Application of TaNAC019B gene in improvement of salt stress harm resistance of plant

Abstract

The invention discloses application of a TaNAC019B gene to improvement of salt stress damage resistance of plants, and belongs to the technical field of molecular biology. The amino acid sequence coded by the TaNAC019B gene disclosed by the invention is as shown in SEQ ID NO: 2. Compared with a receptor variety Fielder and TaNAC019Crispr wheat strain, the wheat strain overexpressed by the TaNAC019B has the advantages that the wilting degree is relatively poor after salt stress treatment, the seed grain length is relatively long, the grain width is relatively wide, the plant height is relatively high, and the thousand grain weight is relatively heavy; the SOD and POD activities of the leaves are relatively high, the MDA content is relatively low, the relative conductivity is reduced, the net photosynthetic rate, the stomatal conductance and the transpiration rate are increased, and the intercellular CO2 concentration is reduced; therefore, the TaNAC019B gene can improve the ability of wheat to resist salt stress harm, and has important application value in salt-tolerant wheat screening and salt-tolerant wheat variety breeding.

Description

Technical Field

[0001] The invention belongs to the technical field of molecular biology, and particularly relates to application of the TaNAC019B gene in improving the ability of plants to resist salt stress damage. Background Art

[0002] Wheat is one of the main food crops for human beings. Soil salinization can cause wheat growth retardation or even death, and its yield and quality will be seriously reduced. Therefore, it is of great significance to cultivate new varieties of salt-tolerant crops.

[0003] Plant salt tolerance is a complex trait controlled by multiple genes, involving ion transport, osmotic regulation, signal transduction, cellular antioxidant and many other aspects. These genes that respond to salt stress are complex and changeable, and they interact with each other to maintain the normal growth of cells. Deeply exploring and cloning crop salt tolerance-related genes, analyzing their molecular mechanisms involved in salt tolerance regulation, and applying them to molecular breeding can accelerate the pace of cultivating salt-tolerant germplasm, shorten breeding time, and reduce breeding scale and workload. Summary of the invention

[0004] In view of the problems existing in the prior art, the object of the present invention is to provide an application of the TaNAC019B gene in improving the ability of plants to resist salt stress.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] The use of the TaNAC019B gene in improving the ability of plants to resist salt stress, the amino acid sequence of the TaNAC019B gene is shown in SEQ ID NO: 2.

[0007] Based on the above scheme, the nucleic acid sequence of the TaNAC019B gene is shown in SEQ ID NO:1.

[0008] On the basis of the above scheme, the ability of plants to resist salt stress is improved by increasing the expression level of the TaNAC019B gene in plants.

[0009] On the basis of the above scheme, the TaNAC019B gene sequence is used to construct a plant expression vector, which is then transformed into a plant body to overexpress it in the plant, thereby increasing the expression level of the TaNAC019B gene in the plant.

[0010] Based on the above scheme, the plant is wheat.

[0011] A method for improving the ability of plants to resist salt stress damage, by increasing the expression level of the TaNAC019B gene in the plant to improve the ability of plants to resist salt stress damage; the amino acid sequence of the TaNAC019B gene is shown in SEQ ID NO: 2.

[0012] Based on the above scheme, the nucleic acid sequence of the TaNAC019B gene is shown in SEQ ID NO:1.

[0013] On the basis of the above scheme, the TaNAC019B gene sequence is used to construct a plant expression vector, which is then transformed into a plant body to overexpress it in the plant, thereby increasing the expression level of the TaNAC019B gene in the plant.

[0014] Based on the above scheme, the plant is wheat.

[0015] On the basis of the above scheme, the method for improving the ability of plants to resist salt stress is to increase the grain length, grain width, plant height and thousand-grain weight of wheat after salt stress; to increase the SOD activity and POD activity of wheat leaves after salt stress, and reduce the MDA content and relative conductivity; to increase the net photosynthetic rate, stomatal conductance and transpiration rate of wheat after salt stress, and reduce the intercellular CO2 concentration.

