Field performance of chitinase transgenic silver birch (Betula pendula Roth): growth and adaptive traits

Abstract

Fifteen transgenic birch lines carrying a chitinase IV gene from sugar beet and non-transgenic control plants were grown in a field trial, and traits connected to growth, quality and adaptation were monitored. Significant variation among the transgenic lines was observed in the growth parameters as well as parameters linked to stress status and leaf phenology of the trees. It was hypothesized that the differences among the lines could be explained by the differences in the level of transgene expression measured as sugar beet chitinase IV transcript accumulation. The level of the transgene expression was not detected to have influence on growth or leaf phenology, but instead it had influence on the parameters related to stress status of a tree. The increased levels of red colour and decreased general condition of the transgenic plants compared to the control plants may indicate physiological stress among the transgenic plants. The proportion of trees infested by Phytobia, larvae of which cause an easthetic defect to birch wood, was lower among many transgenic lines than in controls but the variation in Phytobia occurrence was explained by the differences in plant size only. Three lines out of fifteen were frequently different from the control plants in growth and leaf phenology, and these differences are suggested to be due to the position effect of the transgene. The observed changes in individual transgenic lines were not correlated with the sugar beet chitinase IV expression, and were more likely to impair than improve the traits that are usually considered important in adaptation and birch breeding.

Impact of an 8-Year-Old Transgenic Poplar Plantation on the Ectomycorrhizal Fungal Community

“…Up until now, most of the studies investigating the effect of transgenic trees or transgenic crops on soil microbial communities have observed changes attributable to new traits from GM organisms that are smaller than changes attributable to other factors such as soil type, plant genotype, and stand sites (8, 16, 40, 64). However, transformations leading to deleterious effects on trees (13,57,72) or nontarget organisms (31,36) have been reported, but they involved pleiotropic effects that depend on each unique insertion event. Therefore, future impact studies of GM trees will have to test over a long-term period every transgenic line extensively deployed before large-scale propagation to better evaluate the likelihood of consequences due to transgenic trees for mycorrhizal symbioses and what the consequences are.…”

Doing research, creating impact: using 'PROTEE' to learn from a genetically modified tree field trial

“…Many of them were short and branched: the gene transfer probably had some side-effects (Pasonen et al, 2008). Although these side-effects were in accordance with theoretical understandings and with the results of other studies, it was difficult to be certain, without further genome-scale analyses, about what caused them in this particular case.…”

“…The Innovator assumed that the colleague in question viewed this topic as a potential threat for future funding prospects. Whatever the reason, the somewhat unstable nature of the GM trees was, in the end, given little attention in the project's communications outputs (see, however, Pasonen et al, 2008).…”

Effects of sugar beet chitinase IV on root-associated fungal community of transgenic silver birch in a field trial

“…The transgenic lines, in general, were significantly smaller at the end of the experiment than the wild-type clones. Final heights of the transgenic lines ranged from 0.83 to 2.18 m (Pasonen et al 2008) and the final height range among the wild-type clones was between 2.95 and 4.52 m indicating high variation within both groups (A.-M. Niskanen, unpublished data). However, the height differences among the transgenic lines did not seem to explain the different fungal community structure of line K4, and the height of the clones Ck2, Ck5 and Ck7 were not likely to explain the observed similarity in their fungal community structures revealed by NMS ordination.…”