CN111978388A - Rice UV-B light receptor gene OsUVR8a and application thereof - Google Patents

Abstract

The rice UV-B photoreceptor gene OsUVR8a and its application relate to the fields of biotechnology and genetic engineering. Provide the rice UV‑B photoreceptor gene OsUVR8a. Provide the protein OsUVR8a encoded by the rice UV‑B photoreceptor gene. A recombinant vector comprising the rice UV-B photoreceptor gene OsUVR8a is provided. Transgenic plants CFP‑OsUVR8a/Nip are provided. The application of rice UV-B photoreceptor gene OsUVR8a and photoreceptor gene-encoded protein OsUVR8a in the research and cultivation of radiation-resistant plants is provided. According to the intensity of ultraviolet light in different regions, the OsUVR8a gene can be selectively overexpressed, and rice varieties that are more tolerant to different intensities of ultraviolet light can be cultivated, and the energy of ultraviolet light can be used to improve the yield of rice.

Description

Rice UV-B photoreceptor gene OsUVR8a and its application

technical field

The invention relates to the fields of biotechnology and genetic engineering, in particular to the rice UV-B photoreceptor gene OsUVR8a and its application.

Background technique

Light is one of the most important environmental factors affecting the life activities of animals and plants in nature. Studies have shown that light plays a crucial role in regulating the entire growth and development process of plants from seedlings to adult seedlings. After the seeds of plants are affected by light after germination, the process of completing the differentiation of cells and the formation of tissues and organs is called photomorphogenesis. Photomorphogenesis is the first step to ensure that plants can benefit from light energy for growth and development. This development process basically determines the The quality of subsequent growth and reproduction of plants. UV-B light with a wavelength of 280-315nm is an important part of sunlight. In previous studies, it was found that long-wavelength, low-energy UV-B light can promote the photomorphogenesis of plants and help plants resist high-intensity UV. -B radiation is beneficial to the growth and development of plants, so UV-B light is an important environmental factor involved in regulating the morphogenesis process of plant seedlings (Jenkins, G.I. (2009). Signal transduction in responses to UV-Bradiation. Annu. Rev. . Plant Biol. 60:407-431).

As the intensity of ultraviolet light on the surface continues to increase, it is urgent to study how plants, especially food crops that are related to human survival, respond to ultraviolet light exposure and the impact of ultraviolet light on the growth of these crops. Studies have shown that in Arabidopsis, the UV-B photoreceptor AtUVR8 can receive UV-B light signals, convert from dimers to monomers, and initiate the transduction of UV-B light signals. Adaptation and tolerance of B (Rizzini, L., Favory, J.J., Cloix, C., Faggionato, D., O'Hara, A., Kaiserli, E., Baumeister, R., Schafer, E., Nagy, F., Jenkins, G.I., et al. (2011). Perception of UV-B by the Arabidopsis UVR8 protein. Science 332:103-106). In recent years, different research groups have successively cloned and identified homologous proteins of AtUVR8 in plants such as Populus euphratica, apple, Chlamydomonas reinhardtii, Chrysanthemum chrysanthemum and Northeast white birch, and they all have high homology with AtUVR8. Transferring these homologous proteins back into Arabidopsis uvr8 mutants can complement the phenotype of uvr8 mutants, exhibit UV-B light-induced hypocotyl shortening, and up-regulate UV-B light signaling pathways. important genes. The above results indicate that the functions of AtUVR8 homologous proteins in these species are very conserved.

The study found that Chlamydomonas reinhardtii was more tolerant to UV-B light and high-intensity white light after low-dose UV-B light adaptation treatment, indicating that UV-B photoreceptors were suitable for plants to adapt to the surface in the early stages of biological evolution. The UV-B light plays an important regulatory role. The existence of UV-B photoreceptors in Chrysanthemum and Northeast white birch indicates that UV-B light can be used to cultivate garden flowers and improve the vegetation environment. The UV-B photoreceptors of Populus euphratica suggest that tolerance to UV-B light may make It thrives in deserts and is a major factor in improving the ecological environment. The study of UV-B photoreceptors in apples and grapes also provides a good theoretical basis for the application of UV-B light energy to fruit tree cultivation. The adaptation mechanism of rice, corn, sorghum and cotton to UV-B light shows that UV- The huge application value of B light in agricultural production. It can be seen that UV-B light and UV-B photoreceptors have broad application prospects in the actual production of forest trees, cash crops and food crops.