[0016] The beneficial effects of the present invention are:

[0017] The present invention clones a TaNAC019B gene from wheat. The TaNAC019 gene in wheat contains multiple alleles, including TaNAC019A and TaNAC019D in addition to TaNAC019B. The present invention detects the relative expression of TaNAC019A, TaNAC019B, and TaNAC019D genes in wheat leaves and endosperm before and after salt stress and finds that the expression of TaNAC019B gene increases significantly after wheat salt stress, and is significantly higher than the expression of TaNAC019A and TaNAC019D genes. Therefore, the TaNAC019B gene is related to the salt tolerance of wheat.

[0018] A plant expression vector was constructed and the TaNAC019B gene was transformed into wheat to obtain the TaNAC019B overexpression strain. Compared with the recipient variety Fielder and the TaNAC019 Crispr strain nac019-1, the TaNAC019B overexpression strain (OE-1) had a poorer wilting degree after salt stress treatment, and had longer seeds, wider grains, higher plant height and heavier 1000-grain weight. In addition, after salt stress, the TaNAC019B overexpression strain (OE-1) had higher SOD activity and POD activity, lower MDA content, lower relative conductivity, higher net photosynthetic rate (A), stomatal conductance (gs) and transpiration rate (E), and lower intercellular CO2 concentration (Ci). It can be seen that the TaNAC019B gene can improve the ability of wheat to resist salt stress and has important application value in the screening of salt-tolerant wheat and the breeding of salt-tolerant wheat varieties. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 To identify the expression pattern of TaNAC019 gene at different time points before and after salt stress;

[0020] Figure 2 This is the expression analysis of TaNAC019B gene in transgenic positive lines;

[0021] Figure 3 This is the phenotype of the TaNAC019 transgenic line under salt stress treatment;

[0022] Figure 4 This is the grain, plant height and 1000-grain weight of TaNAC019 transgenic line under salt stress treatment;

[0023] Figure 5 This is an analysis chart of the measurement results of biochemical indicators of TaNAC019 transgenic strains under salt stress;

[0024] Figure 6 This is an analysis chart of the measurement results of photosynthetic indicators of TaNAC019 transgenic strain under salt stress treatment. DETAILED DESCRIPTION

[0025] The terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art. The present invention will be further described in detail below in conjunction with specific examples and with reference to data. The following examples are intended to illustrate the present invention and are not intended to limit the scope of the present invention in any way.

[0026] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The experimental materials, reagents, drugs, etc. used in the following examples, unless otherwise specified, can all be purchased through general channels.

[0027] In the following embodiments,

[0028] Chinese Spring (CS) wheat seeds are maintained by the Wheat Genetics and Breeding Laboratory, College of Agriculture, Qingdao Agricultural University;

[0029] The seeds of the TaNAC019B overexpression line (OE-1) were gifted by China Agricultural University;

[0030] The transgenic recipient wheat Fielder is maintained by the Wheat Genetics and Breeding Laboratory, College of Agriculture, Qingdao Agricultural University;

[0031] The TaNAC019 Crispr strain (nac019-1) has T inserted into the TaNAC019A gene, G deleted from the TaNAC019B gene, and T inserted into the TaNAC019D gene. Its seeds were donated by China Agricultural University.

[0032] Example 1

[0033] Cloning of TaNAC019B gene

[0034] Using the genomic DNA of the wheat variety Chinese Spring (CS) as a template, PCR amplification was performed using specific primers of the TaNAC019B gene to obtain the nucleic acid sequence of the TaNAC019B gene as shown in SEQ ID NO:1, and the amino acid sequence encoded by it as shown in SEQ ID NO:2.

[0035] SEQ ID NO:1(5'→3')

[0036] ATGGCAGACCACCTTCAAGTTCAGCAGCAACAACAACAGTTAGAGCTTCCACCGGGGTTCAGGTTCCACCCTACTGATGAGGAGATCATCACCTCCTACCTTGCCCCTAAGATTCTCAACCCAGCGTTCAACGCCACAGCGATCGGTGAGGTGGACCTGAATAAGAACGAGCCATGGGAGCTTCCCAACAAGGCCAAGATGGGGGAGAATGAGTGGTACTTTTACTGCCAGAAGGACCGCAAGTACCCCACCGGGATACGAACCAACCGGGCCACGAAGGCCGGCTACTGGAAGGCCACGGGTAAGGACAAAGAGATCGTCAACCCACATTGCATGTCCATGCTCATGGGCATGAAGAAGACATTGGTGTTCTACAAGGGCAGAGCTCCCAGCGGGGAGAAGACCAACTGGGTCATGCACGAGTACAGGCTCGAGATCGGCAAGCAGTCAACATCCGGCCTGCCCACCACCATCGCAAATGCCGCTTCCAATAACGTGTCTTCTAAGGAGTATGTGGTTTGCAGGATCTTCCATAAGAACACTGGAAGTGGGGTGTCATCCATGGTGTCACATGAGGGCAACGGCGGTGCAACAACCACCGACAAGATCTTGTCGATGAGCATGCGTACAGGTGGGGCATGTTGA

