Biotechnology provides important tools for the sustainable development of agriculture, fisheries and forestry,
and can be of significant help in meeting an indispensable part in the rise of human civilization. It is indeed
often considered as one of the fields of scientific research in which the most rapid advances have been
made in recent years. It includes the unique roles and functions that trees, major structural constituents of
forest ecosystems have, their special biological characteristics, and their importance in the provision of
environmental, social and economic goods and services. Forest trees have unquestionably entered the
genomic era. Biotechnological tools viz., transgenic technology, RNA interference, functional genomics,
marker assisted selection, QTL and tissue culture etc. have paved road for successful exploitation and
integration of scientific fields with an increased sense of urgency for delivery of cutting edge research in tree
biotechnology, both in academia and industry. Advances and integration of such fields will have a great
impact in many respects, and will continue to provide new information, thereby offering exciting prospects
for future tree improvement programs worldwide.

Aquilaria subintegra belongs to the family Thymelaeaceae, is of economic importance as source of gaharu or agarwood. The main aim of this study was to establish a callus and cell suspension culture production protocol from leaf explants of A. subintegra through in vitro technique. An efficient callus regeneration protocol was established through leaf and proliferation in A. subintegra using Murashige and Skoog medium supplemented with various concentration of plant growth hormones (2,4 D, BAP & NAA) and different concentration of sucrose (30, 40, & 50 g/L). After three weeks, white friable embryogenic callus was developed in MS medium. The MS medium supplemented with 2.0 mg/l 2,4-D + 0.5 mg/l BAP and 30 g/L of sucrose showed higher callus induction (80%). Lower callus formation were observed in MS medium supplemented 2,4-D with NAA. Friable callus produced was transferred into liquid MS medium supplemented with the same combination and maintained in the dark. After one month, suspension cultures were successfully established and showed good proliferation and formation of globular and new cell aggregates. Liquid MS medium supplemented with 3.0 mg/L NAA + 0.5 mg/L BAP and 40 mg/L sucrose showed high proliferation and faster growth rate of cell aggregates.

Embryogenic cultures were initiated and established and somatic embryos produced in Pinus patula using thin sections from the dome of the vegetative shoot apex. Factors affecting initiation, basal medium and plant growth regulators were investigated. We report for the first time the initiation of embryogenic tissue and embryos from shoot apical domes (zones) of 15-year-old Pinus patula trees. The growth of embryogenic lines were comparable to those obtained from zygotic embryos. Plantlets were regenerated.

Efficient shoot regeneration of Eria dalzelli (Dalz.) Lindl. was achieved for the first time using shoot tip transverse thin cell layers (tTCLs) and thidiazuron (TDZ). Protocorm-like bodies (PLBs) or proliferating shoot buds was observed when tTCLs of shoot tip sections were cultured on Mitra et al. (1976) basal medium supplemented with 9.08 μM TDZ. The highest percentage of PLB survival was 96%, producing healthy shoots with 2-3 leaves. Shoots rooted when cultured on the same basal medium supplemented with 11.42 μM IAA. Regenerated plantlets grew normally with a 90% survival rate. This simple protocol will be useful for large-scale propagation of E. dalzelli. _____________________________________________________________________________________________________________

Thin cell layers or TCLs have been one of the most recent yet important techniques for the tissue culture and micropropagation of select forestry species. In this review, we abridge the current state of application of TCL technology to forest tree biotechnology, focusing on Pinus spp., Paulownia spp. and Populus spp. Where conventional methods have not always produced ideal results in the micropropagation of forestry species, TCL technology has now perfected the ability to control developmental and morphogenetic processes in vitro at a finer scale than the use of conventional explants focusing the size and the origin of the explant to ensure successful regeneration for micropropagation and transformation studies. TCLs are fundamental in implementing lab-based experiments to larger scale field-based applications and its application and proven success with three select forestry and timber species provides a frame-work for the development of the technique for other forestry species. __...

