Ecological impacts of trees with modified lignin

Halpin, Claire; Thain, Simon C.; Tilston, Emma L.; Guiney, Emma; Lapierre, Catherine; Hopkins, D. W.

doi:10.1007/s11295-006-0060-2

Cited by 48 publications

(34 citation statements)

References 20 publications

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“…In respect of the numerous functions of lignin, there are various ways modified lignin might affect biological interactions, including effects on herbivory and defence responses against pathogens, decomposition of gm-material, and symbiotic interactions with mycorrhizal fungi (HALPIN et al, 2007). There are only a few reports on the ecological interactions of the lignin-modified trees in vivo (PILATE et al, 2002) or in vitro (TIIMONEN et al, 2005, SEPPÄNEN et al, 2007.…”

Section: Introductionmentioning

confidence: 99%

Paxillus involutus Forms an Ectomycorrhizal Symbiosis and Enhances Survival of PtCOMT-modified Betula pendula in vitro

Tiimonen¹,

Aronen²,

Laakso³

et al. 2008

Silvae Genetica

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The ability of the PtCOMT (caffeate/5-hydroxyferulate O-methyltransferase from Populus tremuloides L.) -modified Betula pendula Roth. lines to form symbiosis with an ectomycorrhizal (ECM) fungus Paxillus involutus Batsch Fr. was studied in vitro. Lignin precursor gene PtCOMT was introduced into two B. pendula clones under the control of the cauliflower mosaic virus 35S promoter or the promoter of the sunflower polyubiquitin gene UbB1. Of the four transgenic lines, one 35S-PtCOMT line (23) had a decreased syringyl/guaiacyl (S/G) ratio of root lignin, and two UbB1-PtCOMT lines (110 and 130) retarded root growth compared to the control clone. Both control clones and all transgenic lines were able to form ECMs with P. involutus, but the transgenic lines differed from the controls in the characteristics of the ECMs. The number of lateral roots covered with fungal hyphae and/or development of a Hartig net (HN) were reduced in line 23 with a decreased S/G ratio, and in lines 110 and 130 with slower root formation and changed root morphology, respectively. However, line 23 benefited more from the inoculation in lateral root formation than the control, and in lines 110 and 130 the percentage of viable plants increased most due to inoculation. The results show that B. pendula plants genetically transformed with the lignin gene PtCOMT could form mycorrhizal symbiosis regardless of changes in either the root S/G ratio or development. The benefits of the symbiosis were variable even in the closed in vitro system, and dependent on the clone or transgenic line and the ECM fungal symbiont.

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Section: Introductionmentioning

confidence: 99%

Paxillus involutus Forms an Ectomycorrhizal Symbiosis and Enhances Survival of PtCOMT-modified Betula pendula in vitro

Tiimonen¹,

Aronen²,

Laakso³

et al. 2008

Silvae Genetica

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“…Some of these have been tested in field trials to determine if the improvements in saccharification rate, pulping, and forage properties observed in the GH trials were maintained during growth in the field . These trials suggest that lignin-modified plants are capable of attaining wild-type statures Halpin et al, 2007;Fornalé et al, 2011). In addition, these transformed plants have also been used to examine the consequences of lignin alteration for plant-soil, plant-insect, and plant-microbe interactions Tilston et al, 2004;Halpin et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

“…Independent glasshouse (GH) and field studies were conducted with antisense CAD-and COMT-silenced poplar (Populus tremula 3 Populus alba; Pilate et al, 2002;Halpin et al, 2007) and CCR-and COMTsilenced (using an RNA interference [RNAi] strategy) perennial ryegrass (Lolium perenne; Tu et al, 2010) plants. These studies revealed that growth conditions had little impact on gene silencing efficiency and associated enzymatic activity, lignin content and chemistry, plant growth, and plant-insect or plant-microbe/ pathogen interactions.…”

mentioning

confidence: 99%

Environmental Stresses of Field Growth Allow Cinnamyl Alcohol Dehydrogenase-Deficient Nicotiana attenuata Plants to Compensate for their Structural Deficiencies

