A method for promoting the expression of Chlamydomonas reinhardtii selenoprotein genes and increasing selenoprotein production

Abstract

The present invention discloses a method for promoting the expression of selenoprotein genes in Chlamydomonas reinhardtii and increasing the yield of selenoproteins. S1. Inoculate Chlamydomonas reinhardtii algae with liquid culture medium at 20-30°C and 0-200 μmol / (m 2 S2, taking the Chlamydomonas reinhardtii culture solution, adding sodium selenite and abscisic acid, the abscisic acid concentration in the culture solution is 10-1000 μmol / L, at 20-30°C, 0-200 μmol / (m 2 ·s) Oscillating culture under light conditions. The present invention adds the plant hormone ABA during the selenium-enriched culture of Chlamydomonas reinhardtii, which not only does not affect the growth and biomass accumulation of microalgae, but also promotes the expression of selenoproteins. It is applied in the production of Chlamydomonas reinhardtii algae powder rich in selenoproteins, and can greatly increase the yield of selenoproteins.

Description

Technical Field

[0001] The invention relates to the technical field of selenoprotein biological preparation, and in particular to a method for promoting the expression of Chlamydomonas reinhardtii selenoprotein genes and increasing the yield of selenoproteins. Background Art

[0002] Selenium (Se) is a trace element necessary for animals and humans. It has biological functions such as anti-oxidation, anti-tumor, prevention of cardiovascular disease, and enhancement of body immunity, and plays an important role in human health. Selenium deficiency can lead to the occurrence of a variety of diseases such as cardiovascular and cerebrovascular diseases, Keshan disease, and Kaschin-Beck disease, which have caused serious impacts on people in selenium-deficient areas in my country.

[0003] Selenium in nature exists mainly in the form of inorganic selenium and organic selenium. Inorganic selenium is mainly selenite and selenate, which are obtained from the by-products of metal mines. Organic selenium includes natural organic selenium, such as selenoproteins in animals and plants; artificial biological transformation of organic selenium, such as selenium-enriched yeast, selenium-enriched edible fungi, etc.; and artificially synthesized organic selenium, such as selenized carrageenan, etc. With the widespread application of nanotechnology, people have developed a new type of selenium preparation - nano-selenium by combining different types of new nanotechnology methods with selenium; nano-selenium is a red elemental selenium in powder form, which is the least toxic form of many selenium elements that have been discovered. After selenium enters the body, it covalently bonds with amino acids in the body to form selenoproteins to express its biological effects, regulating the body's free radical metabolism, antioxidant function, immune function, reproductive function, cell apoptosis and hormone secretion. Therefore, the function of selenium is expressed through selenoproteins.

[0004] Selenium plays a biological role in the human body mainly in the form of selenoproteins. In recent years, the relationship between selenoproteins and human health has received increasing attention. So far, it has been found that humans contain 25 selenoproteins, including glutathione peroxidase (GPX), thioredoxin reductase (TrxR), iodothyronine deiodinase (ID) family, selenoprotein P, etc. Studies have shown that selenoproteins play an important role in the development of the nervous system, immune function regulation, anti-oxidation, disease prevention and treatment. So far, only two selenium-containing amino acids have been found in selenoproteins: one is selenocysteine ​​(Sec), which is formed by the replacement of the sulfur atom in cysteine ​​by a selenium atom. There are 20 basic amino acids that make up human protein, so people call selenocysteine ​​the 21st amino acid in the body. The other is selenomethionine (SeMet, also known as selenomethionine), which is formed by the replacement of the sulfur atom in methionine by a selenium atom. These two selenium-containing amino acids are collectively referred to as "selenoamino acids", and they are both involved in the synthesis of a variety of selenoproteins.

[0005] The codon corresponding to selenocysteine ​​is UGA, which is the main form of selenium in selenoproteins. Proteins containing selenocysteine ​​are called selenoproteins. Proteins that bind selenium in higher plants are called selenoproteins, which do not contain selenocysteine ​​and are not true selenoproteins. Selenocysteine ​​is inserted into selenoproteins by a unique regulatory mechanism, which effectively avoids the phenomenon of random insertion into proteins. Selenocysteine ​​cannot exist alone in a stable form and only exists in selenoproteins.