[0037] SEQ ID NO:2

[0038] MADHLQVQQQQQQLELPPGFRFHPTDEEIITSYLAPKILNPAFNATAIGEVDLNKNEPWELPNKAKMGENEWYFYCQKDRKYPTGIRTNRATKAGYWKATGKDKEIVNPHCMSMLMGMKKTLVFYKGRAPSGEKTNWVMHEYRLEIGKQSTSGLPTTIANAASNNVSSKEYVVC RIFHKNTGSGVSSMVSHEGNGGATTTDKILSMSMRTGGAC*

[0039] The reaction system of the PCR is as follows:

[0040] 2×Phanta Max Master Mix 12.5 μL, Forward Primer (10 μM) 1 μL, Reverse Primer (10 μM) 1 μL, template 2.5 μL, ddH2O 8 μL.

[0041] The amplification procedure of the PCR is:

[0042] Pre-denaturation: 95°C, 3 min; then enter 35 cycles, denaturation: 95°C, 15 sec; annealing: 62°C, 15 sec; extension: 72°C, 19.4 sec (1 kb / 30 sec); complete extension: 72°C, 5 min; store at 4°C.

[0043] The specific primer sequences of the TaNAC019B gene are as follows:

[0044] Forward primer: 5'-ATGGCAGACCACCTTCAAGT-3' (SEQ ID NO: 3);

[0045] Reverse primer: 5'-TCAACATGCCCCACCTGTACGCA-3' (SEQ ID NO: 4).

[0046] Example 2

[0047] Expression patterns of TaNAC019B gene at different time points before and after salt stress

[0048] A salt-sensitive wheat variety, China Spring (CS), was hydroponically cultured to the one-leaf-one-heart stage and treated with 250 mmol / L NaCl solution to simulate salt stress. Leaves were collected at 0 h, 1 h, 3 h, 6 h, 12 h, and 24 h after treatment.

[0049] A salt-sensitive wheat variety, Chinese Spring (CS), was selected for soil culture, and the endosperm was extracted about 20 days after pollination.

[0050] SteadyPure Plant RNA Extraction Kit was used to extract total RNA from the leaves and endosperm according to the instructions, and the RNA was isolated from the leaves and endosperm using the RNA extraction kit from Nanjing Novozyme Biotechnology Co., Ltd. cDNA was obtained by reverse transcription using III RT SuperMix for qPCR (+gDNA wiper) reverse transcriptase.

[0051] The above cDNA was used as a template, ChamQ Universal SYBR qPCR Master Mix (Vazyme) reagent was used, and the expression level of wheat TaActin gene was used as an internal reference. qRT-PCR amplification was performed using primers for real-time quantitative PCR to detect the relative expression levels of TaNAC019A, TaNAC019B, and TaNAC019D genes in wheat leaves and endosperm before and after salt stress.

[0052] The qRT-PCR reaction system is:

[0053] 2×ChamQ Universal SYBR qPCR Master Mix 5μL, Forward Primer (10μM) 0.2μL, Reverse Primer (10μM) 0.2μL, 1μL of first-strand cDNA solution diluted 3 times, 3.6μL of ddH2O.

[0054] The qRT-PCR amplification procedure uses a three-step approach:

[0055] Pre-denaturation: 95℃ for 3 min; Cyclic reaction: 95℃ for 10 s, 60℃ for 20 s, for a total of 40 cycles; Melting curve: 95℃ for 15 s, 60℃ for 60 s, and 95℃ for 15 s.