et al. 2012

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The organized lignocellulosic assemblies of cell walls provide the structural integrity required for the large statures of terrestrial plants. Silencing two CINNAMYL ALCOHOL DEHYDROGENASE (CAD) genes in Nicotiana attenuata produced plants (ir-CAD) with thin, red-pigmented stems, low CAD and sinapyl alcohol dehydrogenase activity, low lignin contents, and rubbery, structurally unstable stems when grown in the glasshouse (GH). However, when planted into their native desert habitat, ir-CAD plants produced robust stems that survived wind storms as well as the wild-type plants. Despite efficient silencing of NaCAD transcripts and enzymatic activity, field-grown ir-CAD plants had delayed and restricted spread of red stem pigmentation, a color change reflecting blocked lignification by CAD silencing, and attained wild-type-comparable total lignin contents. The rubbery GH phenotype was largely restored when field-grown ir-CAD plants were protected from wind, herbivore attack, and ultraviolet B exposure and grown in restricted rooting volumes; conversely, it was lost when ir-CAD plants were experimentally exposed to wind, ultraviolet B, and grown in large pots in growth chambers. Transcript and liquid chromatography-electrospray ionization-time-of-flight analysis revealed that these environmental stresses enhanced the accumulation of various phenylpropanoids in stems of field-grown plants; gas chromatography-mass spectrometry and nuclear magnetic resonance analysis revealed that the lignin of field-grown ir-CAD plants had GH-grown comparable levels of sinapaldehyde and syringaldehyde cross-linked into their lignins. Additionally, field-grown ir-CAD plants had short, thick stems with normal xylem element traits, which collectively enabled field-grown ir-CAD plants to compensate for the structural deficiencies associated with CAD silencing. Environmental stresses play an essential role in regulating lignin biosynthesis in lignin-deficient plants.Plant cell walls are chemically complex, consisting of an extracytosolic matrix composed of extensively cross-linked polysaccharides (cellulose, hemicelluloses, and pectin) and are impregnated with lignin and proteins (Somerville et al

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“…A number of economically important genes (Table 2) (for example, herbicide resistance, insect and disease resistance, reduced lignin, and growth traits) have been transferred to produce transgenic plants in several forest tree species. These include (1) herbicide resistance genes (aroA, BAR, CP4) in Populus (Fillatti et al 1987;Donahue et al 1994;Meilan et al 2002;Li et al 2008a, b), Eucalyptus (Harcourt et al 2000), Pinus radiata and Picea abies (Bishop-Hurley et al 2001;Charity et al 2005); (2) insect resistance gene (Bt) in Populus (Leple et al 1995;Wang et al 1996;Meilan et al 2000;Hu et al 1999;Yang et al 2003); Pinus radiata , Pinus taeda (Tang and Tian 2003) and Picea glauca (Lachance et al 2007); (3) bacterial and fungal resistance genes (D4E1, ChitIV, STS, ESF39A, ech42) in hybrid poplar (Populus tremula 9 P. alba) (Mentag et al 2003), in Betula (Pasonen et al 2004), in Populus , in Ulmus Americana (Newhouse et al 2007), and in Picea mariana and hybrid poplar (Populus nigra 9 P. maximowiczii) (Noël et al 2005); (4) stress tolerance gene (CaPF1) in Pinus strobus (Tang et al 2007) and salt tolerance gene (codA) in Eucalyptus (Yu et al 2009); and (5) lignin modification genes (CAD,4Cl,COMT,CAld5H) in Populus (Hu et al 1999;Pilate et al 2002;Baucher et al 2003;Li et al 2003;Halpin et al 2007;Hancock et al 2007) and Betula pendula (Tiimonen et al 2005). In most of these short-term studies there was a fairly stable and predicable expression of transgenes in the selected transgenic trees under greenhouse and confined field trials.…”

Section: Stability Of Transgene Expressionmentioning

confidence: 99%

Transgene stability and dispersal in forest trees

Ahuja

2009

Trees

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Transgenics from several forest tree species, carrying a number of commercially important recombinant genes, have been produced, and are undergoing confined field trials in a number of countries. However, there are questions and issues regarding stability of transgene expression and transgene dispersal that need to be addressed in long-lived forest trees. Variation in transgene expression is not uncommon in the primary transformants in plants, and is undesirable as it requires screening a large number of transformants in order to select transgenic lines with acceptable levels of transgene expression. Therefore, the current focus of plant transformation is toward fine tuning of transgene expression and stability in the transgenic forest trees. Although a number of studies have reported a relatively stable transgene expression for several target traits, including herbicide resistance, insect resistance, and lignin modification, there was also some unintended transgene instability in the genetically modified (GM) forest trees. Transgene dispersal from GM trees to feral forest populations and their containment remain important biological and regulatory issues facing commercial release of GM trees. Containment of transgenes must be in place to effectively prevent escape of transgenic pollen, seed, and vegetative propagules in economically important GM forest trees before their commercialization. Therefore, it is important to devise innovative technologies in genetic engineering that lead to genetically stable transgenic trees not only for qualitative traits (herbicide resistance, insect resistance), but also for quantitative traits (accelerated growth, increased height, increased wood density), and also prevent escape of transgenes in the forest trees.

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Ecological impacts of trees with modified lignin

Cited by 48 publications

References 20 publications

Paxillus involutus Forms an Ectomycorrhizal Symbiosis and Enhances Survival of PtCOMT-modified Betula pendula in vitro

Paxillus involutus Forms an Ectomycorrhizal Symbiosis and Enhances Survival of PtCOMT-modified Betula pendula in vitro

Environmental Stresses of Field Growth Allow Cinnamyl Alcohol Dehydrogenase-Deficient Nicotiana attenuata Plants to Compensate for their Structural Deficiencies

Transgene stability and dispersal in forest trees

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