Comparative profile of transcripts from anthers of hybrid plants and parental lines of sunflower

Abstract

Most heterosis research over the years has focused on increasing vigour and productivity, and less on the multitude of biochemical and molecular phenotypes as an expression of hybrid superiority under favourable or stressful conditions. Plant productivity depends on the microsporogenesis and microgametogenesis processes highly sensitive to unfavorable environmental conditions and other stress factors that often induce the androsterility. The paper presents the results of the expression polymorphism analysis (by RT-qPCR) of candidate genes with functions in DNA replication, recombination, repair, and mitochondrial morpho-functional organization processes in anthers of homozygous and heterozygous sunflower plants with phenotypic differences in male gametophyte (fertile/sterile). A particular interest in this research represented the identification of gene expression patterns in hybrid (F1) plants in norm, for possible associations of transcriptional response with heterozygous effect, and under conditions of induced stress (gibberellin treatment) as a factor in irreversible phenotype change of anthers from fertile to sterile. Thus, the high proportion of different non-additive and transgressive expression patterns in hybrid plants was established, revealing genetic divergence and expression polymorphisms in parental lines. The sterile anther phenotype of hybrid plants obtained by gibberellin treatment of the inflorescence at the buttoning phase is causally related to changes in allelic gene expression patterns at different phases of microsporogenesis.