Method for predicting development trend of field rice planthopper population by using microbiota

Abstract

The invention provides a method for predicting the population development trend of field rice planthoppers by utilizing microorganisms of immigrated adults for the field of agricultural pests, which is characterized by comprising the following steps: collecting the immigrated adults of the rice planthoppers, and measuring the diversity and relative abundance of the microorganisms carried in the adults; establishing a relation model between the diversity and relative abundance of the microbiota and the life, fecundity and progeny short wing rate of immigrated adults; carrying out microbiota determination on rice planthopper adults of an immigration peak to be predicted to obtain diversity and relative abundance indexes, substituting the diversity and relative abundance indexes into the relation model, and predicting the life, the fecundity and the progeny short wing rate of the rice planthopper adults of the immigration peak; the development trend of the population is predicted when the rice planthoppers migrate according to the standard that the longer the imago life is, the higher the reproductive capacity or the short wing rate of the progeny is, the faster the subsequent number increase of the field rice planthopper population is, the higher the number is, and the heavier the harm is, and the development trend of the population is predicted when the rice planthoppers migrate into the rice planthoppers.

Description

Technical Field

[0001] This invention belongs to the field of agricultural pests, specifically relating to a method for predicting the population development trend of rice planthopper, an important agricultural pest, using microbial communities. Background Technology

[0002] The main planthoppers that damage rice are the white-backed planthopper and the brown planthopper. They are migratory, grow rapidly in population, and cause severe damage to rice, making them a major enemy of rice production and often leading to significant losses. Rice planthoppers are small, numerous, and often hide at the base of rice plants, making them difficult to detect and increasing the difficulty of monitoring and control. Early prediction of rice planthopper population trends is crucial for timely and effective control, thereby reducing rice losses. Therefore, developing an effective method for early prediction of rice planthopper population trends has significant application value in modern rice production.

[0003] Predicting the population development trend of rice planthoppers often relies on the size of the immigrant population. The size of the immigrant population can be obtained through light traps and insect radar monitoring. However, the relationship between the number of rice planthoppers migrating and the number of rice planthoppers in the field is often affected by the year and region. In some years or regions, the number of immigrants and the number of rice planthoppers in the field are positively correlated, while in others, there is no correlation. Therefore, relying solely on the number of immigrants to predict the field development trend of rice planthopper populations is not accurate or effective enough. Rice planthoppers exhibit wing dimorphism. Long-winged individuals are capable of flight but have low reproductive capacity; short-winged individuals are flightless but have high reproductive capacity. An increase in the short-wing rate indicates a rapid increase in population size. Rice planthoppers often carry various microorganisms, known as the microbiota. Microorganisms influence the biological characteristics of the host insect, but whether the characteristics of the microbiota can be used to predict the development trend of brown planthopper populations after migration is currently unclear, and no relevant application methods have been established. Therefore, constructing a new method for predicting the development trend of rice planthopper field populations based on the characteristics of the microbial community of migrating populations will help to accurately predict the development trend of rice planthopper populations in advance, provide sufficient decision-making and preparation time for the precise control of rice planthoppers, thereby improving control efficiency and saving control costs. Summary of the Invention

[0004] The purpose of this invention is to provide a method for predicting the subsequent population development trend of rice planthoppers when they migrate in. This method utilizes the microbial community carried by the rice planthoppers, determines the composition and structure of the microbial community, calculates the diversity index and relative abundance of specific microorganisms, and establishes the relationship between the microbial diversity index, relative abundance of microorganisms, and the fitness (adult lifespan, reproductive capacity, and short-wing rate of offspring) of the migrating rice planthopper population. The future development trend of the rice planthopper population is determined by the fitness level, thus enabling the prediction of the population development trend at the time of migration, allowing sufficient time for subsequent control.

[0005] The objective of this invention is achieved through the following methods: During the migration period of rice planthoppers, adult planthoppers are collected using light traps or other methods; DNA is extracted from the collected adult planthopper samples; using the DNA as a template, high-throughput sequencing is performed on the V3-V4 highly variable regions of the 16S rRNA gene of microorganisms using primers 338F (5′-ACTCCTACGGGAGGCAGCAG-3′) and 806R (5′-GGACTACHVGGGTWTCTAAT-3′) to obtain the composition and quantity of operable taxonomic units (OTUs) of microorganisms carried by rice planthoppers; the diversity index of the microbial community carried by the rice planthopper adult samples is calculated using the Shannon index, and the number ratio method is used to calculate... Wolbachia , Cardinium , Acinetobacter The relative abundance index of microorganisms at the genus level was used to establish a relationship model between the microbial diversity index and the relative abundance index of microbial genera and the lifespan, reproductive capacity, and short-wing rate of offspring of migrating adults of rice planthoppers. Microbial community measurements were performed on the migrating adults to obtain their diversity and relative abundance. These values ​​were then substituted into the relationship model to predict the lifespan, reproductive capacity, and short-wing rate of offspring of the migrating adults. If these indicators were higher than the normal level, it was predicted that the subsequent rice planthopper population in the field would be higher than normal, requiring close monitoring of the insect population changes and preparation for control measures. If they were lower than the normal level, the subsequent insect population in the field would be lower than normal, and monitoring could continue.

