Molecular mechanisms, genetic mapping, and genome editing for insect pest resistance in field crops

Abstract

Key message Improving crop resistance against insect pests is crucial for ensuring future food security. Integrating genomics with modern breeding methods holds enormous potential in dissecting the genetic architecture of this complex trait and accelerating crop improvement. Abstract Insect resistance in crops has been a major research objective in several crop improvement programs. However, the use of conventional breeding methods to develop high-yielding cultivars with sustainable and durable insect pest resistance has been largely unsuccessful. The use of molecular markers for identification and deployment of insect resistance quantitative trait loci (QTLs) can fastrack traditional breeding methods. Till date, several QTLs for insect pest resistance have been identified in field-grown crops, and a few of them have been cloned by positional cloning approaches. Genome editing technologies, such as CRISPR/Cas9, are paving the way to tailor insect pest resistance loci for designing crops for the future. Here, we provide an overview of diverse defense mechanisms exerted by plants in response to insect pest attack, and review recent advances in genomics research and genetic improvements for insect pest resistance in major field crops. Finally, we discuss the scope for genomic breeding strategies to develop more durable insect pest resistant crops.

Advances in genomics for diversity studies and trait improvement in temperate fruit and nut crops under changing climatic scenarios

“…Overall, the integrated omics approaches, viz ., genomics, transcriptomics, metabolomics, and proteomics, could elucidate precise genomic information and may offer further opportunities for their genetic alteration via gene engineering tools like CRISPR (clustered regularly interspaced short palindromic repeats) and RNAi (RNA interference), in terms of better fruit quality and production through accelerating the long breeding generations ( Mathiazhagan et al., 2021 ). Currently, GAB (genomics-assisted breeding) has tremendous utilization in terms of addressing better quality, yield, and several biotic and abiotic stress (drought and salt) resistances (in a wide range of crop species; Ganie et al., 2021 ; Wani et al., 2022 ). Also, several applications of omics platforms have been implemented in the way of different fruit improvements.…”

Plant breeding for increased sustainability: challenges, opportunities and progress

“…Breeding for pest resistance is in most instances more resource demanding and more challenging than fungal or viral disease resistance, but will require more investment in the years to come (Wani et al 2022). Since the fall armyworm has invaded Africa, Asia and Australia, it became a serious threat to maize cultivation in these regions and thus to food security.…”

A novel locus conferring resistance to Puccinia hordei maps to the genomic region corresponding to Rph14 on barley chromosome 2HS

“…Most of the cataloged ASR genes have limited value in breeding because they have been rendered ineffective by pathotypes of P. hordei with matching virulence ( Park et al, 2015 ) or due to possible associated linkage drag ( Bishnoi et al, 2022 ) in the case of those derived from wild species ( H. spontaneum or H. bulbosum ). To enhance the genetic base and durability of effective resistance in combating epidemics caused by new leaf rust pathotypes, there is a need to identify, characterize and map new resistance genes as well as understand their effectiveness, structure, and function ( Park et al, 2015 ; Li et al, 2016 ; Wani et al, 2022 ).…”

“…For example, in barley, Rph13 ( Jost et al, 2020 ), Rph26 ( Yu et al, 2018 ), and Rph27 ( Rothwell et al, 2020 ) have been mapped/fine-mapped in bi-parental mapping populations using SNPs (single nucleotide polymorphisms), CAPS (cleaved amplified polymorphic sequences) and HRM (High resolution melting), and indels (insertion–deletion events), respectively. Gene mapping provides the foundation for map-based cloning, which ultimately helps in understanding the structure and function of genes ( Wani et al, 2022 ). Markers identified through gene mapping can be used in marker-assisted selection (MAS) to increase plant breeding efficiency as well in gene pyramiding to attain durable resistance.…”