Roles of Chloroplast RNA Polymerase Sigma Factors in Chloroplast Development and Stress Response in Higher Plants.

Presents a review of the roles of chloroplast RNA polymerase sigma factors in chloroplast development and stress response in higher plants. Two types of polymerases that performed chloroplast transcription; Assertion that PEP is a eubacteria-type multisubunit enzyme whose catalytic core subunits are encoded by genplast genome, whereas NEP is the nuclear encoded T7 phage-type single subunit enzyme; importance of PEP for the biogenesis and maintenance of chloroplasts and finely tuned by the nuclear encoded sigma units; Involvement of SIG2 in the transcription of several chloroplasts tRNA genes; Factors that make target genes and the physiological role of each sigma subunit clearer.