[0006] Selenium deficiency can cause people to be in a sub-healthy state for a long time, and people have a serious problem of "hidden selenium hunger". The main difficulty in selenium supplementation at present is the lack of high-quality selenium sources. The first generation of selenium supplement raw materials is mainly inorganic sodium selenite, which has high toxicity and low biological activity, and cannot achieve accurate selenium supplementation; the second generation of selenium supplement raw materials mainly come from grains, vegetables and fruits, but higher plants such as grains, vegetables and fruits basically do not contain selenoproteins. Microalgae itself is rich in selenoproteins and is a very potential third-generation selenium supplement raw material.

[0007] Selenoprotein is the most active, least toxic and most efficient high-quality selenium source among all forms of selenium. The main defect of current plant-based selenium-enriched agricultural products: serious shortage of selenoprotein. Higher plants and fungi lack selenoprotein, but current studies have found that algae are rich in selenoprotein. In particular, the edible microalgae Chlamydomonas reinhardtii can convert inorganic selenium into ideal dietary selenium forms such as selenocysteine ​​and selenoprotein, and is a good carrier for biological selenium enrichment. Because it contains rich selenoproteins, it is a natural bioreactor for the production of selenoproteins. Sufficient selenium-rich Chlamydomonas reinhardtii powder will be obtained through industrial fermentation. Chlamydomonas reinhardtii selenoprotein has broad application prospects in the fields of medicines / health products, functional foods, feed additives and cosmetics. Chlamydomonas reinhardtii was approved as a new food raw material in 2022, which is safe, reliable and can be eaten without limit. Chlamydomonas reinhardtii selenoprotein has broad application prospects in the fields of medicines / health products, functional foods, feed additives and cosmetics. Although Chlamydomonas reinhardtii itself contains abundant selenoprotein genes and is an ideal source of high-quality selenium, it contains 10 kinds of selenoproteins, but its selenoprotein content is not high. No exogenous selenium is added during the cultivation of Chlamydomonas reinhardtii, and ideal dietary selenium forms such as selenocysteine ​​and selenoproteins are almost non-existent in the body. How to effectively increase the expression level of Chlamydomonas reinhardtii selenoproteins is the key to the efficient production of Chlamydomonas reinhardtii selenoproteins. The Chlamydomonas reinhardtii algae powder currently on the market is simply obtained by exogenously adding inorganic selenium to obtain ordinary selenium-rich algae powder, and does not further increase the content of high-value by-products such as selenoproteins.

[0008] Microalgae have broad application prospects in the field of biotechnology. They can be used to produce biofuels and accumulate high-value-added metabolites. Microalgae are easy to cultivate, have a simple life cycle, grow fast, have strong phenotypic plasticity, and can accumulate biofuel-related molecules (lipids, starch) or secondary metabolites (such as β-carotene, astaxanthin or DHA). These characteristics make algae one of the most studied biological systems. However, the accumulation of these high-value products requires exogenous stress. For example, the accumulation of TAG (triacylglycerol) (necessary for biodiesel production) is mainly caused by nutritional limitation. The accumulation of other valuable molecules (such as carotene) also depends on nutritional or environmental stress. At the same time, these unfavorable conditions also limit the accumulation of algal biomass. Therefore, when fermenting microalgae to produce specific high-value metabolites, it is particularly important to find an inducer that does not affect the accumulation of microalgae's own biomass and can significantly promote the accumulation of high-value metabolites. Summary of the invention

[0009] One of the purposes of the present invention is to provide a method for promoting the expression of selenoprotein genes in Chlamydomonas reinhardtii and increasing the yield of selenoproteins in order to solve the above problems, comprising the following steps:

[0010] S1. Take Chlamydomonas reinhardtii and inoculate it into liquid culture medium at 20-30°C and 0-200 μmol / (m 2 ·s) culturing under light conditions by shaking until the growth retardation phase to the stable phase to obtain the culture solution of Chlamydomonas reinhardtii;

[0011] S2. Take the culture medium of Chlamydomonas reinhardtii, add sodium selenite and abscisic acid, the concentration of abscisic acid in the culture medium is 10-1000 μmol / L, and incubate at 20-30°C, 0-200 μmol / (m 2 ·s) Shaking culture under light conditions.

