Comprehensive Evaluation Of Salt-Alkali Tolerance Of Brewing Sorghum And Combined Analysis Of Multiple Components

In order to study the response mechanism of sorghum to saline-alkali stress,the genes and metabolites related to saline-alkali tolerance of sorghum were mined,In this experiment,180 brewing sorghum germplasm resources were treated with 1/2Hoagland nutrient solution as control and 1/2 Hoagland nutrient solution mixed with saline-alkali（Na HCO₃:Na₂CO₃=9:1）.It was set up with three treatment gradients of 0,100 mmol/L and 200 mmol/L to determine morphophysiological indicators,transcriptome sequencing,and liquid-liquid chromatography to analyze the differential genes and differential metabolites in brewing sorghum leaves and perform biological analysis.The main findings are as follows:1.In this experiment,180 brewing sorghum were screened,classified and analyzed for salinity-alkali tolerance at seedling stage,and 51 extremely salinity-alkali tolerant materials such as 1298,1104,2456,2534,1111,3045 and 3318 were screened.The relative survival rate after salinity-alkali stress was 100%and the relative root length and seedling length were less affected by saline-alkali stress.Ninety-five saline-alkali sensitive materials,including 1176,1289,1172,1275,4205and 3322,were screened,and their relative survival rates after saline-alkali stress were low and their relative root lengths and relative seedling lengths were affected by salinity-alkali stress.One extremely salinity-alkali tolerant material with good growth and minimal effect of salinity-alkali stress and one salt-alkali sensitive material with the greatest effect of salinity-alkali stress were selected.2.The SOD,POD,CAT,MDA,soluble sugar and proline contents of both the very salt-alkali tolerant material 1298 and the saline-alkali sensitive material 1176were measured and analyzed under salinity-alkali stress.The results showed that the six physiological indicators of both materials changed under salinity-alkali stress.Among them,SOD,POD,CAT and soluble sugar showed a trend of"rise-peak-fall"under salinity-alkali stress,while MDA and proline increased with the increase of salinity-alkali concentration.Compared with 1176,1298 had higher activities of SOP,POD and CAT,and higher contents of MDA,soluble sugar and proline under saline-alkali stress.3.The results of transcriptomic analysis showed that 2849 and 3092 up-regulated genes and 2443 and 1280 down-regulated genes were detected in 1298 and 1176 at100 and 200 mmol/L salinity-alkali stress concentrations,respectively.Functional enrichment analysis by GO and KEGG indicated that metabolic pathways related to phytohormones,flavonoids and amino acids play a key roles under salinity-alkali stress.A total of 53 classes of transcription factors were identified in the transcripts,and they were mainly WRKY,AP2/ERF-ERF,NAC,MYB,etc.Compared with1176,1298 had higher expression levels of plant hormone,flavonoid and amino acid related genes under saline-alkali stress.4.Metabolomic analysis showed that 471 and 950 up-regulated metabolites and366 and 677 down-regulated metabolites were detected at 1298 and 1176 under 100mmol/L and 200 mmol/L salinity-alkali stress concentrations.The differential metabolites were mainly enriched to amino acid metabolism and flavonoid biosynthesis,which are key pathways for plant stress response.Compared with1176,1298 had higher accumulation of plant hormones,flavonoids and amino acid-related metabolites under saline-alkali stress.5.The combined transcriptome and metabolome analyses revealed that the key metabolic pathways for brewing sorghum in response to salinity-alkali stress are flavonoid biosynthesis and amino acid metabolism,which mainly include differential metabolites such as apigenin,galangin,naringenin,p-coumaroyl coenzyme A,cycloalkenylchalcone,N-acetyl-L-citrulline,L-serine and Sobic.001G471100.v3.2,Sobic.002G205100.v3.2,Sobic.002G175600.v3.2 and other differently expressed genes,These related metabolites and genes play an important role in the salinity-alkali tolerance of brewing sorghum.Extremely salt-tolerant varieties have higher levels of antioxidant enzyme a ctivity and antioxidant accumulation than Yu Min salt-tolerant varieties,plant h ormones,flavonoids,amino acids and other related genes and related metabolite s have higher expression and accumulation.