Biology subjects

Divashuk, M.

Publications and source records attributed to Divashuk, M..

3 recordsLinked to original sources

bioRxiv2023

Melanin found in wheat spike husks

Melanin is the dark polymer pigment found in all kingdoms of life. Plant melanin, formed through the oxidation and polymerization of phenolic compounds, does not contain nitrogen, however it possesses similar properties with melanin of animal, fungal or bacterial origin. Melanin in plants is usually found in seed coats or fruit pericarp and is ascribed mechanical barrier or some other protective functions. Wild and formerly locally cultivated wheat species, like Persian wheat (Triticum carthlicum Nevski) frequently exhibit black color of spike husks and awns. The pigment causing it and the biological purpose of this coloration was not clarified before. In this paper using standard chemical extraction procedures for anthocyanins and melanin, ultraviolet-visible-near-infrared spectroscopy and hyperspectral imaging, we prove that the black color of Persian wheat spikes is caused by melanin but not anthocyanins. Also, we show that the dark pigment in husks and awns is located in epiderma and subepidermal sclerenchyma cells, that implies melanin potentially to have mechanical-enhancing and protection function. Other possible functions of melanin in cereals are discussed.

plant biology↗

bioRxiv2021

Illuminating the transposon insertion landscape in plants using Cas9-targeted Nanopore sequencing and a novel pipeline

Transposable element insertions (TEIs) are an important source of genomic innovation by contributing to plant adaptation, speciation, and the production of new varieties. The often large, complex plant genomes make identifying TEIs from short reads difficult and expensive. Moreover, rare somatic insertions that reflect mobilome dynamics are difficult to track using short reads. To address these challenges, we combined Cas9-targeted Nanopore sequencing (CANS) with the novel pipeline NanoCasTE to trace both genetically inherited and somatic TEIs in plants. We performed CANS of the EVADE (EVD) retrotransposon in wild-type Arabidopsis thaliana and rapidly obtained up to 40x sequence coverage. Analysis of hemizygous T-DNA insertion sites and genetically inherited insertions of the EVD transposon in the ddm1 genome uncovered the crucial role of DNA methylation in shaping EVD insertion preference. We also investigated somatic transposition events of the ONSEN transposon family, finding that genes that are downregulated during heat stress are preferentially targeted by ONSENs. Finally, we detected hypomethylation of novel somatic insertions for two ONSENs. CANS and NanoCasTE are effective tools for detecting TEIs and exploring mobilome organization in plants in response to stress and in different genetic backgrounds, as well as screening T-DNA insertion mutants and transgenic plants.

genomics↗

bioRxiv2020

Development of genetic markers for sexing Cannabis sativa seedlings

Cannabis sativa is a dioecious plant with a XY system. Only females produce cannabinoids in large amount. Efficient male removal is an important issue for the cannabis industry. We have recently identified the sex chromosomes of C. sativa, which opens opportunities for developing universal genetic markers for early sexing of C. sativa plants. Here we selected six Y-linked markers and designed PCR primers, which were tested on five hemp cultivars both dioecious and monoecious. We obtained promising results, which need to be extended using a larger number of individuals and a more diverse set of cultivars, including THC producing ones.

plant biology↗