Method for directionally increasing spermine and spermidine in wheat grains by utilizing long illumination

Abstract

The invention belongs to the field of wheat product regulation and control, and particularly relates to a method for directionally increasing spermine and spermidine in wheat grains by utilizing long illumination. Aiming at the technical problem that spermine and spermidine are difficult to naturally enrich in wheat, the invention provides a novel staged and long-illumination wheat cultivation method. According to the method, synergistic enrichment of spermine and spermidine can be achieved, synergistic accumulation of various amino acids is promoted, directional shortening of the growth cycle is achieved, stable yield is guaranteed by promoting tillering, and finally the synergistic effect of polyamine enrichment, amino acid increasing, cycle shortening and yield stabilizing is achieved.

Description

Technical Field

[0001] This invention belongs to the field of wheat product regulation, specifically relating to a method for directionally increasing spermine and spermidine in wheat grains using long-term light exposure. Background Technology

[0002] Spermine and spermidine are essential polyamine bioactive substances that play important roles in human health. These include participating in cell proliferation and repair, improving intestinal mucosal barrier function, delaying aging, regulating immune metabolism, enhancing the body's resistance to pathogens, and acting as neuroprotective factors to maintain normal nervous system function. Ingesting spermine and spermidine through diet is an important way to safeguard human health.

[0003] Wheat is a core food source for humans to obtain polyamines and amino acids, but the natural enrichment of spermine and spermidine in its grains faces multiple challenges. First, under natural cultivation conditions, polyamine synthesis relies on the glutamate-arginine metabolic pathway, which is easily affected by environmental fluctuations such as light and temperature, resulting in low and unstable accumulation of spermine and spermidine. Second, there is metabolic competition between polyamines and amino acids; traditional fertilization or chemical regulation methods often lead to an increase in one substance while a decrease in another, making synergistic enrichment difficult. Third, when conventional techniques shorten the wheat growth cycle to meet crop rotation or disaster avoidance needs, insufficient accumulation of photosynthetic products often occurs, further inhibiting the synthesis and transport of spermine, spermidine, and amino acids. Fourth, existing enhancement technologies mostly rely on the external application of polyamine precursors or chemical reagents, posing residual risks, and are costly and lack universality, failing to meet the requirements of green agriculture development.

[0004] Photoperiod is a core environmental factor regulating plant growth and secondary metabolism. Existing research only focuses on its impact on the growth period or a single nutrient, and has not developed an integrated technical solution that synergistically enhances spermine / spermine-total amino acids and shortens the growth period, which cannot meet the needs of high-quality, health-oriented wheat production. Summary of the Invention

[0005] The purpose of this invention is to provide a method for directionally increasing spermine and spermidine in wheat grains using long-term light exposure.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is: a wheat planting method that controls the light intensity and duration of light exposure during wheat planting. Specifically, the control method is as follows: from wheat seedling stage to tillering stage: light duration 12–13 h / d, light intensity 300–450 μmol·m⁻². -2 ·s -1 From the jointing stage to the flowering stage of wheat: 16–18 h / d of light duration and 550–650 μmol·m² of light intensity. -2 ·s -1Wheat grain-filling to maturity stage: photoperiod 21–22 h / d, light intensity 700–1000 μmol·m⁻² -2 ·s -1 .

[0007] Accordingly, the method is applied to increasing the content of spermine, spermidine, and total amino acids in wheat grains; and to increasing the number of wheat tillers and shortening the wheat growth cycle.

[0008] This invention offers the following beneficial effects: For the first time, this invention discovers that, for the specific wheat variety Zhongke Nuomai 258, prolonged photoperiods activate the phytochrome B (phyB) signaling pathway, upregulate the expression of key genes involved in polyamine synthesis, accelerate the flux of the glutamate-arginine-polyamine metabolic pathway, promote the directional conversion of putrescine to spermine and spermidine, and simultaneously inhibit polyamine oxidase activity, reducing polyamine decomposition and achieving synergistic enrichment of spermine and spermidine. Furthermore, prolonged photoperiods extend the photosynthetic effective time, improve carbon and nitrogen metabolism efficiency, promote nitrogen absorption and assimilation, activate the activity of key enzymes involved in amino acid synthesis such as glutamine synthase and aspartate aminotransferase, and promote the synergistic accumulation of various amino acids, avoiding metabolic competition with polyamine synthesis. Simultaneously, prolonged photoperiods regulate the expression of key flowering genes, accelerate the transition from vegetative growth to reproductive growth, shorten the time from grain filling to maturity, achieve a directional shortening of the growth cycle, and ensure stable yield by promoting tiller formation, ultimately achieving a synergistic effect of "polyamine enrichment + amino acid enhancement + cycle shortening + stable yield."

[0009] Specifically, the present invention has the following advantages:

[0010] 1. Outstanding synergistic regulation effect: It can simultaneously achieve the total spermine content, total spermidine content and total amino acid content in wheat grains, and significantly shorten the growth cycle, breaking through the limitations of traditional technology's "single regulation".

