Poster abstracts
Poster number 101 submitted by Ashwini Shivakumar
Male-specific gene expression during seed development enables early sex identification in Cannabis sativa L.
Ashwini Shivakumar (Department of Plant and Soil Science, University of Kentucky), Manohar Chakrabarti (School of Integrative Biological and Chemical Sciences, University of Texas Rio Grande Valley), Arthur Hunt (Department of Plant and Soil Science, University of Kentucky)
Abstract:
Hemp (Cannabis sativa L.) is an annual dioecious plant, with females carrying XX sex chromosomes and males carrying XY sex chromosomes. Cannabinoids, such as THC and CBD, valued for medicinal use, are concentrated in the glandular trichomes of unfertilized female flowers. Fertilization leads to a substantial reduction in cannabinoid accumulation; therefore, it is highly desirable to maintain unfertilized female plants. To achieve this, farmers must identify and remove male plants before flowering to prevent pollination and ensure high cannabinoid yield. In order to develop tools to assist in this, we are characterizing sex-specific gene expression in hemp. We hypothesize that alternative RNA processing might be one of the mechanisms behind the sex-specific gene expression program. To test this, we extracted RNA from young (7 day old) seedlings whose sexes were then determined and studied genome-wide poly(A) site choice as well as overall gene expression. We find wide-ranging differences in poly(A) site choice in males and females, as well as a distinctive pattern of differentially expressed genes. There is a significant overlap between the sets of genes whose expression are sex-specific and those affected by alternative polyadenylation, implicating APA in the regulation of these genes. To further explore when this sex-specific gene expression program is set, RNA was isolated from plants at multiple developmental stages, such as developing seeds, mature seeds, two-day-old seedlings, and four-day-old seedlings. The analysis of diagnostic male-specific genes was then measured by RT/PCR. The results showed that male-specific transcripts were detectable as early as the seed development stage. These results implicate APA in the sex-specific gene expression program and show that male identity is established during seed development. This discovery provides a promising foundation for the development of molecular assays capable of sex identification prior to germination. Such tools would enable farmers and breeders to selectively cultivate female plants from the earliest stages, thereby improving efficiency and maximizing cannabinoid yield in hemp production.
Keywords: Hemp, sex-specific, APA