Sunflower (Helianthus annuus L) Male Meiocytes Transcriptome Analysis by High-Throughput Sequencing

Meiosis is a fundamental biological process for sexual reproduction in eukaryotes. This process allows to halve the number of chromosomes in the gametes and to reshuffle the genetic variation present in the parents. Understanding how this process is regulated might help plant breeders to create novel allele combinations that could produce superior hybrids, and also increase the knowledge of core meiotic processes in plants, which at date are not completely understood. Sunflower is recognized for being one of the most important crops in the world, as well as a good model organism for studying speciation, introgression, and genetic architecture related topics. The technical feasibility of isolating almost pure populations of male meiocytes in well-defined stages of meiosis, make this plant an excellent model for this study. High-throughput sequencing of mRNA (RNA-seq) for male meiocytes of the high-oil elite line HA89 was conducted. Our preliminary results show high relative expression of genes related with protein metabolism such as proteolysis and phosphorylation. Genes for the histone protein family are also redundant and highly expressed. In addition, the detected expression of putative orthologs of the genes for the AGO protein family suggest the participation of RNA mediated gene silencing and histones modification as a mechanism for regulating the meiosis in sunflower, as described in other model organisms. Expression of orthologous genes implicated in homologous recombination and other meiotic processes in yeast, mouse, human and A.thaliana are also expressed in the sunflower male meiocytes, confirming that many important processes are highly conserved.