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Shanxi University (2021)

Regulation of Sulfur on Drought Stress Resistance and Sulfate Transporter Genes Cloning and Analysis in Foxtail Millet Plants

尹艳芳

Titre : Regulation of Sulfur on Drought Stress Resistance and Sulfate Transporter Genes Cloning and Analysis in Foxtail Millet Plants

Auteur : 尹艳芳

Grade : Master 2021

Université : Shanxi University

Résumé
Sulfur is one of the essential nutrientional elements,and plays an important role in growth and development of plants,as well as in response to adversity stress.Sulfur is mainly absorbed from soil by plant roots in the forms of sulfate ;in addition,when the sulfate is deficiency in soil,sulfur dioxide(SO2)can also be used as a source of sulfur nutrition in the atmosphere.To date,there are few studies on the effect of sulfur in crop’s drought adaptability.Foxtail millet(Setaria italica L.)is a traditional drought-tolerant crop,and grown in arid and semi-arid regions in China.The effects of exogenous application sulfate and SO2derivatives seeds priming on the drought adaptability of foxtail millet seedlings were studied in this research,additionaly,the sulfur regulation on drought stress resistance was discussed of foxtail millet.Moreover,the sulfate transporter family genes(SiSULTR)of foxtail millet leaves were cloned,and the bioinformatics and expression patterns were analysised in this research,the studies provided a basis for subsequent SiSULTR genes function research and further revealed the molecular mechanism of sulfur in regulating the drought resistance of foxtail millet.The main results are as follows :(1)Exogenous application of sulfate could enhance drought resistance by promoting the synthesis of abscisic acid(ABA)in leaves and triggering stomatal closure of drought-stressed foxtail millet seedlings.Sulfur assimilation was promoted by exogenous sulfate application,specifically by enhancing the activities of sulfite reductase(Si R),O-acetylserinelyase(OASTL)and the expression of related genes in drought-stressed seedlings,furthermore,promoted the accumulation of Cys ;Cys induced the production of ABA in the leaves of foxtail millet seedlings by up-regulating the expression of Si ABA3 and Si AAO3,thereby trigged the reduction of leaf stomatal aperture and decreased the rate of water loss,futhermore,enhanced drought resistance of foxtail millet seedlings.(2)SO2 derivatives seeds priming could promote seeds germination and seedlings growth under drought stress.The results showed that SO2derivatives priming led to the increase of total amylase activities of seeds,thereby promoted the germination under PEG stress.Meanwhile,SO2derivatives priming alleviated the oxidative damage by enhancing the activities of antioxidant enzymes and related genes expression in foxtail millet radicles ;furthermore,after SO2 derivatives priming,Cys and glutathione(GSH)content markedly increase was observed,and which was resulted by enhancing Si R,OASTL enzymes activity and related genes expression in radicles.In addition,during the growth stage of seedlings,improved drought resistance induced by SO2 derivatives priming was resulted from increased pyrroline-5-carboxylic acid synthase(P5CS)activity and decreased proline dehydrogenase(PDH)activity,and thereby promoted an accumulation of proline of foxtail millet seedlings.(3)In this research,five SiSULTR genes were cloned from foxtail millet leaves,and named as SiSULTR1 ;1,SiSULTR1 ;2,SiSULTR2,SiSULTR3,SiSULTR4 according to their branching in the phylogenetic tree.The results of multiple amino acid sequence alignment showed that five SiSULTR proteins also contained 10 highly conserved trans-membrane domains and a C-terminal STAS functional domain as the known members of sulfate transporter family,in addition,the results of tissue-specific expression analysis showed that the five SiSULTR genes were expressed in foxtail millet roots,stems,leaves,spikes,and SiSULTR2 had the highest expression in stems,while the remaining four genes were the highest expression in leaves of foxtail millet ;q RT-PCR results also demenstrated that the transcriptional expression of remaining SiSULTR genes are all induced by drought,high salt,heavy metals,ABA stresses,except for the expression of SiSULTR1 ;1 and SiSULTR2 weren’t effected by ABA and high salt stress respectively.Our study aimed to reveal the regulation and relavant mechanisms of sulfur on the drought adaptability of foxtail millet,and the results could provide theoretical basis for improving drought resistance of foxtail millet.

Mots clés : Foxtail millet ;Drought stress ;Sulfate;SO2 derivatives ;SiSULTR;

Présentation (CNKI)

Page publiée le 25 novembre 2021