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Karpaga Raja Sundari B.,Institute of Forest Genetics and Tree Breeding | Ghosh Dasgupta M.,Institute of Forest Genetics and Tree Breeding
Journal of Genetics | Year: 2014

Cellulose synthases (CesA) represent a group of β-1, 4 glycosyl transferases involved in cellulose biosynthesis. Recent reports in higher plants have revealed that two groups of CesA gene families exist, which are associated with either primary or secondary cell wall deposition. The present study aimed at identifying developing secondary xylem specific cellulose synthase genes from Eucalyptus tereticornis,a species predominantly used in paper and pulp industries in the tropics. The differential expression analysis of the three EtCesAgenes using qRT-PCR revealed 49 to 87 fold relative expression in developing secondary xylem tissues. Three full length gene sequences of EtCesA1, EtCesA2and EtCesA3 were isolated with the size of 2940, 3114 and 3123 bp, respectively. Phytohormone regulation of all three EtCesAgenes were studied by exogenous application of gibberellic acid, naphthalene acetic acid, indole acetic acid and 2, 4-epibrassinolide in internode tissues derived from three-month-old rooted cuttings. All threeEtCesA transcripts were upregulated by indole acetic acid and gibberellic acid. This study demonstrates that the increased cellulose deposition in the secondary wood induced by hormones can be attributed to the upregulation of xylem specific CesAs. © 2014, Indian Academy of Sciences.


Veluthakkal R.,Institute of Forest Genetics and Tree Breeding | Dasgupta M.G.,Institute of Forest Genetics and Tree Breeding
Forest Pathology | Year: 2012

Casuarina equisetifolia has the widest distribution of all Casuarina species and is a nitrogen-fixing tree of considerable social, economic and environmental importance. Trichosporium vesiculosum, a causal agent of blister bark disease, is a serious pathogen of C. equisetifolia. In this study, a cDNA clone encoding class I chitinase (CeChi1) belonging to PR-3 family was cloned and characterized from the needle tissues of C. equisetifolia challenged with the toxic exudate of the fungal pathogen T. vesiculosum. The CeChi1 open reading frame comprised 966 nucleotides that encoded 321 amino acid residues with the molecular mass of mature protein being approximately 34 kDa. Analysis of the predicted amino acid sequence revealed the similarity of CeChi1 protein to class I chitinase from other plant species containing a hydrophobic signal peptide domain and hinge domain. The sequence also harboured a cysteine-rich chitin-binding domain and lysozyme-like domain. A hydrophobic C-terminal domain similar to the vacuole targeting sequences of class I chitinases isolated from other plants was also detected. The genomic sequence of CeChi1 indicated that the coding region contained three exons and two introns. In silico analysis of the untranslated regions revealed the presence of several cis-acting regulatory elements associated with hormonal regulation and stress responses. Quantitative real-time PCR analyses at different time points showed upregulation of the transcript during pathogen elicitation and salicylic acid signalling. However, no significant expression of CeChi1 was observed during other abiotic stress condition including wounding, water deficit, salt and heat stress revealing the specific expression of the gene during pathogenesis. This is the first report on isolation of a gene from C. equisetifolia, and the detailed functional analyses of CeChi1 will help in understanding its specific role in defence against pathogens in this tropical tree species. © 2012 Blackwell Verlag GmbH.


Karthikeyan A.,Institute of Forest Genetics and Tree Breeding | Sakthivel K.M.,Institute of Forest Genetics and Tree Breeding
Research Journal of Microbiology | Year: 2011

Eucalyptus camaldulensis Dehn is a commercial tree crop mainly for paper and pulp industries. This tree crop is propagated by vegetative propagation method to obtain genetically superior clones. At the time of vegetative propagation a synthetic rooting hormone Indole Butyric Acid (IBA) is being used in nurseries for successful rooting in E. camaldulensis stem cuttings. To reduce the cost of IBA and improve the rooting and nutrient enrichment as an alternate method a nitrogen fixing bacteria Azotobacter chroococcum was applied in the stem cuttings of E. camaldulensis in present study. The influence of A chroococcum on rooting and subsequent growth of E. camaldulensis cuttings was observed under nursery conditions. An un-inoculated control and IBA treated cuttings were also maintained to compare the growth with A. chroococcum inoculated stem cuttings. Bacterial inoculum (5×10 7 cfu mL -1) at the rate of 5 and 10 mL were applied to the rooting substrate (vermiculite) during cutting installation. Rooting and Biomass was evaluated after 30 days of cutting installation. Additionally, the isolates were screened for their ability to produce Indole Acetic Acid (IAA) under in vitro conditions either in the presence or absence of tryptophan at different concentrations. The results revealed that A. chroococcum produced significant quantities of IAA for root initiation and A. chroococcum inoculated cuttings had higher growth than IBA treated cuttings at p<0.05. From this study, it was concluded that the stem cuttings of E. camaldulensis responded positively to A. chroococcum inoculation through increased root proliferation and growth. © 2011 Academic Journals Inc.


