AtCAF-1 mutants show different DNA damage responses after ultraviolet-B than those activated by other genotoxic agents in leaves

EVANGELINA MAULIÓN; MARÍA SOL GOMEZ; CLAUDIA ANABEL BUSTAMANTE; PAULA CASATI

PLANT, CELL AND ENVIRONMENT (PRINT)

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2019

0140-7791

Chromatin assembly factor-1 (CAF-1) is a histone H3/H4 chaperone that participates in DNA and chromatininteraction processes. In this manuscript, we show that organs from CAF-1 deficient plants respond differentlyto ultraviolet-B (UV-B) radiation than to other genotoxic stresses. For example, CAF-1 deficient leaves toleratebetter UV-B radiation, showing lower cyclobutane pyrimidine dimer (CPD) accumulation, lower inhibitionof cell proliferation, increased cell wall thickness, UV-B absorbing compounds, and ploidy levels, whereasprevious data from different groups have shown that CAF-1 mutants show shortening of telomeres, loss of45S rDNA, and increased homologous recombination, phenotypes associated to DNA breaks. Interestingly,CAF-1 deficient roots show increased inhibition of primary root elongation, with decreased meristem size dueto a higher inhibition of cell proliferation after UV-B exposure. The decrease in root meristem size in CAF-1mutants is a consequence of defects in programmed cell death after UV-B exposure. Together, we provideevidence demonstrating that root and shoot meristematic cells may have distinct protection mechanismsagainst CPD accumulation by UV-B, which may be linked with different functions of the CAF-1 complex inthese different organs.