Thallus sectioning as an efficient monospore release method in Pyropia yezoensis (Bangiales, Rhodophyta)

Abstract

The red seaweed Pyropia yezoensis is a marine crop of important economic value and is widely cultivated in the coastal areas of northern China. The current seedling-raising system relies on the germination of conchospores, a process not fast enough to meet the increasing demand from farmers. In this study, we developed a monospore-dependent seedling method based on the asexual reproduction of the Pyropia thallus. The Pyropia thallus was physically sectioned into small pieces (microthalli) that were cultivated at 15°C. The algal cells in the microthalli became morphologically condensed, underwent cell division, and then developed into monospores on the 5th day. The monospores were able to attach to the seeding rope in 24 h and germinated into healthy thalli. To optimize the efficiency of monospore release, we tested the effect of temperature and the size and original positions of the microthalli as well as the age of the mother thallus. Microthalli with a size of 30-50 cells from the middle and apex of 21-day-old thalli cultivated at 15°C yielded the optimum production of monospores. Theoretically, in this thallus-tothallus seeding strategy, 0.1 g of thallus could produce at least 10 7 monospores, with the same number of offspring thallus seedlings. Taking all of these advantages together, including the high efficiency, short time, low cost and easy operation, this physical sectioning method could serve as a promising seed source especially for new cultivars with superior traits in Pyropia farming and rapid replenishment of seedlings when thalli undergo disastrous diseases.

Fine Mapping to Identify the Functional Genetic Locus for Red Coloration in Pyropia yezoensis Thallus

“…Generally, the single-genotype sectors of chimeric blades cannot be visually distinguished Shimizu et al, 2007). Asexual reproduction of the laver blades results in the release of a large number of monospores that grow into blades, thereby providing large amounts of materials that were used in parallel repeated measurements of the singlegenotype trait at one time (Chen et al, 2019).…”

Insights into the spatio-temporal composition, diversity and function of bacterial communities in seawater from a typical laver farm

“…This finding suggest that a significant increase in metabolic exchange and transformation nutrients occurred in the seawater in the laver farm during the early and late stage of laver cultivation. Cells at the edge of an intact laver thallus can differentiate into archeospores during early growth stage of N. yezoensis (Chen et al, 2020). The mature N. yezoensis may release zygotospores during late stage of cultivation.…”

Comparative Gene Expression and Physiological Analyses Reveal Molecular Mechanisms in Wound-Induced Spore Formation in the Edible Seaweed Nori

“…Previously, researchers found that N. yezoensis blades cut into small fragments of 30–50 cells can proliferate through cell division and fully redifferentiate into spores that can subsequently develop into individual blades in 5 days ( Hafting, 1999 ; Chen et al, 2019 ; Suda and Mikami, 2020 ). With recent genomic advances in N. yezoensis ( Cao et al, 2020 ; Wang et al, 2020 ), this fate transition from vegetative cells to spores provides an ideal research model to study the molecular mechanisms involved in cell reprogramming in red algae.…”