Induction of somatic embryogenesis in different varieties of sugarcane (Saccharam officinarum L.)

This investigation for the first time highlights TDZ induced callus formation, somatic embryogenesis and plant regeneration using leaf explants of different varieties (Co94032,CoC671, Co86032, SNK754, SNK61 and SNK44) of sugarcane (Saccharam officinarum). Leaf explants cultured on the full strength inorganic salts Murashige and Skoog (1962) basal medium supplemented with 4.52 μM 2, 4-D and 4.54 μM TDZ induced embryogenic tissue after 3-4 weeks. The percentage of somatic embryogenesis was not similar in all the tested varieties of sugarcane. This study indicates a high embryogenic potential of leaf explants of tested sugarcane varieties, and also opened up the possibility for large-scale clonal propagation of sugarcane for the genetic improvement programmes

Journey of a single cell to a plantlet via in vitro cloning mature trees of conifers

During cloning of mature conifers, isolated somatic cells from apical meristematic tissue under any external stress conidions of cold\heat or chemical are induced to form a somatic embryo. This review paper highlights the difference between embryogenesis patterns in angiosperms and gymnosperms and updates information on the current progress made in the cloning of mature trees of conifers. Insights gained through these systems  has already lead to the development of cloning methodologies that could aid in reprogramming apical meristematic cells of recalcitrant mature conifers for clonal forestry

Induction of somatic embryogenesis in Papaya (Carica papaya)

This study highlights the induction of somatic embryogenesis using immature zygotic embryos of Carica papaya commercial varieties viz. Coorg Honey dew, Washington, Honey dew, Pusa delicious, Pusa nanha, Taiwan 786, Taiwan 785, Sunrise, Solo, Co-1, C0-7, and Co-3 respectively. Somatic embryos formed in the presence of thidiazuron (TDZ) in combination with 2, 4-dichlorophenoxy acetic acid (2, 4-D), but never on  explants cultured on control medium lacking plant growth regulators. Embryogenic callus could be induced from immature zygotic embryos after 4-6 weeks of culture on full-strength Murashige and Skoog inorganic salts, which served as the basal medium supplemented with 4.52 μM 2, 4-D and 2.27 μM TDZ (induction and maintenance medium). The ability to induce  embryogenic tissue varied for different papaya tested varieties, and there was a mixed genotypic response on the induction of embryogenic cultures. The highest percentage of somatic embryogenesis was noticed in a papaya variety Taiwan-786 (87.0±4.2a), followed by Taiwan- 785  (85.0±3.0a), and Coorg Honey dew (81.0±3.2a) respectively. This protocol is simple and reproducible, and could be useful for regenerating large number of plants as well as provide a target tissue for genetic  transformation experiments

TDZ induced in vitro propagation of an epiphytic orchid Xenikophyton smeeanum (Reichb. f.)

An efficient shoot regeneration of Xenikophyton smeeanum (Reichb. f.). was achievedusing shoot tip sections and thidiazuron (TDZ). Protocorm-like bodies (PLB’s) orproliferating shoot buds was observed when thin cell layers of shoot tip sections werecultured on Mitra et al. (1976) basal medium supplemented with 11.35μM thidiazuron.Shoots produced roots when cultured on Mitra et al (1976) basal medium supplementedwith 8.56 μM IAA. This simple protocol will be useful for large-scale propagation of nativeepiphytic orchid Xenikophyton smeeanum

Evidence of WUSCHEL (WOX2) gene expression during induction of somatic embryogenesis from apical shoot buds of mature trees of Pinus roxburghii

This study highlights for the first time the expression of transcription factor, WOX2(WUSCHEL homeobox 2) in the embryogenic tissue derived from the apical shoot buds of mature trees of 3 genotypes of P. roxburghii. Therefore, PrWOX2 could be used as a potential molecular signature for the identification of embryogenic cultures during the early development of somatic embryos in conifers. On the other hand, the non-embryogenic tissue of shoot bud cultures which were initiated without cold treatment (control) failed to showthe expression of WOX2. This clearly demonstrates the role of WOX2 in the somatic embryogenesis pathway and might be directly related to the stress conditions

Synthesis of silver nanoparticles from in vitro derived plants and callus cultures of Costus speciosus (Koen.); Assessment of antibacterial activity

This study demonstrates for the first time the efficiencies of in vitro derived plantsand callus cultures of Costus speciosus extract in the rapid biosynthesis of stable silve rnanoparticles. Synthesis of silver nanoparticles may be influenced directly or indirectly byphytochemicals in plants such as phenolics, flavonoids, and diosgenin compounds. Thisstudy also highlights a cost effective and environment friendly technique for green synthesisof silver nanoparticles. These silver nanoparticles were found to be highly toxic againstdifferent multi drug resistant clinical samples such as gram-positive bacteria Bacillus subtilis and Staphylococcus aureus, and the gram-negative bacteria Escherichia coli and Klebsiella pneumoniae. This also provides evidence for developing large scale commercial productionof value-added products for biomedical / nanotechnology based industries, which is animportant step in the field of application of nanotechnology

Factors influencing cloning mature trees of conifers

At present an embryogenic system derived from vegetative shoot apices or secondaryneedles of mature pines have been well established in at least a few conifers. This is themajor breakthrough in forest biotechnology, and certainly solves the current problems oftree breeding. During cloning of mature conifers, isolated somatic cells under any externalstress conditions of cold/heat or chemical are induced to form a somatic embryo. Cloning ofmature conifers was influenced by many factors such as pH, carbohydrate source, plantgrowth regulators, and activated charcoal. The embryogenic cells are very important becausethey differentiate, and undergo cleavage polyembryony to form somatic embryos at a latertime in conifers

Recent advances in plant derived vaccine antigens against human infectious diseases

The use of plants for the production of vaccine is one of the important applications in the modern medicine. There are many advantages of using plants as the production system compared to traditional mammalian system. Many plant species have been exploited to accumulate vaccine antigens for human infectious diseases, and vaccine candidates are approaching the market. The transgenic plants are considered as cheap source and found alternative approach to fermentation for large-scale production of vaccine antigens. The autotrophic growth of plants requires only soil minerals, water, nitrogen, sunlight energy for the synthesis of vaccine antigens. Therefore, vaccine production by using plants is one of the cheap and efficient technologies. This review covers the recent advances of plant derived vaccine antigens for the prevention of human infectious diseases and focuses on the current methods

Activation of cambial layer influences cloning of mature trees of conifers

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

Influence of bud break and apical meristematic tissue competence during cloning mature trees of conifers

This review paper highlights the influence of bud break and apical meristematic tissue competence in inducing embryogenic tissue during cloning mature trees of conifers. Bud burst depends on dormancy release by chilling or heat due to increase in the day temperature, and accumulation of thermal time above a species-specific threshold. The buds collected immediately after the bud burst were found very responsive for the in vitro cloningof P. kesiya, P. roxburghii and P. wallichiana, P. patula, and P. sylvestris, This might be duethe activation of the apical meristematic cells showing active growth of shoots in most of theconifers. The active dividing and totipotent cells might be positioned only at the cambiallayer of the apical meristematic tissue in conifers, so that their growth and division leads to acontinuous flow of progeny cells. These cambial layer cells under stress conditions undergodifferentiation and leading to the embryogenic pathway in conifers