Rice is native to China and India. As early as 7,000 years ago, people in the Yangtze River Basin of China have been growing rice. Rice is an important food crop in China, and its output is directly related to China's food security. At present, the environmental problem of ultraviolet light pollution is becoming more and more prominent. As a high-light crop, the yield of rice is inevitably affected by the increase of ultraviolet light intensity. Therefore, if the UV-B photoreceptor gene in rice can be cloned and analyzed, it will help to help The adaptation of rice to ultraviolet light has considerable practical application value. If it can be applied to the current breeding strategy, it is expected to develop rice varieties that are more tolerant to ultraviolet light, and it is even expected to use ultraviolet light energy to improve rice yield. This is of extraordinary significance for ensuring global food security.

SUMMARY OF THE INVENTION

The first object of the present invention is to provide the rice UV-B photoreceptor gene OsUVR8a.

The second object of the present invention is to provide the protein OsUVR8a encoded by the rice UV-B photoreceptor gene.

The third object of the present invention is to provide a recombinant vector comprising the rice UV-B photoreceptor gene OsUVR8a.

The fourth object of the present invention is to provide a transgenic plant CFP-OsUVR8a/Nip comprising the rice UV-B photoreceptor gene OsUVR8a.

The fifth object of the present invention is to provide the application of the rice UV-B photoreceptor gene OsUVR8a.

The sixth object of the present invention is to provide the application of the protein OsUVR8a encoded by the rice UV-B photoreceptor gene.

The rice UV-B photoreceptor gene OsUVR8a has the cDNA sequence shown in SEQ ID NO.1.

SEQ ID NO. 1:

The protein OsUVR8a encoded by the rice UV-B photoreceptor gene is derived from Oryza sativa Japonica Group, and its amino acid sequence is shown in SEQ ID NO.2.

SEQ ID NO.2

The protein OsUVR8a encoded by the rice UV-B photoreceptor gene consists of 453 amino acid residues and is a homologous protein of the Arabidopsis UV-B photoreceptor protein AtUVR8.

On the basis of the above scheme, the present invention also provides an expression cassette, a recombinant expression vector, a transgenic plant and a recombinant strain containing the rice UV-B photoreceptor gene OsUVR8a.

A recombinant expression vector containing the OsUVR8a gene can be constructed using a plant expression vector. When using OsUVR8a to construct a recombinant expression vector, any constitutive promoter or enhanced promoter, or other plant gene promoters can be added before its transcription initiation nucleotide.

The plant expression vector includes binary Agrobacterium vector and the like.

The plant expression vector may also contain the 3' untranslated region of the exogenous gene, i.e., the polyadenylation signal and any other DNA fragments involved in mRNA processing or gene expression.

In order to facilitate the identification and screening of transgenic plant cells or plants, the plant expression vector can be processed, such as adding genes (GUS gene, luciferase gene, GUS gene, luciferase gene) that can be expressed in plants encoding enzymes that can produce color changes or luminescent compounds. , fluorescent protein tags, etc.) and resistant antibiotic markers (ampicillin marker, kanamycin marker, etc.).

The transgenic plant of the rice UV-B photoreceptor gene OsUVR8a is CFP-OsUVR8a/Nip.

The rice UV-B photoreceptor gene OsUVR8a can be applied in the research and cultivation of radiation-resistant plants, and can induce the photomorphogenesis of plants under UV-B light.

The protein OsUVR8a encoded by the rice UV-B photoreceptor gene can be applied in the research and cultivation of radiation-resistant plants, and can be applied in the photomorphogenesis induced by UV-B light.

The invention also utilizes CRISPR-Cas9 technology to obtain the double mutant plant osuvr8 of OsUVR8a and its homologous gene OsUVR8b. The plant does not have the normal function of OsUVR8. Under UV-B light, the plant height of the seedling increases, the length of the first and second internodes increases, and the tolerance to UV-B light is weakened, which is not conducive to the induction of UV-B light by rice. The light form was built.

