| The accumulation of soil salinity has become a global agricultural problem that threatens the high quality and high yield of crops.Tomato has a very important edible status and economic value,so it is of great significance to study the salt tolerance of its germination period.cGMP as an important second messenger molecule plays an indispensable role in plant response stress.This experiment uses "delicious" cherry tomatoes as a material,setting 20 ?M,40 ?M cGMP with 0,50,100,150,200 mM NaCl.Interacting tomato seeds to screen for concentration,Using physiological and biochemical,RNA-Seq and bioinformatics methods to explore the effects of exogenous cGMP on tomato seed germination and growth,stress resistance,secondary metabolites and transcription levels under NaCl stress,and clarify exogenous cGMP in tomato The mechanism of seed germination tolerance to salt adaptation.The following results are obtained:(1)Exogenous application of 20 ?M cGMP could enhance the amylase activity of cherry tomato under salt stress,which was 44.30% higher than that of salt alone.The amylase content was decreased by 21.01% compared with salt stress alone.The root length,hypocotyl length,fresh weight and dry weight of cherry tomato plants were increased by 94.29%,34.59%,35.08%and 32.81% compared with 50 mM NaCl stress,which effectively promoted the seed germination and seedling growth of cherry tomato under salt stress.(2)Exogenous application of 20 ?M cGMP increased the soluble sugar and proline content of cherry tomato plants under salt stress by 32.51% and 16.01%,respectively;The activities of POD,SOD,CAT and APX increased by 28.38%,26.94%,25.32% and 55.39%,respectively.Exogenous cGMP promotes the significant accumulation of osmotic adjustment substances in cherry tomatoes under salt stress by inducing the expression of related genes such as PaCoA,GAPDHs,UDPG,PMEs,PG,PL and PODs in the carbohydrate metabolism pathway,rationally distributing carbon source materials and increasing penetration.Regulating abilityreduces osmotic potential and enhances antioxidant enzyme activity to scavenge free radicals to avoid cellular toxicity.(3)Exogenous administration of 20 ?M cGMP induced the expression of PAL,CoMT,PODs,CAD,DFR and other related genes in the phenylpropanoid metabolic pathway under salt stress,and promoted the production of secondary metabolites,including flavonoids and lignin content increased by 38.07% and 34.02%,respectively.which not only eased the oxidative damage caused by salt stress,but also promoted the enrichment of cherry tomato plant biomass,enhanced the hydrophobic properties and mechanical strength of cell wall and alleviated salt stress.Water stress caused by cherry tomato plants.(4)Exogenous application of 20 ?M cGMP under salt stress induced the expression of FADs and ADs in fatty acid metabolism,thickened wax and cuticle to reduce non-porous water loss,and maintain the stability of plasma membrane structure and composition.Compared with salt stress,the MDA content was reduced by 20.04%,which reduced the degree of membrane lipid peroxidation,effectively inhibited the inhibition of salt stress on the growth and development of cherry tomato.The qRT-PCR validation is almost identical to the RNA-seq sequencing data,demonstrating that the acquired sequencing data is reliable.The results provide theoretical guidance for the promotion of cherry tomato cultivation in salinized areas and breeding of varieties,and provide reference for the screening and research of salt tolerance genes in Solanaceae crops. |
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