CRISPR-Based Genetic Control Strategies for Insect Pests to Mitigate Classical Insecticidal Approaches

Nutraceutical properties of food have always been an important interface of concern as food directs both physical and mental health and forms the base of well-being. In the food chain and food web, the crop is a feed of all organisms of the niche. The insects have always been the catch as they effect crop production qualitatively as well as quantitatively. Quantitatively they decrease net production either by decreasing photosynthetic efficacy or by damaging various plant parts. Qualitatively they leave deleterious components as exoskeleton or release toxins or inhibitory compounds which are either lethal or threat to human health. Classically insect population was either controlled by using various insecticides or by using resistant crop varieties, or in recent years, crops were genetically modified to disable insect feeding behavior. In recent years clustered regularly interspaced short palindromic repeat (CRISPR)-based genome editing approaches are used to check detrimental effect of insect population either by causing mutation in the genes responsible for insect-crop receptivity or by shifting the insect population toward more male sex. Some of the most deployed technologies involve CRISPR-based gene drive which is used for population suppression, by incorporating effect or gene that causes lethality or sex bias leading to a reduction of offspring in each successive generation, or for population modification, by spreading a genetic variant that eliminates a harmful trait but sustains the population of the insect species. The system works on transposons specifically having maternal effect dominant embryonic arrest (Medea). The other system uses CRISPR-engineered genetic-sexing strains (CRISPR-engineered GSS) and CRISPR-Cas9 sex-ratio distortion (CRISPR-Cas9 SRD) which incorporates “W-shredding” system, thereby cleaving W chromosome which cause sex distortion toward males. CRISPR-based strategies for maintaining the modified insect population with their ecological safety will lead to the next generation of pest control strategies.