Physiological Response And Membrane Lipid Metabolism In Maize Leaves Under Low Phosphorus Stress

Phosphorus is one of the most important nutrient elements for maize growth and development.Low phosphorus content in soil will seriously affect maize yield.At the same time,phosphorus is an important component of plasma membrane lipids.The lack of phosphorus will affect the composition and function of plasma membrane.In this study,maize variety 344 was used as the experimental material,and high-throughput transcriptome sequencing and lipid group detection techniques were used to analyze the lipid metabolism regulation and gene expression of maize under phosphorus stress(-P:5?M KH2PO4;+P:1000?M KH2PO4).The key genes related to lipid metabolism and physiological changes under low-phosphorus stress were explored.Below are key research findings:All of the genes obtained by sequencing were aligned with the respective proteins or nucleic acid sequences of the corresponding five large databases(COG,GO,KEGG,Swiss-Prot,NR)using Blast software.Three time point treatments in the differential gene GO classification were annotated into 42,44 and 44 groups,respectively.The differentially expressed genes in the three time point comparison groups of the differential gene KEGG classification were annotated into 75,73 and57 metabolic pathways,respectively.Among the three time points in the differential gene COG classification,the number of differentially expressed genes was the highest in the "General function prediction only",with 34 in 1d,39 in 3d,and 41 in 7d.article.The up-regulated and down-regulated genes with a change in expression(Fold Change)of 1or more(Log2FC?1)were selected from the three control groups,and the differentially expressed genes were compared with the transcription factor database for annotation.20,24,and15 families of transcription factors were found at three time points.1.Physiological response and gene expression of maize under low-phosphorus stressAmong the genes related to chlorophy ll,most of the genes involved in chlorophy ll synthesis are down-regulated,and most of the genes involved in the degradation process are up-regulated.Among them,the PSBY(GRMZM2G134130)gene was down-regulated most significantly.Most of SOD and POD related genes were up-regulated,and SOD and POD activities of-P-treated maize leaves were higher than +P treatment.The expression of membranelipid peroxidation genes LOX3,LOX6 and LOX10 was also significantly upregulated under-P treatment.The MDA content of the-P treated maize leaves was higher than the +P treatment at any time point.A total of 6 phospholipids(PC,PE,PA,PI,PS and PG),2 galactolipids(MGDG and DGDG),1 sulfatide(SQDG)and 3 lysophospholipids(LPG,LPC and LPA).The ratio of galactose MGDG and DGDG in maize leaves was the highest,close to 25% and 45%,respectively,and the rest were phospholipids.Under low phosphorus stress,the percentage of DGDG,MGDG and SQDG increased,while the content of phospholipids such as PS decreased.In this study,DGD and SQD from different plant species also aggregated into two subgroups as well as MGD,and were labeled as Type A and Type B with reference to MGD.Under low phosphorus conditions,the expression of Type B MGD gene in maize and Arabidopsis thaliana was significantly increased in leaf and root tissues.Compared with type A SQD,the expression of Type B SQD gene in maize and Arabidopsis thaliana was in leaf and Significant induction in root tissue.The expression of Zm MGD and Zm DGD genes was significantly affected by temperature stress,especially Type A Zm MGDs,while Type B Zm SQD was more sensitive to temperature and salt stress.It is worth noting that most of the maize MGD,DGD and SQD genes are inhibited by UV treatment.