Proteomics-based Analysis Of The Effect Of Accelerated Ageing On The Viability Of Alliummongolicum Seeds

The Allium mongolicum is a perennial herb of the genus Allium in the lily family.Seed propagation is the most common way of reproducing A.mongolicum populations,and is one of the most domesticated forms of cultivation.However,after maturation,the seeds of A.mongolicum will be prone to aging with the extension of storage time,causing problems such as reduced seed vigour and germination rate,which seriously affects the exploitation of A.mongolicum and the long-term conservation of germplasm resources.Therefore,in this study,the wild seeds from the meadow of Ordok Qianqi,Ordos City,which were harvested in 2019（kept at 4℃during the period）,were subjected to artificially accelerated ageing at high temperature and high humidity,and the germination rate,vigour index,mineral elements and amino acids in the seeds were studied during the ageing process to investigate various physiological and biochemical changes of A.mongolicum seeds.The proteomics approach was used to analyse the differential proteins and related pathways during the ageing process,with a view to providing evidence on the protein expression level for the study of the ageing mechanism of A.mongolicum seeds.The main findings are as follows.All germination indexes of A.mongolicum seeds showed a significant decrease with the increase of ageing time;among them,at T₄ treatment,the viability index of A.mongolicum seeds was 0,and the values of other germination indexes also tended to 0,indicating that sand onion seeds were completely inactivated.In addition,during the artificial ageing process,K⁺and Na⁺in A.mongolicum seeds showed a trend of decreasing and then increasing with the extension of ageing time,with the lowest content of K⁺in T₂ treatment and the lowest content of Na⁺in T₃ treatment,and the K⁺/Na⁺ratio was smaller than that of the CK;the content of Mg²⁺was significantly higher than that of the control in T₁treatment and the lowest in T₃ treatment;Ca²⁺showed a trend of increasing and then decreasing with the extension of ageing time.Ca²⁺showed a trend of increasing and then decreasing as the ageing time increased,and the increase was greatest at T₁ treatment and highest at T₃ treatment.It can be seen that the ion content in the seeds of A.mongolicum showed different trends during the accelerated ageing process.The A.mongolicum is rich in amino acids,mainly glutamic acid,arginine,aspartic acid,lysine,leucine,valine,serine and phenylalanine,with glutamic acid having the highest content.It is possible that the ageing treatment has caused the destruction of some of the thermally unstable amino acids in the protein,causing the glutamic acid content to rise.Proteomic analysis of unaged（CK）,lightly aged（T₁）and heavily aged（T₄）seeds was performed using TMT technology,and a total of 4336 proteins were identified,of which 291 were significantly differentially expressed.36 differentially expressed proteins were screened in T₁.vs.CK,including 16 up-regulated expression and 20 down-regulated expression;in T₄.vs.139 differentially expressed proteins were present,of which 64 were significantly up-regulated and 75 were significantly down-regulated;a total of 116differentially expressed proteins were identified in T₄.vs.T₁,51 were up-regulated and 65were down-regulated.There were a total of 4 identical differentially expressed proteins in the three comparison groups.