Levels and expression patterns of endogenous hormones during seed germination of dongxiang wild rice

Abstract

Dongxiang wild rice (Oryza rufipogon Griff, hereafter DXWR), is very precious rice germplasm resource for maintaining genetic diversity of rice germplasm, but it has a strong dormancy property which will hinder the utilization of its germplasm resources. Here, the changes of endogenous hormone and the expression of endogenous hormone gene in DXWR and cultivated rice (9311) were analyzed using enzyme linked immunosorbent quantification and qRT-PCR. The result showed that only 30% of DXWR germination rate at 36-h and the highest germination rate displayed 83% at 92-h. The content of ABA and JA in DXWR mature seeds was higher than 9311, and the contents of GA and IAA for DXWR only slightly fluctuated during germination. The expression of ABA catabolic genes NCED and OsABA8OH in DXWR fast decreased before germination onset, however GAMYB and DAD (catabolic genes of GA and IAA, respectively) are low expression quantity during seed germination. These results provide important information about the seed dormancy release mechanism of DXWR and provide the theoretical basis for applying this wild rice germplasma.