Genetic effect in leaf and xylem transcriptome variations among Eucalyptus urophylla x grandis hybrids in field conditions

International audienceTo assess the genetic and environmental components of gene-expression variation among trees we used RNA-seq technology and Eucalyptus urophylla x grandis hybrid clones tested in field conditions. Leaf and xylem transcriptomes of three 20 month old clones differing in terms of growth, repeated in two blocks, were investigated. Transcriptomes were very similar between ramets. The number of expressed genes was significantly (P<0.05) higher in leaf (25,665 +/- 634) than in xylem (23,637 +/- 1,241). A pairwise clone comparisons approach showed that 4.5 to 14 % of the genes were differentially expressed (false discovery rate [FDR]<0.05) in leaf and 7.1 to 16 % in xylem. An assessment of among clone variance components revealed significant results in leaf and xylem in 3431 (248) genes (at FDR<0.2) and 160 (3) (at FDR