<abstract><title style='display:none'>Abstract</title> The identification of AFLP markers and their subsequent conversion to SCAR-markers linked to wood density of Norway Spruce (Picea abies L [Karst.]) is described for the first time. In AFLP-analyses, 102 different primer enzyme combinations were screened in a bulked segregant approach comparing individuals with high and low wood density. A total of 107 polymorphic AFLP fragments were obtained between the DNA-pools. Twenty-three markers were selected for further analyses to verify their linkage to wood density based on individuals used for pool constitution and additional unrelated clonal material. For 15 markers, a significant linkage to wood density was confirmed by a two-sided Fisher’s-exact test. Four markers were converted into SCAR markers and validated for plant material assayed for wood density by X-ray microdensitometry. For each marker a monomorphic band was obtained using sets of nested primers or restriction site-specific primers (RSS), which include the AFLP-restriction recognition sites. For two markers that are linked to high wood density, a separation from unlinked size homologous marker-alleles was realized by a PCR-restriction approach. Validation of these markers in different full-sib families confirmed their usability to separate the classes for low and high wood density of Picea abies.</abstract>

Identification of Molecular Markers for Selected Wood Properties of Norway Spruce Picea abies L. (Karst.) I. Wood Density

<abstract><title style='display:none'>Abstract</title> Malus sylvestris is the only apple species native to Central Europe. Its genetic integrity may be threatened by hybridization with the cultivated apple (Malus × domestica). A total of 883 genotypes, 477 putative wild apples in Germany and Luxembourg and 406 old to modern cultivars has been investigated. Wild apples growing in Germany originated from Rhineland-Palatinate, North Rhine-Westphalia, Saxony-Anhalt and Saxony. The genetic structure was analysed at ten isozyme marker loci, and morphology was studied by fruit size, leaf pubescence, and a complex morphological description performed in advance. A model-based cluster analysis applied to all nuclear data resulted in two clearly differentiated gene pools for putative wild and cultivated apples with moderate proportions of admixture in the wild group on average (0.138 total, 0.111 German sample). At the individual level, the percentages of both hybrids and feral cultivars together ranged from 2.3% in Rhineland-Palatinate to 28.8% in Luxembourg. The intraspecific variability in fruit diameter ranged from 21 to 40 mm, and that in leaf pubescence in autumn ranged from score 0 to score 1. No single morphological trait of a specimen appeared to be sufficient for identification. Even the correspondence between the complex morphological and complex genetic determinations for individuals did not exceed 93% in pure wilds and 64% in hybrids. Genetic variation in pure wild apple is high (species level: P = 90%, A/L = 3.1, He = 0.369). Allelic differentiation &amp; was 0.089, pairwise genetic distance (d0) ranged from 0.065 to 0.148 among five samples. Correspondence between genetic and geographic distance of populations was observed to a certain extent.</abstract>

Hybridization and Genetic Diversity in Wild Apple (Malus sylvestris (L.) MILL.) from Various Regions in Germany and from Luxembourg

<abstract><title style='display:none'>Abstract</title> We describe the development of a SCAR-marker linked to low extractives content of Norway Spruce (Picea abies L [Karst.]) derived from AFLPs. In these analyses 57 different primer enzyme combinations were used in a bulked segregant analysis approach comparing individuals with high and low extractives content. A total of 14 polymorphic AFLP markers were detected between the pools. Five markers were selected for further analyses to verify their linkage to extractives content based on individuals used for pool constitution. One AFLP marker, found to be significant linked to low extractives content was converted into a SCAR marker for further validation. For this marker, a monomorphic band was obtained by using sets of nested primers or restriction site specific primers (RSS) which include the AFLP-restriction recognition site. The separation of the marker from unlinked size homologous marker-alleles was realized by a SSCP-approach. Validation of the marker on different full-sib families confirmed the usability to separate the classes for low and high extractives content of Picea abies.</abstract>

Identification of Molecular Markers for Selected Wood Properties of Norway Spruce Picea abies L. (Karst.) II. Extractives Content

