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Lanzhou University (2017)

Salt-tolerance Mechanisms of Populus Euphratica and P. Pruinosa Using Multiple Transcriptome Comparisons

罗文春;

Titre : Salt-tolerance Mechanisms of Populus Euphratica and P. Pruinosa Using Multiple Transcriptome Comparisons

Auteur : 罗文春;

Grade : Doctoral Dissertation 2017

Université : Lanzhou University

Résumé
Populus euphratica and P pruinosa,are two sister desert poplars characterized by high tolerance of salt stress but the latter with higher salt tolerance than the former.Both of them are distributed on the desert regions of northwest China as the key species for scattered forests in the deserts.They play an important role for maintaining the local arid ecosystems.In this study,we used the second-generation sequencers to examine gene expression changes of two species under salt stress through sequencing transcriptomes.1.Expression differences between these two salt tolerant species and two other salt sensitive ones under salt stressIn contrast to high salt tolerance of P.euphratica and P pruinosa,both P.trichocarpa and P.tomentosa,are salt-sensitive congeners.In order to identify the common adaptations of these two groups of poplars in response to salt stress,we compared gene expression changes of four poplars through sequencing transcriptomes of callus under salt stress.We identified 7822 1:1 orthologs between the four species and 702 differentially expressed genes(DEGs)during the 48 h salt stress.The results of the hierarchical clustering suggested that the patterns of gene expression were significantly different between two groups of poplars.In the salt-sensitive poplar species,we found six genes had a consistent response to salt stress,including 6-phosphogluconolactonase 4,Raffinose synthase,Hsp20,WRKY,Peroxidase 15 and Fatty acid desaturase,which are related to stress response and energy metabolism previously reported in plants.In the salt-tolerance poplars,we found five genes with consistent responses consistence,including oxidoreductase activity,plant peroxidase,NADH,cytochrome P450 and lipase GDSL ;all of them were reported as the salt tolerance genes in plants.2.Gene expression changes of seed germinations of P.euphratica and P.pruinosa under salt stressAlthough both P.euphratica and P.pruinosa are tolerant of salt stress,the latter is more salttolerant than the former.We examined gene expression profiles of two species during seed germination during seed germination through sequencing transcriptomes.We found that in both species,gene expressions related ribosomes and energy metabolism were significantly inhibited when the salt concentration increased,which comprised 14 ribosomal related genes,fructose 1-6,diphosphate dehydrogenase(MSTRG.17398.2)in the glycolysis reaction and an aminotransferase(CCG021502.1)involved in photorespiration.We also identified the commonly up-regulated genes related to the high salt-tolerance,including trehalose phosphorylase(TRP,MSTRG.15348.2),deubiquitination-specific protease(UBP9,MSTRG.23479.3)and a GDSL lipase(GLIP1,CCG030033.1).Expression of several genes might explain the higher salt tolerance of P.pruinosa than P.euphratica,which comprised SCARECROW-like 8(CCG030097.1),vitamin B6 synthase(PDX1,CCG023950.1),Chitin elicitor receptor kinase 1(CERK1,MSTRG.17436.3),catalase 2(CATALASE 2,MSTRG.2944.19)and acetolactate synthesis catalyzed enzyme(CSR1,CCG012489.1).In addition,two genes shut down P.pruinosa are probably related to increasing the salt-tolerance of plants.One is the methionine lyase gene,the high-expression of which caused Arabidopsis thaliana more sensitive to oxidative stress by salt.The other is one of A NUDX family hydrolase genes,whose silence in Arabidopsis thaliana was reported to increase the efficiency of NADPH cycle and therefore improve salt stress.The silence of these two genes is likely to be the major reason for the more resistance of P.pruinosa than P.euphratica although further molecular experiments are required

Mots clés : Populus pruinosa; Populus euphratica; salt-tolerance; transcriptome; gene expression;

Présentation (CNKI)

Page publiée le 16 janvier 2018