Special trends in CBF and DREB2 groups in Eucalyptus gunnii vs Eucalyptus grandis suggest that CBF are master players in the trade‐off between growth and stress resistance

Abstract

Annotation of the Eucalyptus grandis genome showed a large amplification of the dehydration-responsive element binding 1/C-repeat binding factor (DREB1/CBF) group without recent DREB2 gene duplication compared with other plant species. The present annotation of the CBF and DREB2 genes from a draft of the Eucalyptus gunnii genome sequence reveals at least one additional CBF copy in the E. gunnii genome compared with E. grandis, suggesting that this group is still evolving, unlike the DREB2 group. This study aims to investigate the redundancy/neo- or sub-functionalization of the duplicates and the relative involvement of the two groups in abiotic stress responses in both E. grandis and E. gunnii (lower growth but higher cold resistance). A comprehensive transcriptional analysis using high-throughput quantitative real-time polymerase chain reaction (qRT-PCR) was performed on leaves, stems and roots from the two Eucalyptus species after cold, heat or drought treatment. A large CBF cluster accounted for most of the cold response in all the organs, whereas heat and drought responses mainly involved a small CBF cluster and the DREB2 genes. In addition, CBF putative target genes, known to be involved in plant tolerance and development, were found to be cold-regulated. The higher transcript amounts of both the CBF and target genes in the cold tolerant E. gunnii contrasted with the higher CBF induction rates in the fast growing E. grandis. Altogether, the present results, in agreement with previous data about Eucalyptus transgenic lines over-expressing CBF, suggest that these factors, which promote both stress protection and growth limitation, participate in the trade-off between growth and resistance in this woody species.

Characterization of the Key Region and Phosphorylation Sites of EcaICE1 for its Molecular Interaction with EcaHOS1 Protein from Eucalyptus camaldulensis

“…Eucalyptus can increase freezing tolerance by cold acclimation as well as other plant species. CBF genes have been cloned from Eucalyptus [20,21,22,25] and their overexpression in cold-sensitive Eucalyptus could improve the freezing tolerance [23]. Cao et al further reported that there were 17 CBF orthologs in the E .…”

“…Therefore, it is necessary to discover the molecular regulation mechanism of cold response and carry out genetic improvement on freezing tolerance in Eucalyptus . Although CBF genes have been isolated and characterized from Eucalyptus [20,21,22,23,24,25], the knowledge about its upstream regulator ICE1 and its positive and negative regulation pathway needs to be investigated. Our precious studies have revealed that ectopic expression of EcaICE1 from E. camaldulensis confers improved cold tolerance and the expression level of downstream genes in transgenic tobaccos [16].…”

Wood Architecture and Composition Are Deeply Remodeled in Frost Sensitive Eucalyptus Overexpressing CBF/DREB1 Transcription Factors

“…Notably, CBF genes are overrepresented in the E. grandis genome as compared to most other plant genomes with the exception of Medicago that also contains 17 CBF members [22]. This subfamily expansion is even more important in E. gunnii, which is one of the most frost-tolerant Eucalyptus [23]. Some of these CBFs are strongly induced in stems in response to cold treatment [23].…”

“…This subfamily expansion is even more important in E. gunnii, which is one of the most frost-tolerant Eucalyptus [23]. Some of these CBFs are strongly induced in stems in response to cold treatment [23]. To the best of our knowledge, no study has ever investigated the effects of CBF overexpression on secondary growth and wood formation.…”

Isolation and characterization of a c-repeat binding factor gene from <i> Tevang-1</i> maize cultivar

“…The CBF/DREB1 belonging to the A-1 subgroup are mainly participated in plant response to low temperature (Akhtar et al, 2012). CBF genes have been found in a wide range of plants, such as AtCBFs from Arabidopsis thaliana (Gilmour et al, 2004), BnCBFs from Brassica napus (Jaglo et al, 2001), CbCBF from Capsella bursa-pastoris (Wang et al, 2004), CfCBF3 from sweet pepper (Yang et al, 2011), EglCBFs from Eucalyptus (Nguyen et al, 2017;Navarrete-Campos et al, 2017), HvCBF3 from barley (Choi et al, 2002), LpCBF3 from perennial ryegrass (Xiong & Frei, 2006), OsCBF1 from rice (Choi et al, 2002), PpCBF3 from bluegrass (Zhuang et al, 2015), PaCBF from sweet cherry (Kitashiba et al, 2004), ScCBF from rye (Jaglo et al, 2001), LeCBFs from tomato (Zhang et al, 2004), TaCBFs from wheat (Babben et al, 2018), TmCBFs from Triticum monococcum (Miller et al, 2006), VvCBFs from grapevine (Londo & Garris, 2015), and ZmCBF3 from maize (Wang et al, 2008). CBF proteins contain several conserved domains including the DNA-binding domain -AP2, the N-terminus nuclear localization signal (NLS), and the acidic domains present in C-terminus.…”