<abstract>
<title style='display:none'>Abstract</title>
Many dioecious angiosperms are trees, which only flower after years of vegetative development and do not usually exhibit marked secondary sexual dimorphism. Nevertheless, if the genetic basis of sex determination is known, the sex of an individual can be determined using molecular markers. Here, we report that in the genus <italic>Populus</italic> sect. Populus an XY system of sex determination, which is found in <italic>P. tremula</italic> and <italic>P. tremuloides</italic>, likely re-evolved from a ZW system present in <italic>P. alba, P. adenopoda</italic> and <italic>P. qiongdaoensis</italic>. Strikingly, this new XY system is mechanistically identical to the older system found in several species of the <italic>Populus</italic> sections Tacamahaca, Aigeiros and Turanga demonstrating a remarkable example of convergent evolution. In both XY systems, male-specific inversely repeated sequences appear to silence the <italic>ARR17</italic> gene, which functions as a sex switch, via small interfering RNAs and DNA methylation. In the ZW system, female-specific copies of <italic>ARR17</italic> appear to regulate dioecy. With this detailed information on the genetic basis of sex determination it was possible to develop molecular markers that can be utilized to determine the sex in seedlings and non-flowering trees of different poplar species. We used the female-specific <italic>ARR17</italic> gene to develop a sex marker for <italic>P. alba</italic> and <italic>P. adenopoda</italic>. For <italic>P. grandidentata</italic>, we employed the male-specific <italic>ARR17</italic> inverted repeat. Finally, we summarize previously described markers for P. <italic>tremula</italic>, <italic>P. tremuloides</italic>, <italic>P. trichocarpa</italic>, <italic>P. deltoides</italic> and <italic>P. nigra</italic>. These markers can be useful for poplar ecologists, geneticists and breeders.
</abstract>

The genetic basis of sex determination in <italic>Populus</italic> provides molecular markers across the genus and indicates convergent evolution

<abstract>
<title style='display:none'>Abstract</title>
The equatorial region of the world includes areas of Tropical Rainforest (Af) and Tropical Monsoon (Am) climate zones, which are distinguished by high temperatures and high rainfall, but soils which are often deficient. Potential productivity of plantation forestry in this area is high, and so are the pest and disease dangers which threaten it. This paper describes the <italic>Eucalyptus</italic> and <italic>Corymbia</italic> species which are adapted to this situation and also resistant to the main diseases like leaf blights. Based on the highly adapted <italic>E. biterranea</italic> and <italic>E. deglupta</italic> and several more, hybridization combined with vegetative propagation is discussed as an excellent alternative to obtain quick gains in short rotations while maintaining wide genetic diversity in such plantations. Management remedies are given for the possible backlash of quick soil depletion.
</abstract>

Eucalypts for Tropical Rainforest (Af) climate

<abstract><title style='display:none'>Abstract</title> Pollution of soil and water with heavy metals such as mercury, cadmium and arsenic, is a worldwide problem. Phytoremediation, the use of plants to remove, sequester or detoxify pollutants, including heavy metals, offers an environmentally-friendly alternative to engineering- based methods for remediation. Forest trees have multiple features that make them particularly useful for removal of toxic heavy metals, especially if they can be engineered with genes allowing them to handle high levels of these elements. Although still in its infancy, research with transgenic trees carrying genes allowing them to detoxify or sequester some heavy metals has already made promising progress. Most of the work to date has been performed using poplar species and hybrids, although other woody species could be equally as useful. Trees have been engineered with genes for the handling of mercury, cadmium, copper and arsenic following two main approaches, phytoextraction and phytotransformation/ phytovolatilizaton. In vitro studies have shown the transgenic trees to have enhanced abilities to tolerate and/or accumulate these metals, and preliminary results from field tests indicate that the trees are functioning. New combinations of genes involved in metal transport or conversion may further enhance the heavy metal remediation capabilities of the transgenic trees. Given the environmentally friendly application, forest trees engineered for phytoremediation may be some of the first transgenic forest trees approved for operational deployment.</abstract>

Engineering Forest Trees with Heavy Metal Resistance Genes

<abstract>
<title style='display:none'>Abstract</title>
Forest tree breeding faces challenges due to long generation times and high costs. To address these issues, the concept of “breeding without breeding” (BwB) offers the opportunity to accelerate breeding cycles by using naturally generated half- sib and full-sib families. An isolated population of trees may provide an ideal environment to identify full-sib families for genetic mapping without the need for controlled pollination. In this study, paternity analysis based on genotyping of 16 SSR markers in 1232 seedlings identified three large full-sib families of <italic>Quercus rubra</italic> (Qr_N - Qr_W with 576 siblings, Qr_N - Qr_S with 175 siblings and 124 siblings in the family Qr_P - Qr_11). Paternity assignments were effectively corroborated by segregation analysis, resulting in large F1 full-sib families for further experiments such as Quantitative Trait Locus (QTL) mapping.
</abstract>

