Open AccessMutS‐Homolog2 silencing generates tetraploid meiocytes in tomato ( Solanum lycopersicum )
Author(s) -
Sarma Supriya,
Pandey Arun Kumar,
Sharma Kapil,
Ravi Maruthachalam,
Sreelakshmi Yellamaraju,
Sharma Rameshwar
Publication year - 2018
Publication title -
plant direct
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.211
H-Index - 11
ISSN - 2475-4455
DOI - 10.1002/pld3.17
Subject(s) - meiocyte , biology , meiosis , msh2 , genetics , ploidy , dna mismatch repair , microbiology and biotechnology , gene , dna repair
MSH 2 is the core protein of MutS‐homolog family involved in recognition and repair of the errors in the DNA . While other members of MutS‐homolog family reportedly regulate mitochondrial stability, meiosis, and fertility, MSH 2 is believed to participate mainly in mismatch repair. The search for polymorphism in MSH 2 sequence in tomato accessions revealed both synonymous and nonsynonymous SNP s; however, SIFT algorithm predicted that none of the SNP s influenced MSH 2 protein function. The silencing of MSH 2 gene expression by RNA i led to phenotypic abnormalities in highly silenced lines, particularly in the stamens with highly reduced pollen formation. MSH 2 silencing exacerbated formation of UV ‐B‐induced thymine dimers and blocked light‐induced repair of the dimers. The MSH 2 silencing also affected the progression of male meiosis to a varying degree with either halt of meiosis at zygotene stage or formation of diploid tetrads. The immunostaining of male meiocytes with centromere localized CENPC (centromere protein C) antibody showed the presence of 48 univalent along with 24 bivalent chromosomes suggesting abnormal tetraploid meiosis. The mitotic cells of root tips of silenced lines showed diploid nuclei but lacked intervening cell plates leading to cells with syncytial nuclei. Thus, we speculate that tetraploid pollen mother cells may have arisen due to the fusion of syncytial nuclei before the onset of meiosis. It is likely that in addition to mismatch repair ( MMR ), MSH 2 may have an additional role in regulating ploidy stability.