Isolation And Function Analysis Of Soybean GmWRKYs

Abastract:Low phosphorus and aluminum toxicity are primary factors limiting soybean production on acidic soils of south China.WRKY transcription factors are one of the largest family of transcriptional regulators found in plants. They have diverse biological functions especially in plant abiotic stress responses. There are at least 127 members of WRKY family in soybean.In the present study, we select four WRKY genes belongs to group IIa by bioinformatics analyzed. Then we analysis the subcellular locolization, transcriptional activation and relative expression of these four WRKYs. According to the results, we further analyzed the function of GmWRKY7 in response to aluminum toxicity and low phosphorus. Main results are showed below:1) Through the homeodomain analysis of Gm WRKY with At WRKY40, we select four Gm WRKY genes named by the position of their chromosome, GmWRKY7, Gm WRKY8, Gm WRKY13 and Gm WRKY15 respectively. These four WRKY proteins contain a domain composed of the conserved WRKY construct in their N-terminal, and belong to group IIa of WRKY family.2) Results of transcriptional activation analysis showed that these four Gm WRKYs have no transcriptional activation. Further the results showed that subcellular locolization of these four WRKYs are in different position. GmWRKY7 and Gm WRKY8 located in nuclear; Gm WRKY13 located in nuclear and plasmid; Gm WRKY15 only located in plasmid.3) Results of the relative expression of these Gm WRKYs indicate that expression of these four genes in different organ regulated by nutrient deficiency. Expression of Gm WRKYs in root and leaves was induced by P deficiency and Fe deficiency. However in root, expression of GmWRKY7 and Gm WRKY15 was induced by N deficiency as well as Gm WRKY8 was reduced. Expression of GmWRKY7 and Gm WRKY8 was significant reduced and expression of Gm WRKY15 was not influence by S deficiency. Expression of Gm WRKY15 in old leaves was repressed and induced in other parts under K deficiency. Expression of these three genes young leaves and expression of Gm WRKY15 in old leaves were repressed under Ca deficiency, but the expression of GmWRKY7 and Gm WRKY8 was induced under deficiency, and expression of Gm WRKY15 has no significant difference in root under the Ca deficiency.4) Expression of Gm WRKYs also regulated by hormones. GmWRKY7 was significant induced by GA3, ABA and IAA in a short time treatment and repressed under KT treatment. Expression of Gm WRKY8 was induced under GA3 and IAA treatment in a short time, but was significantly reduced under the 6-BA and KT treatment. In addition, expression of Gm WRKY15 was depressed by 6-BA and KT and was induced by ABA treatment, no significant difference under other hormones treatment.5) Expression of GmWRKY7, Gm WRKY8 and Gm WRKY15 in root tip was significantly induced by aluminum treatment. To compare with Al sensitive genotypes, the relative expression of GmWRKY7 was higher, however Gm WRKY8 and Gm WRKY15 has opposite results.6) GmWRKY7 was selected for further function analysis. The result of yeast one hybrid shows that Gm WKRY7 can binding to the promoter of Gm ALMT1. And overexpression of GmWRKY7 in Arabidopsis can significant induce the anthocyanin accumulation in response to phosphorus deficiency.In conclusion, in this research, through the subcellular localization analysis ?transcriptional activation analysis and the relative expression of these four IIa type Gm WRKYs, we were analyzed biological function of soybean GmWRKY7 in response to Al toxicity and low p. Futhermore this study also provide useful informations for future research of Gm WRKYs in soybean.