Identification of three large full-sib families of <italic>Quercus rubra</italic> for genetic mapping in an isolated planting outside the species’ range in Germany

<abstract>
<title style='display:none'>Abstract</title>
<italic>Balfourodendron riedelianum</italic> is an important timber species of South America used in civil construction and carpentry. Knowing the genetic variation, heritability and correlation between traits is an essential prerequisite for guiding selection of the best genotypes in tree improvement. In this study, growth (diameter and height) and wood density (mean, pith, middle and bark position) traits were investigated in 30-year-old trees planted in a <italic>B. riedelianum</italic> provenance and progeny test established in two sites, Luiz Antônio (LA) and Pederneiras (PE), in São Paulo State (Brazil). ANOVA results showed significant differences between sites for all traits, among provenances and families for wood density traits in the LA site and among families for growth traits in PE. Provenance x site and family x site interactions were significant for almost traits, and genetic correlation between sites was low for all traits (0.17–0.20). Genetic variation (<italic>CV</italic>g) was higher (4.0–5.4 %) and mean family heritability (<italic>h</italic>m2) was lower for growth (0.12–0.20) compared to wood density (<italic>CV</italic>g: 2.3–3.8%, <italic>h</italic>m2: 0.31–0.59) traits. Genetic correlation was significantly positive and ranged from moderate to high between growth traits (0.47–0.68) and between wood density traits (0.42–0.83) and non-significant between growth and wood density (-0.22–0.30) traits. An analysis of different radial positions showed that heritability tended to increase from pith to the bark position. Our results show a lower environmental effect on wood density traits, allowing the possibility of selecting superior provenances and families with high wood quality in breeding programs in both sites.
</abstract>

Genetic parameters and correlations in growth and wood density traits of <italic>Balfourodendron riedelianum</italic> based on provenance and progeny testing

<abstract>
<title style='display:none'>Abstract</title>
<italic>Podocarpus lambertii</italic> (Podocarpaceae) is an endangered conifer, endemic to Brazil and occurring in continuous forest and forest-grassland landscapes from the Araucaria Forest. Aiming to support conservation efforts for <italic>P. lambertii</italic> populations and gain insights into the preservation of forest-grassland mosaics in southern Brazil, we assessed the spatial pattern, genetic diversity, and fine-scale genetic structure (FSGS) within a population situated in a forest-grassland mosaic. The study was conducted in a 9-ha plot in forest-grassland mosaic. All <italic>P. lambertii</italic> individuals with height ≥ 0.1 m were sampled and the population was stratified into four demographic categories (Seedling, Juvenile, Immature, and Reproductive). For each of these categories, we used 13 allozyme markers to evaluate the spatial pattern, genetic diversity and FSGS. All individuals occurred inside the forest-patches, presenting an aggregated pattern of distribution. Low genetic diversity was recorded for all categories and for the population (<inline-formula>
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<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mover accent="true"><mml:mi>H</mml:mi><mml:mo>⌢</mml:mo></mml:mover></mml:mrow><mml:mi>E</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mi> </mml:mi><mml:mn>0.046</mml:mn></mml:mrow></mml:math>
<tex-math>{\mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over H} _E} = \,0.046</tex-math>
</alternatives>
</inline-formula>), as well as a high number of rare alleles (20). Positive and significant FSGS was estimated only for the Juveniles (<inline-formula>
<alternatives>
<inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_sg-2024-0006_eq_002.png"/>
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mover accent="true"><mml:mi>θ</mml:mi><mml:mo>⌢</mml:mo></mml:mover></mml:mrow><mml:mrow><mml:mi>x</mml:mi><mml:mi>y</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mi> </mml:mi><mml:mn>0.012</mml:mn></mml:mrow></mml:math>
<tex-math>{\mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over \theta } _{xy}} = \,0.012</tex-math>
</alternatives>
</inline-formula>) up to maximum distance of 7.1 m, and the minimum viable area for the long-term conservation of Reproductive genetic diversity was approximately 68 ha. The set of our findings suggests that conservation actions need to enhance connectivity among forest-patches to prevent the loss of rare alleles due to genetic drift. Additionally, we highlight the significance of preserving forest-patches as repositories of species diversity and as crucial connectors between populations.
</abstract>

