Physiological Response And Differential Expression Genes Of Soybean Varieties With Different Iron Efficiency Under Iron Deficiency Stress

In this study,iron efficient soybean varieties（Jiyu 99）and iron inefficient soybean varieties（Jiyu 93）were used as experimental materials,using hydroponic method,were treated under iron deficiency stress（1μM Fe）and control treatment（25μM Fe）,The relevant indexes of iron absorption characteristics,antioxidant enzyme activity and gene expression of soybean varieties with different iron efficiency treated in early stage（1 h and 6 h）and long stage（V1,V2 and V3）were measured,The roots of soybean varieties with different iron efficiency treated in early stage were selected for transcriptome sequencing.This study will comprehensively study the differences of physiological response and gene expression of soybean varieties with different iron efficiency in response to iron deficiency stress.The results are as follows:（1）The iron content in leaves and roots,chlorophyll content in leaves,p H value in rhizosphere and Fe³⁺reductase activity in roots of soybean varieties with different iron efficiency were affected by iron deficiency stress.Under iron deficiency stress,the iron content in leaves and roots and chlorophyll content in leaves of iron efficient soybean varieties were higher than that of iron inefficient soybean varieties,reaching a significant level at V1,V2 and V3;The p H value in rhizosphere of iron efficient soybean varieties was lower than that of iron inefficient soybean varieties;The Fe³⁺reductase activity in roots of iron efficient soybean varieties was higher than that of iron inefficient soybean varieties,reaching a significant level at 6 h,V1,V2 and V3.（2）The activities of SOD,POD and CAT in leaves and roots of soybean varieties with different iron efficiency were affected by iron deficiency stress.Under iron deficiency stress,the SOD activity in leaves and roots of iron efficient soybean varieties were higher than that of iron inefficient soybean varieties,reaching a significant level at 1 h,6 h,V1,V2 and V3;The POD activity in leaves and roots of iron efficient soybean varieties were higher than that of iron inefficient soybean varieties,reaching a significant level at V1,V2 and V3;The CAT activity in leaves and roots of iron efficient soybean varieties were higher than that of iron inefficient soybean varieties,reaching a significant level at 6 h,V1,V2 and V3.（3）By analyzing the differential expression genes of soybean varieties with different iron efficiency in response to early iron deficiency stress,it was found that the functional classification trend of differential expression genes of soybean varieties with different iron efficiency was the same.In the KOG functional classification,the differential expression genes of soybean varieties with different iron efficiency were mainly annotated with the functions of posttranslational modification,protein turnover,chaperones,secondary metabolites biosynthesis,transport and catabolism;In the KEGG enrichment analysis,the differential expression genes of soybean varieties with different iron efficiency were significantly enriched in phenylpropane biosynthesis,sesquiterpenoid and triterpenoid biosynthesis.（4）By analyzing the specific differential expression genes of soybean varieties with different iron efficiency in response to early iron deficiency stress,In the KOG functional classification,the functions annotated of the differential expression genes in only iron efficient soybean varieties mainly included carbohydrate transport and metabolism,lipid transport and metabolism,and the functions annotated of the differential expression genes in only iron inefficient soybean varieties mainly included inorganic ion transport and metabolism,energy production and conversion;In the KEGG enrichment analysis,the metabolic pathways with significant enrichment of the differential expression genes in only iron efficient soybean varieties mainly included glycerophospholipid metabolism,phenylpropanoid biosynthesis,glycolysis/gluconeogenesis,and the metabolic pathways with significant enrichment of differential expression genes in only iron inefficient soybean varieties mainly included MAPK signaling pathway-plant,starch and sucrose metabolism,photosynthesis.（5）By analyzing the common differential expression genes of soybean varieties with different iron efficiency in response to early iron deficiency stress,In the KOG functional classification,the differential expression genes were mainly annotated with the functions of posttranslational modification,protein turnover,chaperones,secondary metabolites biosynthesis,transport and catabolism,transcription;In the KEGG enrichment analysis,the differential expression genes were significantly enriched in sesquiterpenoid and triterpenoid biosynthesis,phenylpropane biosynthesis;In transcription factor analysis,differential expression genes were mainly divided into WRKY,MYB,HSF,b HLH and other transcription factor families.（6）Under iron deficiency stress,the relative expression of AHA2,FRO2,b HLH59 and IRT1 genes in soybean varieties with different iron efficiency were higher than the control treatment,and the relative expression of AHA2,FRO2,b HLH59 and IRT1 genes in iron efficient soybean varieties were higher than the iron inefficient soybean varieties;In iron efficient soybean varieties,compared with the control,the expression of AHA2 gene began to significantly up-regulated at 6 h of iron deficiency stress treatment,the expression of FRO2 gene began to significantly up-regulated at 14 d（V1）of iron deficiency stress treatment,the expression of b HLH59 gene began to significantly up-regulated at 6 h of iron deficiency stress treatment,and the expression of IRT1 gene began to significantly up-regulated at 12 d（V1）of iron deficiency stress treatment.（7）Compared with the control,the expression of Glyma.06G266700,Glyma.03G038300,Glyma.06G134900,Glyma.01G108300,Glyma.13G046200,Glyma.11G235000,Glyma.11G062700 genes was affected by iron deficiency stress,and there were differences in expression among soybean varieties with different iron efficiency.