[0056] The primer sequences used for real-time quantitative PCR in this step are as follows:

[0057] TaActin-qRT-F: 5'-TATGCCAGCGGTCGAACAAC-3' (SEQ ID NO: 5)

[0058] TaActin-qRT-R: 5'-GGAACAGCACCTCAGGGCAC-3' (SEQ ID NO: 6)

[0059] TaNAC019-qRT-AL:5'-TGCAGGATCTTCCATAAGAACG-3'(SEQ ID NO:7)

[0060] TaNAC019-qRT-AR:5'-TGTACCCATGCTCATCGACC-3'(SEQ ID NO:8)

[0061] TaNAC019-qRT-BL:5'-ATGAGGACGTTGGGACCG-3'(SEQ ID NO:9)

[0062] TaNAC019-qRT-BR:5'-AACATGCCCCACCTGTACG-3'(SEQ ID NO:10)

[0063] TaNAC019-qRT-DL: 5'-GCCGCTTCCATTAACGC-3' (SEQ ID NO: 11)

[0064] TaNAC019-qRT-DR: 5'-ATGCTCATAGACGAGATCTTGTG-3' (SEQ ID NO: 12)

[0065] Result analysis The comparative threshold method was used to quantitatively analyze the real-time quantitative PCR results, set the fluorescence threshold, and determine the cycle number Ct value under the fluorescence threshold. According to the Ct value, the C value was calculated. C = 2 -△Ct , △Ct=Ct 目的基因 -Ct 内参基因 The average of the three repeated C values ​​was calculated as the relative expression level of the target gene.

[0066] The results are as follows Figure 1 As shown in the figure, the expression results of TaNAC019 in Chinese spring leaves before and after salt stress showed that TaNAC019 increased after 1 hour of salt treatment, reached a peak at 6 hours, and then decreased slightly. Among them, the expression levels of TaNAC019B and TaNAC019D were higher than those in the endosperm at 6 hours, and the expression level of TaNAC019B was higher than that of TaNAC019D. Although the expression level of TaNAC019A gene increased slightly after salt stress, it was significantly lower than that in the endosperm.

[0067] Example 3

[0068] Expression analysis of TaNAC019B gene in transgenic wheat after salt stress

[0069] The TaNAC019B overexpression strain (OE-1), transgenic recipient wheat Fielder, and TaNAC019 Crispr strain (nac019-1) were treated with 250mmol / L NaCl solution to simulate salt stress. Total RNA from leaves was collected at 0h, 1h, 3h, 6h, and 12h after treatment, and reverse transcribed into cDNA. This was used as a template, and primers TaNAC019-qRT-BL and TaNAC019-qRT-BR were used for qRT-PCR. The system and conditions were the same as in Example 2 to detect the expression of the TaNAC019B gene. The results are shown in Figure 2 As shown, the expression level of TaNAC019B overexpression line (OE-1) at different time points before and after salt stress was higher than that of Fielder.

[0070] Example 4

[0071] Application of TaNAC019B gene in improving wheat's ability to resist salt stress

[0072] 1. Phenotypic analysis of TaNAC019B transgenic lines under salt stress

[0073] Thirty seeds of the receptor variety Fielder, TaNAC019B overexpression strain (OE-1) and TaNAC019Crispr strain (nac019-1) of the same size were selected, disinfected with 1% NaClO for 10 minutes, and then rinsed with distilled water 4-5 times. After culturing in a culture dish for 1-2 days and turning white, they were transplanted into a 20 cm diameter pot for soil culture. Two treatments and three replicates were set for each variety. Salt stress treatment was performed with 500 mmol / L NaCl solution 7 days after transplanting, and the concentration was increased every 5 days until the phenotype appeared. The results are shown in the figure. Figure 3 As shown, compared with the control Fielder, the wilting and yellowing of leaves in the TaNAC019B overexpression line OE-1 were milder after salt stress; the wilting degree of the TaNAC019 Crispr line nac019-1 was aggravated and the leaves turned yellow severely.

