Single-stranded DNA and RNA binding protein that maintains plastid genome stability by preventing break-induced and short homology-dependent illegitimate recombinations. Functions in RNA metabolism and is involved in the maturation of the atpF and 23S ribosomal RNAs. Homotetramer. Can localize to both chloroplast and nucleus. Albino seedlings lacking plastid ribosomes. Belongs to the Whirly family.