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MSH 1 maintains organelle genome stability and genetically interacts with RECA and RECG in the moss Physcomitrella patens
Author(s) -
Odahara Masaki,
Kishita Yoshihito,
Sekine Yasuhiko
Publication year - 2017
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13573
Subject(s) - physcomitrella patens , biology , organelle , genome , moss , microbiology and biotechnology , genetics , botany , gene , mutant
Summary Chloroplast and mitochondrial DNA encodes genes that are essential for photosynthesis and respiration, respectively. Thus, loss of integrity of the genomic DNA of organelles leads to a decline in organelle function and alteration of organelle genetic information. RECA ( RECA 1 and RECA 2) and RECG , which are homologs of bacterial homologous recombination repair ( HRR ) factors RecA and RecG, respectively, play an important role in the maintenance of integrity of the organelle genome by suppressing aberrant recombination between short dispersed repeats ( SDR s) in the moss Physcomitrella patens . On the other hand, MutS homolog 1 ( MSH 1), a plant‐specific MSH with a C‐terminal GIY ‐ YIG endonuclease domain, is involved in the maintenance of integrity of the organelle genome in the angiosperm Arabidopsis thaliana . Here, we address the role of the duplicated MSH 1 genes, MSH 1A and MSH 1B , in P. patens , in which MSH 1A lacks the C‐terminal endonuclease domain. MSH 1A and MSH 1B localized to both chloroplast and mitochondrial nucleoids in protoplast cells. Single and double knockout ( KO ) mutants of MSH 1A and MSH 1B showed no obvious morphological defects; however, MSH 1B KO and double KO mutants, as well as MSH 1B GIY ‐ YIG deletion mutants, exhibited genomic instability due to recombination between SDR s in chloroplasts and mitochondria. Creating double KO mutations of each combination of MSH 1B , RECA 2 and RECG synergistically increased recombination between SDR s in chloroplasts and mitochondria. These results show the role of MSH 1 in the maintenance of integrity of the organelle genome and the genetic interaction between MSH 1 and homologs of HRR factors in the basal land plant P. patens .