[0074] The receptor variety Fielder, TaNAC019B overexpression strain (OE-1) and TaNAC019 Crispr strain (nac019-1) were planted in the base of Qingdao Agricultural University in Pingdu City, Shandong Province and the Dongying Saline-alkali Land Agricultural Postgraduate Training Base, and their plant heights, grain lengths, grain widths and thousand-grain weights were measured after maturity. Figure 4 As shown in the figure, under salt stress conditions, compared with Fielder, the seeds of the TaNAC019B overexpression line (OE-1) were longer, wider, taller, and had a heavier 1000-grain weight, while the grain length, grain width, plant height, and 1000-grain weight of the TaNAC019 Crispr line (nac019-1) were inferior to those of Fielder. The above results indicate that under salt stress conditions, the TaNAC019B gene can affect the grain shape, plant height, and 1000-grain weight of wheat.

[0075] 2. Determination of biochemical indices of TaNAC019B transgenic lines under salt stress

[0076] After the recipient varieties Fielder, TaNAC019B overexpression line (OE-1) and TaNAC019 Crispr line (nac019-1) showed phenotypes under salt stress treatment, their leaves were taken to measure the biochemical indicators relative conductivity, SOD, POD, and MDA.

[0077] (1) Plant electrical conductivity

[0078] ① Select three leaves of different strains under different treatments as experimental materials, wash them twice with distilled water, dry them with clean filter paper, and cut the leaves into small pieces of 1 to 2 cm long;

[0079] ② Place the cut materials into large test tubes with labels, and add 20 mL of distilled water to each test tube to submerge the leaves;

[0080] ③Put the three prepared materials into a vacuum dryer and use a vacuum pump to extract air from the intercellular spaces for about 15 minutes;

[0081] ④ Slowly release air again, the water will be pressed into the tissue and the leaves will sink (if there is no vacuum dryer, you can also soak the leaves in distilled water for 4 to 6 hours);

[0082] ⑤ Under room temperature, measure the conductivity of the solution with a conductivity meter;

[0083] ⑥Put the solution in a 100℃ boiling water bath for 15-20 minutes to kill the plant tissue, bring it to room temperature, and measure its boiling conductivity;

[0084]

[0085] (2) SOD enzyme activity assay

[0086] ① Weigh 0.2g wheat leaves in a pre-cooled mortar, add 1mL of pre-cooled extract and grind to homogenate, 4℃, 10000rpm, 15min, take the supernatant as SOD crude solution;

[0087] ② Add 1.5 mL of 0.05 mol / L PBS solution, 0.3 mL of 130 mmol / L Met solution, 750 μmol / L NBT solution, 20 μmol / L riboflavin solution and 100 μmol / L EDTA-Na2 solution to the control tube and the assay tube in sequence, add 0.1 mL of enzyme solution to the assay tube, and do not add enzyme solution to the control tube, but replace it with 0.1 mL of buffer solution, and fill the total volume to 3.3 mL with distilled water;

[0088] ③ Set up three replicates, shield one of the control tubes from light and place it under a 4000lx fluorescent lamp with the other tubes for 20-30 minutes at 25-35℃, then compare the color at 560nm;

[0089]

[0090] Ao: light absorption value of the illumination control tube

[0091] As: light absorption value of the sample tube

[0092] Vt: Total volume of sample solution (mL)

[0093] V1: Sample volume during measurement (mL)

[0094] FW: fresh weight of sample (g)

[0095] (3) POD enzyme activity assay

[0096] ① Weigh 0.25 g of leaves, add 5 times the amount of (M / V) pH 7.0 PBS, grind at 15000 rpm on ice for 15 min, and the supernatant is the crude POD extract;

[0097] ② Add 1 mL of 0.3% H2O2, 0.95 mL of 0.2% guaiacol, and 1 mL of PBS (pH 7.0) to the reaction tube in sequence, and finally add 0.05 mL of enzyme solution to start the reaction, and record the increasing rate at 470 nm (an increase of 0.01 OD per minute is defined as 1 activity unit);

[0098]

[0099] ΔA 470 : Change in absorbance during reaction time

[0100] W: plant fresh weight (g)

[0101] Vt: Total volume of enzyme extraction solution (mL)

[0102] Vs: Volume of enzyme solution used in the assay (mL)

[0103] t: reaction time (min)

