A low-field nuclear magnetic resonance analysis-based early rice scald rapid detection method

Abstract

The application discloses a kind of early rice scald rapid detection method based on low-field nuclear magnetic analysis, comprising the following steps, collection detection sample;The low-field nuclear magnetic resonance analysis is carried out to each rice kernel sample obtained, echo signal is collected, and the echo attenuation curve data of each rice kernel sample is obtained;Inversion obtains the transverse relaxation time T2 curve of sample, compares the relaxation time T2 curve atlas of sample, identifies whether specific peak exists in the relaxation time T2 curve of sample, if specific peak exists, then rice kernel is infected with rice scald bacteria, otherwise, rice kernel is not infected with rice scald bacteria;Using the application can quickly detect whether rice kernel has rice scald.

Description

Technical Field

[0001] This invention relates to the field of agricultural technology, and in particular to a rapid detection method for early rice false smut based on low-field nuclear magnetic resonance analysis. Background Technology

[0002] Rice blast fungus only affects rice grains. After invading the grain, the pathogen produces hyphae inside the glume that wrap around the floral organs. The hyphae then gradually expand, forming hyphal masses that fill the interior of the glume and eventually break through the gap between the inner and outer glumes, forming rice blast balls. Rice blast balls can be observed 15 days after artificial inoculation. Rice blast fungus produces blastotoxin; a concentration of 0.5% in diseased grains can cause poisoning in humans and animals.

[0003] Early detection of rice grains is necessary to determine whether they are infected with rice false smut fungus. Current techniques employ microscopic grain dissection for detection. The specific steps involve taking a rice grain, using tweezers to separate the inner and outer husks, and observing under a stereomicroscope whether the floral organs are intact and whether they are enveloped by the white hyphae of the rice false smut fungus. This method is inefficient and only suitable for random sampling. For naturally occurring rice false smut grains in the field, which are extremely rare, using this method to identify diseased grains in the field is like finding a needle in a haystack—impractical. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the above-mentioned and / or existing technical problems of low efficiency in detecting rice false smut in rice grains, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to provide a rapid detection method for early rice false smut based on low-field nuclear magnetic resonance analysis. Using the method of this invention, it is possible to quickly detect whether rice grains have rice false smut.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a rapid detection method for early rice false smut based on low-field nuclear magnetic resonance analysis, comprising the following steps: Collect and test samples; Low-field nuclear magnetic resonance analysis was performed on each rice grain sample to collect nuclear magnetic resonance echo signals and obtain echo attenuation curve data for each rice grain sample. The transverse relaxation time T2 curve of the sample was obtained by inversion. By comparing the relaxation time T2 curve spectrum of the sample, it was determined whether there was a specific peak in the relaxation time T2 curve of the sample. If a specific peak was present, the rice grains were infected with rice false smut fungus. Otherwise, the rice grains were not infected with rice false smut fungus.

[0008] As a further improvement of the present invention, rice false smut is artificially inoculated at the end of the booting stage of rice, and rice grains collected 6 days and 9 days after inoculation are used as the test samples.

[0009] As a further improvement of the present invention, a low-field nuclear magnetic resonance (NMR) instrument is used for low-field NMR analysis. The CPMG pulse sequence method is used to acquire NMR echo signals. The parameters used in the CPMG pulse sequence method are: 90-degree pulse width P1: 6 μs, 180-degree pulse width P2: 13 μs, repetition sampling wait time Tw: 1000-10000 ms, analog gain RG1: [10 to 20], digital gain DRG1: [2 to 5], both analog gain RG1 and digital gain DRG1 are integers, preamplifier gain PRG: [1, 2, 3], repetition count: 4, 8, 16, number of echoes: 1000-10000, receiver bandwidth SW: 100, 200, start sampling time control parameter RFD: 0.002-0.08 ms, and delay DL1: 0.1-0.5 ms.

[0010] Compared with the prior art, the present invention has the following technical effects: the present invention is simple to operate, has a short detection time, and uses the difference in relaxation spectrum data as the main identification basis to achieve rapid and accurate detection of whether rice grains are infected with rice false smut in the early stage. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 (a) and (b) in the figure are the relaxation time T2 curves of rice grain A samples 6 days and 9 days after inoculation, respectively.

[0012] Figure 2 (a) and (b) in the figure are the relaxation time T2 curves of rice grain B samples 6 days and 9 days after inoculation, respectively. Detailed Implementation

[0013] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0014] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0015] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0016] As a first embodiment of the present invention, this embodiment provides a rapid detection method for early rice false smut based on low-field nuclear magnetic resonance analysis, which includes the following steps: Rice grains were randomly selected from the field as test samples. Low-field nuclear magnetic resonance analysis was performed on the obtained rice grain samples. The nuclear magnetic resonance echo signal was acquired using the CPMG pulse sequence method (which is an existing technology) to obtain the echo attenuation curve data of each rice grain sample. The transverse relaxation time T2 curve of the sample was obtained by inversion fitting. By comparing the relaxation time T2 curve spectrum of the sample, it was determined whether there was a specific peak in the 1-3ms range of the relaxation time T2 curve of the sample. If a specific peak was present, the rice grains were infected with rice false smut fungus; otherwise, the rice grains were not infected with rice false smut fungus.

