Transcriptome Profile in Response to Frost Tolerance in Eucalyptus globulus

Abstract

The genetic improvement of trees for freezing tolerance is one of the most important goals to extend the plantations to colder areas. RNA-Seq technology has become a key tool in transcriptome studies. It can quantify overall expression levels for each gene simultaneously with high efficiency and speed through in silico gene expression, where differentially expressed genes can be identified by measuring the reads mapped for each transcript. In this study, the results of ESTs libraries from two Eucalyptus globulus genotypes showing contrasting differences in frost tolerance after cold acclimation using mRNA-Seq and in silico gene expression are discussed. A total of 14,265 non-redundant transcripts were predicted, where 163 corresponded to upregulated and 537 to downregulated genes. Pathway analyses of upregulated transcripts indicated that differences in frost tolerance might be regulated by the tree response to chemical and osmotic stimulus and organic substances, principally by overexpressing proteins that respond to hormone stress. These results suggest that genes coding for dehydrins, outer envelope, and voltage-dependent anion channel proteins are likely to participate in the regulation of the cold acclimation process and may have an important role in frost tolerance. The transcription factor analysis allowed identifying that those most differentially expressed in a resistant genotype were participating in the regulation of transcription, hormone regulation, photosynthesis, and response to stress. Additionally, the screening of polymorphic EST-SSR in silico and the validation of these markers in a reference population lead to identify a polymorphic EST-SSR with potential use for plant breeding and genotype discrimination.

Seasonal Variation of Carbon Metabolism in the Cambial Zone of Eucalyptus grandis

“…Transcriptomic analyzes of different Eucalyptus tissues have been reported in an attempt to understand wood quality (Salazar et al, 2011 , 2013 ), cold acclimation (Liu et al, 2014 ), frost tolerance (Fernández et al, 2015 ), and water stress (Thumma et al, 2012 ). In this study we analyzed a set of transcripts related to primary metabolism by RT-qPCR.…”

Incidencia del estrés hídrico sobre la biosíntesis de metabolitos secundarios y la predisposición a la defoliación: un análisis metabolómico en especies forestales de interés comercial para Chile.

“…In Chile, as in the rest of the world, plantations of E. globulus have been confined to relative frost climates that usually challenge its adaptability, affecting growth and productivity (Geldres and Schlatter, 2004). While attention has been paid to the acquired tolerance mechanisms that enhance cold acclimation in this species (Aguayo et al, 2019;Fernández et al, 2015;123 Navarrete-Campos et al, 2017), E. nitens is often used for replacement, given its higher cold hardiness (Close, 2012;. At the same time, breading programs for developing inter-specific hybrids between these two species, E. nitens × globulus (En×Egg), have been gaining interest in Chile to improve the growth and productivity of eucalypts plantations under sites of frequent frost events (Ipinza et al, 2014;.…”