The Choline Oxidase Gene codA Confers Salt Tolerance to Transgenic Eucalyptus globulus in a Semi-Confined Condition

Abstract

The performance of tree species is influenced by environmental factors and growth stages. To evaluate the practical performance of transgenic tree species, it is insufficient to grow small, young trees under controlled conditions, such as in a growth chamber. Three transgenic Eucalyptus globulus lines, carrying the choline oxidase gene, were investigated for their salt tolerance and expression of the transgene at the young plantlet stage in a special netted-house. To clarify the characteristics at the young as well during the later stages, salt tolerance and the properties of the transgenic lines at large juvenile and adult stages were evaluated in the special netted-house. All transgenic lines showed high glycinebetaine content, particularly in young leaves. Trees of the transgenic line 107-1 showed low damage because of salinity stress based on the results from the chlorophyll analysis and malondialdehyde content, and they survived the high-salt-shock treatment at the large juvenile and adult stages. Only this line showed salt tolerance at all stages in the special netted-house. In this evaluation in the special netted-house, the tolerant line among young plantlets might perform better at all stages. Since evaluation in these special netted-house mimics field evaluation, line 107-1 is a potential tolerant line.

Environmental biosafety assessment on transgenic Eucalyptus globulus harboring the choline oxidase (codA) gene in semi-confined condition

“…The abiotic stress-tolerant transgenic Eucalyptus is expected to have increased woody material and ameliorate the deteriorating natural environment. We are collaborating to develop transgenic Eucalyptus with abiotic stress tolerance (Kikuchi et al 2006Matsunaga et al 2012;Yu et al 2009Yu et al , 2013aYu et al , 2013b. E. globulus is one of the most variable species for industrial surfaces.…”

“…E. globulus is one of the most variable species for industrial surfaces. We developed salt-tolerant E. globulus harboring a choline oxidase gene (codA) driven by the Eucalyptus ubiquitin promoter (Yu et al 2013a). The codA gene was isolated from the soil bacterium A. globiformis (Ikuta et al 1997).…”

“…It indicated that this transgene might be a useful gene that enhances the salt tolerance of various tree species without affecting the ecosystem. The evaluation performed in the special netted-house (semi-contained conditions) showed that the transformant line 107-1 had strong salt tolerance in small plantlets ) and in mature trees (Yu et al 2013a).…”

Assessing Utilization and Environmental Risks of Important Genes in Plant Abiotic Stress Tolerance

“…Recently, some tree species have been engineered with genes conferring abiotic stress tolerance and these examples are reviewed ( Gambino and Gribaudo, 2012 ; Osakabe et al, 2012 ). The important tree species with salt and drought tolerance traits are pines, poplars and eucalyptus ( Kikuchi et al, 2006 , 2009 ; Tang et al, 2007 ; Li et al, 2009 ; Yu et al, 2009 , 2013a , b ). Field trials and risk assessment studies have been conducted on some forest and non-forest trees in the USA, New Zealand, Australia and Japan and these information and data are available ( APHIS, 2012 ; Japan Biosafety Clearing-House [J-BCH], 2012 ; NZEPA, 2012 ; Office of the Gene Technology Regulator [OGTR], 2012b ).…”

Development and evaluation of novel salt‐tolerantEucalyptustrees by molecular breeding using anRNA‐Binding‐Proteingene derived from common ice plant (Mesembryanthemum crystallinumL.)

“…We have speculated that the breeding of abiotic stress‐tolerant plantation trees could be one way to combat global climate change and contribute to the sustainable development of humankind. We have conducted molecular breeding of abiotic stress‐tolerant Eucalyptus trees using genetic resources of abiotic stress‐tolerant genes from halobacteria and/or halophytes (Kikuchi et al ., ; Matsunaga et al ., ; Oguchi et al ., ; Tran et al ., ; Yu et al ., , ,b,c,d). Mangrin was found to be a candidate salt‐tolerant gene isolated from a cDNA library from suspension‐cultured cells of a mangrove plant, Bruguiera sexangula by a functional screening for cDNA encoding proteins essential for salt tolerance (Yamada et al ., ).…”