanese morning glory), I. purpurea (the common morningglory) and I. tricolor.

I. Flower pigmentation patterns

The wild type morning glories produce flowers with auniformly pigmented corolla. For our study, we collectedmutants displaying pigmentation patterns. Flower pigmentation patterns are easily observable and the molecular mechanisms underlying these phenomena provide useful modelsystems for investigating genomic variability.
Recessive mutations, duskish of I. nil and pearly-v of I.
tricolor, confer variegated flowers caused by a stable insertionof a transposable element into a gene for flower pigmentation,
regulated by epigenetic mechanisms (Figure 1). We intend toanalyze detailed molecular mechanisms of these mutations.

II. Whole-genome analysis of various I. nil lines

The National BioResource Project (NBRP) MorningGlory (described below) maintains ~3,500 lines, including 2 standard lines: the Tokyo Kokei Standard and Violet.
A high-quality draft whole-genome sequence of the Tokyo
Kokei Standard, which is accessible from our database, hasbeen published. The NBRP Genome Information Upgrading
Program supported whole-genome sequencing of 100 representative lines. We chose lines based on the needs of theresearch community and to provide information regarding
their polymorphisms and gene mutations. We included themultiple mutants called “Henka-Asagao,” which covered
the major mutations, and the wildtype plants isolated fromnatural populations outside Japan. From this, we discovereda total of 25,000 Tpn1 transposon-induced insertion polymorphisms and SNPs, Indels, and CNVs at 25 million loci.
Several of those polymorphisms were tightly linked to morphological mutations, including the mutations that “HenkaAsagao” carry.

Figure 2. The I. nil lines used for the whole-genome analysis. (a) Violet:
The most widely used standard line. (b) Africa: The wildtype line isolated in
Guinea in 1956. (c) Nepal: The wildtype line isolated by Dr. Sasuke Nakao
in Nepal in 1952. (d) Danjuro, one of the most popular cultivars, named after
the reddish-brown color of the costume used by Danjuro Ichikawa II in his
Kabuki play “Shibaraku.” (e) The tiny mutant has small organs. White spots
on the leaves are due to the variegated mutation. (f) A mutant line of “HenkaAsagao” showing double flowers with narrow flower petals and sepals.

III. Flower opening and time control

The time of flower opening is important for the reproductive strategy of plants, and many plants are known toflower at specific times during the day. However, little isknown about the molecular mechanisms that determine
flower opening time as well as flower opening itself. As
their name suggests, morning glories typically bloom in theearly morning. There is significant physiological knowledge
about the circadian rhythm that controls flower opening time.
To elucidate these molecular mechanisms, we have begun afunctional analysis of genes for petal opening and the circadian rhythm.

IV. Morning glory bio-resources

NIBB is the subcenter for the NBRP dedicated to morning
glories. In this project, we collect, maintain, and distributestandard and mutant lines for flower pigmentation and DNA
clones from EST and BAC libraries of I. nil and its relatedspecies. I. nil is one of the most popular floricultural plants inJapan and has a 100-year history of extensive related geneticstudies. Our collection includes 241 lines and 177,000 DNA
clones. The whole-genome sequence, the transcriptome

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National Institute for Basic Biology

Evolutionary Biology and Biodiversity

sequences, and the end sequences of the DNA clones can beviewed via the I. nil genome database (http://viewer.shigen.
info/asagao/index.php).

Publication List:〔Original paper〕

K., Furuta, T., Yamaji, N., Kuniyoshi, D., Ishihara, M.,• Nagaki,Kishima, Y., Murata, M., Hoshino, A., and Takatsuka, H. (2021).

Effectiveness of Create ML in microscopy image classifications: asimple and inexpensive deep learning pipeline for non-data scientists.
Chromosome Res. 29, 361–371. DOI: 10.1007/s10577-021-09676-z

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