Fertility Alternation of Thermo-Photo-Sensitive Genic Male Sterile (TGMS) Wheat Line C412S and its Association with Adenine Phosphoribosyltransferase Gene Expression

C412S, a novel thermo-photo-sensitive genic male sterile (TGMS) wheat (Triticum aestivum L.) line, is derived from a cross between TGMS line C49S and the conventional line C412. The objectives of this study were to examine the fertility alternation of C412S planted at different sowing dates and to investigate the possible function of APRT1 and APRT2 in the fertility alternation of thermo-photo-sensitive wheat. Under the 10 treatments of seeding date from 26 October to 10 December in 2005–2007 growing seasons, C412S showed fertility variations from complete sterility to high sterility, semisterility, low sterility, and normal fertility, which were achieved by adjusting the environmental temperature and photoperiod conditions during the development of male sex cells. Smear and squash microscopic technique was employed to follow the developmental progress of pollen mother cell (PMC) meiosis and microsporogenesis. Fertility-sensitive period of C412S was from PMC formation stage to mature pollen stage, especially from PMC formation to PMC meiosis stage. C412S pollen abortion, which belongs to spherical abortion type, reached peak level at later mononucleate stage of microsporogenesis. Moreover, the full length of adenine phosphoribosyltransferase gene (APRT) was cloned from C412S and its control line C412. Sequences analysis showed that there were a few base differences in APRT1 between C412S and C412. However, the deducted amino acid sequences of C412S and C412 are identical. According to the results of semiquantitative reverse transcription PCR (RT-PCR), the transcriptional level of APRT genes in the young spikes of the sterile line C412S was lower than that of the fertile line C412 from PMC formation to mononucleate microspore stage. This indicates that the transcriptional level of APRT in young spikes may associate with fertility alternation in TGMS wheat.