As the UV-B photoreceptor gene of rice, an important food crop, OsUVR8a not only has considerable practical application value for rice to adapt to the increasingly strong ultraviolet light in the environment, but also can be used in current breeding strategies. Ultraviolet intensity, selectively overexpressing the OsUVR8a gene can cultivate rice varieties that are more tolerant to different intensities of ultraviolet light, and can use ultraviolet light energy to improve rice yield; cultivated more tolerant to ultraviolet light , and rice varieties that can use ultraviolet light energy for higher yields, thereby further improving rice yields are of great significance.

Description of drawings

Figure 1 shows the homology comparison results of the amino acid sequences of rice UV-B photoreceptor protein OsUVR8a and Arabidopsis thaliana UV-B photoreceptor protein AtUVR8.

Figure 2 shows the phenotypes and statistical results of wild-type rice and double mutant plants of rice UV-B photoreceptor genes OsUVR8a and OsUVR8b osuvr8 under white light and white light plus UV-B light conditions.

Figure 3 shows the results of UV-B light damage experiments on wild-type rice and double mutant plants of rice UV-B photoreceptor genes OsUVR8a and OsUVR8b osuvr8.

Figure 4 shows the phenotypes and statistical results of wild-type rice and CFP-OsUVR8a OE plants overexpressing the UV-B photoreceptor gene OsUVR8a in white light and white light plus UV-B light.

Fig. 5 shows the results of UV-B light damage experiments in wild-type rice and CFP-OsUVR8a OE plants overexpressing the UV-B photoreceptor gene OsUVR8a in rice.

Detailed ways

The following embodiments will further illustrate the present invention in conjunction with the accompanying drawings.

As shown in Figure 1, the present invention found that the gene OsUVR8a, which is homologous to the UV-B photoreceptor gene AtUVR8 in Arabidopsis thaliana, exists in rice through sequence homology alignment, and then cloned this gene from rice to confirm that its encoding The proteins can also respond to UV-B light signals and help plants resist UV-B light damage. At the same time, it was found that rice plants with double mutation of OsUVR8a and its homologous gene OsUVR8b could not respond to UV-B light to promote rice growth and development, and their tolerance to UV-B light was significantly weakened. Under -B light, it is an ideal compact plant type, and has a strong tolerance to UV-B light, which provides a good foundation for its later growth and fruiting.

Example 1: cDNA cloning of rice UV-B photoreceptor gene OsUVR8a.

1) Extraction of total RNA from rice:

The leaves of wild-type rice (Nipponbare) grown for 2 weeks under white light were taken, placed in a 1.5 mL RNase-free EP tube, snap-frozen in liquid nitrogen, immediately ground or stored at -80°C.

First, the related utensils such as mortar, pestle, medicine spoon, etc. were baked at 180°C for 4 hours and then lowered to room temperature, and then the above-mentioned utensils were pre-cooled with liquid nitrogen, and then the rice leaves were ground. Dispense 100μL of powder, add 500uL of RNA lysis solution, and dissolve on ice until there is no flocculent precipitate. Then, add 500 μL of RNA diluent and mix by pipetting. After standing at room temperature for 5 min, centrifuge at 12,000 rpm for 10 min at room temperature. Take 800 μL of supernatant into a new RNase-free EP tube, add 400 μL of absolute ethanol, and mix by inversion. Then transferred to a 2mL spin column, centrifuged at 12000rpm for 1min, discarded the filtrate, added 600μL of RNA wash solution, centrifuged at 12000rpm for 1min, discarded the filtrate and idling at 12000rpm for 2min. Add 50uL DNase I to the center of the membrane and incubate for 30min. After incubation, 600 μL of RNA wash solution was added, centrifuged at 12,000 rpm for 1 min, and the filtrate was discarded. Add 50 μL of nuclease-free water and centrifuge at 12,000 rpm for 2 min. Repeated centrifugation can improve the RNA yield.

