Leaf angle(LA)is a crucial factor that affects planting density and yield in maize.However,the regulatory mechanisms underlying LA formation remain largely unknown.In this study,we performed a comparative histological...Leaf angle(LA)is a crucial factor that affects planting density and yield in maize.However,the regulatory mechanisms underlying LA formation remain largely unknown.In this study,we performed a comparative histological analysis of the ligular region across various maize inbred lines and revealed that LA is significantly influenced by a two-step regulatory process involving initial cell elongation followed by subsequent lignification in the ligular adaxial sclerenchyma cells(SCs).Subsequently,we performed both bulk and single-nucleus RNA sequencing,generated a comprehensive transcriptomic atlas of the ligular region,and identified numerous genes enriched in the hypodermal cells that may influence their specialization into SCs.Furthermore,we functionally characterized two genes encoding atypical basic-helix-loop-helix(bHLH)transcription factors,bHLH30 and its homolog bHLH155,which are highly expressed in the elongated adaxial cells.Genetic analyses revealed that bHLH30 and bHLH155 positively regulate LA expansion,and molecular experiments demonstrated their ability to activate the transcription of genes involved in cell elongation and lignification of SCs.These findings highlight the specialized functions of ligular adaxial SCs in LA regulation by restricting further extension of ligular cells and enhancing mechanical strength.The transcriptomic atlas of the ligular region at single-nucleus resolution not only deepens our understanding of LA regulation but also enables identification of numerous potential targets for optimizing plant architecture in modern maize breeding.展开更多
Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting trigge...Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting triggers shade avoidance responses(SARs)that optimize light absorption but impair plant vigor and performance,limiting yield improvement through increasing plant density.In this study,we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B(phyB1/B2),the primaryphotoreceptor responsible for perceiving red(R)and far-red(FR)light in maize.We found that maize phyB physically interacts with the LIGULELESS1(LG1),a classical key regulator of leaf angle,to coordinately regulate plant architecture and density tolerance.The abundance of LG1 is significantly increased by phyB under high R:FR light(low density)but rapidly decreases under low R:FR light(high density),correlating with variations in leaf angle and plant height under various densities.In addition,we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade.Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells.Taken together,these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance,providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.展开更多
The electric catfish(Malapterurus electricus),belonging to the family Malapteruridae,order Siluriformes(Actinopterygii:Ostariophysi),is one of the six branches that has independently evolved electrical organs.We assem...The electric catfish(Malapterurus electricus),belonging to the family Malapteruridae,order Siluriformes(Actinopterygii:Ostariophysi),is one of the six branches that has independently evolved electrical organs.We assembled a 796.75 Mb M.electricus genome and anchored 88.72%sequences into 28 chromosomes.Gene family analysis revealed 295 expanded gene families that were enriched on functions related to glutamate receptors.Convergent evolutionary analyses of electric organs among different lineage of electric fishes further revealed that the coding gene of rho guanine nucleotide exchange factor 4-like(arhgef4),which is associated with G-protein coupled receptor(GPCR)signaling pathway,underwent adaptive parallel evolution.Gene identification suggests visual degradation in catfishes,and an important role for taste in environmental adaptation.Our findings fill in the genomic data for a branch of electric fish and provide a relevant genetic basis for the adaptive evolution of Siluriformes.展开更多
基金supported by the National Natural Science Foundation of China(32270263)the Key R&D Program of Shandong Province(ZR202211070163)the Taishan Scholars program(to B.L.),and the China Postdoctoral Science Foundation(2023M742154).
文摘Leaf angle(LA)is a crucial factor that affects planting density and yield in maize.However,the regulatory mechanisms underlying LA formation remain largely unknown.In this study,we performed a comparative histological analysis of the ligular region across various maize inbred lines and revealed that LA is significantly influenced by a two-step regulatory process involving initial cell elongation followed by subsequent lignification in the ligular adaxial sclerenchyma cells(SCs).Subsequently,we performed both bulk and single-nucleus RNA sequencing,generated a comprehensive transcriptomic atlas of the ligular region,and identified numerous genes enriched in the hypodermal cells that may influence their specialization into SCs.Furthermore,we functionally characterized two genes encoding atypical basic-helix-loop-helix(bHLH)transcription factors,bHLH30 and its homolog bHLH155,which are highly expressed in the elongated adaxial cells.Genetic analyses revealed that bHLH30 and bHLH155 positively regulate LA expansion,and molecular experiments demonstrated their ability to activate the transcription of genes involved in cell elongation and lignification of SCs.These findings highlight the specialized functions of ligular adaxial SCs in LA regulation by restricting further extension of ligular cells and enhancing mechanical strength.The transcriptomic atlas of the ligular region at single-nucleus resolution not only deepens our understanding of LA regulation but also enables identification of numerous potential targets for optimizing plant architecture in modern maize breeding.
基金the National Natural Science Foundation of China(32270263 to G.L.,32130077 to H.W.,and 32272140 to P.L.)the Shandong Provincial Natural Science Foundation(ZR2022QC095,ZR2020MC023,ZR2022MC019).
文摘Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting triggers shade avoidance responses(SARs)that optimize light absorption but impair plant vigor and performance,limiting yield improvement through increasing plant density.In this study,we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B(phyB1/B2),the primaryphotoreceptor responsible for perceiving red(R)and far-red(FR)light in maize.We found that maize phyB physically interacts with the LIGULELESS1(LG1),a classical key regulator of leaf angle,to coordinately regulate plant architecture and density tolerance.The abundance of LG1 is significantly increased by phyB under high R:FR light(low density)but rapidly decreases under low R:FR light(high density),correlating with variations in leaf angle and plant height under various densities.In addition,we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade.Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells.Taken together,these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance,providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.
基金supported by the major scientific and technological projects of Hainan Province(ZDKJ2019011)the special funding of“Blue granary”scientific and technological innovation of China(2018YFD0900301-05).
文摘The electric catfish(Malapterurus electricus),belonging to the family Malapteruridae,order Siluriformes(Actinopterygii:Ostariophysi),is one of the six branches that has independently evolved electrical organs.We assembled a 796.75 Mb M.electricus genome and anchored 88.72%sequences into 28 chromosomes.Gene family analysis revealed 295 expanded gene families that were enriched on functions related to glutamate receptors.Convergent evolutionary analyses of electric organs among different lineage of electric fishes further revealed that the coding gene of rho guanine nucleotide exchange factor 4-like(arhgef4),which is associated with G-protein coupled receptor(GPCR)signaling pathway,underwent adaptive parallel evolution.Gene identification suggests visual degradation in catfishes,and an important role for taste in environmental adaptation.Our findings fill in the genomic data for a branch of electric fish and provide a relevant genetic basis for the adaptive evolution of Siluriformes.