Veluthakkal R.,Institute of Forest Genetics and Tree Breeding | Dasgupta M.G.,Institute of Forest Genetics and Tree Breeding
Trees - Structure and Function | Year: 2010

Trees occupy more than 30% of the land biosphere. They are important from both ecological and environmental standpoints and provide some of the most valuable commodities in the world economy. The perennial nature and size of trees are the critical determinants of their survival in response to biotic and abiotic stresses. The identification of the defense pathways at biochemical and genetic levels in tree pathosystems are beginning to be addressed. The basic physiological and biochemical mechanisms in woody perennials in response to pathogen is homologous to the model annual crop like Arabidopsis, but their secondary metabolic processes and ecological survival strategies are likely to be divergent from their annual counterparts. The limited domestication in tree species makes its molecular mechanisms less comparable to the highly pedigreed crop species. Recent reports have highlighted that the possible difference in genetic programs responding to invasive pathogens between annuals and perennials could be the spatial and temporal pattern of gene regulation. Several reviews on pathogen defense with reference to crop species are available, while similar reports from the tree species are limited to few commercially important species like Populus, Pinus, Picea, Eucalyptus, Castanea, and Pseudotsuga. This paper reviews the present status of pathogenesis-related genes and proteins from tree species with emphasis on the resistant genes and the proteins induced during systemic acquired resistance and highlights the ecological and evolutionary significance of defense-related genes from tree species. © 2010 Springer-Verlag.


Arumugasundaram S.,Institute of Forest Genetics and Tree Breeding | Ghosh M.,Institute of Forest Genetics and Tree Breeding | Veerasamy S.,Institute of Forest Genetics and Tree Breeding | Ramasamy Y.,Institute of Forest Genetics and Tree Breeding
PLoS ONE | Year: 2011

Eucalyptus camaldulensis and E. tereticornis are closely related species commonly cultivated for pulp wood in many tropical countries including India. Understanding the genetic structure and linkage disequilibrium (LD) existing in these species is essential for the improvement of industrially important traits. Our goal was to evaluate the use of simple sequence repeat (SSR) loci for species discrimination, population structure and LD analysis in these species. Investigations were carried out with the most common alleles in 93 accessions belonging to these two species using 62 SSR markers through cross amplification. The polymorphic information content (PIC) ranged from 0.44 to 0.93 and 0.36 to 0.93 in E. camaldulensis and E. tereticornis respectively. A clear delineation between the two species was evident based on the analysis of population structure and species-specific alleles. Significant genotypic LD was found in E. camaldulensis, wherein out of 135 significant pairs, 17 pairs showed r 2≥0.1. Similarly, in E. tereticornis, out of 136 significant pairs, 18 pairs showed r 2≥0.1. The extent of LD decayed rapidly showing the significance of association analyses in eucalypts with higher resolution markers. The availability of whole genome sequence for E. grandis and the synteny and co-linearity in the genome of eucalypts, will allow genome-wide genotyping using microsatellites or single nucleotide polymorphims. © 2011 Arumugasundaram et al.


Karthikeyan A.,Institute of Forest Genetics and Tree Breeding
Journal of Tropical Forest Science | Year: 2016

Casuarina equisetifolia fixes atmospheric nitrogen (N) to produce root nodules where actinomycete fixes atmospheric N for all metabolic activities of plant. Two strains of Frankia (CeFr1, CeFr2) were isolated, cultured in artificial propionic acid medium and analysed for nitrogenase activity by acetylene reduction assay to ascertain their capabilities in N fixation. Seedlings of C. equisetifolia were inoculated with Frankia strains in the nursery and their growth performances were assessed. Seedlings inoculated with Frankia strains showed improved growth, biomass and tissue N content over control seedlings. Nitrogenase activity of Frankia strains were significantly (p < 0.05) and negatively correlated with tissue N content. Inoculated seedlings were then planted on a farmland without adding fertilisers and assessed after 2 years. Seedlings inoculated with CeFr1 and CeFr2 showed significantly improved growth in height (9.5 and 8.4 m respectively) compared with control. Seedlings inoculated with Frankia strains achieved > 95% survival and had improved biomass and N fixation. © Forest Research Institute Malaysia.


Dasgupta M.G.,Institute of Forest Genetics and Tree Breeding | George B.S.,Institute of Forest Genetics and Tree Breeding | Bhatia A.,CSIR - Central Electrochemical Research Institute | Sidhu O.P.,CSIR - Central Electrochemical Research Institute
PLoS ONE | Year: 2014

