Effects of somatic embryogenesis on gene expression of cloned coffee heterozygous hybrids

Abstract

Our analyses suggest that no major genome organization occurred during SE process implying the nonoccurrence of somaclonal variation. However, the genetic background determines the quality of the in vitro response. Cloning of superior coffee plants by somatic embryogenesis can assist breeding programs on reducing the cost and time for launch of new cultivars. This study aimed to evaluate the efficiency of this methodology for cloning coffee trees with high heterozygosity, and to gather evidence that clonal progenies are faithful copies of mother plants. Selected plants IAC1 and IAC 2 from Coffea arabica breeding populations, resistant to leaf rust and leaf miner, respectively, were cloned via indirect somatic embryogenesis. Expression of selected genes involved in biological processes potentially affected by in vitro cultivation was evaluated by quantitative analysis. Genes encoding proteins associated with maintenance of DNA integrity and control of cell cycle presented predictable expression patterns along the clonal multiplication process. There were differences in the expression pattern of genes linked to in vitro cultivation-related stress, which were observed comparing either IAC 1 and IAC2 genotypes or clones and their corresponding mother plant. Those analyses suggest that the somatic embryogenesis does not lead to major genomic instability and clones are identical copies of mother plants, even with detected differences in the expression of genes that influence the response of in vitro cultivation.