[0011] 2. Highly targeted and without side effects: It can precisely activate the synthesis pathways of polyamines and amino acids, and the core yield indicators such as thousand-grain weight are not significantly different from the field control. The number of tillers is greatly increased, achieving accelerated growth and rich nutrition.

[0012] 3. Green, safe, and widely adaptable: It only controls the duration and intensity of light, without adding any chemical reagents, so the risk of residue is zero; it can be adapted to multiple scenarios such as greenhouses, artificial climate chambers, and field supplemental lighting, without the need for complex equipment modifications, and the promotion cost is low.

[0013] 4. Enhanced nutrition and economic benefits: Increased polyamine content strengthens the health benefits of wheat, increased total amino acid content improves nutritional quality, shortened growth cycle improves planting efficiency, and balances consumer health needs with producer economic benefits, significantly increasing the added value of wheat products. Attached Figure Description

[0014] Figure 1 Images of wheat grain morphology under different light treatments;

[0015] Figure 2 A schematic diagram showing the effect of different light treatments on the content of free polyamines in various wheat grains;

[0016] Figure 3 A schematic diagram showing the effect of different light treatments on the content of bound polyamines in various wheat grains;

[0017] Figure 4 This is a schematic diagram showing the effect of different light treatments on the content of fixed polyamines in various wheat grains. Detailed Implementation

[0018] This invention provides a method for effectively increasing the content of spermine and spermidine in wheat grains. The method involves subjecting wheat at different growth stages to different light treatments, using full-spectrum light. The wheat variety used is Zhongke Nuomai 258. The specific treatment includes the following steps:

[0019] 1. Wheat seedling to tillering stage: photoperiod 12-13 h / d, light intensity 300-450 μmol·m -2 ·s -1 The purpose of this step is to ensure the accumulation of photosynthetic products and the reserve of polyamine synthesis precursors.

[0020] 2. From the jointing stage to the flowering stage of wheat: 16–18 h / d of light duration and 550–650 μmol·m² light intensity. -2 ·s -1 The purpose of this step is to target the activation of the expression of key genes involved in polyamine synthesis.

[0021] 3. From the grain-filling stage to maturity of wheat: 21–22 hours of sunshine per day, light intensity 700–1000 μmol·m⁻² -2 ·s -1 The purpose of this step is to promote the transport and stable accumulation of spermine, spermidine, and amino acids into the grains.

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art, and the data obtained are all average values ​​obtained after at least three repetitions, and each repetition yields valid data.

[0023] Example 1: Effects of the method of the present invention on Zhongke Nuomai 258

[0024] Zhongke Nuomai 258 was selected as the experimental material. The experimental method was as follows: On October 30, 2023, wheat was planted in both the field and greenhouse, with three replicates per group. The field planting site was the Shuangliu Experimental Base of the Chinese Academy of Sciences (103°52′E, 30°34′N). The planting method was as follows: two rows were planted per replicate, each row being 1.2m long and 0.25m wide, with 12–15 seeds sown per row. The management method was as follows: basal fertilizer (N: 25%) was applied before planting. 10%; The application rate of 10% was 450 kg / ha. Different light treatments were set up in the greenhouse, including: (1) conventional greenhouse light treatment, the treatment method was: from October 30, 2023 to February 25, 2024, that is, from the wheat seedling stage to the wheat maturity stage, the light treatment was 14 h / d, and the light intensity was 600 μmol·m -2 ·s -1 (2) Greenhouse long-day photoperiod treatment: From October 30, 2023 to November 29, 2023, i.e., from the wheat seedling stage to the tillering stage, the photoperiod was 12 h / d and the light intensity was 400 μmol·m. -2 ·s -1 From November 30, 2023 to December 19, 2023, during the wheat's jointing to flowering stage, the day length was 17 hours / day and the light intensity was 600 μmol·m². -2 ·s -1 From December 20, 2023 to January 11, 2024, during the wheat grain-filling to maturity stage, the day length was 22 hours / day and the light intensity was 800 μmol·m². -2 ·s -1 The temperature was set to 22℃ during illumination and 17℃ during darkness.

[0025] The standard for wheat maturity was defined as 50% of the wheat plants turning yellow and the grains becoming dry and hard. After the wheat grains matured in each group, the appearance of the wheat was observed. Figure 1 As shown in Table 1. The results showed that the treatments had no significant effect on the appearance of wheat grains. The maturity time of wheat varied among the groups, as detailed in Table 1.

[0026] Table 1. Effects of different light treatments on wheat growth cycle

[0027]

[0028] The results showed that the entire growth period of the long light treatment group was only 73 days, which was 110 days shorter than the field control and 45 days shorter than the greenhouse conventional light control. This achieved a targeted and efficient shortening of the growth cycle, which can meet the total output of uninterrupted and efficient continuous planting in greenhouses.

[0029] The contents of spermidine, spermine, and total amino acids in wheat grains of each group were measured using high performance liquid chromatography (HPLC). The results are shown in Table 2. Lowercase letters in Table 2 indicate significant differences (P < 0.05).

[0030] Table 2. Effects of different light treatments on the content of substances in wheat grains.