[0012] In step S2, sodium selenite is added to the culture solution of Chlamydomonas reinhardtii until the concentration of sodium selenite is 2-200 mg / L, and abscisic acid is added to the culture solution until the concentration of abscisic acid is 10-800 μmol / L.

[0013] Preferably, the concentration of sodium selenite in the culture solution in step S2 is 2-100 mg / L or 2-50 mg / L or 2-30 mg / L or 2-10 mg / L or 2-8 mg / L or 2-6 mg / L or 2-4 mg / L;

[0014] The abscisic acid concentration in the culture medium is 10-600 μmol / L or 10-500 μmol / L or 10-100 μmol / L or 10-50 μmol / L or 50-500 μmol / L or 100-500 μmol / L.

[0015] Preferably, in step S1 / S2, the culture conditions of Chlamydomonas reinhardtii are 25-30°C, 150-250 rpm shaking conditions, 50-200 μmol·m -2 ·s -1 Lighting conditions: 14-18h:6-10h alternating light and dark.

[0016] Preferably, in step S1, the Chlamydomonas reinhardtii species are inoculated into a liquid culture medium and then cultured with shaking until the logarithmic growth phase to the stable phase.

[0017] Preferably, the liquid culture medium is TAP or BG-11 liquid culture medium.

[0018] Preferably, in step S2, the shaking culture is performed for 0.5 to 5 days, more preferably 1 to 5 days or 3 to 5 days.

[0019] The selenoprotein genes include GPX1, SelW2, SelT, SelM1, SelM2, and MsrA1.

[0020] The Chlamydomonas reinhardtii is Chlamydomonas reinhardtii RZTCr-1, which is deposited in China Center for Type Culture Collection with a deposit number of CCTCCNO: M 2023564.

[0021] Another object of the present invention is to provide the use of the plant hormone abscisic acid in any of the following:

[0022] (1) Promote the expression of Chlamydomonas reinhardtii selenoprotein genes;

[0023] (2) Promote the production of selenoproteins in Chlamydomonas reinhardtii;

[0024] (3) Producing a Chlamydomonas reinhardtii product rich in selenoprotein; preferably, the product is algae powder. The beneficial effects of the present invention are:

[0025] The results of the examples in the present invention show that when 4 mg / L sodium selenite is added exogenously for selenium-enriched culture of Chlamydomonas reinhardtii, only 10 μM concentration of ABA is required to significantly promote the expression of Chlamydomonas reinhardtii selenoprotein genes. When Chlamydomonas reinhardtii algae powder rich in selenoprotein is produced by large-scale fermentation, only 2.6 grams of ABA is added exogenously to 1 ton of fermentation liquid to achieve the effect of promoting selenoprotein synthesis, so the cost is low.

[0026] At present, a series of methods for improving the productivity of microalgae, including light induction, ultrasound, nitrogen deficiency, high salt and other treatments, can improve the production capacity of by-products, but usually limit the increase of microalgae biomass. The present invention adds the plant hormone ABA during the selenium-enriched culture of Chlamydomonas reinhardtii, which not only does not affect the growth and biomass accumulation of microalgae, but also promotes the expression of selenoproteins, achieving the effect of "1+1>2". The present invention applies ABA to the production of Chlamydomonas reinhardtii powder rich in selenoproteins, which provides an important reference for improving the productivity of microalgae and high-value by-products, and also expands the application of plant hormones. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Shows the growth of Chlamydomonas reinhardtii RZTCr-1 under Na2SeO3 treatment.

[0028] Figure 2 Shows the photosynthetic efficiency of Chlamydomonas reinhardtii RZTCr-1 on the 7th day under Na2SeO3 treatment.

