Molecular Analysis for Sex Determination in Dioecious Seabuckthorn Using Genomic Approaches

Abstract

Seabuckthorn is a dioecious shrub which belongs to family Elaeagnaceae. There are seven species of genus Hippophae, out of which three are found in India, namely H. rhamnoides, H. salicifolia and H. tibetana. In current study SCAR based sex linked markers HrX1 and HrX2 developed for H. rhamnoides were validated on H. salicifolia and H. tibetana. HrX1 produced female specific amplification in 85% of females in H. salicifolia while in case of H. tibetana it amplified in 100% of females plants. HrX1 did not amplify in male plants of either H. salicifolia or H. tibetana. HrX2 did not amplify in either male or female plants of H. salicifolia or H. tibetana. Previous molecular marker based studies in seabuckthorn failed to identify genetic locus responsible for sex determination, thus mechanism governing gender determination in seabuckthorn still remains unknown. In pursuit to identify such genetic elements for regulating sex determination, literature survey was conducted to identify probable floral regulatory genes as well as transcription factors which may be involved in sex determination in seabuckthorn. The expression pattern of the identified genes and transcription factors was studied three temporal developmental stages of seabuckthorn male and female flowers using qRT-PCR. Out of the 21 probable genes analysed for differential expression, HrCO showed male specific expression while the higher expression level of HrCRY2 was recorded in female flower buds. The expression level of transcription factor HrTF_AP2 was found highest in female flowers. On the other hand transcription factors HrTF_AUX_IAA and HrTF_SRF showed significant expression in male flowers. newline