Genetic diversity and fine-scale genetic structure of the conifer <italic>Podocarpus lambertii</italic> in a forest-grassland mosaic from Southern Brazil

<abstract>
<title style='display:none'>Abstract</title>
Genetic variation and performance of up to 40-year-old Norway spruce (<italic>Picea abies</italic> (L.) Karst.) families from half-diallel crosses made in natural populations where studied, and the results were compared with results from nursery test of seedlings (1-2 years from seed) and short-term farm-field tests at 6-10 years from seed. The diallel analyses revealed significant levels of additive genetic variance for growth and phenology traits. The non-additive genetic variance was generally small to moderate. Strong genetic correlations for growth performance were found between the short-term and long-term trials but not between the nursery and long-term trials. Similarly, genetic correlations for phenology traits were strong between short-term trials and long-term trials, whereas the nursery tests generally did not predict phenology at older age well. The findings indicate that early selection for growth and adaptive traits based on short-term trials is effective for improvement of long-term performance in field if the test site is not outside the normal range of deployment of the reproductive material.
</abstract>

Diallel crosses in <italic>Picea abies</italic> V. Can early testing predict long-term performance?

<abstract><title style='display:none'>Abstract</title>
The present study measured the growth traits of 98 open-pollinated half-sibling families from the second-generation clonal seed orchard of Chinese fir for 6 consecutive years from age 2 to 7, the change patterns of genetic variation in growth traits and genetic parameters were analyzed, and best linear unbiased prediction (BLUP) was used for early selection to determine the excellent families. The growth traits of Chinese fir revealed highly significant differences between families, indicating that there was significant genetic variation at the family level, which serves as the foundation for exceptional family selection. The heritabilities of family and individual for H (height) ranged from 0.61 to 0.65 and 0.41 to 0.46, respectively; for DGH (the diameter at ground height)/DBH (the diameter at breast height), they were 0.55 to 0.66 and 0.35 to 0.46, respectively; and for V (tree volume), they were 0.66 to 0.70 and 0.48 to 0.49, respectively. The growth traits of genetic control were at a greater level at age 5. The findings of the coefficient of variation analysis demonstrated that the phenotypic variation coefficient were larger than the genetic variation coefficient for three growth traits at various ages. The juvenile-mature genetic and phenotypic correlations revealed an increasing tendency with age, and mainly controlled by genetic factors. Compared to other age groups for growth traits, age 5 had greater phenotypic and genetic association coefficients, as well as greater efficiency of early selection. Based on the selection method of breeding value, nine families were selected with a 9.2 % selection rate.
</abstract>

Age trends of genetic variation and early selection for growth traits in <italic>Cunninghamia lanceolata</italic> open-pollinated families

<abstract><title style='display:none'>Abstract</title>
In Mexico, <italic>Magnolia</italic> species of the section <italic>Macrophylla</italic> have been segregated based on phenotypic characteristics. However, the wide environmental variation throughout their distribution area in the eastern region of the country could be the main cause of the high degree of morphological variation among the taxa of this section. Therefore, it is necessary to carry out studies at the genetic level to confirm the taxonomic identity of these species. In the present study, the diversity and genetic structure of the populations of <italic>Magnolia rzedowskiana</italic> and <italic>M. zotictla</italic> were estimated using simple sequence repeat markers. We evaluated whether the taxonomic delimitation as independent species is consistent with their degree of genetic differentiation, comparing three regions of chloroplast DNA: trnH-psbA, ORF350, and rpl32-trnL. The DNA was obtained from four populations of the two species, which are distributed in the states of Hidalgo, Querétaro and San Luis Potosí. The populations presented intermediate–high genetic diversity (He = 0.52–0.60), limited gene flow (Nm = 0.62) and high genetic differentiation (Fst = 0.288), which may be related to their low density and strong geographic isolation, caused by the high degree of fragmentation of their habitat. The phylogenetic analysis and the genetic differentiation values indicate that each of the populations of the two <italic>Magnolia</italic> species analyzed behaves as an independent evolutionary unit, so the taxonomic delimitation of the three <italic>M. rzedowskiana</italic> populations must be reconsidered. The results obtained could be very useful for implementing management and conservation strategies for these populations in the short term.
</abstract>