[0029] Figure 3 The cell density of Chlamydomonas reinhardtii hx-1, JUV, 21gr, and 849 under Na2SeO3 treatment is shown.

[0030] Figure 4 The selenium form composition and content of Chlamydomonas reinhardtii RZTCr-1 after selenium-enriched culture are shown.

[0031] Figure 5 The selenoprotein genes whose relative expression levels changed significantly under the treatment of different concentrations of Na2SeO3 were shown.

[0032] Figure 6 Shown is the effect of MeJA treatment on the growth of Chlamydomonas reinhardtii RZTCr-1.

[0033] Figure 7 Shown is the effect of NAA treatment on the growth of Chlamydomonas reinhardtii RZTCr-1.

[0034] Figure 8 Shown are the effects of ABA treatment on the growth of Chlamydomonas reinhardtii RZTCr-1.

[0035] Fig. 9 It showed that ABA treatment increased the expression level of RZTCr-1 selenoprotein gene in Chlamydomonas reinhardtii. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with embodiments, but the present invention is not limited thereto.

[0037] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0038] The experimental material Chlamydomonas reinhardtii RZTCr-1 of the embodiment of the present invention has been disclosed in Chinese patent application CN202311067054.5 (publication number CN 117025401 A), and its deposit information is as follows:

[0039] Chlamydomonas reinhardtii RZTCr-1 was deposited in China Center for Type Culture Collection (CCTCC) in April 2023, located at Luojia Mountain, Bayi Road, Wuchang District, Wuhan City, Hubei Province. The deposit date is April 20, 2023, the deposit number is CCTCCNO: M 2023564, and the classification name is Chlamydomonas reinhardtii RZTCr-1.

[0040] Example 1

[0041] This example compares the tolerance of Chlamydomonas reinhardtii RZTCr-1 and other Chlamydomonas reinhardtii to sodium selenite, determines the optimal selenium-enriched conditions, and analyzes the selenium form composition after selenium-enriched culture of Chlamydomonas reinhardtii RZTCr-1.

[0042] A single colony of Chlamydomonas reinhardtii was picked from the seed plate and placed in 30 mL of liquid TAP (TRIS-ACETATE-PHOSPHATE) medium. The medium was placed at 150 rpm, 25 °C, and a light intensity of 120 μmol / (m 2 ·s), and cultured in a constant temperature incubator with 16h:8h light and dark alternation to obtain seed solution. After the seed solution was cultured to the logarithmic phase, the OD 750nm =0.1 final concentration into a new 50mL liquid TAP medium, then add sodium selenite (Na2SeO3) to treat Chlamydomonas reinhardtii (the Chlamydomonas reinhardtii strains used for comparison in this example are RZTCr-1, hx-1, JUV, 21gr, cc849), so that the final concentration of sodium selenite in the TAP medium is 0, 2, 4, 6, 8, 10 mg / L, and the untreated group is used as the CK control group. For 7 consecutive days, the OD was measured every day by an ELISA instrument 750nm The Fv / Fm and YⅡ levels were measured using a modulated chlorophyll fluorescence imaging system (Heinz Walz Gmbh Effeltrich, Würzburg, Germany) to detect the chlorophyll fluorescence parameters of Chlamydomonas reinhardtii. The results of cell density detection showed that RZTCr-1 was relatively more tolerant to sodium selenite than Chlamydomonas reinhardtii numbered hx-1, JUV, 21gr, and cc849 ( Figure 1 , Figure 3 ), indicating that RZTCr-1 has a stronger selenium-enriching capacity than other algae strains. The results of photosynthetic efficiency test showed that the sodium selenite concentration below 4 mg / L did not affect the photosynthesis of RZTCr-1 at all ( Figure 2), so the concentration of sodium selenite used in the subsequent selenium-enriched culture of Chlamydomonas reinhardtii RZTCr-1 was 4 mg / L.

