耐盐砧木'抗砧3号'对葡萄微嫁接苗光合作用的影响OA

[Objective]This research aims to systematically analyze the physiological and molecular re-sponse mechanisms of photosynthesis in salt-tolerant grape rootstock micro-grafted seedlings under salt stress,to reveal the potential mechanisms by which salt-tolerant rootstock micrografting regulates grape salt tolerance.[Method]With'Pinot Noir',a salt-sensitive grape variety,as the scion and'Kangzhen No.3',which was salt-tolerant,as the rootstock,grafted seedlings were obtained through micrografting operations.Three types of grape seedlings,including'Pinot Noir'own-rooted seedlings,'Kangzhen No.3'own-rooted seedlings,and grafted seedlings,were transplanted into flowerpots and cultivated for 30 days,then they were treated with 200 mmol/L NaCl for 6 days.The changes in photosynthetic gas exchange parameters(Pn,Gs,Tr,Ci),relative chlo-rophyll content(SPAD),and chlorophyll fluorescence parameters(F0,Fm,Fv/Fm)in the leaves of own-rooted'Pinot Noir'seedlings and grafted seedlings under salt stress were determined and compared.Transcriptome se-quencing was performed to analyze the differentially expressed genes(DEGs)and their response characteristics between own-rooted'Pinot Noir'seedlings and grafted seedlings.Gene functional annotations of DEGs were conducted based on the GO database and KEGG database.Six DEGs were selected for RT-qPCR analysis to verify their consistency with the transcriptome data.[Result]After 6 days of treatment with 200 mmol/L NaCl,Pn,Gs,Tr,Ci,SPAD,F0,Fm and Fv/Fm of the grafted seedlings were significantly increased by 101.2%,51.9%,51.4%,81.1%,40.7%,58.4%,51.5%and 26.9%respectively,compared with those of the own-rooted seed-lings of'Pinot Noir'.Transcriptome sequencing analysis revealed 2 704 common DEGs between grafted seed-lings and'Pinot Noir'own-rooted seedlings under salt stress.GO functional annotation showed that these DEGs were mainly enriched in three categories:biological processes,molecular functions,and cellular compo-nents.KEGG analysis indicated that they were significantly enriched in pathways such as photosynthesis-an-tenna proteins pathway,photosynthesis pathway,and pathway of carbon fixation in photosynthetic organisms.Key genes in photosynthetic pathways,including LHCA6,LHCA5,LHCB4.1,LHCB5,ATPG,ATPD,ATPC,GAPC2,and GAPC,were significantly upregulated in grafted seedlings.The RT-qPCR results showed that the relative expression levels of key DEGs LHCA5,LHCB5,ATPD,ATPC,GAPC2,and GAPCP1 in grafted seedlings under salt stress were consistent with the change trends of TPM values in transcriptome se-quencing,confirming the reliability of the transcriptome data.[Conclusion]Under salt stress conditions,key genes in the photosynthetic pathway of grafted seedlings were up-regulated,enhancing light energy capture,electron transport efficiency,and ATP/NADPH synthesis,optimizing the carbon fixation process in the Calvin cycle,improving light energy utilization and carbon fixation capacity,which indicated that the photosynthetic per-formance was significantly enhanced.