When cultivating mozuku, germling ‘seeds’ are grown in flasks, and transferred to nets in tanks after budding. The nets are then moved to the ocean the place the mozuku grows into mature, edible seaweed. The yield of mozuku adjustments yearly, as a result of cultivation difficulties. Credit: OIST
A easy PCR take a look at could possibly be used to enhance cultivation of the edible brown seaweed, Okinawa mozuku, and even support makes an attempt at producing heat-tolerant strains, reported scientists from the Okinawa Institute of Science and Technology Graduate University (OIST). The PCR take a look at, described in a brand new examine revealed June 9, 2022 in Phycological Research, detects 9 genes that reveal the mozuku algae’s lifecycle stage, in addition to its intercourse.
Okinawa mozuku (Cladosiphon okamuranus) is a much-loved algal superfood in Japan, which farmers have cultivated alongside the Okinawan seashore for the reason that Eighties. In the autumn, the farmers domesticate mozuku germlings, or “seeds,” in tanks, to induce their buds. Then, the farmers switch them to the ocean on nets to develop till they’re harvested in spring. Around 15,000 to twenty,000 tons of mozuku are collected annually, contributing greater than 2 billion yen to the native financial system.
However, mozuku farmers presently face three main issues in the course of the cultivation course of. Firstly, among the mozuku seeds do not bud. Secondly, because the mozuku grows within the ocean, it typically detaches from the nets and is swept away by present and tides. Finally, the seaweed is especially prone to warmth, with rising ocean temperatures stunting their progress.
“In 2010, the yield fell to lower than half the extent of a typical 12 months, which is considered as a result of an unusually heat winter,” stated Dr. Koki Nishitsuji, a employees scientist in OIST’s Marine Genomics Unit, led by Professor Noriyuki Satoh. “As local weather change happens, the frequency of hotter winters may enhance, so new heat-resilient strains are wanted.”
One of the best methods to engineer traits reminiscent of warmth tolerance is thru crossbreeding, which is when people from two completely different strains are bred collectively to create a brand new combined pressure. However, scientists have struggled to crossbreed algae as a result of difficulties with distinguishing male germ cells from feminine germ cells.
“In different organisms, reminiscent of egg and sperm in mammals, there are seen variations,” defined Dr. Nishitsuji. “But for algae, the germlings cannot be recognized by eye, solely by their DNA.”
In the mozuku lifecycle, germlings happen as haploids and diploids. The germlings look the identical however farmers solely need to tradition the diploid germlings, which can bud and kind mature mozuku. Credit: OIST
Over the previous few years, the analysis workforce from the Marine Genomics Unit decoded the genome of the 4 completely different S-, Okay-, O- and C-strains of Okinawa mozuku, and the associated species Nemacystus decipiens, often known as ito-mozuku in Japanese.
Now, by making use of this wealth of genomic data, the workforce have been capable of determine 9 key sex-determining genes. When the scientists ran PCR assessments on the mozuku germlings, 5 of those genes have been solely detected in males, whereas the opposite 4 have been solely present in females.
“Now that we will determine the intercourse, we have begun crossbreeding the O-strain with each the S-strain and the Okay-strain, to see if this ends in a extra heat-tolerant pressure, stated Dr. Nishitsuji. “We are additionally engaged on figuring out genes that may act as markers for the completely different strains, in order that we will absolutely verify that the crosses have been profitable.”
As properly as introducing warmth resistance into newly developed strains, crossbreeding can even assist the researchers deal with the problem of mozuku getting swept out to sea, by creating strains of mozuku that connect extra firmly to the nets.
Although primarily developed to assist crossbreeding, the PCR take a look at may also be utilized by mozuku farmers in the course of the “seeding” stage of cultivation, by permitting them to determine what lifecycle stage the germlings are in.
The lifecycle of mozuku is difficult and distinctive, in comparison with animals and land crops. Humans (and most different animals) are diploid, which implies that our physique cells comprise two units of DNA—one set from our mom, and one other set from our father. Our germ cells (eggs and sperm) are haploid, which suggests they’ve only one set of DNA. At fertilization, the haploid egg and sperm mix to kind a diploid embryo.
PCR assessments of a diploid, male haploid and feminine haploid germlings have been developed, bettering the effectivity of cultivation and aiding makes an attempt at crossbreeding. Credit: OIST
However, in mozuku, germlings happen at two completely different phases of the lifecycle, as haploids and diploids. But solely the diploid germlings bud and grow to be the edible mature mozuku that the farmers need to domesticate. If the tank is contaminated with haploid germlings, then much less budding happens, with decrease yields of mozuku in the end harvested.
“Diploid germlings look the identical because the female and male haploid germlings, so it is a widespread method for farmers to lose yield,” stated Dr. Nishitsuji. “But now, our PCR take a look at can be utilized early on to examine whether or not they’re diploid, as these germlings will comprise all 9 female and male genes.”
In the autumn, the workforce will collaborate with the Okinawa Prefectural Fisheries and Marine Technology Center in Itoman, and Onna Fisheries Cooperative, utilizing the PCR assessments to attempt to enhance their ultimate yield.
Importantly, the sex-determining marker genes recognized on this examine are more likely to be related for different brown algae, like Undaria pinnatifida (wakame in Japanese) and Saccharina japonica (kombu), that are additionally economically essential crops.
Genome examine opens pathway towards sustainable edible seaweed
More data:
Development of DNA markers that distinguish female and male haploid germlings of the brown alga, Cladosiphon okamuranus, Phycological Research (2022). DOI: 10.1111/PRE.12489
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Okinawa Institute of Science and Technology
Citation:
PCR take a look at for Okinawa mozuku may enhance yields and result in climate-tolerant strains (2022, June 9)
retrieved 9 June 2022
from https://phys.org/information/2022-06-pcr-okinawa-mozuku-yields-climate-tolerant.html
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