[0043] The detection method of selenium form composition is as follows:

[0044] 1. Extraction of selenium forms: Weigh about 0.05 grams of sample (freeze-dried algae powder) and place it in a pre-cleaned polytetrafluoroethylene microwave digestion container. Add 8 mL of 4 M methanesulfonic acid and 0.1 mL of β-mercaptoethanol, and the digestion program is completed in 55 minutes with a maximum power of 300 W. The temperature rises linearly to 150°C in the first 20 minutes and is maintained at this temperature for 20 minutes. The container is cooled to room temperature in the last 15 minutes. After digestion, add another 0.1 mL of β-mercaptoethanol to prevent oxidation of selenoamino acids, then dilute the sample to 25 mL with distilled water and refrigerate. Filter the solution using a 0.45 μm polytetrafluoroethylene filter before HPLC-IPC MS analysis.

[0045] 2. HPLC-IPC MS: Separation was performed on an Agilent 1100 HPLC system using a Hamilton PRPX-100 column (strong anion exchange resin, 150×4.1 mm, 10 μm particles) in a 10 mM ammonium citrate buffer at pH 4.5 containing 2% methanol (volume fraction), and detection was performed using an Agilent 7700x ICP MS in helium collision mode.

[0046] After treatment with different concentrations of sodium selenite for 12 hours and 24 hours, samples were taken and the selenium forms of Chlamydomonas reinhardtii were analyzed by LC-ICP-MS. The results showed that the main selenium forms of Chlamydomonas reinhardtii RZTCr-1 after selenium-enriched culture were methylselenocysteine ​​(MeSeCys), sodium selenite (SeO3 2- ), selenocystine (SeCys2) and selenomethionine (SeMet), and as the selenium-enriched culture time increases, the accumulated selenium amino acid content increases, among which selenocystine (SeCys2) accounts for the highest proportion among all selenium forms. In the Chlamydomonas reinhardtii algae powder cultured for 12 hours, selenocystine (SeCys2) accounts for 65% ( Figure 4 ).

[0047] Example 2: Expression levels of selenoprotein genes in Chlamydomonas reinhardtii RZTCr-1 treated with different concentrations of sodium selenite

[0048] It is reported (for example, document 1: doi:10.1093 / emboj / cdf372. Document 2: doi:10.3390 / antiox11081630.) that there are 10 kinds of selenoproteins in Chlamydomonas reinhardtii. In this example, the expression levels of these selenoprotein genes were detected.

[0049] Sodium selenite at different concentrations was added to carry out selenium-enriched culture of Chlamydomonas reinhardtii RZTCr-1. The culture method of Chlamydomonas reinhardtii and the sodium selenite treatment method were the same as those in Example 1.

[0050] After treatment with sodium selenite at different concentrations for 12 hours and 24 hours, samples were taken, and the treated Chlamydomonas reinhardtii cells were collected by centrifugation. Total RNA was extracted using the RNAprep Pure Plant Kit (TIANGEN, Beijing) of Tiangen Company. The expression levels of related genes were analyzed by the quantitative PCR instrument QuantStudio 3Real-Time PCR System (ThermoFisher, USA). The primers for quantitative PCR are shown in Table 1, in which Chlamydomonas reinhardtii βACTIN was used as the internal reference gene. SYBRGreen SuperReal PreMix Plus Kit (TIANGEN, Beijing) was used as the quantitative PCR polymerase, and the quantitative PCR program was: 95℃5min pre-denaturation; 95℃15s denaturation, 60℃30s extension, a total of 40 cycles. The melting curve program was: 95℃15s, 60℃30s and 95℃15s. The data of quantitative PCR were calculated using the formula 2- △△Ct To calculate the relative expression level of genes, each data set contained 3 biological replicates.

[0051] result( Figure 5 ) showed that the glutathione peroxidase GPX1 gene in RZTCr-1 had the highest up-regulation fold, and the relative expression level of the GPX1 gene under 24h treatment was higher than that under 12h. Under treatment with different concentrations of sodium selenite such as 2, 4, 6, 8, and 10 mg / L, the relative expression level of the GPX1 gene was up-regulated by 69.98 times, 93.8 times, 32.88 times, 68.51 times, and 119.01 times, respectively. Under treatment with different concentrations of Na2SeO3, the relative expression levels of other selenoprotein genes, such as MsrA1, GPX2, SelT, and SelM1, were also significantly up-regulated.

