Darshna Chaudhary

TDZ-induced direct shoot organogenesis and somatic embryogenesis on cotyledonary node explants of lentil (Lens culinaris Medik.)

An efficient and simple procedure for inducing high frequency direct shoot organogenesis and somatic embryogenesis in lentil from cotyledonary node explants (without both the cotyledons) in response to TDZ alone is reported. TDZ at concentration lower than 2.0 μM induced shoot organogenesis whereas at higher concentration (2.5–15 μM) it caused a shift in regeneration from shoot organogenesis to somatic embryogenesis. The cotyledonary node and seedling cultures developed only shoots even at high concentrations of BAP and TDZ, respectively. TDZ at 0.5 and 5.0 μM was found to be optimal for inducing an average of 4–5 shoots per cotyledonary node in 93 % of the cultures and 55 somatic embryos in 68 % of the cultures, respectively. The somatic embryos were germinated when transferred to lower TDZ concentration (0.5–1.0 μM). The shoots were rooted on MS basal medium containing 2.5 μM IBA. The plantlets were obtained within 8 weeks from initiation of culture and were morphologically similar to seed-raised plants. The possible role of stress in thidiazuron induced somatic embryogenesis is discussed.

Progress and Challenges in Improving the Nutritional Quality of Rice (Oryza sativa L.)

ABSTRACT Rice is a staple food for more than 3 billion people in more than 100 countries of the world but ironically it is deficient in many bioavailable vitamins, minerals, essential amino- and fatty-acids and phytochemicals that prevent chronic diseases like type 2 diabetes, heart disease, cancers, and obesity. To enhance the nutritional and other quality aspects of rice, a better understanding of the regulation of the processes involved in the synthesis, uptake, transport, and metabolism of macro-(starch, seed storage protein and lipid) and micronutrients (vitamins, minerals and phytochemicals) is required. With the publication of high quality genomic sequence of rice, significant progress has been made in identification, isolation, and characterization of novel genes and their regulation for the nutritional and quality enhancement of rice. During the last decade, numerous efforts have been made to refine the nutritional and other quality traits either by using the traditional breeding with high through put technologies such as marker assisted selection and breeding, or by adopting the transgenic approach. A significant improvement in vitamins (A, folate, and E), mineral (iron), essential amino acid (lysine), and flavonoids levels has been achieved in the edible part of rice, i.e., endosperm (biofortification) to meet the daily dietary allowance. However, studies on bioavailability and allergenicity on biofortified rice are still required. Despite the numerous efforts, the commercialization of biofortified rice has not yet been achieved. The present review summarizes the progress and challenges of genetic engineering and/or metabolic engineering technologies to improve rice grain quality, and presents the future prospects in developing nutrient dense rice to save the everincreasing population, that depends solely on rice as the staple food, from widespread nutritional deficiencies.

Sesame (Sesamum indicum L.).

Sesame (Sesamum indicum L.) is an important oilseed crop grown in India, China, Korea, Russia, Turkey, Mexico, South America, and several countries of Africa. Sesame seeds are rich in oil, proteins, unsaturated fatty acids, vitamins, minerals, and folic acid. Nearly 70% of the worlds sesame is processed into oil and meal, while the remainder is channeled to food and confectionery industries. Production of sesame is limited by several fungal diseases, water logging, salinity, and shattering of seed capsules during harvest. Introgression of useful genes from wild species into cultigens by conventional breeding has not been successful due to postfertilization barriers. The only alternative for the improvement of S. indicum is to transfer genes from other sources through genetic transformation techniques. Here, we describe a simple, fast, and reproducible method for the Agrobacterium-mediated genetic transformation of S. indicum which may be employed for the transfer of desirable traits into this economically important oilseed crop.

Evaluation of carbon sources, gelling agents, growth hormones and additives for efficient callus induction and plant regeneration in Indian wheat ( Triticum aestivum L.) genotypes using mature embryos

Various factors affecting in vitro regeneration like different carbon sources, different gelling agents, and growth additives were assessed comprehensively for callus induction and plant regeneration for five Indian wheat cultivars using mature embryos as the explants for the first time. The tissue culture responses of cultivars WH-1105, HD-2967, and PBW-343 have not been reported earlier. Besides, the effect of different concentrations of the cytokinin, zeatin has also been optimized. Using the optimized factors, the efficiency of five different varieties, i.e., HD 2967, C 306, RAJ 3765, WH 1105, and PBW 343 was evaluated for regeneration. Modified MS basal medium containing dicamba reduced precocious germination of the embryo and induced embryogenic callus more efficiently. Removal of embryogenic calli from non-regenerable structures during early callus phase improved plant regeneration. These calli on zeatin (1.0 mgl-1) and dicamba (0.1 mgl-1) containing medium showed the highest regeneration frequency (98%) with a maximum of 8-9 shoots per calli. Maltose had the maximum callusing and regeneration percentage than other carbon sources. Various gelling agents did not have any significant difference on the regeneration. Of all the varieties, C-306 and HD-2967 were found to be more regenerative and can be used in transformation experiments.

GM Crops for Developing World in the Era of Climate Change: For Increase of Farmer’s Income, Poverty Alleviation, Nutrition and Health

Overexpansion of population and poor availability of resources in developing countries have resulted in serious problems of poverty, malnutrition, and poor health. Rapidly changing climate as a result of global warming is making the situation worse. Farmers are deviating from agriculture due to increased input costs and low benefits. Tools of plant biotechnology like GM crops have improved the present situation and undoubtedly have contributed to the increase of farmer’s income, nutrition and health, and poverty reduction leading to a step toward food and nutritional security in the developing world. As a result, GM crops have emerged as the fastest adopted crop technology in the history of modern agriculture in spite of a strong opposition initially, which is nullifying gradually.