Development and Applications of Transplastomic Plants; A Way Towards Eco-Friendly Agriculture

With distribution of genetic materials and advance molecular characteristics, the chloroplast is prokaryotic compartments within the eukaryotic plants that have turned into a crucial source for the genetic engineering and transplastomic plants are becoming more popular means of agricultural development with elevated crop yield. To address global agricultural problems, genetic modification of crop plants is a rapid and promising solution to adapt the environment-friendly and well-controlled farming system. The transplastomic plant with high accumulation of foreign proteins (up to 45-46% TSP) and stable transgene expression with gene containment can be a unique choice for the agricultural innovation of coming centuries. Although the transplastomic plants still facing encumber to ensure the full potential exploitation and expansion as an economical means, the removal of hardness and obstacles of this technology and commercialization can contribute for the sustainable development of future agriculture. In this book chapter, we intend to recapitulate the up to date development and achievement of transplastomic plant including gene transfer procedures in plastid genomes, regulable expression of plastid transgenes, plant trait improvement by foreign gene expression, biopharmaceuticals production, engineering of metabolic pathways in plant, study of transformation mediated RNA editing technologies, bio-safety issues and public concerns on transplastomic plants and overall beneficial aspects. We believe that the utilization of transplastomic plants will ensure an eco-friendly approach in agriculture with minimized hazards and public concerns. © Springer Nature Switzerland AG 2020

Biotechnological Perspective of Reactive Oxygen Species (ROS)-Mediated Stress Tolerance in Plants

All environmental cues lead to develop secondary stress conditions like osmotic and oxidative stress conditions that reduces average crop yields by more than 50% every year. The univalent reduction of molecular oxygen (O2) in metabolic reactions consequently produces superoxide anions (O2•−) and other reactive oxygen species (ROS) ubiquitously in all compartments of the cell that disturbs redox potential and causes threat to cellular organelles. The production of ROS further increases under stress conditions and especially in combination with high light intensity. Plants have evolved different strategies to minimize the accumulation of excess ROS like avoidance mechanisms such as physiological adaptation, efficient photosystems such as C4 or CAM metabolism and scavenging mechanisms through production of antioxidants and antioxidative enzymes. Ascorbate-glutathione pathway plays an important role in detoxifying excess ROS in plant cells, which includes superoxide dismutase (SOD) and ascorbate peroxidase (APX) in detoxifying O2•−radical and hydrogen peroxide (H2O2) respectively, monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) involved in recycling of reduced substrates such as ascorbate and glutathione. Efficient ROS management is one of the strategies used by tolerant plants to survive and perform cellular activities under stress conditions. The present chapter describes different sites of ROS generation and and their consequences under abiotic stress conditions and also described the approaches to overcome oxidative stress through genomics and genetic engineering