Expression And Analysis Of MiR160/164 And Its Targets In Beet(Beta Vulgaris)Seedlings Under Salt/Drought Stress

Soil salinization and drought are important factors affecting global food production and quality.Therefore,the molecular mechanism of plant salt tolerance and drought tolerance has become a hotspot in agricultural science.In recent years,studies have shown that there are multiple genes and transcription factors in plants involved in salt and drought stress response.MiRNAs are highly conserved gene expression regulatory elements that are commonly found in plants and animals and play an important role in plant stress response.The miR160/164 family is widely involved in drought and salt stress response processes in various plants.Beta vulgaris is an important sugar crop in China with many advantages,for example,salt tolerance,resistance to barren,wide adaptability and so on.Understand the mechanism of salt tolerance and drought tolerance in sugar beet and enrich the salt and drought tolerance gene resources is of great significance to the selection of salt-tolerant and drought-tolerant sugar beet.In this paper,the expression of miR160/164 and its target gene in beta vulgaris seedling under the salt/drought stress of beet was studied by means of bioinformatics analysis and molecular biology verification.The following results were obtained.1.The target gene of miR160 and miR164 was predicted by bioinformatics and highthroughput sequencing.The miR160 target genes ARF17/18 and miR164 target genes NAC(21/22)/100 were predicted respectively.2.A P5 CS gene sequence(ID: KY019201)was cloned,total length of which is 2,325 bp and its coding frame is 2,151 bp,encoding the 716 amino acid.The molecular weight of the encoded protein is 77.4 KD,the isoelectric point is 5.72,the number of negative charge residues is 96,the number of positive charge residues is 83,and the hydrophobic coefficient is-0.095.It is a non-secreted hydrophilic protein with no transmembrane region and stable P5 CS enzyme domain,involved in the proline biosynthesis process.3.The beta vulgaris seedlings were subjected to salt stress treatment using 300 mM NaCl.The expression of miR160/164,target genes and P5 CS gene in beta vulgaris samples under different time nodes were analyzed.The results showed that the expression of P5 CS gene was positively correlated with the treatment time under drought stress.miR160/164 expression was significantly down-regulated and followed by a certain pattern of temporal and spatial expression,while the expression of the target gene was significantly up-regulated.4.The beta vulgaris seedlings were subjected to drought stress treatment using 15% PEG6000.The expression of miR160/164,target genes and P5 CS gene in beta vulgaris samples under different time nodes were analyzed.The results showed that the expression of P5 CS gene was positively correlated with the treatment time under drought stress.miR160/164 expression was significantly down-regulated and followed by a certain pattern of temporal and spatial expression,while the expression of the target gene was significantly up-reg?Lated.5.The miR160/164 and their target pathways were predicted by KEGG and other online software.The results showed that miR160 and its target genes were involved in plant hormone signal transduction(map04075)and MAPK signal pathway(map04016)under stress.