Assessment of the salt tolerance and environmental biosafety of Eucalyptus camaldulensis harboring a mangrin transgene

Abstract

Increasing soil salinization of arable land has a major impact on the global ecosystem. One approach to increase the usable global forest area is to develop transgenic trees with higher tolerance to conditions of salt stress. An allene oxide cyclase homolog, mangrin, contains a core protein domain that enhances the salt tolerance of its host. We utilized this feature to develop improved salt-tolerant eucalyptus trees, by using transgenic Eucalyptus camaldulensis carrying the mangrin gene as a model. Since the Japanese government requires an environmental biosafety assessment for the surrounding biosphere, we performed experiments on trees grown in a special netted-house. This study examined the transgenic E. camaldulensis carrying the mangrin gene to assess the feasibility of using these transformants, and assessed their salt tolerance and environmental biosafety. We found that seven of 36 transgenic genotypes had significantly higher salt tolerance than non-transformants, and more importantly, that these plants had no significant impact on environmental biosafety. These results suggest that introduction of the mangrin gene may be one approach to safely enhance salt tolerance in genetically modified Eucalyptus species, and that the transformants have no apparent risks in terms of environmental biosafety. Thus, this study provides valuable information regarding the use of transgenic trees in situ.

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

“…They were grown in a special netted-house for 14-month-old trees in Experiment 1 and 3, and 11-month-old trees in Experiment 2. Using the sandwich method (Fujii et al 2003;Yu et al 2013b), we found that the germination rate and sprout growth of lettuce seedlings were almost the same in both transgenic line 107-1 and non-transgenic line No. 8-8 ( Figure 1A).…”

“…In the soil-mix method (Shiomi et al 1992;Yu et al 2013b), the germination rate and sprout growth of lettuce seedlings seemed to be almost the same for the transgenic line 107-1 and non-transgenic line No. 8-20 (Figure 2A), except for the hypocotyl length.…”

“…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.…”

Cloning of SjCA gene and its expression analysis on upland cottons

“…and converted it in Escherichia coli, yeasts, and tobacco, improving the salt tolerance of the obtained transformant [34] . Yu et al converted the salt-tolerant gene mangrin into Eucalyptus and also acquired a transformant with enhanced salt tolerance [35] . Gao et al obtained wheat plants with higher salt and drought tolerance by GmDREB gene transgenosis [36] .…”

Genome engineering of woody plants: past, present and future

“…Although Eucalyptus plants are relatively difficult to regenerate in tissue culture compared to Populus plants, several research groups have developed improved tissue culture and transformation protocols [21,22], and both endogenous and exogenous genes have been introduced into Eucalyptus cells to produce Eucalyptus plants with modified secondary cell wall [23] and improved salt tolerance [24,25].…”