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Lanzhou University (2018)

Functional Divergence of AOX1a from Populus Euphratica and P.pruinosa in Response to Abiotic Stresses

雷文丽;

Titre : Functional Divergence of AOX1a from Populus Euphratica and P.pruinosa in Response to Abiotic Stresses

Auteur : 雷文丽;

Grade : Master’s Theses 2018

Université : Lanzhou University

Résumé partiel
In higher plant,there are two respiratory pathways on mitochondrial membrane,cyanide-sensitive cytochrome C oxidase(COX)pathway and cyanide-insensitive alternative oxidase(AOX)pathway.Once plants are subjected to various stresses,the AOX pathway will be activated by alternative oxidases(AOXs),which are located in the mitochondrial inner membrane and act as terminal oxidase in the mitochondrial electron transport chain.The AOX gene family is coded by a small gene family,and AOXs have been established as one of the essential defence components in the response of plant to biotic and abiotic stresses.In this study,we have isolated and identified AOX genes from P.euphratica and P.pruinosa respectively,and compared their functions divergence after diversification of the two desert poplars.The results were as follows :(1)The duplication of AOX genes in poplars.A total of four orthologus AOX genes were identified in genome of Populus euphratica and P.pruinosa respectively.Of them,AOX1a,AOX1b and AOX1c located on the chromosome 12 while AOX1d is located on chromosome 3that would attribute to one whole genome duplication event occurred in genome of Populus species.Whereas AOX1a,AOX1b and AOX1c were suggested duplicated by tandem duplications.The collinear analysis of the four genes confirmed this deduce,it was found that the duplication block of AOX1a,AOX1b and AOX1c had a collinear relationship with that of AOX1d,and the distance between AOX1a,AOX1b and AOX1c were less than 200kb on chromosome 12.(2)The over-expression of AOX1a from P.euphratica and P.pruinosa enhance proportion of cyanide-resistant respiration in total respiration.We investigated total respiration rate(Vt),cytochrome c respiration rate(Vcyt)and cyanide-resistant respiration rate(Valt)of the transgenic Arabidopsis lines,respectively.The results showed that there was no significant difference between Vt,Vcytyt and Valtlt except for that of in aox1a lines,but the ratio of Vcyt/Vt of aox1a was significantly higher than that of other lines,and the ratio of Valt/Vt was significantly lower than that of other lines.However,in terms of Vcyt/Vt and Valt/Vt,no significant difference were found between the WT and AOX over-expressed lines.These results suggested that over-expression of AOX could increase alternate respiratory activity to WT level.

Mots clés : alternative pathway; AOX; gene duplication; functional divergence; abiotic stress;

Présentation (CNKI)

Page publiée le 20 mai 2019