An Investigation into the Effects of Environmental Stresses on Gene Family Expression in Eucalyptus

Many RNA-seq studies have analyzed the effects of individual biotic and abiotic stresses on gene expression in Eucalyptus. Until now, RNA-seq data has not been used to investigate the effect of several environmental stresses on the expression of gene families in one study in Eucalyptus. We organized an analysis of 18 studies that investigated the effects of various biotic and abiotic stresses on gene expression in Eucalyptus. In this study, six environmental stresses including fungus, high temperature and elevated CO2, drought, potassium deficiency, nitrogen deficiency and phosphor deficiency were used. These stresses fall into four categories including drought, climate change, nutrient deficiency and fungus. We found that the expression of over 341 gene families (protein kinase gene superfamily, Glycoside hydrolase (GH) gene family, ABC transporter gene family, etc.) in a range of Eucalyptus species and hybrids changed after exposure to biotic and abiotic stresses. Among of these gene families, only glycoside hydrolase gene family was found to be differentially expressed in all six of the stresses. The proportion of differentially expressed genes (DEG) that were down relative to up-regulation, was significantly higher in the main biological processes. Many of the gene families that responded to biotic and abiotic stresses encoded products involved in response to stimulus and metabolic process, developmental process, localization and cellular component organization or biogenesis. The results from this work will be used to further characterize the gene regulatory networks underlying stress responsive genes in Eucalyptus.