| Baicalein is the main effective component of Scutellaria baicalensis Georgi.,with the continuous deepening of its research,the application field of baicalein is expanding,which leads to the increasing demand of Scutellaria baicalensis Georgi.with baicalein as the main extraction material.However,due to the increasing shortage of wild Scutellaria baicalensis Georgi.resources,the wild Scutellaria baicalensis Georgi.can not meet the market demand,and the relevant provinces begin to carry out large-scale artificial cultivation in the natural distribution areas of wild Scutellaria baicalensis Georgi.cultivation and artificial cultivation of Scutellaria baicalensis have become the mainstream products in the market.However,the content of baicalein in cultivated Scutellaria baicalensis Georgi.is generally low,and the individual difference is obvious,which seriously restricts the development of related manufacturers taking baicalein as the extraction target.Therefore,it is urgent to study the key cultivation measures to improve the content of baicalein.According to the relevant studies,the content of baicalein is affected by both heredity and environment.The climate conditions in Chengde,Hebei Province are most suitable for the accumulation of baicalein,and the content is also higher than that in other areas.However,due to the long-term cultivation without selection,the germplasm degradation is serious.Therefore,the research on the breeding of high content baicalein varieties in Chengde area of Hebei Province is of great significance to reduce the production cost of baicalein and meet the increasing market demand.But at present,the breeding of Scutellaria baicalensis Georgi.mostly depends on traditional breeding,and the traditional breeding is mainly based on phenotype selection.This method has some problems,such as long breeding time,easy to be affected by environment,poor genetic stability and so on.With the development of molecular biology and genomics,molecular breeding has been widely used in the field of agriculture as a rapid and environmentfriendly variety breeding technology,but no related technology has been found in the field of Scutellaria baicalensis Georgi.Single nucleotide polymorphism(SNP)is considered as one of the most promising molecular markers because of its wide distribution and high-throughput detection.This project aims to screen SNPs associated with baicalein from the whole genome based on simplified genome-wide sequencing.So as to find new genetic markers,provide theoretical basis and data support for the breeding of high content baicalein varieties.In addition,because Scutellaria baicalensis Georgi.is mainly planted in the northern region of water deficit,the difficulty of seedling emergence and establishment has become an important factor restricting the cultivation and utilization of Scutellaria baicalensis Georgi.Water priming technology is to use water soaking treatment,at the same time,take certain methods to control the speed of seed water absorption,and then break the seed dormancy,improve the seed germination rate and seedling stress resistance.Because of its low cost and simple operation,it has been widely used,and it is also widely used in the field of Scutellaria cultivation.For example,in some areas,warm water soaking is often used to accelerate the germination of Scutellaria baicalensis Georgi.This method can improve the field seedling rate of Scutellaria baicalensis Georgi.in the rainy area in autumn to a certain extent.However,the seeds of Scutellaria baicalensis Georgi.after accelerating the germination are easy to return to bud in the light drought,resulting in a serious lack of seedlings,which is not suitable for spring sowing and sowing in arid areas.There is a time difference from seed companies to farmers and then to field sowing,that is to say,the seeds triggered by water will not be directly used for sowing,while the vigor of seeds that do not return to dry after water triggered will decline seriously,which may affect the emergence rate and seedling resistance of Scutellaria baicalensis Georgi.to a certain extent.In conclusion,water treatment can improve the germination rate of Scutellaria baicalensis Georgi.seeds,but the drought resistance of Scutellaria baicalensis Georgi.seeds with no back drying treatment is poor,and inducing back drying can slow down the decline rate of seed vigor.Therefore,it is necessary to evaluate the drought resistance and optimize the conditions of water treated Scutellaria baicalensis Georgi.seeds.Based on the above problems,we studied the optimization of SNPs significantly related to baicalein content and water priming conditions of Scutellaria baicalensis Georgi.seeds.