Multiple plant lineages have independently evolved sex chromosomes and variable karyotypes to maintain their sessile lifestyles through constant biological innovation.Morus notabilis,a dioecious mulberry species,has t...Multiple plant lineages have independently evolved sex chromosomes and variable karyotypes to maintain their sessile lifestyles through constant biological innovation.Morus notabilis,a dioecious mulberry species,has the fewest chromosomes among Morus spp.,but the genetic basis of sex determination and karyotype evolution in this species has not been identified.In this study,three high-quality genome assemblies were generated for Morus spp.[including dioecious M.notabilis(male and female)and Morus yunnanensis(female)]with genome sizes of 301–329 Mb and were grouped into six pseudochromosomes.Using a combination of genomic approaches,we found that the putative ancestral karyotype of Morus species was close to 14 protochromosomes,and that several chromosome fusion events resulted in descending dysploidy(2n=2x=12).We also characterized a~6.2-Mb sex-determining region on chromosome 3.Four potential male-specific genes,a partially duplicated DNA helicase gene(named MSDH)and three Ty3_Gypsy long terminal repeat retrotransposons(named MSTG1/2/3),were identified in the Y-linked area and considered to be strong candidate genes for sex determination or differentiation.Population genomic analysis showed that Guangdong accessions in China were genetically similar to Japanese accessions of mulberry.In addition,genomic areas containing selective sweeps that distinguish domesticated mulberry from wild populations in terms of flowering and disease resistance were identified.Our study provides an important genetic resource for sex identification research and molecular breeding in mulberry.展开更多
20-hydroxyecdysone(20E)induced transcription factor E93 is important for larval–adult transition,which functions in programmed cell death of larval obsolete tissues,and the formation of adult new tissues.However,the ...20-hydroxyecdysone(20E)induced transcription factor E93 is important for larval–adult transition,which functions in programmed cell death of larval obsolete tissues,and the formation of adult new tissues.However,the apoptosis-related genes directly regulated by E93 are still ambiguous.In this study,an E93 mutation fly strain was obtained by clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein 9-mediated long exon deletion to investigate whether and how E93 induces apoptosis during larval tissues metamorphosis.The transcriptional profile of E93 was consistent with 3 RHG(rpr,hid,and grim)genes and the effector caspase gene drice,and all their expressions peaked at the initiation of apoptosis during the degradation of salivary glands.The transcription expression of 3 RHG genes decreased and apoptosis was blocked in E93 mutation salivary gland during metamorphosis.In contrast,E93 overexpression promoted the transcription of 3 RHG genes,and induced advanced apoptosis in the salivary gland.Moreover,E93 not only enhance the promoter activities of the 3 RHG genes in Drosophila Kc cells in vitro,but also in the salivary gland in vivo.Our results demonstrated that 20E induced E93 promotes the transcription of RHG genes to trigger apoptosis during obsolete tissues degradation at metamorphosis in Drosophila.展开更多
基金supported by the National Key R&D Program of China(Grant No.2019YFD1000604)the China Agriculture Research System(Grant No.CARS-18-ZJ0201)+1 种基金the Forestry Promotion by Science and Technology Program of Chongqing,China(Grant No.Yulinkeyan2020-2)the Sichuan Science and Technology Program,China(Grant No.22NSFSC3680).
文摘Multiple plant lineages have independently evolved sex chromosomes and variable karyotypes to maintain their sessile lifestyles through constant biological innovation.Morus notabilis,a dioecious mulberry species,has the fewest chromosomes among Morus spp.,but the genetic basis of sex determination and karyotype evolution in this species has not been identified.In this study,three high-quality genome assemblies were generated for Morus spp.[including dioecious M.notabilis(male and female)and Morus yunnanensis(female)]with genome sizes of 301–329 Mb and were grouped into six pseudochromosomes.Using a combination of genomic approaches,we found that the putative ancestral karyotype of Morus species was close to 14 protochromosomes,and that several chromosome fusion events resulted in descending dysploidy(2n=2x=12).We also characterized a~6.2-Mb sex-determining region on chromosome 3.Four potential male-specific genes,a partially duplicated DNA helicase gene(named MSDH)and three Ty3_Gypsy long terminal repeat retrotransposons(named MSTG1/2/3),were identified in the Y-linked area and considered to be strong candidate genes for sex determination or differentiation.Population genomic analysis showed that Guangdong accessions in China were genetically similar to Japanese accessions of mulberry.In addition,genomic areas containing selective sweeps that distinguish domesticated mulberry from wild populations in terms of flowering and disease resistance were identified.Our study provides an important genetic resource for sex identification research and molecular breeding in mulberry.
基金the National Science Foundation of China(Grants No.32070491 to Kang Li)Laboratory of Lingnan Modern Agriculture Project(NT2021003 to Sheng Li)the National Science Foundation of Guangdong Province(Grants No.2022A1515010457 to Kang Li),English was polished by the Nature Publishing Group.
文摘20-hydroxyecdysone(20E)induced transcription factor E93 is important for larval–adult transition,which functions in programmed cell death of larval obsolete tissues,and the formation of adult new tissues.However,the apoptosis-related genes directly regulated by E93 are still ambiguous.In this study,an E93 mutation fly strain was obtained by clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein 9-mediated long exon deletion to investigate whether and how E93 induces apoptosis during larval tissues metamorphosis.The transcriptional profile of E93 was consistent with 3 RHG(rpr,hid,and grim)genes and the effector caspase gene drice,and all their expressions peaked at the initiation of apoptosis during the degradation of salivary glands.The transcription expression of 3 RHG genes decreased and apoptosis was blocked in E93 mutation salivary gland during metamorphosis.In contrast,E93 overexpression promoted the transcription of 3 RHG genes,and induced advanced apoptosis in the salivary gland.Moreover,E93 not only enhance the promoter activities of the 3 RHG genes in Drosophila Kc cells in vitro,but also in the salivary gland in vivo.Our results demonstrated that 20E induced E93 promotes the transcription of RHG genes to trigger apoptosis during obsolete tissues degradation at metamorphosis in Drosophila.
