Phosphorus Efficiency Evaluation And Low Phosphorus Stress Responsive Gene Screening For Seedling Wheat In Hydroponics Of 24 Varieties From Huanghuai Area Of China

ABSTRACTTo investigate the response characteristic to low phosphorus (P) stress of different wheat genotypes, wheat seedlings of 24 varieties were measured for physiological traits after exposed to different P regimes in hydroponics. The difference of physiological indexes among these wheat genotypes showed two characteristics of phosphorus efficiency, phosphorus use efficiency (PUE) and phosphate acquisition efficiency (PAE). The expression profiling of different wheat genotypes was analyzed using the cDNA-AFLP. followed by isolation of the differentially expressed transcript derived fragments (TDFs). Real-time PCR was used to verify the cDNA-AFLP patterns of selected low phosphorus response genes. The main results obtained as follow:1. By compared 24 wheat genotypes in four factors:relative biomass, P uptake and P concentration, biomass or P uptake allocation between shoot and root, P uptake per root dry weight, we found Xinong979 and Zhengmai9023 were high phosphorus use efficiency genotype (PUEg), Jimail7, Xiaoyan6 and Xiaoyan54 were high phosphate acquisition efficiency genotype (PAEg).2.106 selective-primer pairs in cDNA-AFLP system were used to analyze the transcripts of 96 samples (shoot and root samples of 24 genotypes under two different P supplies), we gained 22 transcript derived fragments (TDFs), among which 2 TDFs (TaSNX 1 and TaASP L 1) may play pivotal role in response to low P stress of wheat.3. The results of quantitative Real-time PCR for TaSNX 1 showed that under low P stress, TaSNX1 relative expression in PUEg wheat was significantly up-regulated, but reverse in PAEg wheat and changed very little in remaining employed genotypes of wheat. TaSNX1 had been reported to be involved in auxin sorting process, its detailed role in P metabolic network of wheat deserves further exploration.