Citation: Bulle, M.; Sheri, V.; Aileni, M.; Zhang, B. Chloroplast Genome Engineering: A Plausible Approach to Combat Chili Thrips and Other Agronomic Insect Pests of Crops. Plants 2023, 12, 3448. https:// doi.org/10.3390/plants12193448 Academic Editor: Alex Troitsky Received: 4 September 2023 Revised: 27 September 2023 Accepted: 28 September 2023 Published: 30 September 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). plants Review Chloroplast Genome Engineering: A Plausible Approach to Combat Chili Thrips and Other Agronomic Insect Pests of Crops Mallesham Bulle 1, * ,† , Vijay Sheri 2 , Mahender Aileni 3 and Baohong Zhang 2, * 1 Agri Biotech Foundation, Agricultural University Campus, Rajendranagar, Hyderabad 500030, India 2 Department of Biology, East Carolina University, Greenville, NC 27858, USA; sheriv22@ecu.edu 3 Department of Biotechnology, Telangana University, Dichpally, Nizamabad 503322, India; ailenidrmahender@gmail.com * Correspondence: malleshsjgc@gmail.com (M.B.); zhangb@ecu.edu (B.Z.) † Current Address: Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA. Abstract: The world population’s growing demand for food is expected to increase dramatically by 2050. The agronomic productivity for food is severely affected due to biotic and abiotic constraints. At a global level, insect pests alone account for ~20% loss in crop yield every year. Deployment of noxious chemical pesticides to control insect pests always has a threatening effect on human health and environmental sustainability. Consequently, this necessitates for the establishment of innovative, environmentally friendly, cost-effective, and alternative means to mitigate insect pest management strategies. According to a recent study, using chloroplasts engineered with double-strand RNA (dsRNA) is novel successful combinatorial strategy deployed to effectively control the most vexing pest, the western flower thrips (WFT: Frankliniella occidentalis). Such biotechnological avenues allowed us to recapitulate the recent progress of research methods, such as RNAi, CRISPR/Cas, mini chromosomes, and RNA-binding proteins with plastid engineering for a plausible approach to effectively mitigate agronomic insect pests. We further discussed the significance of the maternal inheritance of the chloroplast, which is the major advantage of chloroplast genome engineering. Keywords: chloroplast engineering; CRISPR; double-stranded RNA; mini chromosomes; RNA-binding proteins; thrips 1. Introduction The global demand for food is projected to rise from 35% in 2010 to 56% by the year 2050 [1]. However, agronomic productivity is severely affected by environmental factors, as well as infestations of insect pests and diseases. Thus, insect pests alone contribute to an approximately 20% reduction in crop productivity every year at a global scale [2]. Thrips are among the most significant members of a broad group of agronomic invasive pests. Over 150 crops, including peppers, cotton, strawberries, citrus, tomato, and many other crops, are known to have invasive pests’ threat [3]. Because of their broad range of hosts, tiny size, and rapid reproduction and growth, these pests show devastating effect in their productivity not only in fields, but also on crop production in other conditions, such as in greenhouses [4]. Chili pepper (Capsicum spp.) is widely cultivated and is among the most popular horticultural crops globally. The fruits of different Capsicum species are largely consumed due to their nutritional and pharmaceutical significance. Among different chili growing countries, India holds the top position as the world’s leading producer, accounting for 36% (0.45 million tons annually), followed by China, Thailand, Ethiopia, and Indonesia [3]. Chili pepper plants are most vulnerable to native and invasive pests during their growth and development. The genetic mechanisms that govern thrips’ Plants 2023, 12, 3448. https://doi.org/10.3390/plants12193448 https://www.mdpi.com/journal/plants