Structure, diversity, and genetic delimitation of two <italic>Magnolia </italic>species endemic to eastern Mexico

<abstract><title style='display:none'>Abstract</title> Conifers are the most widely distributed group of gymnosperms in the world. They have large genome size (1C-value) compared with most animal and plant species. The genome size ranges from ~6,500 Mb to ~37,000 Mb in conifers. How and why conifers have evolved such large genomes is not understood. The conifer genome contains ~75% highly repetitive DNA. Most of the repetitive DNA is composed of non-coding DNA, including ubiquitous transposable elements. Conifers have relatively larger rDNA repeat units, larger gene families generated by gene duplications, larger nuclear volume, and perhaps larger genes, as compared to angiosperm plants. These genomic components may partially account for the large genome size, as well as variation in genome size, in conifers. One of the major mechanisms for genome size expansion and evolution of species is polyploidy, which is widespread in angiosperms, but it is rare in conifers. There are only a few natural polyploids in one family of conifers, Cupressaceae. Other conifers, including well-studied pines, are nearly all diploids. Whether ancient polyploidy has played a role in the evolution of genome size in conifers still remains an open question. The mechanisms that account for the variation and evolution of genome size in conifers are addressed in this review.</abstract>

Evolution of Genome Size in Conifers

<abstract><title style='display:none'>Abstract</title> The aim of the study was to determine source variation in Jatropha curcas seeds collected from ten locations in Central India. A significant seed source variation was observed in seed morphology (colour, size and weight), seed germination (viability, germination percent, germination energy, germination value) and seedling growth parameters (survival percentage, seedling height, collar diameter, leave/plant, and seedling biomass). The seed source of Chhindwara (M.P.) was found as the best source in comparison to others. The phenotypic and genotypic variance, their coefficient of variability and broad sense heritability also showed a sizeable variability. This offers a breeder ample scope to undertake screening and selection of seed sources for the desired traits. Further, high percentage of heritability coupled with moderate intensity of genetic gain, was observed for seed germination traits, which signifies that germination is under strong genetic control and good amount of heritable additive genetic component can be exploited for improvement of this species.</abstract>

Seed Source Variation in Morphology, Germination and Seedling Growth of Jatropha curcas Linn. in Central India

<abstract><title style='display:none'>Abstract</title> Results of a seed source evaluation trial of Jatropha curcas Linn. laid out in 1996 at Jabalpur (M.P), a semi arid region of India are reported and discussed. Seeds collected from ten sources from central India representing the states Madhya Pradesh and Maharashtra viz. Gondia, Bichia, Balaghat, Niwas, Khandwa, Burhanpur, Nasik, Chindwara, Kundam and Jabalpur were evaluated for their growth performance from nursery stage (3 months) to field (two years). Variation in seed oil content of different sources were also studied and reported. Significant differences between the seed sources at age 27 months were observed for height, collar diameter, number of branches leaf area and field survival. Seeds collected from different sources also varied significantly in respect of seed and kernel weight and oil content in seed/kernel. The Chhindwara (M.P.) source performed the best and yielded a maximum oil of 39.12% from whole seed and 58.12% from kernel. The oil content ranged from 33.02 to 39.12% in whole seeds and 47.08 to 58.12% in kernel, across the seed sources. The performance of Kundam (M.P.), Jabalpur (M.P.), Bichia (M.P.), Niwas (M.P.) and Nasik (Maharashtra) sources were also found satisfactory for oil yield. Results indicate that genetic differences exist between the seed sources of J. curcas. The growth traits showed significant positive correlation with each other. Fair differences between phenotypic and genotypic coefficient of variability were observed. Heritability (broad sense) values were fairly good with regard to leaf area, height and collar diameter in comparison to survival percent. The relative performance of these sources was fairly consistent throughout the observation period.</abstract>

Seed Source Variation in Growth Performance and Oil Yield of Jatropha curcas Linn. in Central India

