Transcriptome And Proteome Analysis Of Maize Leaf Under High Temperature Stress

Maize is the most important food crop in China,which was susceptible to high temperatures.With the gradual increase of global atmospheric temperature,the impact of heat damage on maize production has received increasing attention.In order to explore the responding mechanism induced by high temperature in maize,to search for heat-resistant related genes,the transcriptome and proteome of maize high temperature stress response were studied.This study will provide reference for the identification of heat-tolerant maize germplasm and the breeding of new heat-tolerant varieties.In this study,maize inbred line Chang 7-2 and waxy maize hybrid HN5872 were supplied as the material.The plants were grown in greenhouse at 25°C till the fifth leaf was fully expanded.The seedlings were then subjected to high temperature treatment at 40°C for 1 hour.Maize seedlings contained at 25°C were set as the control.RNA and protein extraction were performed on the intact 5th leaf,following the response genes of Chang 7-2 and HN5872 under high temperature stress studied by RNA-seq and DIA techniques.The results were obtained as following:(1)Quantitative and comparative analysis of high temperature treated/non-treated for Chang 7-2 and HN5872 leaf genes of the relative expression levels by RNA-seq.Using padj<0.05 as the threshold,a total of 8243 differential genes were screened in the two materials,of which 4954 were in Chang 7-2(2452 genes was up-regulated,2502 genes was down-regulated).There were 4641 differently expressed genes in HN5872(2354 genes up-regulated,and 2287 genes was down-regulated).There are 1353 differential genes captured in both of the two lines.Gene ontology(GO,Gene Ontology)showed that these consensus genes involved in 29 gene functions,of which 119 genes were enriched in nucleotide binding function,followed by 27 genes annotated as transcription factor genes.(2)The differentially expressed genes in Chang 7-2 are significantly enriched in photosynthesis and metabolite synthesis by GO enrichment and KEGG(Kyoto Encyclopedia of Genes and Genomes),which may mainly affect photosynthesis and metabolism.In HN5872,the main differently expressed genes were aboudent at photosynthesis and complex formation.(3)With Log2 Fold Change ? 1.5 and padj<0.05 as the thresholds,86 transcription factors were distigushed in Chang 7-2,and 144 transcription factors were picked out in HN5872.These transcription factors were mainly related to abiotic stress response,including ethylene response transcription factors,MYB transcription factors,WRKY transcription factors,etc.These transcription factors may be the regulators of heat stress response.(4))Screening differentially expressed proteins in leaves with protein abundance ratio ?1.5,or ?0.67,significant p<0.05 as thresholds,there were 20 differentially expressed proteins distigushed.Including permease-like protein,1-pyrroline-5-carboxylate synthase,pyrophosphate-activated tonoplast proton pump,L-ornithine N5-acetyl transfer Enzyme,NADH dehydrogenase,glutathione S-transferase.24 differentially expressed proteins were detected in HN5872,including heat shock protein,glycerol transporter,ferredoxin,calcium sensitive receptor,Xaa-Pro dipeptidase,non-specific lipid transfer proteins,phenylalanine ammonia lyase,etc.Among these differently expressed proteins,calcium sensitive receptor,glycerol transporter,heat shock proteins,ferredoxins,and non-specific lipid transfer proteins,are also present in the transcriptome.These proteins are involved in biological metabolism and synthesis and have the function of maintaining the balance of the intracellular environment,They may be involved in regulating intracellular osmotic pressure balance and reducing cell damage.