Cloning and Expression Analysis of TaG3BP Gene Related to Fertility Conversion in Male Sterile Lines of Wheat

Thermo-photoperiod sensitive male sterile(TMS) wheat(Triticum astivum L.) is a valuable material for heterosis study and utilization by means of two-line system.YS-type TMS lines are applicable in hybrid wheat in major wheat growing areas in northern China.The objective of this study was to reveal the molecular basis of fertility conversion in YS-type TMS wheat.YS-type TMS line A3017 was grown in a phytotron with controlled temperatures in favor of male sterility and fertility,respectively.Two suppression subtractive hybridization(SSH) cDNA libraries were constructed using cDNA from the male sterile and fertile young spikes of the same individuals that were orderly treated with temperature cycle(day/night) of 16℃/12℃ and 25℃ /16℃.Using a pair of primers designed on the basis of aligned homological sequence,RT-PCR amplification was carried out and an EST of 1 230 bp in length(GenBank accession number:DY543200) was obtained from the fertile SSH-cDNA library,which encodes 409 amino acid residues.The cDNA fragment contained the typical NTF2 and RRM domains of G3BP,and designated TaG3BP(GenBank accession number:GU475149).The deduced amino acids had 79% of similarity with G3BP(Ras-GTPase activating protein SH3 domain-binding protein) gene from Oryza sativa(BAD07751).The expression pattern of TaG3BP was analyzed with Real-time PCR using anthers from the TMS line in various developmental periods under male sterile and fertile conditions.In fertile anthers,TaG3BP gene was expressed in a higher level at the critical stage of fertility conversion(between uninucleate and binucleate stages) as compared with that in sterile anthers.In the K-type male-sterile lines and their maintainers of 1B/1R,1B,and non 1B/1R types,TaG3BP gene showed higher expression levels in the young spike of maintainers than in that of the male-sterile lines.These results suggest that the expression of TaG3BP gene is related to fertility conversion in male-sterile wheat lines.