[0017] Low-field NMR analysis was performed using a low-field NMR spectrometer. NMR echo signals were acquired using the CPMG pulse sequence method. The parameters used for the CPMG pulse sequence method were: 90-degree pulse width P1: 6 μs, 180-degree pulse width P2: 13 μs, repetition sampling wait time Tw: 1000-10000 ms, analog gain RG1: [10 to 20], digital gain DRG1: [2 to 5] (both analog and digital gains DRG1 are integers), preamplifier gain PRG: [1, 2, 3], repetition count NS: 4, 8, 16, number of echoes NECH: 1000-10000, receiver bandwidth SW: 100, 200, start sampling time control parameter RFD: 0.002-0.08 ms, and delay DL1: 0.1-0.5 ms.

[0018] This invention uses the differences in relaxation spectrum data as the main identification basis to achieve rapid and accurate detection of rice false smut in grains at an early stage. The detection using this invention is simple to operate, and the results are highly accurate, reproducible, stable, and efficient.

[0019] Example 2 Referring to the figure, this embodiment is based on embodiment 1. This embodiment uses scientific verification methods to prove that the present invention can effectively and quickly detect whether rice grains are infected with rice false smut.

[0020] (1) Collect test samples; (2) Place the test sample under a stereomicroscope for identification. Gently separate the inner and outer husks of the grain with tweezers to distinguish between uninfected grains and grains infected with rice false smut. The normally growing grains in the control group are used as control sample A, and the grains infected with rice false smut are used as sample B. (3) Low-field nuclear magnetic resonance analysis was performed on 0.5g of each rice grain sample obtained in step (2). The nuclear magnetic resonance echo signal was acquired by using the CPMG pulse sequence method. The echo attenuation curve data of each rice grain sample were obtained and inverted and fitted to obtain the transverse relaxation time T2 curve of the two samples. By comparing the relaxation time T2 curves of the two samples, it was identified that the rice false smut fungus infected grain, i.e., sample B, had a specific peak at T2 (1-3ms).

[0021] The low-field NMR method used a MesoMR23-060V-I low-field NMR spectrometer. The parameters used for the CPMG pulse sequence method were as follows: 90-degree pulse width, P1: 6μs, 180-degree pulse width, P2: 13μs, repetitive sampling wait time Tw: 1000-10000ms, analog gain RG1: [10 to 20], digital gain DRG1: [2 to 5], preamplifier gain PRG: [1, 2, 3], NS: 4, 8, 16, number of echoes NECH: 1000-10000, receiver bandwidth SW: 100, 200, start sampling time control parameter RFD: 0.002-0.08ms, and delay DL1: 0.1-0.5ms.

[0022] The test results are shown in the figure. Figure 1 and Figure 2 As can be seen, the transverse relaxation time T2 curve corresponding to sample A does not contain a specific peak, while the transverse relaxation time T2 curve corresponding to sample B contains a specific peak. Figure 2 The middle arrow indicates the location of the specific peak, demonstrating that the present invention can accurately detect whether rice grains are infected by rice false smut.

[0023] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A rapid detection method for early rice false smut based on low-field nuclear magnetic resonance analysis, characterized in that: Includes the following steps, Collect and test samples; Low-field nuclear magnetic resonance analysis was performed on each rice grain sample to collect nuclear magnetic resonance echo signals and obtain echo attenuation curve data for each rice grain sample. The transverse relaxation time T2 curve of the sample is obtained by inversion. By comparing the relaxation time T2 curve spectrum of the sample, it is determined whether there is a specific peak in the relaxation time T2 curve of the sample. If there is a specific peak, and the specific peak is located at 1-3 ms in the relaxation time T2 curve, then the rice grains are infected with rice false smut. Otherwise, the rice grains are not infected with rice false smut. Specifically, rice was artificially inoculated with rice false smut at the late booting stage, and rice grains collected 6 and 9 days after inoculation were used as the test samples. Low-field nuclear magnetic resonance (NMR) analysis was performed using a low-field NMR spectrometer, and NMR echo signals were acquired using the CPMG pulse sequence method. The parameters used in the CPMG pulse sequence method were: 90-degree pulse width P1: 6 μs; 180-degree pulse width P2: 13 μs; resampling wait time Tw: 1000-10000 ms; analog gain RG1: [10 to 20]. Digital gain DRG1: [2 to 5]; Analog gain RG1 and digital gain DRG1 are both integers; Preamplifier gain PRG: [1, 2, 3]; Number of repetitions: 4, 8, 16; Number of echoes: 1000-10000; Receiver bandwidth SW: 100 kHz, 200 kHz; Control parameter for start sampling time RFD: 0.002-0.08 ms; Delay DL1: 0.1-0.5 ms.

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