GSE64475
Alterations to hormone regulated defense and stress response networks contribute to the greater growth of Arabidopsis F1 hybrids
Heterosis, or hybrid vigor, has been exploited in agriculture to deliver increases in crop yields for over a century, yet the molecular basis is not well understood  We have studied the transcriptomes of 15 day old seedlings from intraspecific Arabidopsis hybrids with varying levels of heterosis and their parental lines in order to identify drivers of heterosis.  The patterns of altered gene expression in the hybrids point to a reduction in basal defense levels that could reflect the antagonism between plant immunity and plant growth.  Associated with this theme are changes to the salicylic acid and auxin regulated networks which are known to control abiotic and biotic defense responses as well as being important regulators of plant growth.  Increased auxin response correlates with the heterotic phenotype of greater leaf cell numbers, whereas reduced salicylic acid levels and response promotes increased leaf cell size in hybrids involving C24.  By manipulating salicylic acid levels in each of our hybrid systems, we can alter levels of heterosis, promote additional growth in the hybrids, and generate increased growth in the parents, especially C24. Overall design: Aerial tissues of 15 days after sowing seedlings from C24, Ler, Col and their reciprocal hybrid offspring.  In total 7 biological replicates for both the C24 and Ler parents, 2 biological replicates for Col, 10 biological replicates for C24/Ler and 4 biological replicates for both C24/Col and Col/Ler were sequenced and analysed.  Each replicated consisted of a pools of 5-15 seedlings (see publication for more details)