ABSTRACT
Several abiotic stresses, such as drought, salinity, heat, flooding, ion toxicity, and radiation, are the most important constraints to agricultural practice. The understanding of the molecular basis of plant response to these various environmental factors has been a main concentration of research in the last few decades. Several genes/pathways and regulatory networks involved in stress responses are figured out employing various different approaches.
In tropical countries, sugarcane is an important crop in the terms of sugar and ethanol production because it is increasing its area of cultivation and biomass yield is increasing. Water is the one of the major abiotic stresses affecting sugarcane productivity. The development of a drought-tolerant cultivar of sugarcane is one an important goal for all key sugarcane-producing countries.
Genome-editing technology is used routinely to modify plant genomes by targeted alteration/editing of specific genes, and it provides a method for introducing targeted mutation, insertion/deletion (indel), and precise sequence modification using customized nucleases during a big variety of organisms. Most regularly used genome-editing tools are transcriptional activator-like effector nucleases (TALENs), clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 (CRISPR-associated nuclease 9), and zinc-finger nucleases (ZFNs). In general, these sequence-specific nucleases cause double-strand breaks (DSBs) at the target genomic locus/loci, which is/are repaired by the intracellular repair pathways, nonhomologous end-joining (NHEJ), or homology-directed repair (HDR). NHEJ results in the introduction of indels and HDR are often wont to introduce specific point mutations or insertion of desired sequences (such as tags or new domains) via recombination. Simple designing and cloning methods were involved in CRISPR/Cas9 genome editing, with the same Cas9 being potentially available for use with different guide RNAs for targeting multiple sites in the genome.
In this chapter, we emphasize on methodologies to improve genome-editing technology (CRISPR-Cas9 system) to increase abiotic stress tolerance/resistance in sugarcane and summarize the process used to generate new mutant alleles of environmental stress response genes in sugarcane. Such studies suggest further applications in molecular breeding to enhance plant function using optimized plant gene-editing systems.
