Abstract
Maintenance of genomic integrity is critical for the perpetuation of all forms of life including humans. Living organisms are constantly exposed to stress from internal metabolic processes and external environmental sources causing damage to the DNA, thereby promoting genomic instability. To counter the deleterious effects of genomic instability, organisms have evolved general and specific DNA damage repair (DDR) pathways that act either independently or mutually to repair the DNA damage. The mechanisms by which various DNA repair pathways are activated have been fairly investigated in model organisms including bacteria, fungi, and mammals; however, very little is known regarding how plants sense and repair DNA damage. Plants being sessile are innately exposed to a wide range of DNA-damaging agents both from biotic and abiotic sources such as ultraviolet rays or metabolic by-products. To escape their harmful effects, plants also harbor highly conserved DDR pathways that share several components with the DDR machinery of other organisms. Maintenance of genomic integrity is key for plant survival due to lack of reserve germline as the derivation of the new plant occurs from the meristem. Untowardly, the accumulation of mutations in the meristem will result in a wide range of genetic abnormalities in new plants affecting plant growth development and crop yield. In this review, we will discuss various DNA repair pathways in plants and describe how the deficiency of each repair pathway affects plant growth and development.
Highlights
DNA replication is a fundamental process required for all organisms to divide and grow
We have explored the roles of various proteins in DNA damage response and maintenance of genome integrity
The aberrant transcripts (“aRNA”) transcribed as a result of DNA damage are unresponsive to RNA polymerase inhibitors and are amplified by RdRPs and processed into small RNA known as quelling-induced RNA
Summary
DNA replication is a fundamental process required for all organisms to divide and grow. The primary source of this alteration is the occasional incorporation of errors during the duplication of DNA by enzymes called DNA polymerases (Ganai and Johansson, 2016) Plant Genome Integrity in the newly synthesized DNA occasionally escape the proofreading by the exonuclease site of the DNA polymerases, thereby generating errors (Joyce, 1997). These errors during the process of cell division can have severe consequences on the fitness and viability of an offspring. The deletion of ATM and Abbreviation:DDR, DNA damage repair; ATM, ataxia telangiectasia mutated; ATR, ataxia telangiectasia mutated and Rad related; MRE11, meiotic recombination 11; RAD50, radiation sensitive 50; NBS1, Nijmegen breakage syndrome 1; MRN, Mre11-Rad50-Nbs; ROS, reactive oxygen species; BER, base excision repair; NER, nucleotide excision repair; MMR, mismatch repair; HRR, homologous recombination repair; NHEJ, non-homologous end-joining; ICL, interstrand cross-links; DRR, direct reversal repair; ssDNA, singlestranded DNA; dsDNA, double-stranded DNA; CPD, cyclobutane pyrimidine dimers; MTHFpolyGlu, N5, N10 methenyl-tetrahydrofolylpolyglutamate; FADH, flavin adenine dinucleotide; 6-4 PP, 6-4 Photoproducts; MGMT, O6methylguanine-DNA methyltransferase; 1 meA, 1-methyladenine; MMS, methyl methanesulfonate; XRCC1, X-ray repair cross-complementing protein 1; Pol δ/ε, DNA polymerase δ/ε; PCNA, proliferating cell nuclear antigen; FEN1, flap endonuclease 1; EXO1, exonuclease 1; RPA, replication protein A; 8-oxoG, 7,8-dihydro-8-oxoguanine; AP, apurinic/apyrimidinic; Pol β, DNA polymerase B; AtLIG1, Arabidopsis DNA ligase 1; PARP, poly(ADP-ribose) polymerase; GGR, global genomic repair; TCR, transcription-coupled repair; XPC, xeroderma pigmentosum group C; AtCEN2, Arabidopsis thaliana CENTRIN2; DSB, doublestrand break; SSB, single-strand break; DSBR, double-strand break repair; dHJ, double Holliday junction; c-NHEJ, classical/canonical NHEJ; b-NHEJ, backup-NHEJ pathway; Alt-NHEJ, alternative NHEJ; ncRNA, non-coding RNA; aRNA, aberrant transcripts; qiRNA, quelling-induced RNA; diRNA, DSB-induced small RNA; siRNA, small interfering RNA; DDB2, DNA damage-binding protein 2; AGO1, argonaute 1; DCL4, Dicer-like-4; I-SceI, intron-encoded endonuclease from Saccharomyces cerevisiae; ZFNs, zinc-finger nucleases; TALENs, transcription activator–like effector nucleases; CRISPR-Cas, clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9; tracrRNA, transactivating crRNA; sgRNA, single-guide RNA
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