Effects Of Biofertilizer On Growth And Development Of Corn Seedlings Under Drought Stres

Corn is the biggest for the growth area grain crop in China,mainly used as primary food,breeding feed and deep processing raw materials.Due to the influence of global warming,the area of arid and semi-arid cultivated land in China continues to increase,and the drought level in most parts of the country is on the rise.At present,the annual reduction of corn caused by drought in China is as high as 15～20%,and drought has become one of the important restricting factors affecting the stable production and production in China.Soil microorganisms are the most active component in the soil ecosystem,which play an important role in maintaining plant growth and stress response through their participation in the formation and transformation of soil organic matter,chemical element circulation,and plant nutrition and primary production.The adaptive response of soil microbial communities to stress signals can be explained by the "cry-for-help" model,namely,the stressed plants change the chemical components of their root secretions and affect the soil microbial community structure in the rhizosphere,and the altered microbial communities directly inhibit or indirectly affect plant gene expression,and thus improve plant tolerance to stress stress.Arbuscular mycorrhizal fungi(arbuscular mycorrhizal fungi,AMF)inoculation can affect the cellular osmotic pressure,antioxidant system activity and photosynthetic efficiency of many plants under drought stress,and then improve their drought resistance.Soil phospholysis can transform soil insoluble phosphorus into water-soluble phosphorus easily available to plants,which can not only increase the absorbable soil nutrient elements,but also enrich specific soil microbial populations under drought stress,and improve the tolerance of plants to oxidative stress and osmotic stress to a certain extent.Corn for continuous drought stress,through the comparative analysis of maize leaf cell resistance physiological and biochemical index change,and through the whole transcriptome sequencing analysis of AP fertilizer affect the molecular mechanism of corn drought resistance response,the main conclusions are as follows:(1)Effect of AP bacterial fertilizer application on the height and physiological andbiochemical indexes of maize plants under drought stressAt 15 d of drought stress,the P,A,and AP groups were 3.89%,10.26,and 13.37%higher than the CK group,respectively.Compared with the other three groups,the application of AP bacterial fertilizer can significantly promote the growth of corn.With the extension of stress time,MDA level in CK group continued to increase significantly(P<0.05),and MDA level in stress 5,10 and 15 d in AP group was significantly lower than that in CK group(P <0.05).By the 15 th d of stress,MDA levels increased 1.83,1.28,1.21,and 0.77 times higher than before stress initiation.During the drought stress treatment,the SOD activity of all CK group increased first and then decreased,with the maximum SOD activity in group P,group A and AP group to the 10 th d of drought stress.At 5 d and 10 d,the AP group had significantly higher SOD activity than the other groups(P <0.05).A,AP and CK and P at 5 and 10 d of drought treatment(P <0.05).At 10 d of drought treatment,the maximum POD activity reached each treatment,and the POD activity of AP,A,P,and CK groups increased by 30.6%,12.5%,13.9%,and 9.32% compared with day 0,respectively.During the drought stress treatment,the overall CAT activity of each group showed a trend of rising first and then decreasing.CAT activity in the AP fertilizer group was significantly higher than in the other three groups(P <0.05).By comparing the changes of MDA and antioxidant enzyme activities in each group during drought stress,AP microbial fertilizer could improve the oxidative stress tolerance level of corn,which is more beneficial for the plants to resist drought stress.(2)Effect of AP bacterial fertilizer application on differential m RNA expression in maizeleaf cells under drought stress Compared with CK group,the total number of differentially expressed genes in maize leaves of AP group under drought stress was 320,of which 204 were upregulated and 116 were downregulated.The proportion of DEGs in the three main categories of GO enrichment to biological processes,cell components and molecular function was 34.33%,43.12% and 22.55%,respectively,The more enriched subcategories include catalytic activity,binding,cell,cell components,and metabolic processes.197 DEGs annotated to103 taxonomic metabolic pathways in the KEGG database,Among them,plant-pathogen interaction,starch and sucrose metabolism,other types of O-glycan biosynthesis,zeatin biosynthesis,and galactose metabolism and 6 metabolic pathways,including amino acid biosynthesis,are significantly enriched pathways,A total of 41 DEGs of these significantly enriched pathways,Of these,25 were upregulated,16 expression groups were downregulated.(3)Effect of AP fertilizer on differential expression of noncoding RNA in maize leaf cellsunder drought stress The numbers of lnc RNA,mi RNA,and circ RNA were 75,18,and 14,respectively.KEGG pathway enrichment analysis was performed on the differentially expressed lnc RNA target genes,and the differentially expressed lnc RNA cis-target genes were mainly involved in plant hormone signaling,MAPK signaling pathway,etc.Differentially expressed lnc RNA trans target genes are mainly involved in plant pathogen interaction,phenylpropanoid biosynthesis,etc.Mi RNA enrichment to differential expression is involved in phenylpropanoid biosynthesis and endocytosis.Differentially expressed circ RNA enrichment factors are mainly concentrated in the purine metabolism pathway and oxidative phosphorylation.