2) RNA reverse transcription into cDNA

Add 2μg RNA and 0.5μg oligo(dT), anneal at 70℃ for 5min, and then perform reverse transcription with the following system:

The reverse transcription mixed system is shown in Table 1:

Table 1

reagent Volume (μL) Nuclease-free Water 6.9 Go Script^TM 5×Raection Buffer 4 PCR Nuclease Mix 1 MgCl₂ 1.6 Go Script Reverase Transcriptase 1 Inhibitor 0.5

3) Design primers P1 and P2 according to the sequence of the rice UV-B photoreceptor gene OsUVR8a coding region, and the sequences of the primers are as follows:

P1:5'-ACGCGTCGACATGCATTCGACCGGCATGGAGATGG-3'

P2:5'-CGGGATCTCAGACGCGCATCCTCTTCACATCT-3'

The size of the PCR product was detected by electrophoresis in a 1% agarose gel, and a band with the expected size was obtained, and then the gel was cut and recovered. The target fragment was ligated with the pCAMBIA2300-35S-CFP vector by the method of T4 enzyme ligation, and the ligated product was transferred into E. coli DH5α competent cells, and positive clones were screened according to the kana resistance marker on the pCAMBIA2300-35S-CFP vector. Then confirm whether the recombinant plasmid contains the complete and correct nucleotide sequence of the target gene by sequencing. Thus, the recombinant vector of pCAMBIA2300-35S-CFP-OsUVR8a was obtained.

Example 2: Knockout of rice UV-B photoreceptor genes OsUVR8a and OsUVR8b using CRISPR-Cas9 technology to construct double mutant plant osuvr8.

According to the laboratory of Professor Liu Yaoguang, South China Agricultural University (Ma, X., Zhang, Q., Zhu, Q., Liu, W., Chen, Y., Qiu, R., Wang, B., Yang, Z., Li , H., Lin, Y., et al. (2015). A Robust CRISPR/Cas9 System for Convenient, High-Efficiency Multiplex Genome Editing in Monocot and Dicot Plants. Molecular Plant 8:1274-1284.) Proposed monocotyledons pYLCRISPR/Cas9-MTmono vector system for CRISPR knockout in rice. The targets selected by the OsUVR8a and OsUVR8b genes are Site1 and Site2, respectively, and the sequences are as follows:

Site1: 5'-AGGAGCTGCAGCTCTACAG-3'

Site2: 5'-GAGGACCGGCTGGTGCCGA-3'

The vectors for knocking out OsUVR8a and OsUVR8b genes in rice were constructed according to the methods mentioned above. The constructed vector is transformed into Agrobacterium, and the callus of wild-type rice is infected and transformed to construct transgenic crops (which can be constructed by conventional methods, or entrusted to a professional company for cultivation, such as the Frontier Laboratory of Crop Design of Unnamed Xingwang System) (Beijing) Co., Ltd.), the T0 generation plants were obtained by induction and differentiation, and then they were screened.

Example 3: Screening of rice UV-B photoreceptor gene OsUVR8a and OsUVR8b double mutant osuvr8.

1) Extraction of rice DNA by CTAB method.

(1) Take the young leaves of rice with a length of 2 cm and grind them with liquid nitrogen;

(2) Add 550 μL CTAB, incubate at 65°C for 30 min, shake 3 times during this period;

(3) After incubation, add 550 μL of 24:1 chloroform/isoamyl alcohol, mix well, and let stand for 10 minutes at room temperature (this operation has peculiar smell and should be carried out in a fume hood);

(4) room temperature, 12000rpm centrifugation for 5min;

(5) After centrifugation, 400 μL of the supernatant was added to an EP tube pre-cooled at -20°C and filled with 500 μL of absolute ethanol, and placed at -20°C for 15 minutes;

(6) Centrifuge at 12000rpm for 5min at room temperature, discard the supernatant;

(7) Add 300 μL of 75% ethanol and mix well, centrifuge at 12000 rpm for 5 min at room temperature, and discard the supernatant;

(8) Air-dry at room temperature until there is no ethanol, add 100ul ddH ₂ O to dissolve.