The cloning of mature conifers by somatic embryogenesis is potentially a low-cost method and is capable of producing unlimited numbers of normal individuals. This paper highlights for the first time the role of salicyclic acid (SA) on induction of embryogenic cultures using thin cell layers of vegetative shoot apices of mature trees of P. roxburghii. Embryogenic cultures were successfully initiated at a high percentage (12 to 31%) in 10 different genotypes following the addition of 1.0 mg l SA to DCR basal medium. On the other hand, DCR basal medium lacking SA (control) showed a lower percentage (0 to 13%) of somatic embryogenesis in these 10 genotypes. SA improved the initiation of embryogenic cultures and also resulted in the formation and development of more pro-embryos on maintenance medium than in our previous protocols of somatic embryogenesis which lacked SA. Higher concentrations (2.0 and 5.0 mg) of SA resulted in the browning of cultures, and thus had an inhibitory effect. ...

The shoot apical meristems are organized pools of undifferentiated or embryonic cells (stem cells) maintained by a dynamic balance between cell division and differentiation. On the basis of our mature tree cloning of pines, it is found that actively dividing and totipotent cells (stem cells) are positioned only at the cambial layer of the apical meristematic tissue in conifers, so that their growth and division under in vitro conditions leading to a continuous flow of progeny cells. These progeny cells (stem cells) under stress conditions (cold/heat) undergo differentiation due to signal activation in cambial region and leading to the embryogenic pathway in conifers. On the other hand the rest of the layers (epidermis, cortex region and central pith or medulla) of the transverse thin section of shoot apical meristems of mature trees have  induced non--embryogenic tissue under in vitro conditions in conifers.

Somatic cells are induced to form embryos by the application of stress and high doses of auxin treatments. Hence, embryogenic cells can be considered totipotent cells based on their aptitude to regenerate or develop into an embryo under certain conditions. During conversion of somatic to embryogenic transition, cells have to differentiate, activate their cell division cycle and reorganize their physiolory, metabolism and gene expression patterns. Cell differentiation depends on the froper and sequential expression of key genes required for conversion of somatic cells into embryogenic pattern. The homeobox transcription factor WUSCHEL (WUS) has been shown to cause dedifferentiation when expressed on somatic cells that can lead to somatic embryogenesis or organogenesis. The expression of ZU,Sgene in the embryogenic tissue derived from the mature trees of Pinus roxburghii revealed that WUS mi$tbe influencing the molecular mechanism that mediates the vegetative-to-embryogenic transition. WUYPGAf also plays a key role during embryogenesis, presumably by promoting the vegetative-to-embryogenic hansition in conifers too.

The shoot apical meristems are organized pools of undifferentiated or embryonic cells (stem cells) maintained by a dynamic balance between cell division and differentiation. On the basis of our mature tree cloning of pines, it is found that actively dividing and totipotent cells (stem cells) are positioned only at the cambial layer of the apical meristematic tissue in conifers, so that their growth and division under in vitro conditions leading to a continuous flow of progeny cells. These progeny cells (stem cells) under stress conditions (cold/heat) undergo differentiation due to signal activation in cambial region and leading to the embryogenic pathway in conifers. On the other hand the rest of the layers (epidermis, cortex region and central pith or medulla) of the transverse thin section of shoot apical meristems of mature trees have induced non-embryogenic tissue under in vitro conditions in conifers.

Aquilaria malaccensis is a tropical tree which produces gaharu or agarwood in its trunk often after being wounded and attacked by pathogens or insects. Fungi are generally viewed as the main microbial component responsible for gaharu formation. The objective of this study is to produce gaharu component via in vitro method using shoot culture and inoculated with fungi. In this study, in vitro shoot inoculated with spore suspension fungi (P1 and P2) for 45 days before subjected to hydrodistillation and analyzes by gas chromatography-mass spectrometer (GC-MS). A total of ten components were identified from the in vitro shoot of A. malaccensis inoculated with spore suspension fungi (P1) and nine components were identified from the in vitro shoot that are inoculated with spore suspension fungi (P2) in analytical GC-MS. Both chemical components from shoot inoculated with spore suspension fungi (P1 and P2) were having 10epi-γ -eudesmol as most major component with 73.15% and 76.02%. The other abundant chemical components of shoot oil inoculated with spore suspension fungi (P1) were caryophellene oxide (12.05%), hexadecanoic acid (7.42%) and αguaiene (4.30%). The other abundant chemical components of shoot inoculated with spore suspension fungi (P2) were caryophellene oxide (10.21%), tetradecanoic acid (6.69%), αguaiene (3.22%) and hexadecanoic acid (2.45%). The rest of the components were found in small amount less than 2%. Some of the chemical component present in this study showed very much similar with previous report and similar with natural resin impregnated wood of Aquilaria species.