[0104] (4) Determination of MDA content

[0105] ① Weigh 1g of wheat leaves, add 2mL 10% TCA and grind in a mortar, then add 8mL TCA and continue grinding until homogenized, 4000rpm, 10min, the supernatant is the crude MDA extract;

[0106] ②Take 2 mL of the supernatant, add 2 mL of 0.6% TBA, mix well, react in boiling water for 15 min, take the supernatant, and measure the absorbance at 450, 532 and 600 nm;

[0107] MDA concentration = 6.45*(D 532 -D 600 )-0.56*D 450

[0108] MDA content = 2MDA concentration * extract volume (mL) / fresh weight (g) / 1000

[0109] The results are as follows Figure 5 As shown in the data, under salt stress conditions, the TaNAC019B overexpression line (OE-1) had higher SOD activity and POD activity, lower MDA content, and lower relative conductivity compared with Fielder, while the TaNAC019 Crispr line (nac019-1) was the opposite. This indicates that overexpressing the TaNAC019B gene in wheat can improve wheat's resistance to damage caused by salt stress.

[0110] 3. Determination of photosynthetic indices of TaNAC019 transgenic lines under salt stress

[0111] The portable photosynthetic meter LI-6800 was used to measure the transpiration rate, net photosynthetic rate, stomatal conductance and intercellular CO2 concentration of the recipient variety Fielder, TaNAC019B overexpression line (OE-1) and TaNAC019 Crispr line (nac019-1) before and after salt stress treatment.

[0112] The results are as follows Figure 6 As shown in the figure, under salt stress conditions, compared with Fielder, the net photosynthetic rate (A), stomatal conductance (gs), and transpiration rate (E) of the TaNAC019B overexpression line (OE-1) increased, and the intercellular CO2 concentration (Ci) decreased, while the situation of the TaNAC019Crispr line (nac019-1) was the opposite, which was consistent with the results of the above-mentioned physiological and biochemical indexes.

[0113] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. The use of TaNAC019B gene in improving the ability of plants to resist salt stress, characterized in that: The amino acid sequence of the TaNAC019B gene is shown in SEQ ID NO:

2.

2. The use of the TaNAC019B gene according to claim 1 in improving the ability of plants to resist salt stress, characterized in that: The nucleic acid sequence of the TaNAC019B gene is shown in SEQ ID NO:

1.

3. The use of the TaNAC019B gene according to claim 1 in improving the ability of plants to resist salt stress, characterized in that: By increasing the expression level of the TaNAC019B gene in plants, the ability of plants to resist salt stress can be improved.

4. The use of the TaNAC019B gene according to claim 3 in improving the ability of plants to resist salt stress, characterized in that: The TaNAC019B gene sequence is used to construct a plant expression vector, which is then transformed into a plant body to overexpress the gene in the plant, thereby increasing the expression level of the TaNAC019B gene in the plant.

5. The use of the TaNAC019B gene according to any one of claims 1 to 4 in improving the ability of plants to resist salt stress, characterized in that: The plant is wheat.

6. A method for improving the ability of plants to resist salt stress, characterized in that: By increasing the expression level of the TaNAC019B gene in the plant, the ability of the plant to resist salt stress is improved; the amino acid sequence of the TaNAC019B gene is shown in SEQ ID NO:

2.

7. The method for improving the ability of plants to resist salt stress according to claim 6, characterized in that: The nucleic acid sequence of the TaNAC019B gene is shown in SEQ ID NO:

1.

8. The method for improving the ability of plants to resist salt stress according to claim 6, characterized in that: The TaNAC019B gene sequence is used to construct a plant expression vector, which is then transformed into a plant body to overexpress the gene in the plant, thereby increasing the expression level of the TaNAC019B gene in the plant.

9. The method for improving the ability of plants to resist salt stress according to any one of claims 6 to 8, characterized in that: The plant is wheat.

10. The method for improving the ability of plants to resist salt stress according to claim 9, characterized in that: The method for improving the ability of plants to resist salt stress is to increase the grain length, grain width, plant height and thousand-grain weight of wheat after salt stress; to increase the SOD activity and POD activity of wheat leaves after salt stress, and to reduce the MDA content and relative conductivity; to increase the net photosynthetic rate, stomatal conductance and transpiration rate of wheat after salt stress, and to reduce the intercellular CO2 concentration.

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