Structural Aspects of DNA Repair and Recombination in Crop Improvement

Abstract

The adverse effects of global climate change combined with an exponentially increasing human population have put substantial constraints on agriculture, accelerating efforts towards ensuring food security for a sustainable future. Conventional plant breeding and modern technologies have led to the creation of plants with better traits and higher productivity. Most crop improvement approaches (conventional breeding, genome modification, and gene editing) primarily rely on DNA repair and recombination (DRR). Studying plant DRR can provide insights into designing new strategies or improvising the present techniques for crop improvement. Even though plants have evolved specialized DRR mechanisms compared to other eukaryotes, most of our insights about plant-DRRs remain rooted in studies conducted in animals. DRR mechanisms in plants include direct repair, nucleotide excision repair (NER), base excision repair (BER), mismatch repair (MMR), non-homologous end joining (NHEJ) and homologous recombination (HR). Although each DRR pathway acts on specific DNA damage, there is crosstalk between these. Considering the importance of DRR pathways as a tool in crop improvement, this review focuses on a general description of each DRR pathway, emphasizing on the structural aspects of key DRR proteins. The review highlights the gaps in our understanding and the importance of studying plant DRR in the context of crop improvement.

Advances in Agrobacterium transformation and vector design result in high‐frequency targeted gene insertion in maize

“…Third, it allows single‐strand invasion in both directions – from genomic DNA and from donor template (Huang and Puchta, 2019 ). Fourth, it probably simplifies the second end resolution through homologous recombination, thus increasing proportion of perfect HDR‐based insertion events (Verma et al., 2020 ). Finally, it might be even more advantageous when considering recent results indicating that damaged DNA might be transported to specific loci in the nucleus for further repair (Caridi et al., 2018 ).…”

An Insight Into the Mechanism of Plant Organelle Genome Maintenance and Implications of Organelle Genome in Crop Improvement: An Update

“…The detrimental effects of global climate change along with the augmented increase in human population have put a substantial impact on agriculture and thus, emphasis has now been given toward ensuring food security for a sustainable future ( Foley et al, 2011 ; Tilman et al, 2011 ; Verma et al, 2020 ). Conventional plant breeding for generating plants with high productivity is often found to be a comparatively labor-intensive and time-consuming procedure as compared to plant genetic engineering approaches, which is believed to enhance crop productivity more efficiently ( Christou, 2013 ).…”

“…Although DNA damage has been considered for its mutagenic effect, the persistence of damaged bases in DNA also harms plant growth and development. Due to their immobile nature and obligatory dependence on sunlight for photosynthesis, as like the other plants, crop plants’ genome also remains continuously exposed to various genotoxic factors, including solar UV and ionizing radiation, soil salinity, heavy metal contamination and also the by-products of endogenous metabolic processes, such as ROS, which may frequently result in the accumulation of spontaneous mutations ( Verma et al, 2020 ). Although these mutations have been found to enrich the genetic diversity in the already existing genetic pool, the process is too slow to keep pace with the ever-increasing demand.…”

“…Although these mutations have been found to enrich the genetic diversity in the already existing genetic pool, the process is too slow to keep pace with the ever-increasing demand. At present, various crop improvement tools are used, which can be broadly categorized into major three types, such as the chemical and physical mutagenesis, transgenics, and genome editing approaches ( Manova and Gruszka, 2015 ; Verma et al, 2020 ). Intriguingly, DNA damage response or DDR has taken the central stage in almost all crop improvement techniques.…”

“…Further identification and functional characterization of different genes involved in these processes therefore may provide important insight into the molecular mechanisms of DNA repair. Induction of mutations in the crucial genes involved in DNA damage response and repair in organellar genomes have been found to alter the efficacy of these important processes, resulting in more effective mutagenesis ( Verma et al, 2020 ).…”