[0006] Effects of the present invention: Compared with the commonly used method of predicting the future field population based on the number of rice planthoppers that migrate in, the present invention has the following beneficial effects: (1) The microbial community is used to characterize the lifespan, reproductive capacity and short-wing rate of the offspring of the migrating rice planthopper population. This not only considers the quantity of the migrating population, but also its quality. The combination of quantity and quality can more accurately reflect the development trend of the subsequent field population and improve the accuracy of rice planthopper population prediction; (2) The established relationship between the diversity of the microbial community and the relative abundance of various microorganisms and the lifespan, reproductive capacity and short-wing rate of the offspring of the migrating rice planthopper adults can be used to select one or more indicators for prediction according to the actual situation to meet the needs of users with different conditions. If users have the conditions to determine the composition and structure of the microbial community, they can use the diversity of the microbial community and the relative abundance of each microorganism to jointly predict the development trend of the population. If users only have the conditions to determine the relative abundance of a certain type of microorganism, they can use the relative abundance of a certain type of microorganism to make predictions. The application of this method is relatively broad. (3) By measuring the characteristics of the microbial community of the migrating adult insects, the prediction of the development trend of the rice planthopper population can be brought forward to the time of migration. The development trend of the rice planthopper population can be predicted as soon as it migrates in. Compared with the commonly used field survey prediction method, it is at least 20 days earlier. (4) The collection of migrating adult insects can be automatically collected by insect-attracting lamps, and the detection of the microbial community can be completed in one stop by the equipment. Therefore, this method can be completed entirely by the equipment, without the need for manual field surveys and sampling, which greatly saves labor costs and reduces the professional requirements for rice planthopper prediction work, thus expanding the user group. Detailed Implementation

[0007] The method of the present invention can be implemented in the following ways, but is not limited to these ways.

[0008] Collection of migrating adult rice planthoppers: In the monitoring area, migrating adult planthoppers were attracted by light traps, counted, and classified. During the peak period of light trapping, adult rice planthoppers were selected, and DNA extraction and microbial sequencing were performed on samples of 10 planthoppers each. Three or more samples were collected during each peak period.

[0009] Microbial community sequencing: High-throughput sequencing of the V3-V4 highly variable region of the bacterial 16S rRNA gene was performed using extracted DNA samples and primers 338F (5′-ACTCCTACGGGAGGCAGCAG-3′) and 806R (5′-GGACTACHVGGGTWTCTAAT-3′) to obtain the composition and number of operable taxonomic units (OTUs) of microorganisms.

[0010] Microbial diversity calculation: The Shannon diversity index value of the microbial community of each sample was calculated using the number of each OTU determined.

[0011] Calculation or determination of relative abundance of microbial genera: Calculate the relative abundance of microbial genera in the sample by using the number of OTUs (overseas unit numbers) of each microbial genera. Wolbachia , Cardinium , Acinetobacter The relative abundance index (i.e., the ratio of the number of organisms to the total number of organisms). Alternatively, quantitative PCR can be used to determine the relative abundance of each microbial genera in each DNA sample, i.e., the relative abundance index.

[0012] Establishment of the relationship between microbial community characteristics and rice planthopper fitness: Using light-trapped adults collected during different migration peak periods, fitness indicators such as adult lifespan, reproductive capacity, and short-wing rate of offspring were measured. Relationship models between each indicator and the diversity index and relative abundance index of the microbial community were established, such as linear regression models.

[0013] Prediction of rice planthopper population development trends: High-throughput sequencing of the microbial community of rice planthoppers at the predicted peak migration period is performed to obtain the composition and structure of the microbial community, calculate the diversity index (Shannon index) and the relative abundance of each microbial genera, or perform... Wolbachia , Cardinium and Acinetobacter Quantitative PCR was used to determine the relative abundance of microorganisms. The results were then input into an established model relating microbial indicators to adult lifespan, fertility, and short-wing rate of offspring to calculate the fitness levels of the rice planthopper. These values ​​were compared with the historical performance of these indicators to predict the development trend of the migrating population. If the predicted adult lifespan, fertility, and short-wing rate of offspring were higher than the historical average, the future population size of the migrating rice planthopper would be higher than the historical average, requiring control measures. If these indicators were lower than the historical average, the future population size would be lower than the historical average, requiring no control measures. If they were close to the historical average, the field population size would be similar to the historical average. This method allows for the prediction of the subsequent development trend of the rice planthopper population upon its migration.

