Slat Tolerance Physiology And Screening And Analysis Related Genes In Solanum Tuberosum L.

Soil salinization has become a global concern in the world.The aggravation of salinization and secondary salinization of arable land makes food security face severe challenge.With the development of the national potato main grain strategy,the planting area of other grain crops is stable and there is little space to improve the unit yield,it is of great significance for the national grain production safety to make use of the vast number of salinized or secondary salinized land to produce potatoes.In this study,the key genes of potato salt stress response were studied by using tetraploidcultivated potato as research material.An in vitro identification method of potato salt tolerance was established to evaluate the salt tolerance of potato germplasm,to explore the effect of salt stress on physiology and biochemistry of potato,and to scan and analyze the key genes of potato response to salt stress,which enriched the study on the mechanism of potato salt tolerance.The main findings are as follows:1.The effects of 0 mmol/L,40 mmol/L,80 mmol/L,120 mmol/L and 160 mmol/L NaCl on the plant height,total biomass,bud fresh quality and rooting percentage of Leshu No.1,Zhongshu No.7,Kexin No.1 and Kangshu53 were studied.The appropriate concentration of salt-tolerant screening was determined to be 100 mmol/L.And 52 potato germplasms were stressed via the concentration.The results show that the plant height,the total biomass,the bud fresh quality and the rooting percentage can be used as indicators for selection of salt-tolerant potato.The method of membership function and cluster analysis was effective and feasible to identify salt tolerance.Comprehensive evaluation showed that the extreme salt-tolerant materials were Longshu No.5 and LZ111,and salt-sensitive material were Qingshu No.9,LongshuNo.8,Zhongshu No.14 and 04P48-3.The salt tolerance of germplasm derived from northern monoculture region was better than that of breeding area in china.2.The effects of salt stress on antioxidant and membrane lipid peroxidation,osmotic substances and ions in Potatopathway of potato were studied.The activities of catalase?CAT?,peroxidase?POD?,superoxide?SOD?and the contents of proline?PRO?,soluble sugar,soluble protein,malonaldehyde?MDA?and of Longshu No.5 and Qingshu No.9 were determined under 500 mmol/L NaCl at 0 h,20 h,24 h,48 h,72 h and 96 h,respectively;The Na⁺,K⁺,Ca²⁺in the root surface of the Longshu No.5 and Qingshu No.9were determinated under 200 mmol/LNaCl.The results showed that the The POD and SOD activities of Longshu No.5 were significantly different from those of the control,but there was no significant difference in Qingshu No.9;The CAT activity of Qingshu No.9 decreased significantly,but there was no significant difference between salt stress and the control in Longshu No.5;The response time of soluble protein and soluble sugar to NaCl was earlier than that of PRO;Na⁺was efflux,K⁺was stabilization and Ca²⁺was influx in Longshu No.5,and the K⁺was efflux in Qingshu No.9;The salt tolerance of Longshu No.5 was stronger than that of Qingshu No.9 according to the membership function of physiological indexes.Therefore,antioxidation,osmotic substances or ions regulation may be the main ways to produce salt tolerance differences between the two genotypes.3.The RNA-Seq was used to compare the transcriptome of potato tissue culture seedlings of 24 h,48 h,72 h,96 h under normal growth and 500 mmol/L NaCl stress,and the potato?PGSC?DM?v4.03?was used as the reference genome.The results showed that more than 84.36%readscan be accurately matched to the reference sequence,indicating that the results of RNA-Seq and the reference sequence were reliable;8204 genes were selected to be induced by salt stress according to|log2FC|?1 and FDR?0.01,of which 631DEGs were continuously up-regulated and 92 were continuously down-regulated over 4periods.GO enrichment revealed that DEGs was mainly involved in transcription factors,catalytic activity,signal transduction activity,transporter and membrane composition,and KEGG enrichment analysis showed that DEGs was enriched in MAPK signaling pathway,oxidative phosphorylation,calcium signaling pathway,starch and sucrose metabolism.Therefore,the possible salt tolerance molecular mechanisms of transcription factors,MAPK signal pathway,oxidative phosphorylation,ion transport and calcium signal pathway in potato were proposed,and 20 key genes of salt tolerance were screened.Finally,the reliability of the RNA-Seq results were confirmed via the expression patterns of 11 DEGs by qPCR,and the result was consistent with the results of RNA-Seq analysis.