(1)Based on this,the content of baicalein in cultivated Scutellaria baicalensis Georgi.in Chengde of Hebei Province was measured by HPLC,and the whole genome of cultivated Scutellaria baicalensis Georgi.in Chengde of Hebei Province was resequenced to obtain SNPs significantly related to the content of baicalein,which provided a theoretical basis for the development of molecular markers with high content of baicalein and directional breeding of cultivated varieties.(2)The difficulty of emergence and planting is an important factor limiting the cultivation and utilization of Scutellaria baicalensis Georgi.in the water deficit area of North China.Seed water priming technology can promote seed germination and seedling growth,improve seed vigor,enhance seedling resistance,and improve seedling establishment rate.In this study,the seeds of Datong in Shanxi Province were selected as the experimental materials,and 10%PEG6000 solution was used to simulate the drought conditions.The germination rate,germination potential and simple vigor index were used as the evaluation indexes.The single factor test and response surface method were used to optimize the water priming conditions of Scutellaria baicalensis Georgi.seeds,and the best water priming conditions were obtained.At the same time,in order to explore the applicability of the best water priming conditions to the seeds of Scutellaria baicalensis Georgi.from different areas,the seeds of Scutellaria baicalensis Georgi.from Datong City,Yuncheng City,Zhang jia kou City and Long hua County of Shanxi Province were used as materials,and PEG-6000 solution was used to simulate different drought conditions to analyze the germination rate,germination potential and simple vigor index of Scutellaria baicalensis seeds under adversity.The results are as follows:(1)SNP sites significantly related to baicalein content were mined based on resequencing technology.In this study,the content of baicalein in cultivated Scutellaria baicalensis Georgi.in Chengde,Hebei Province was measured by HPLC.The samples with significant difference in baicalein content were selected for genome resequencing with coverage depth of 10x.One SNP were detected in the high content group,which could affect the synthesis of baicalein to a certain extent.However,there may be many reasons for the difference of baicalein content,such as gene variation,gene expression and epigenetic modification.This study only discussed the SNP site difference from the gene level,and the exact reasons need to be further explored.(2)Optimization of water priming of Scutellaria baicalensis seeds.In this study,the seeds of Datong in Shanxi Province were selected as the experimental materials,and 10%PEG-6000 solution was used to simulate the drought conditions.The germination rate,germination potential and simple vigor index were used as the evaluation indexes.The single factor test and response surface method were used to optimize the water priming conditions of Scutellaria baicalensis seeds,and the best water priming conditions were obtained.At the same time,in order to explore the applicability of the best water priming conditions to the seeds of Scutellaria baicalensis Georgi.from different areas,the seeds of Scutellaria baicalensis Georgi.from Datong City,Yuncheng City,Zhangjiakou City and Longhua County of Shanxi Province were used as materials,and PEG-6000 solution was used to simulate different drought conditions to analyze the germination rate,germination potential and simple vigor index of Scutellaria baicalensis Georgi.seeds under adversity.The results showed that when the amount of water added was 7 times of the initial weight of seeds,the initiation temperature was 15℃,and the initiation time was 4 h,the germination rate of seeds was 1,It can be used as the optimum condition for water priming of Scutellaria baicalensis seeds in Datong and Yuncheng of Shanxi Province to a certain extent,but it can significantly inhibit the seed vigor of Zhangjiakou and Longhua of Hebei Province.This phenomenon indicates that the water priming conditions of Scutellaria baicalensis seeds from different areas are different,and different areas should explore the water priming conditions according to their own conditions.To sum up,with the increasing market demand for baicalein monomer and Scutellaria baicalensis Georgi,increasing the selective breeding of Scutellaria baicalensis Georgi varieties and the cultivation of seedlings can solve the imbalance between supply and demand in the market to a certain extent.In this study,SNP sites related to baicalein content were found,which laid a foundation for the development of molecular markers for high baicalein content.At the same time,the water priming conditions of Scutellaria baicalensis seeds were optimized,which provided a theoretical basis for improving the emergence rate of Scutellaria baicalensis. |
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