Retrograde signals arise from reciprocal crosstalk within plastids

Enami, Kazumasa; Tanaka, Kan; Hanaoka, Mitsumasa

doi:10.4161/psb.7.1.18451

Cited by 8 publications

(5 citation statements)

References 16 publications

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“…Early phase of chloroplast differentiation is regulated by checkpoints at proplastid development, including the stability of plastomes and effective transcription and translation processes occurring in proplastids [ 54 , 75 ]. Decrease of the number of plastid genomes is frequently observed during chloroplast differentiation associated with plant development [ 76 ].…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2021

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

show abstract

Section: Discussionmentioning

confidence: 99%

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

et al. 2021

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show abstract

“…Early phase of chloroplast differentiation is regulated by checkpoints at proplastid development, including the stability of plastomes and effective transcription and translation processes occurring in proplastids [51,67]. Decrease of the number of plastid genomes is frequently observed during chloroplast differentiation associated with plant development [68].…”

Section: Discussionmentioning

confidence: 99%

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

Gajecka

Marzec

Chmielewska

et al. 2020

Preprint

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

show abstract

“…Early phase of chloroplast differentiation is regulated by checkpoints at proplastid development, including the stability of plastomes and effective transcription and translation processes occurring in proplastids [54,75]. Decrease of the number of plastid genomes is frequently observed during chloroplast differentiation associated with plant development [76].…”

Section: Discussionmentioning

confidence: 99%

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

Gajecka

Marzec

Chmielewska

et al. 2020

Preprint

View full text Add to dashboard Cite

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

show abstract

Retrograde signals arise from reciprocal crosstalk within plastids

Cited by 8 publications

References 16 publications

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

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

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

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

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Retrograde signals arise from reciprocal crosstalk within plastids

Cited by 8 publications

References 16 publications

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

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

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

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

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