<abstract><title style='display:none'>Abstract</title> There are only a few natural polyploids in gymnosperms. These have been reported in Ephera spp. (Gnetales), and Juniperus chinensis ‘Pfitzeriana’ (2n = 4x = 44), Fitzroya cupressoides (2n = 4x = 44), and the only hexaploid conifer Sequoia sempervirens (2n = 6x = 66) (Coniferales). Sporadic polyploids and aneuploids occur at a very low frequency in nurseries in conifers, but most of them show growth abnormalities, remain dwarf, and may not reach maturity. One exception is an autotetraploid tree of Larix decidua (2n = 4x = 48) that has survived in a private estate in Denmark. Colchicine-induced polyploids (colchiploids) have been produced in a several genera of conifers, including, Pinus, Picea, and Larix. These colchiploids (Co) were hybridized to untreated diploids to produce C1 and C2 generations to investigate their chromosome behavior. The colchiploids showed a wide range of chromosome variability, ranging from diploids, triploids, and tetraploids, and many were mixoploids. The colchiploids also show growth retardation, remain dwarf, and their future potential applications in forestry remains uncertain. However, genetic variability in the colchiploids still offers prospects for isolating genetically stable new genotypes. Even though polyploidy is rare in extant conifers, is it possible that ancient polyploidy or paleopolyploidy, that is prevalent in angiosperms, has also played a role in the evolution of conifers. In this paper we shall review the current status of polyploidy in gymnosperms.</abstract>

Polyploidy in Gymnosperms: Revisited

<abstract><title style='display:none'>Summary</title> Four-year old clones (FG1 and FG11) of teak (Tectona grandis Linn. f.), differing in rejuvenation capacity were grown in glazed earthenware pots. Drought treatments were imposed by withholding water for 20 days and rewatered to the field capacity daily for 5 days and the possible role of biochemical alteration and antioxidant metabolism in conferring photosynthetic capacity was determine by measuring photosynthetic traits, cellular damage and assaying activities of the superoxide dismutase (SOD) and peroxidase (PER) enzymes. Growth, relative water content (RWC), net photosynthetic rate (Pn), stomatal conductance (gs), chlorophyll fluorescence (Fv/Fm) and chlorophyll a, b, total chlorophyll and soluble protein content decreased significantly with increasing drought treatments from 5 to 20 days. Droughtinduced stress significantly increased the carotenoids content, relative electrolyte leakage and malondialdehyde (MDA) content, and, at the same time, accumulated free proline, free amino acid and soluble sugars in both clones. After re-watered to the field capacity daily for 5 days, both clones were shown significant recovery in the studied parameters. As compared with the FG11, the FG1 clone was more tolerant to drought as indicated by higher level of antioxidant enzyme activities as well as lower MDA content and electrolyte leakage. Similarly, drought stress caused less pronounced inhibition of Pn in FG1 than in FG11 clone. After re-hydration, the recovery was relatively quicker in FG1 than in FG11 clone. FG1 clone showed significant recovery in maximum quantum yield or photochemical efficiency of PSII (Fv/Fm) after 5 days of re-watering. The FG11 compared to the FG1, the former clone was less tolerant to drought than the latter. These results demonstrated that the different physiological strategies including antioxidative enzymes employed by the FG1 and FG11 clones of T. grandis to protect photosynthetic apparatus and alleviate drought stress. Furthermore, this study also provides ideas for teak improvement programmes and may be useful in breeding or genetic engineering for their tolerance to drought stress.</abstract>

Growth Characteristics, Physiological and Metabolic Responses of Teak (Tectona Grandis Linn. f.) Clones Differing in Rejuvenation Capacity Subjected to Drought Stress

<abstract><title style='display:none'>Abstract</title> We report a reduction of lignin content in the woody plant Eucalyptus camaldulensis by the suppression of gene expression of the LIM domain transcription factor. Previously, we identified a cDNA encoding the tobacco (Nicotiana tabacum) LIM domain transcription factor, Nt1iml, involved in lignin biosynthesis and that specifically binds to an important cis-acting element, the PALbox sequence. The orthologous Eucalyptus gene of Ntliml, namely Ecliml, was isolated from the E. camaldulensis cDNA library (84% amino acid identity). The antisense Ntliml construct with a kanamycin-resistant gene was introduced into E. camaldulensis. The transgenic Eucalyptus plants grown in the greenhouse showed decreased expression levels of severallignin biosynthesis genes, phenylalanine ammonialyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-hydroxycinnamate CoA ligase (4CL). The abnormal phenotypic changes and a 29% reduction of lignin content were observed in the line LG12, in which the transcript level of Ecliml was most1y suppressed. Ec1iml is one of the key transcription factors involved in lignin biosynthesis.</abstract>

Reduction of Lignin Content by Suppression of Expression of the LIM Domain Transcription Factor in Eucalyptus camaldulensis

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