[0052] Table 1 RT-qPCR primer sequences

[0053]

[0054]

[0055] Example 3 Effects of different plant hormones (NAA, MeJA and ABA) on the growth of Chlamydomonas reinhardtii RZTCr-1

[0056] After the RZTCr-1 Chlamydomonas reinhardtii seed solution was cultured to the logarithmic phase, the OD 750nm=0.1 final concentration was inoculated into a new 50 mL liquid TAP medium, and then the plant hormones α-naphthylacetic acid (NAA, Solebol, purity 98%, CAS: 86-87-3), methyl jasmonate (MeJA, MacLean, purity 98%, CAS: 39924-52-2), and abscisic acid (ABA, Coolaber, purity 98%, CA1011-1g) were added to treat Chlamydomonas reinhardtii, so that the final concentrations of the plant hormones were 0, 10, 50, 100, 500, and 1000 μmol / L. The untreated group was used as the CK control group, and the cell density (OD 750nm ).

[0057] The results showed that under different concentrations of MeJA treatment, the growth of algae cells was inhibited to varying degrees. As the treatment concentration increased, the inhibition of algae cells became more serious. When the MeJA concentration reached 1000μM, algae cells died significantly and were almost impossible to count. At the same time, during the treatment process, it was also observed that there was a significant color difference between the 1000μM MeJA treatment group and the CK control group ( Figure 6 ), under MeJA treatment, the accumulation of photosynthetic pigments in Chlamydomonas reinhardtii cells may be affected. Under different concentrations of NAA treatment, although there was no significant difference in the color of the algae solution, it had a certain effect on the cell density. The higher the NAA concentration, the more obvious the inhibition of cell density ( Figure 7 Compared with NAA and MeJA, RZTCr-1 has a stronger tolerance to ABA, and the treatment concentration of 1000 μM has almost no effect on cell density ( Figure 8 ).

[0058] Example 4: Effect of ABA treatment on the expression of selenoprotein gene in Chlamydomonas reinhardtii RZTCr-1

[0059] According to the results of treating Chlamydomonas reinhardtii RZTCr-1 with different plant hormones (NAA, MeJA and ABA) in Example 3, it was shown that Chlamydomonas reinhardtii had strong tolerance to ABA, and high concentration ABA treatment did not affect the accumulation of Chlamydomonas reinhardtii biomass. Therefore, ABA was selected as an inducer for efficient synthesis of selenoproteins by Chlamydomonas reinhardtii.

[0060] A single colony of algae was picked from the RZTCr-1 seed plate and placed in 30 mL of liquid TAP medium (containing 4 mg / L sodium selenite) at 120 rpm, 25 °C, and a light intensity of 120 μmol / (m 2 ·s), and cultured in a constant temperature incubator with 16h:8h light and dark alternation to obtain selenium-rich Chlamydomonas reinhardtii culture solution. After the culture solution was cultured to the logarithmic phase, 4 mg / L sodium selenite was added, and ABA was added to treat Chlamydomonas reinhardtii, with the final ABA concentrations of 0, 10, 50, 100, and 500 μmol / L. The untreated group was used as the CK control group, and the culture was continued at 120 rpm, 25°C, 120 μmol / (m2 ·s) light intensity and 16h:8h light-dark alternation. After treating Chlamydomonas reinhardtii with different concentrations of ABA for 12 hours, RNA was extracted and then converted into cDNA, and the expression level of selenoprotein genes was detected by RT-qPCR analysis.

