Changes in plastid biogenesis leading to the formation of albino regenerants in barley microspore culture

Abstract Background Microspore embryogenesis is potentially the most effective method of obtaining doubled haploids (DH) which are utilized in breeding programs to accelerate production new cultivars. However, regeneration albino plants significantly limits exploitation androgenesis for DH cereals. Despite many efforts, precise mechanisms leading development regenerants have not yet been elucidated. The objective this study was reveal genotype-dependent molecular differences chloroplast differentiation that lead formation green and microspore culture barley. Results We performed a detailed analysis plastid at successive stages two barley cultivars, ‘Jersey’ ‘Mercada’ differed their ability produce regenerants. demonstrated lack transition from NEP-dependent PEP-dependent transcription plastids cv. produced mostly culture. failed NEP-to-PEP associated with activity Sig2 gene encoding sigma factor necessary rRNA genes. A very low level 16S 23S transcripts impaired translation machinery resulted inhibition photomorphogenesis regenerating embryos Furthermore, present differentiating contained number plastome copies whose replication always completed. Contrary ‘Mercada’, 90% regenerants, showed high PEP polymerase, highly increased expression , rRNAs tRNA Glu indicated NEP inhibition. GLKs genes factors required induction also observed Conclusions Proplastids microspore-derived albino-producing genotypes did pass early checkpoints further light-dependent chloroplasts. activation plastid-encoded RNA polymerase during inability regenerate better understanding underlying may be helpful overcoming problem albinism cereal androgenesis.