Withania somnifera (L.) Dunal is a valued medicinal plant with pharmaceutical applications. The present study was undertaken to analyze the salicylic acid induced leaf transcriptome of W. somnifera. A total of 45.6 million reads were generated and the de novo assembly yielded 73,523 transcript contig with average transcript contig length of 1620 bp. A total of 71,062 transcripts were annotated and 53,424 of them were assigned GO terms. Mapping of transcript contigs to biological pathways revealed presence of 182 pathways. Seventeen genes representing 12 pathogenesis-related (PR) families were mined from the transcriptome data and their pattern of expression post 17 and 36 hours of salicylic acid treatment was documented. The analysis revealed significant up-regulation of all families of PR genes by 36 hours post treatment except WsPR10. The relative fold expression of transcripts ranged from 1 fold to 6,532 fold. The two families of peroxidases including the lignin-forming anionic peroxidase (WsL-PRX) and suberization-associated anionic peroxidase (WsSPRX) recorded maximum expression of 377 fold and 6532 fold respectively, while the expression of WsPR10 was downregulated by 14 fold. Additionally, the most stable reference gene for normalization of qRT-PCR data was also identified. The effect of SA on the accumulation of major secondary metabolites of W. somnifera including withanoside V, withaferin A and withanolide A was also analyzed and an increase in content of all the three metabolites were detected. This is the first report on expression patterns of PR genes during salicylic acid signaling in W. somnifera. © 2014 Ghosh Dasgupta et al.


Karthikeyan A.,Institute of Forest Genetics and Tree Breeding
Symbiosis | Year: 2016

Impact of different levels of elevated CO2 on the activity of Frankia (Nitrogen-fixing actinomycete) in Casuarina equisetifolia rooted stem cuttings has been studied to understand the relationship between C. equisetifolia, Frankia and CO2. The stem cuttings of C. equietifolia were collected and treated with 2000 ppm of Indole Butyric Acid (IBA) for rooting. Thus vegetative propagated rooted stem cuttings of C. equisetifolia were inoculated with Frankia and placed in the Open top chambers (OTC) with elevated CO2 facilities. These planting stocks were maintained in the OTC for 12 months under different levels of elevated CO2 (ambient control, 600 ppm, 900 ppm). After 12 months, the nodule numbers, bio mass, growth, and photosynthesis of C. equisetifolia rooted stem cuttings inoculated with Frankia were improved under 600 ppm of CO2. The rooted stem cuttings of C. equisetifolia inoculated with Frankia showed a higher number of nodules under 900 ppm of CO2 and cuttings without Frankia inoculation exhibited poor growth. Tissue Nitrogen (N) content was also higher under 900 ppm of CO2 than ambient control and 600 ppm levels. The photosynthetic rate was higher (17.8 μ mol CO2 m−2 s−1) in 900 ppm of CO2 than in 600 ppm (13.2 μ mol CO2 m−2 s−1) and ambient control (8.3 μ mol CO2 m−2 s−1). This study showed that Frankia can improve growth, N fixation and photosynthesis of C. equietifolia rooted stem cuttings under extreme elevated CO2 level conditions (900 ppm). © 2016 Springer Science+Business Media Dordrecht


Chezhian P.,Institute of Forest Genetics and Tree Breeding | Yasodha R.,Institute of Forest Genetics and Tree Breeding | Ghosh M.,Institute of Forest Genetics and Tree Breeding
New Forests | Year: 2010

India is the largest grower of Eucalyptus with an area of 3. 943 million hectares under plantations and E. tereticornis is the predominant species in the plains of southern India with an average productivity of 12-25 m3 ha-1 year-1. With the aim to establish seedling seed orchards of the species, seed lots of fifteen provenances were imported from Australia and a trial was laid. In the present study the genetic diversity existing in the seed orchard was estimated using ISSR-PCR. Seven ISSR primers amplified 663 amplicons in the size ranging from 255 to 2,711 bp. The total number of polymorphic bands varied from 59 to 123 with 100% polymorphic banding profiles. The average gene diversity (Hj) of all the provenances ranged from 0. 0589 to 0. 1109 and the total gene diversity estimated was low (HT = 0.130) when compared to the earlier reports from other eucalypts species. Analysis of Molecular Variance partitioned the ISSR variation into inter and intra population components. The inter population component accounted for 55.2% of the variation and the intra population component accounted for 46.3% (P < 0. 001). A neighbour-joining analysis was done using the dissimilarity matrix to determine the aggregation of the individuals into clusters. Existence of population structure among the populations was revealed in STRUCTURE analysis but geographical region based clustering was not observed. The assessment of intra and inter genetic variation documented in the present study suggests that, along with the phenotypic traits, knowledge about genetic diversity measured at the DNA level in individuals of seed orchards provide an objective guide for selective culling of trees for maintaining optimal diversity for enhanced genetic gains. © 2009 Springer Science+Business Media B.V.


Jayaraj R.S.C.,Institute of Forest Genetics and Tree Breeding
Australian Journal of Botany | Year: 2010

Casuarina junghuhniana Miq., introduced into India in 1996, is gaining importance as an agroforestry species, with potential use in pulp and paper industry. Tree improvement of the species and attempts at clonal forestry are in progress. A hybrid of Casuarina equisetifolia L. and C. junghuhniana, introduced in 1951 from Thailand, is also planted in India, with the wrong identity as Casuarina junghuhniana. The present paper reviews the silviculture and tree improvement of the species, especially the attempts at introduction to various parts of the world by CSIRO, Australia, with special reference to India. The paper also attempts to resolve the confusion between the hybrid and the pure species, among the planting agencies in India. © 2010 CSIRO.

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