2) Design PCR amplification primers P3 and P4 according to the OsUVR8a target position, design PCR amplification primers P5 and P6 according to the OsUVR8b target position, and use the DNA of the plant to be screened as a template for PCR amplification. The sequences of these primers are as follows:

P3:5'-CCTAGGCGGTGGTTAATTATCTG-3'

P4:5'-GGAGGGTGTCGTAATACATGAAA-3'

P5: 5'-TTGCCGGCCGCTTCTATC-3'

P6:5'-ATGGGCAGATGGCTGTTT-3'

The PCR products were sequenced, and the obtained sequencing results were compared with the original sequences to confirm the type of mutation.

Example 4: Construction of rice UV-B photoreceptor gene OsUVR8a overexpressing plant CFP-OsUVR8a.

The constitutively expressed CFP-OsUVR8a was transformed into wild-type rice varieties using the recombinant vector pCAMBIA2300-35S-CFP-OsUVR8a, and the T0 generation plants were obtained and screened. The T0 generation plants were transplanted to the field for cultivation, and the T1 generation seeds were collected. Then, the T1 generation seeds were screened with G418 resistant medium, and the lines that met the separation ratio of 3:1 were transplanted to the field for cultivation, and the T2 generation seeds were collected. Then, the T2 generation seeds were screened with G418 resistant medium, and the whole live line was transplanted into the field for breeding.

Example 5: Detecting the effect of the rice UV-B photoreceptor gene OsUVR8a gene on the growth and development of rice under UV-B light.

In order to use the above-constructed transgenic materials (osuvr8 and CFP-OsUVR8a) to detect the effect of the rice UV-B photoreceptor gene OsUVR8a gene on the growth and development of rice under UV-B light, the inventors spread rice seeds on a petri dish at 37°C. After dark treatment for 3 days, they were placed under the illumination conditions of white light and white light plus UV-B light for 7 days, and then the growth of each plant was photographed. The total length of the whole aerial part of rice, the length of the first internode and the second internode were measured by Image J software, and the measurement results are shown in Figures 2 and 4.

Example 6: Experimental method for UV-B light damage experiment.

The inventors spread the rice on a petri dish, treated it in the dark at 37°C for 3 days, and placed it under the illumination conditions of white light and white light plus UV-B light for 7 days, and then transferred the plants to the culture medium to continue culturing. Rice seedlings grown under the above two light conditions were treated with white light plus UV-B light for 2 days, and then allowed to recover under white light for 1 day. Then take the tip of the opposite leaf for scanning, and obtain a clear picture for observing the damage degree of the leaf, as shown in Figures 3 and 5.

sequence listing

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Claims (9)

1. Rice UV-B photoreceptor gene OsUVR8a, characterized in that it has the cDNA sequence shown in SEQ ID NO.1. 2. The protein OsUVR8a encoded by the rice UV-B photoreceptor gene, characterized in that its amino acid sequence is shown in SEQ ID NO.2. 3. The protein OsUVR8a encoded by the rice UV-B photoreceptor gene according to claim 2, characterized in that it consists of 453 amino acid residues, and is a homologous protein of the Arabidopsis UV-B photoreceptor protein AtUVR8. 4. A recombinant expression vector, characterized in that it comprises the rice UV-B photoreceptor gene OsUVR8a as claimed in claim 1. 5. recombinant expression vector as claimed in claim 4 is characterized in that constructing with plant expression vector, when constructing, can add any constitutive promoter or enhanced promoter before its transcription initiation nucleotide, or other Promoters of plant genes. 6. recombinant expression vector as claimed in claim 5, is characterized in that described plant expression vector comprises binary Agrobacterium vector; In described plant expression vector, also comprises the 3 ' end untranslated region of exogenous gene, namely comprises polyadenylation nucleotide signals and any other DNA fragments involved in mRNA processing or gene expression. 7. A transgenic plant of rice UV-B photoreceptor gene OsUVR8a, characterized in that it comprises the rice UV-B photoreceptor gene OsUVR8a according to claim 1, and the transgenic plant is CFP-OsUVR8a/Nip. 8. The application of the rice UV-B photoreceptor gene OsUVR8a according to claim 1 in the research and cultivation of radiation-resistant plants. 9. The application of the protein OsUVR8a encoded by the rice UV-B photoreceptor gene according to claim 2 in the research and cultivation of radiation-resistant plants.

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