Peanut Root Morphology Shovelomics And MiRNA Regulation Mechanism In Response To Nitrogen And Potassium Deficiency

The root morphology plays a very important role in plant growth and development,and the root architecture is closely related to the absorption efficiency of water and nutrients.In this study,89 kinds of peanuts with different genotypes were used as materials.Field shovelomics and indoor paper rolling method were used to conduct a 2-year(2017 and 2018)field and indoor(2018)experiment.Variation and stability in the environment.At the same time,under indoor conditions,the effects of nitrogen and potassium deficiency on physiological indicators such as biomass,root characteristic parameters,fluorescence parameters,root respiration,etc.of peanut seedlings and the expression of miRNA and their targets related to regulating root growth were studied through hydroponic experiments to clarify The mechanism of nitrogen and potassium deficiency on the regulation of peanut seedling growth and root architecture.The results showed that there were large variations between the plant growth and root traits of 89 different genotypes of peanut,and the coefficient of variation was between 8.28%and 53.05%.There were significant correlations between different types of peanuts in dry weight above ground,dry weight of root system,total root length,number of lateral roots,density of lateral roots and number of nodules(P<0.05,0.24<R~2<0.75),according to lateral root density and root system cluster analysis based on the included angle shows that the root configuration of most peanut varieties(66.29%)belongs to the same root type during two years.Therefore,it is believed that the peanut root configuration has certain stability between two-year field trials.Correlation studies have shown that dry weight and root dry weight above ground are significantly correlated with total root length,root surface area,total root volume and number of nodules,which indicates that root growth is closely related to aboveground growth.In addition,field tests and laboratory tests are also significantly related.The lateral root density and root angle of seedlings cultivated indoors for 7 days were significantly correlated with the lateral root density and root angle measured in field trials,respectively.This shows that some root traits identified at the seedling stage can reflect the growth status of the root system at the later growth stage.The results of potassium deficiency in indoor peanut seedlings showed that potassium deficiency significantly inhibited the growth of peanut seedlings,reduced the leaf area,plant dry weight,total root length,root surface area,and root oxygen consumption of peanut seedlings,and increased the main root length and lateral root area length.And root vitality.At the same time,potassium deficiency induces abnormal expression of miRNA and its targets.Under the condition of low potassium treatment,the expression of miR160 was the highest in the expression analysis,and the expression of ARF2 was the highest in the target gene.On the 4th day of transplantation,the expression folds of miR319,miR857,miR390 and miR169 were the highest,and on the 8th day after transplantation,all miRNAs were inhibited.The induction rate of target genes GRF1 and ARF2 was the highest on the 4th day after transplantation,and the target gene was suppressed on the 8th day after transplantation.At the same time,miRNA and its target genes were negatively correlated during potassium deficiency treatment.The results of nitrogen deficiency in indoor peanut seedlings showed that nitrogen deficiency significantly inhibited the growth of peanut seedlings and reduced the dry and fresh weight,leaf area,stem length,total root length,root surface area,root volume,main root length,lateral root zone length,lateral root of peanut The number,lateral root density,root vitality and chlorophyll fluorescence parameters Fv and Fm also increased root diameter and oxygen consumption of leaves,main root tips and lateral roots.Under the conditions of low nitrogen treatment,the expression of miR160 was the highest,and the expression of the target gene SPL1 was the highest,followed by the bHLH74 transcription factor gene.The expression of mi395 was the highest,and the target genes were suppressed.At the same time,there was a negative correlation between miRNA and its target genes during nitrogen deficiency treatment.In this study,the roots of different varieties of peanuts were analyzed for the first time,and different root configurations were classified to provide a basis for nitrogen and potassium utilization.By combining field and indoor,the root form of indoor seedlings can be used to provide a theoretical basis for field production.