Expression analysis of abiotic stress-responsive genes in two rice heterotic crosses under cold, heat and drought stresses

Heterosis refers to the phenomenon in which the hybrid progeny of two inbred varieties exhibits enhanced growth or agronomic performance. Although a century-long history of research has generated several hypotheses regarding the genetic basis of heterosis, the molecular mechanisms underlying heterosis and heterotic gene activity remain elusive. In this study, two rice heterotic crosses PA64Sx93-11 and Y58Sx93-11 were used as plant materials to analyse the activities of 10 abiotic stress-responsive genes under cold, heat and drought stresses by quantitative real-time PCR. The obtained result demonstrated that the expression levels of genes analysed in hybrids is unexpectedly higher, compared to those of both parental lines. More than 50% of the cases displayed over-parent expression levels. The combined allelic expression pattern was found in hybrid, and under different stress conditions, different alleles were differentially expressed in hybrid.