[0031]

[0032] The results showed that long-day photoperiod treatment significantly increased the contents of spermine and spermidine in wheat grains. The total spermidine content increased by 52.8% compared to the field control and by 163.6% compared to the greenhouse control under conventional light; the total spermine content increased by 241.1% compared to the field control and by 47.1% compared to the greenhouse control under conventional light, with statistically significant differences in the content of all polyamine forms. This indicates that phased long-day photoperiod treatment can precisely activate the glutamate-arginine-polyamine metabolic pathway, breaking through the bottleneck of insufficient polyamine accumulation under natural cultivation and achieving targeted enrichment of spermine and spermidine.

[0033] The total amino acid content in the long-day treatment group was 52.6% higher than that in the field control and 33.6% higher than that in the greenhouse control under conventional light, showing significant differences. This indicates that long-day treatment can coordinate carbon and nitrogen metabolism balance, avoid metabolic competition between polyamines and amino acids, thereby achieving synergistic optimization of the two types of nutrients and significantly improving the nutritional quality of wheat grains.

[0034] The thousand-grain weight, number of grains per ear, and number of tillers for each group were measured, and the results are shown in Table 3.

[0035] Table 3. Effects of different light treatments on core indicators of wheat

[0036]

[0037] The results showed that the thousand-grain weight of the long-day treatment group was not significantly different from that of the field control (P>0.05), but was significantly higher than that of the greenhouse conventional light control (P<0.05). The number of tillers in the long-day treatment group increased by 135.7% compared with the field control and by 364.8% compared with the greenhouse conventional light control. Although the number of grains per ear decreased, the significant increase in the number of tillers compensated for the insufficient number of grains per ear, ensuring the overall yield potential and solving the core pain point of "yield reduction" in traditional short-growth technology.

[0038] Example 2: Comparison of the effects of long-day photoperiod treatment on different wheat varieties

[0039] Simultaneously, Zhongke Nuomai 258 and Zhongke Mai 181 were planted. Zhongke Nuomai 258 is a whole glutinous wheat bred by the Chengdu Institute of Biology, Chinese Academy of Sciences (Sichuan Approval No. 20210010), with an average amylopectin (starch content) content of 97%, meeting the standard for glutinous wheat. Zhongke Mai 181 is a conventional wheat bred by the Chengdu Institute of Biology, Chinese Academy of Sciences (Chongqing Approval No. 20220002). The treatment method included: normal field sowing (Field) on October 30, 2023, as the control group. Each group had 3 replicates, with two rows per replicate, each row 1.2m long and 0.25m apart, with 12-15 seeds planted per row. The artificially controlled long-day photoperiod group was established on October 30, 2023, in a plant factory-based speedbreeding (PF) environment, where the photoperiod duration from wheat seedling stage to tillering stage was 12 h / d and the light intensity was 400 μmol·m⁻¹. -2 ·s -1 The duration of light exposure from the jointing stage to the flowering stage is 17 h / d, and the light intensity is 600 μmol·m⁻¹. -2 ·s -1 The duration of sunlight from the grouting stage to the maturity stage is 22 h / d, and the light intensity is 800 μmol·m⁻². -2 ·s -1 .

[0040] Using the condition that 50% of the plants in the population turn yellow and the grains become dry and hard as the standard for wheat maturity, high-performance liquid chromatography (HPLC) was used to measure the polyamine content in the wheat grains of each group after wheat maturity. The results are as follows: Figures 2-4 As shown in the figure. The results showed that under the same light treatment, Zhongke Mai 181 did not exhibit the same pattern as Zhongke Nuomai 258. Compared to the field environment, free and fixed spermidine in Zhongke Mai 181 were significantly reduced under the PF environment, while bound spermidine was significantly increased; while in Zhongke Nuomai 258, free, bound, and fixed spermidine were all significantly increased under the PF environment. In Zhongke Mai 181, free spermidine was significantly reduced under the PF environment, while in Zhongke Nuomai 258, free spermidine was significantly increased under the PF environment. The two wheat varieties exhibited different patterns under the same conditions, which may be due to the different genetic backgrounds of the two wheat varieties, thus affecting polyamine metabolism.

[0041] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, alterations, substitutions, or variations made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for planting wheat, characterized in that: The specific methods for controlling light intensity and duration of light exposure during wheat cultivation are as follows: Wheat seedling to tillering stage: photoperiod 12-13 h / d, light intensity 300-450 μmol·m -2 ·s -1 ; From the jointing stage to the flowering stage of wheat: photoperiod 16-18 h / d, light intensity 550-650 μmol·m -2 ·s -1 ; From grain-filling stage to maturity of wheat: photoperiod 21–22 h / d, light intensity 700–1000 μmol·m -2 ·s -1 .

2. The application of the method of claim 1 in increasing the spermine content of wheat grains.

3. The application of the method of claim 1 in increasing the spermidine content of wheat grains.

4. The application of the method of claim 1 in increasing the total amino acid content of wheat grains.

5. The application of the method of claim 1 in increasing the number of wheat tillers.

6. The application of the method of claim 1 in shortening the wheat growth cycle.

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