Here,we report a concise and divergent enantioselective total synthesis of marine sesquiterpene quinone meroterpenoids(+)-dysidavarones A–C(1–3)using predysidavarone 6 as a key common intermediate.The highly straine...Here,we report a concise and divergent enantioselective total synthesis of marine sesquiterpene quinone meroterpenoids(+)-dysidavarones A–C(1–3)using predysidavarone 6 as a key common intermediate.The highly strained and bridged eight-membered carbocycle of predysidavarone 6 was constructed by a one-pot intermolecular alkylation and intramolecular arylation of Wieland–Miescher ketone derivative 11 and benzyl bromide 12.The total synthesis of(+)-dysidavarones A–C(1–3)was achieved from predysidavarone 6 in a divergent manner by a late-stage introduction of the ethoxy group,which reveals the possible source of the ethoxy group within(+)-dysidavarones A–C(1–3)and provides a late-stage modifiable route for the synthesis of dysidavarone analogs for further anti-cancer activity evaluation.展开更多
A nuclear-encoded sigma(σ) factor is essential for the transcriptional regulation of plant chloroplastencoded genes. Five putative maize r factors have been identified by database searches, but their functions are un...A nuclear-encoded sigma(σ) factor is essential for the transcriptional regulation of plant chloroplastencoded genes. Five putative maize r factors have been identified by database searches, but their functions are unknown. We report a maize leaf color mutant etiolated/albino leaf 1(eal1) that was derived from space mutation breeding. The eal1 mutant displays etiolated or albino leaves that then gradually turn to normal green at the seedling stage. The changes in eal1 leaf color are associated with changes in photosynthetic pigment content and chloroplast development. Map-based cloning revealed that a single amino-acid deletion changing Val_(480)-Val_(481)-Val_(482) to Val_(480)-Val_(481), in the C-terminal domain σ_(4) of the putative σ factor ZmSig2A, is responsible for the eal1 mutation. In comparison with the expression level of the wild-type(WT) allele ZmSig2A^(+) in WT plants, much higher expression of the mutant allele ZmSig2A^(⊿V) in eal1 plants was detected before the eal1 plants turned to normal green. ZmSig2A shows the highest similarity to rice OsSig2A and Arabidopsis SIG2. Ectopic expression of ZmSig2A^(+) or ZmSig2A^(⊿V) driven by the cauliflower mosaic virus 35 S promoter rescued the pale green leaf of the sig2 mutant, but ectopic expression of ZmSig2A^(⊿V) driven by the SIG2 promoter did not. We propose that the Val deletion generated a new weak allele of ZmSig2A that cannot completely abolish the ZmSig2A function. Some genes involved in chloroplast development and photosynthesis-associated nuclear genes showed significant expression differences between eal1 and WT plants. We conclude that ZmSig2A encoding a r factor is essential for maize chloroplast development. The eal1 mutant with a weak allele of ZmSig2A represents a valuable genetic resource for investigating the regulation of ZmSig2A-mediated chloroplast development in maize.The eal1 mutation may be useful as a marker for early identification and elimination of false hybrids or transgene transmission in the application of genetic ma展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22171146,21971121,and 22188101 to ZL)the China Postdoctoral Science Foundation(No.2021M701775 to CC)。
文摘Here,we report a concise and divergent enantioselective total synthesis of marine sesquiterpene quinone meroterpenoids(+)-dysidavarones A–C(1–3)using predysidavarone 6 as a key common intermediate.The highly strained and bridged eight-membered carbocycle of predysidavarone 6 was constructed by a one-pot intermolecular alkylation and intramolecular arylation of Wieland–Miescher ketone derivative 11 and benzyl bromide 12.The total synthesis of(+)-dysidavarones A–C(1–3)was achieved from predysidavarone 6 in a divergent manner by a late-stage introduction of the ethoxy group,which reveals the possible source of the ethoxy group within(+)-dysidavarones A–C(1–3)and provides a late-stage modifiable route for the synthesis of dysidavarone analogs for further anti-cancer activity evaluation.
基金supported by the National Key Research and Development Program of China (2016YFD0102104)Platform for Mutation Breeding by Radiation of Sichuan (2016NZ0106)Applied Basic Research Program of Sichuan Provincial Science and Technology Department (2020YJ0249)。
文摘A nuclear-encoded sigma(σ) factor is essential for the transcriptional regulation of plant chloroplastencoded genes. Five putative maize r factors have been identified by database searches, but their functions are unknown. We report a maize leaf color mutant etiolated/albino leaf 1(eal1) that was derived from space mutation breeding. The eal1 mutant displays etiolated or albino leaves that then gradually turn to normal green at the seedling stage. The changes in eal1 leaf color are associated with changes in photosynthetic pigment content and chloroplast development. Map-based cloning revealed that a single amino-acid deletion changing Val_(480)-Val_(481)-Val_(482) to Val_(480)-Val_(481), in the C-terminal domain σ_(4) of the putative σ factor ZmSig2A, is responsible for the eal1 mutation. In comparison with the expression level of the wild-type(WT) allele ZmSig2A^(+) in WT plants, much higher expression of the mutant allele ZmSig2A^(⊿V) in eal1 plants was detected before the eal1 plants turned to normal green. ZmSig2A shows the highest similarity to rice OsSig2A and Arabidopsis SIG2. Ectopic expression of ZmSig2A^(+) or ZmSig2A^(⊿V) driven by the cauliflower mosaic virus 35 S promoter rescued the pale green leaf of the sig2 mutant, but ectopic expression of ZmSig2A^(⊿V) driven by the SIG2 promoter did not. We propose that the Val deletion generated a new weak allele of ZmSig2A that cannot completely abolish the ZmSig2A function. Some genes involved in chloroplast development and photosynthesis-associated nuclear genes showed significant expression differences between eal1 and WT plants. We conclude that ZmSig2A encoding a r factor is essential for maize chloroplast development. The eal1 mutant with a weak allele of ZmSig2A represents a valuable genetic resource for investigating the regulation of ZmSig2A-mediated chloroplast development in maize.The eal1 mutation may be useful as a marker for early identification and elimination of false hybrids or transgene transmission in the application of genetic ma