[0014] Implementation Results: In this case study, during July-October 2023 and 2024, different time periods of migrating adult rice planthoppers were observed and attracted using light traps in Jurong, Jiangsu Province. Samples of migrating adults were obtained, and high-throughput sequencing was performed on the V3-V4 highly variable regions of the 16S rRNA genes of bacteria within the attracted adult rice planthoppers to obtain the OTUs of each bacteria. The Shannon diversity index and relative abundance of each bacterial taxonomic unit (phylum, class, order, family, and genus) were calculated. Simultaneously, migrating adult rice planthoppers were attracted and paired at a 1:1 ratio (male to female) and reared on standard cup-grown rice seedlings in an incubator (27℃, 14h:10h photoperiod). The number of surviving individuals was observed and recorded daily until the adults died, thus obtaining the adult lifespan. Female rice planthoppers lay their eggs in the rice seedling tissue. When nymphs hatched on the seedlings, the number of nymphs was counted daily, and all were removed and reared on new rice seedlings until no more nymphs hatched, thereby obtaining the adult reproductive capacity. When the nymphs reared on the new rice seedlings develop into adults, the number of long-winged and short-winged adults is counted daily and removed from the seedling cups until all nymphs emerge, thus calculating the short-wing rate of the offspring. A model was built using the diversity index and relative abundance of the microbial community carried by rice planthoppers at different stages of migration, along with adult lifespan, fertility, and the short-wing rate of the offspring. The results showed that the diversity index of the microbial community carried by the rice planthoppers was positively correlated with adult lifespan, fertility, and the short-wing rate of the offspring, and the diversity index was significantly positively correlated with the short-wing rate of the offspring of the migrating adults. A prediction model for the short-wing rate (Y) of the offspring based on the microbial diversity index (X) was established as: Y = 0.3822X + 0.02969; Wolbachia The relative abundance of [a specific insect species] was negatively correlated with adult lifespan, fertility, and the percentage of short-winged offspring, and the correlation with the percentage of short-winged offspring was significant. This led to the establishment of a [further research model based on this]. Wolbachia The prediction model for the short-wing percentage (Y) of offspring based on relative abundance (X) is: Y = -0.8464X + 0.785; (The text abruptly ends here, likely due to an incomplete sentence or missing information.) Cardinium The relative abundance of these insects was positively correlated with adult lifespan, fertility, and the percentage of short-winged offspring. A model based on this was established. Cardinium The prediction model for adult lifespan (Y) based on relative abundance (X) is: Y = 0.02903X - 0.1454, and the prediction model for offspring short-wing rate (Y) is: Y = 0.387X + 0.6302. This utilizes the diversity of the microbial community carried by adult rice planthoppers and... Wolabchia , Cardinium Relative abundance can effectively characterize adult lifespan and the short-wing rate of their offspring (Table 1). The longer the lifespan of adult rice planthoppers or the higher the short-wing rate of their offspring, the faster their subsequent population grows, and the more severe the damage to rice. The diversity and relative abundance of microorganisms carried within the population can be used to predict the development trend of migrating rice planthopper populations.

[0015] The implementation of this method shows that by measuring the structural composition of the microbial community, adult lifespan, reproductive capacity, and short-wing rate of offspring in adult rice planthoppers collected by light traps, a system based on microbial community diversity and... Wolbachia , Cardinium A model for predicting the lifespan of migrating adult rice planthoppers and the short-wing rate of their offspring based on relative abundance indices has been developed. This model demonstrates excellent performance and can be used to predict the population development trend after migration. This method only requires attracting rice planthoppers by light during the migration season and measuring the structural composition of the microbial community or the relative abundance of specific genera within the adults to easily predict the future development trend of the migrating population. Currently, automated intelligent identification and counting of light-attracted rice planthoppers are possible, and the entire microbial community measurement process can be completed using specialized equipment. Therefore, using microbial community detection methods to predict the development trend of rice planthopper populations eliminates the need for manual field surveys and sampling, significantly reducing the labor intensity and workload of field monitoring. Furthermore, it allows for prediction of population development trends at the time of rice planthopper migration, greatly advancing the prediction time and facilitating subsequent control measures.

[0016] Table 1. Linear regression models for predicting adult lifespan, fertility, and short-wing rate of rice planthoppers using diversity indices and relative abundance of microbial communities carried by migrating populations.

Claims

1. A method for predicting the population development trend of rice planthoppers in the field using microbial communities, characterized in that, Migrating adult rice planthoppers were collected, and the composition and structure of their internal microbial community were determined. The diversity index and relative abundance of the microbial community were calculated, and a model was established to establish the relationship between the diversity index and relative abundance and the lifespan, fertility, and short-wing rate of the offspring of the adults. Microbial community measurements were performed on adult rice planthoppers during the peak migration period to obtain the diversity index and relative abundance of the microbial community. These values ​​were then substituted into the relationship model to predict the lifespan, fertility, and short-wing rate of the offspring of the migrating adults, thereby predicting the development trend of the field population when rice planthoppers migrate.

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