Investigation Based on cDNA-AFLP Approach for Differential Expressed Genes Responding to Deficient-Pi in Wheat

Abstract

To date,differential expression genes in response to deficient-Pi stress have been identified and well studied in Arabidopsis thaliana,and totally 612 up-regulated and 254 down-regulated genes with various functions were reported.However,there is no similar report in wheat(Triticum aestivum L.).In this study,seedlings of wheat cultivar Shixin 828 with high phosphorus use efficiency were treated with 20 μmol L?1 Pi for 1 to 144 h,and the differential expressed sequence tags(ESTs) with up-regulated and down-regulated patterns were investigated based on cDNA-AFLP approach after deficient-Pi treatment for short term(1-6 h),medium term(12-48 h),and long term(72-144 h).A total of 142 nonredundant ESTs with up-regulated pattern were identified,in which 23,53,and 66 ESTs expressed in treatments of short,medium,and long term,respectively.Simultaneously,94 nonredun-dant ESTs with down-regulated pattern were detected in treatments of short(17),medium(39),and long term(38).These ESTs were classified into several functional groups with Blast in GenBank.Except for 44 function-unknown ESTs with the up-regulated pattern,the remained up-regulated ESTs conferred functions of signal transduction,transcription regulation,metabolism,stress response,development,transport,and lipid metabolism.Besides the above functions,protein synthesis and protein degradation were also observed in the down-regulated ESTs.Some genes of transcription factors(such as the transcription factor genes with high homologous to rice OsPTF1 and Arabidospsis ZAT10),mitogen activated protein kinase(MAPK1a),calcium-dependent protein kinase(CPK1A),and protein kinase(such as serine/threonine kinase),high-affinity phosphate transporter(PHT3 and PT2),peroxidase(such as peroxidase 73) and glutathione(glutathione S-transferase) were specifically up-regulated under deficient-Pi condition.This suggested that they might play important roles in promoting adaptation to deficient-Pi environment.