Investigation of Differential Expressed Genes Responding to Deficient-Pi in Wheat as Revealed by cDNA-AFLP Analysis

Abstract

The objective of this study was to disclose the possible mechanism of tolerance to Pi-deficiency in wheat ( Triticum aestivum L.) at the gene-expression level. Seedlings of wheat cultivar Shixin 828, which has high phosphorus use efficiency, were treated with 20 µmol L −1 Pi for short (1–6 h), medium (12–48 h), and long terms (72–144 h). The differentially expressed sequence tags (ESTs) were identified using complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) technique. A total of 143 and 94 nonredundant differential ESTs with up- and down-regulated patterns were identified, of which 23, 54, and 66 ESTs enhanced expression after the short-, medium-, and long-term treatments, and 17, 39, and 38 ESTs declined expression after the 3 treatments, respectively. These ESTs were classified into several functional groups according to the BLAST analysis. The up-regulated ESTs, except for 44 with unknown function, confer functions of signal transduction, transcription regulation, metabolism, stress response, development, transport, and lipid metabolism. The down-regulated ESTs are involved in the above functions and protein synthesis and protein degradation. Under the Pi-deficient condition, some genes were specifically up-regulated, such as OsPTF1 and ZAT10 homologues and genes encoding mitogen activated protein kinase, calcium-dependent protein kinase and protein kinase, high-affinity phosphate transporter, peroxidase and glutathione S-transferase. These genes are conjectured to play important roles in promoting adaptation to Pi-deficient environment.