[0061] The results showed that when only ABA was added without sodium selenite, the expression level of selenoprotein genes in Chlamydomonas reinhardtii did not change significantly. Under selenium-rich culture conditions, the exogenously added plant hormone ABA and sodium selenite produced a synergistic effect in Chlamydomonas reinhardtii RZTCr-1, exerting the effect of "1+1>2", and significantly promoted the expression of selenoprotein genes GPX1, SelW2, SelT, SelM1, SelM2, and MsrA1 in Chlamydomonas reinhardtii ( Fig. 9 ), and with the increase of ABA treatment concentration, the expression levels of most selenoprotein genes increased. Among them, GPX1 and SelT had the highest up-regulation folds.

[0062] It can be seen that applying ABA to Chlamydomonas reinhardtii under selenium-rich conditions will significantly increase the expression of most selenoprotein genes of Chlamydomonas reinhardtii, and the content of selenoproteins produced can be greatly increased. Chlamydomonas reinhardtii has been approved as a new food raw material and can be eaten directly. After the selenoprotein of cultured Chlamydomonas reinhardtii is greatly increased by the method of this embodiment, algae powder is obtained, pressed into selenium-rich Chlamydomonas reinhardtii algae slices or the total protein of Chlamydomonas reinhardtii is extracted for the development of health products (such as algae-derived selenoproteins). The method of this embodiment has broad application prospects.

Claims

1. A method for promoting the expression of selenoprotein genes in Chlamydomonas reinhardtii and increasing the yield of selenoproteins, characterized in that: The steps include: S1. Take Chlamydomonas reinhardtii and inoculate it into liquid culture medium at 20-30°C and 0-200 μmol / (m 2 ·s) culturing under light conditions by shaking until the growth retardation phase to the stable phase to obtain the culture solution of Chlamydomonas reinhardtii; S2. Take the culture medium of Chlamydomonas reinhardtii, add sodium selenite and abscisic acid, the concentration of abscisic acid in the culture medium is 10-1000 μmol / L, and incubate at 20-30°C, 0-200 μmol / (m 2 ·s) Shaking culture under light conditions.

2. The method according to claim 1, characterized in that: In step S2, sodium selenite is added to the culture solution of Chlamydomonas reinhardtii until the concentration of sodium selenite is 2-200 mg / L, and abscisic acid is added to the culture solution until the concentration of abscisic acid is 10-800 μmol / L.

3. The method according to claim 2, characterized in that: In step S2, the concentration of sodium selenite in the culture solution is 2-100 mg / L or 2-50 mg / L or 2-30 mg / L or 2-10 mg / L or 2-8 mg / L or 2-6 mg / L or 2-4 mg / L; The abscisic acid concentration in the culture medium is 10-600 μmol / L or 10-500 μmol / L or 10-100 μmol / L or 10-50 μmol / L or 50-500 μmol / L or 100-500 μmol / L.

4. The method according to claim 1, characterized in that: In step S1 / S2, the culture conditions of Chlamydomonas reinhardtii are 25-30°C, 150-250 rpm shaking, 50-200 μmol·m -2 ·s -1 Lighting conditions: 14-18h:6-10h alternating light and dark.

5. The method according to claim 1, characterized in that: In step S1, the Chlamydomonas reinhardtii algae species are inoculated into a liquid culture medium and then cultured with shaking until the logarithmic growth phase to the stable phase.

6. The method according to claim 1, characterized in that: The liquid culture medium is TAP or BG-11 liquid culture medium.

7. The method according to claim 1, characterized in that: In step S2, the shaking culture is performed for 0.5 to 5 days, preferably 1 to 5 days or 3 to 5 days.

8. The method according to claim 1, characterized in that: The selenoprotein genes include GPX1, SelW2, SelT, SelM1, SelM2, and MsrA1.

9. The method according to claim 1, characterized in that: The Chlamydomonas reinhardtii is Chlamydomonas reinhardtii RZTCr-1, which is deposited in China Center for Type Culture Collection with a deposit number of CCTCC NO: M 2023564.

10. Use of the plant hormone abscisic acid in any of the following: (1) Promote the expression of Chlamydomonas reinhardtii selenoprotein genes; (2) Promote the production of selenoproteins in Chlamydomonas reinhardtii; (3) Producing a Chlamydomonas reinhardtii product rich in selenoprotein; preferably, the product is algae powder.

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