Preliminary Analysis Of The Effect Of Exogenous Amino Acids On The Protein Synthesis In Arabidopsis Thaliana

Plant growth and development is affected by many environmental factors,such as temperature,humidity,light,nutrition and so on.Nitrogen is widely present in nature and is one of the most important elements in plant growth and development.It is not only an nutrition source,but also an important part of biological macromolecules,such as proteins,nucleic acids,phospholipids and so on.As for the endogenous factors affecting plant growth,proteins synthesis is an important factor in regulating plant growth and development.Exogenous amino acids,as an important organic nitrogen in soil,plays an important role in the growth and development of plants.However,the studies on exogenous amino acids in plants are contradictory,and whether exogenous amino acids is involved in the regulation of signal transduction related of proteins synthesis as a signal molecule remains unclear.And FRONIA as a type of receptor protein kinase,directly regulates the protein synthesis rate of downstream factor EBP1.To further explore the effects of exogenous amino acids on protein synthesis in Arabidopsis thaliana,in this paper,we studied the influence of exogenous amino acids on protein synthesis in Arabidopsis thaliana using Col-0?FRONIA mutant and overexpression as materials.The specific research results of this study are as follows:(1)The phenotype of Col-0 caused by nitrogen deficiency was rescued by adding exogenous arginine(Arg),alanine(Ala),asparagine(Asn),glutamine(Gln),asparagine(Asp),and glycine(Gly),and the weight,dry weight and chlorophyll content of Col-0 were significantly increased(P <0.05)after treatment with the above six amino acids.The results showed that Arabidopsis can absorb exogenous amino acids,and Arg,Ala,Asn,Gln,Asp,and Gly could be used as potential organic nitrogen sources to promote plant growth and development.(2)It was found that the primary root length of Col-0 was significantly longer than the untreated,and the side root occurred after nitrogen deficiency treat ment.After the addition of Gln,the root length of Col-0 was significantly shortened(P <0.05),and was similar to that under untreated condition(Mock),but not sensitive to Ala and Asn.Gly and Asp significantly promoted the root length of Col-0(P <0.05).In addition,after adding Arg,the root length of Col-0 was significantly shortened and shorter than that of Mock(P <0.05),but cotyledon development was normal.After the addition of 7 other amino acids,the root length of Col-0 was significantly shortened and cotyledon development was abnormal.This indicates that different amino acids have different effects on plant root growth.(3)The fluorescence of 35 S :: EBP1-GFP indicate that Gly,Ala,Arg and Gln could promote the fluorescence accumulation of 35 S :: EBP1-GFP.The absorbance curves of each ribosome component at A260 nm and the relative m RNA expression of EBP1 in the polyribosome component(layer 8-11)were further determined by ribosome density gradient centrifugation experiments.The results indicate that Gly,Arg and Ala can promote the protein accumulation of EBP1 at the translation level.The protein levels of EBP1 in wild-type was further detected after treatment with 3 m M different amino acids.It was found that the protein quantity of EBP1 decreased after nitrogen deficiency treatment compared to untreated.After adding Ala and Gln,protein quantity of EBP1 increased.It indicates that Ala and Gln promote the accumulation of EBP1 protein at the prot ein level.(5)FERONIA mutant fer-4 was not responsed to amino acides compared to Col-0.Using widely-targeted metabolomics to compare the metabonomics of Col-0 and fer-4,there are 804 metabolites were detected in total,295 metabolites was significantly different,127 metabolites of which were up-regulated and 168 metabolites of which were down-regulated.The up-regulated significant differential metabolites mainly included proanthocyanins and anthocyanins,indicating that FERONIA is involved in the nitrogen metabolic process of Arabidopsis thaliana and plays a key role in regulating the dynamic balance of nutrient metabolism.Through KEGG enrichment analysis,we obtained 20 key pathways related significant differences metabolites between Col-0 and fer-4,including 1 amino acid synthesis pathway and 3 amino acid metabolism pathways.The results suggested that FERONIA mutant fer-4 was insensitive to amino acids might caused by the abnormal metabolic pathway of amino acids.Due to amino acids are key components of protein synthesis,the results also suggested that FERONIA may be involved in protein synthesis.In conclusion,the results of this study showed that exogenous amino acids can promote EBP1 protein synthesis.And FERONIA mutation cause metabolic disorders.