Maria Khalid

Chapter 9 – Preventing Potential Diseases of Crop Plants Under the Impact of a Changing Environment

Occurrence of a certain disease in a plant depends on a multitude of factors including a disease-causing virulent pathogen, a vulnerable host plant, and the environment. This forms a three key factor triangle for the development of diseases. Changing climate become a significant issue and may be intensely associated with increases in yield losses in the coming years. An increased level of ozone and carbon dioxide, altered precipitation patterns, flooding, drought, temperature extremes, global warming, and salinity are the outcomes of climatic changes. These all directly or indirectly affect the occurrence and severity of diseases in plants. Conditions more optimum to pathogenic spread, such as humidity and increased temperature, may lead to increases in the number of epidemics in plants in new geographical areas. Thus, there is a significant necessity for new agricultural strategies to prevent the potential hazards that may be the result of pathogens due to climatic change. This chapter reviews different research strategies in order to characterize the root cause of diseases in major crops worldwide.

Physiological, biochemical and agronomic traits associated with drought tolerance in a synthetic-derived wheat diversity panel

Abstract. Synthetic hexaploid wheat and their advanced derivatives (SYN-DERs) are promising sources for introducing novel genetic diversity to develop climate-resilient cultivars. In a series of field and laboratory experiments, we measured biochemical, physiological and agronomic traits in a diversity panel of SYN-DERs evaluated under well-watered (WW) and water-limited (WL) conditions. Analysis of variance revealed significant differences among genotypes, treatments and their interaction for all agronomic and physiological traits. Grain yield (GY) was reduced by 62.75% under WL, with a reduction of 38.10% in grains per spike (GS) and 19.42% in 1000-grain weight (TGW). In a Pearson’s coefficient correlation, GY was significantly correlated with GS, number of tillers per plant and TGW in both conditions. Path coefficient analysis showed that TGW and GS made the highest contribution to GY in WW and WL conditions, respectively. The traits examined in this experiment explained 59.6% and 63.01% of the variation in GY under WL and WW conditions, respectively; TGW, canopy temperature at spike and superoxide dismutase were major determinants of GY under WL conditions. The major flowering-time determinant gene Ppd-D1 was fixed in the diversity panel, with presence of the photoperiod-insensitive allele (Ppd-D1a) in 99% accessions. Wild-type alleles at Rht-B1 and Rht-D1, and presence of the rye translocation (1B.1R), favoured GY under WL conditions. Continuous variation for the important traits indicated the potential use of genome-wide association studies to identify favourable alleles for drought adaptation in the SYN-DERs. This study showed sufficient genetic variation in the SYN-DERs diversity panel to improve yields during droughts because of better adaptability than bread wheat.

Nanobiotechnology in Agricultural Development

Nanobiotechnology is the field of science that has recently emerged by conjugation of biotechnology and nanoscience. An extensive range of applications of the field of nanoscience (nanoparticles) have been established in several fields of biosciences and biomedicine with wide applications in industry. Since the potential of this newly emerged field of research and medicine is beyond the scope of this chapter, we will be focusing on their applications in agriculture solely. Since this is a hybrid technique, so it employs all the biotechnological tools for its applications. Their key applications include use in treating plant diseases through site-specific targeting of diseased organs, transforming plants through gold/tungsten nanoparticles coated with engineered plasmid, targeted delivery and controlled release of bioactive substances, etc. Their use in crop protection is just in its infancy. Recently, the concept of using nanoparticles in plant treatment has been established and their applications in the parasitic control in plants are practised successfully. The chapter will focus on the development and use of ‘nanodevices’ for formulating agriculturally important chemicals (fertilizers) with more useful properties and their direct delivery as well as their applications in various agricultural sectors. Still the limitations are there which hinder their use on large scale (commercially).

Plant Proteomics: An Overview

The proteins encoded in a plant have a significant role in its survival and adaptation to external stresses. The cell wall, being the outermost layer, helps in defense against pathogens by production of glycoside hydrolases and proteases that degrade the pathogen external wall. The cell membrane assists in the movement of different molecules into and out of the cell. Different cells communicate with each other with the help of specific signals. Osmotic and salt concentrations are maintained by the embedded ion pumps in the cell membrane. The chloroplast, the only photosynthetic apparatus present in plants, leads to production of energy and also utilizes sunlight for the process of photosynthesis. A number of complex reactions, cycles, and pathways are present in the chloroplast. The mitochondria, also called the powerhouses of the cells, are rich in energy-producing cycles that are required for most of the activities of plants. In the matrix and cristae, a number of enzymes are active continuously. The mitochondrial membrane assists in the survival of the mitochondrion as an independent organelle. The nucleolus, the hub of all the protein-encoding genome, contains many processes. When we begin the analysis of a protein, protein extraction is the first issue. The plant possesses a cell wall that is a critical barrier which should be overcome. Many detergents and other chemicals are applied to break the bonding present in the cell wall, and we then extract our target protein, which is separated using gel electrophoresis. Two-dimensional sodium dodecyl-sulfate-polyacrylamide gel electrophoresis (2D SDS-PAGE) facilitates the reaction by separating the proteins with respect to isoelectric point as well as molecular weight. Target proteins are visualized and then digested in gel to process it further for identification of the protein. A mass spectrometer is applied for this purpose to characterize each protein on the basis of charge to mass ratio, leading to unambiguous results. Bioinformatics tools are also used for confirmation of our target protein.