Establishment of the evaluation system of salt tolerance on transgenic woody plants in the special netted-house

Abstract

Salinity is regarded as a major factor impacting the growth of plants such as trees. Transgenic technology is considered an effective approach to minimizing salt damage by enhancing a plant's salt tolerance. Currently, most of the research on transgenic woody plants is still limited to the laboratory level in vitro and in growth chambers. However, the confined laboratory evaluation of salt tolerance condition yields minimal information since various factors that significantly impact growth, such as weather and season, do not come into play. Field level evaluation of salt tolerance is necessary but is limited in Japan. Transgenic plants should be evaluated in semi-confinement before they are moved to open fields. Therefore, an effective evaluation method for salt tolerance in woody plants is needed in semi-confinement. To evaluate the salt tolerance of transgenic Eucalyptus under semi-confined conditions, we initially developed a new evaluation method using non-transgenic E. camaldulensis. The duration of salt treatment was determined to be the point in time when half of the plants started to exhibit wilting. Additionally, the plants were continuously irrigated with fresh water as a final procedure. With the evaluation system in place, the salt tolerance of transgenic E. globulus containing the choline oxidase (codA) gene was measured. The transgenic plants showed higher survival rates than the non-transgenic plants. This result indicated that the salt tolerance of transgenic E. globulus was enhanced by the introduced codA gene and also established that the new evaluation system is valuable for testing transgenic plants in semi-confinement and will contribute to an increase in the useful applications of transgenic plants.

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.…”

“…a growth room, a special netted-house, and an isolated field) (Kikuchi et al 2006;Schomberg 1998;Yu et al 2009). A series of environmental biosafety assessments on the transgenic Eucalyptus should also be performed before they are planted in a commercial field so that the possible impact of these transgenic plants on the native ecosystem can be determined.…”

“…The trees belonging to this genus are used to produce pulp and fuel (Turnbull and Pryor 1984). Transgenic Eucalyptus has been developed in recent years to increase its stress tolerance (Hibino 2009;Kikuchi et al 2006;Matsunaga et al 2012;Yu et al 2009) and pulp production ). The abiotic stress-tolerant transgenic Eucalyptus is expected to have increased woody material and ameliorate the deteriorating natural environment.…”

Development of transgenic plants in jatropha with drought tolerance

“…For quantitative analysis of glycine betaine in transgenic plants, the amount of glycine betaine in plants was measured by capillary electrophoresis-mass spectrometry (CE-MS) as described in Yu et al (2009).…”

Mycorrhizal colonization of transgenic Eucalyptus camaldulensis carrying the mangrin gene for salt tolerance

“…Among the nontransgenic control lines, CML2 showed high salt tolerance (Ͼ50% survival rate) compared with the other two lines (Ͻ40% survival rate) when irrigated with 600 mM NaCl (Yu et al 2009). Among the transgenic lines, F15 and F65 were highly salt-tolerant with a relative survival rate of more than 1.5 compared with CML2, whereas F60 was removed from the high salt-tolerant category because relative survival rate was between 1.0 and 1.5 (Yu et al unpublished data).…”