| In order to explore the physiological response and molecular regulation mechanism of B.inermis under salt stress,18 samples of B.inermis from Xinjiang province were used as research materials.Salt tolerance of plant at seedling stage under NaCl stress was evaluated to screen salt-tolerant materials.The physiological indexes of salt-tolerant plants were determined,and the Third-generation sequencing platform of PacBio Sequel was used for sequencing to select differential genes related to salt tolerance.From the perspective of the combination of physiology and transcription,we explored the molecular regulation mechanism of salt tolerance and laid the foundation for molecular genetic improvement of B.inermis.The results showed as followings:1.Evaluation and screening of salt-tolerance in 18 B.inermis germplasms.After treatment with 200 mmol·L-1 NaCl for 12 days,Seedling height and Root Length,Relative electrolyte leakage,Relative water content,Proline content,Malondialdehyde content,SPAD and K+/Na+ratios in leaves were determined.These 8 single indexes were converted into 4 main factor comprehensive indicators,and the comprehensive evaluation D value was calculated based on the comprehensive indicator value and the membership function value.Based on D value cluster analysis,the 18 B.inermis materials were divided into moderate salt tolerance types including 9,salt tolerance types including 6 and salt sensitive types including 3.2.Changes in physiological response of B.inermis seedlings under NaCl stress.BL-12,which was obtained through salt stress screening,was treated with 300 mmol·L-1 NaCl stress for 0 h,12 h,24 h,36 h,and 48 h.Then the K+concentration,Na+concentration,REL,RWC,Pro,MDA,SPAD,Fv/Fm,Superoxide dismutase,Peroxidase and Catalase indicators of BL-12 leaves of the material were measured respectively.The results showed that the activities of antioxidant enzymes such as SOD,POD and CAT increased,the osmotic regulator Pro increased,and the maximum photochemical efficiency of PS Ⅱ in the leaves was affected.3.The full-length transcript sequencing technology was used to analyze the transcription and expression of genes in leaves and roots of B.inermis under NaCl stress,and 19.67 G Polymerase Read Bases,355836 bp full-length transcripts were obtained.A total of 116578 DEGs related to NaCl stress were identified.Through the enrichment analysis of GO and KEGG,these DEGs are involved in different metabolic pathways regulated to salt stress response,mainly involving overlapping or differentiating pathways in the molecular network cascade,such as signal sensing,signal transduction,transcription regulation,and antioxidant network defense.Through analysis of transcription factors,it was found that bHLH,bZIP,NAC,WRKY,MYB,and WGRS increased after salt stress.Using actin as the internal reference gene,RTqPCR was performed on 10 differentially expressed genes,and the gene expression results were consistent with the transcriptome data.4、Genes related to photosynthesis in the leaves of B.inermis under NaCl stress,such as Psb28s,PsbAs,PsbOs,PsbPs and PsbQs were decreased,and the PSⅡ maximum photochemical conversion capacity Fv/Fm value was decreased,which indicated that salt stress caused damage to photosynthesis in B.inermis leaves.Analysis of differential expression of DEGs found that these DEGs were involved in signal sensing,signal transduction,transcriptional regulation,and participation in the antioxidant defense system.The comprehensive analysis of genes was carried out,such as anti-oxidase of APX,POD,GPX,SOD and CATrelated genes.The gene expression of Ca2+signaling-related pathways including RLKs,CLMs,CIPKs,CDPKs,MAPKs and SOS3s;genes associated with abscisic acid signals including PYR/PYLs,PP2Cs and SnPK2s related to;as well as genes associated with ion conduction and osmotic stress including AKTs,HKTs,SOS1s,NHXs and P5CSs,and the results showed that the expression of these genes increased expression after salt stress. |
PDF Full Text Request