The recretohalophyte Limonium bicolor thrives in high-salinity environments because salt glands on the above-ground parts of the plant help to expel excess salt.Here,we characterize a nucleus-localized C3HC4(RING-HC)-...The recretohalophyte Limonium bicolor thrives in high-salinity environments because salt glands on the above-ground parts of the plant help to expel excess salt.Here,we characterize a nucleus-localized C3HC4(RING-HC)-type zinc finger protein of L.bicolor named RING ZINC FINGER PROTEIN 1(LbRZF1).LbRZF1 was expressed in salt glands and in response to NaCl treatment.LbRZF1 showed no E3 ubiquitin ligase activity.The phenotypes of overexpression and knockout lines for LbRZF1 indicated that LbRZF1 positively regulated salt gland development and salt tolerance in L.bicolor.lbrzf1 mutants had fewer salt glands and secreted less salt than did the wild-type,whereas LbRZF1-overexpressing lines had opposite phenotypes,in keeping with the overall salt tolerance of these plants.A yeast two-hybrid screen revealed that LbRZF1 interacted with LbCATALASE2(LbCAT2)and the transcription factor LbMYB113,leading to their stabilization.Silencing of LbCAT2 or LbMYB113 decreased salt gland density and salt tolerance.The heterologous expression of LbRZF1 in Arabidopsis thaliana conferred salt tolerance to this non-halophyte.We also identified the transcription factor LbMYB48 as an upstream regulator of LbRZF1 transcription.The study of LbRZF1 in the regulation network of salt gland development also provides a good foundation for transforming crops and improving their salt resistance.展开更多
Halophytes have evolved specialized strategies to cope with high salinity.The extreme halophyte sea lavender(Limonium bicolor)lacks trichomes but possesses salt glands on its epidermis that can excrete harmful ions,su...Halophytes have evolved specialized strategies to cope with high salinity.The extreme halophyte sea lavender(Limonium bicolor)lacks trichomes but possesses salt glands on its epidermis that can excrete harmful ions,such as sodium,to avoid salt damage.Here,we report a high-quality,2.92-Gb,chromosome-scale L.bicolor genome assembly based on a combination of Illumina short reads,single-molecule,real-time long reads,chromosome conformation capture(Hi-C)data,and Bionano genome maps,greatly enriching the genomic information on recretohalophytes with multicellular salt glands.Although the L.bicolor genome contains genes that show similarity to trichome fate genes from Arabidopsis thaliana,it lacks homologs of the decision fate genes GLABRA3,ENHANCER OF GLABRA3,GLABRA2,TRANSPARENT TESTA GLABRA2,and SIAMESE,providing a molecular explanation for the absence of trichomes in this species.We identified key genes(LbHLH and LbTTG1)controlling salt gland development among classical trichome homologous genes and confirmed their roles by showing that their mutations markedly disrupted salt gland initiation,salt secretion,and salt tolerance,thus offering genetic support for the long-standing hypothesis that salt glands and trichomes may share a common origin.In addition,a whole-genome duplication event occurred in the L.bicolor genome after its divergence from Tartary buckwheat and may have contributed to its adaptation to high salinity.The L.bicolor genome resource and genetic evidence reported in this study provide profound insights into plant salt tolerance mechanisms that may facilitate the engineering of salt-tolerant crops.展开更多
基金supported by Natural Science Research Foundation of Shandong Province(project no.ZR2023YQ021 and ZR2020QC031)National Natural Science Research Foundation of China(project nos.32000209 and 32170301)China Postdoctoral Science Foundation(project no.2020M672114)。
文摘The recretohalophyte Limonium bicolor thrives in high-salinity environments because salt glands on the above-ground parts of the plant help to expel excess salt.Here,we characterize a nucleus-localized C3HC4(RING-HC)-type zinc finger protein of L.bicolor named RING ZINC FINGER PROTEIN 1(LbRZF1).LbRZF1 was expressed in salt glands and in response to NaCl treatment.LbRZF1 showed no E3 ubiquitin ligase activity.The phenotypes of overexpression and knockout lines for LbRZF1 indicated that LbRZF1 positively regulated salt gland development and salt tolerance in L.bicolor.lbrzf1 mutants had fewer salt glands and secreted less salt than did the wild-type,whereas LbRZF1-overexpressing lines had opposite phenotypes,in keeping with the overall salt tolerance of these plants.A yeast two-hybrid screen revealed that LbRZF1 interacted with LbCATALASE2(LbCAT2)and the transcription factor LbMYB113,leading to their stabilization.Silencing of LbCAT2 or LbMYB113 decreased salt gland density and salt tolerance.The heterologous expression of LbRZF1 in Arabidopsis thaliana conferred salt tolerance to this non-halophyte.We also identified the transcription factor LbMYB48 as an upstream regulator of LbRZF1 transcription.The study of LbRZF1 in the regulation network of salt gland development also provides a good foundation for transforming crops and improving their salt resistance.
基金supported by the National Natural Science Research Foundation of China(NSFC)(project nos.3217030131770288.and 31600200)the MOE Layout Foundation of Humanities and Social Sciences(21YJAZH108)the Shandong Provincial Bohai Granary Science and Technology Demonstration Project(2019BHLC004)。
文摘Halophytes have evolved specialized strategies to cope with high salinity.The extreme halophyte sea lavender(Limonium bicolor)lacks trichomes but possesses salt glands on its epidermis that can excrete harmful ions,such as sodium,to avoid salt damage.Here,we report a high-quality,2.92-Gb,chromosome-scale L.bicolor genome assembly based on a combination of Illumina short reads,single-molecule,real-time long reads,chromosome conformation capture(Hi-C)data,and Bionano genome maps,greatly enriching the genomic information on recretohalophytes with multicellular salt glands.Although the L.bicolor genome contains genes that show similarity to trichome fate genes from Arabidopsis thaliana,it lacks homologs of the decision fate genes GLABRA3,ENHANCER OF GLABRA3,GLABRA2,TRANSPARENT TESTA GLABRA2,and SIAMESE,providing a molecular explanation for the absence of trichomes in this species.We identified key genes(LbHLH and LbTTG1)controlling salt gland development among classical trichome homologous genes and confirmed their roles by showing that their mutations markedly disrupted salt gland initiation,salt secretion,and salt tolerance,thus offering genetic support for the long-standing hypothesis that salt glands and trichomes may share a common origin.In addition,a whole-genome duplication event occurred in the L.bicolor genome after its divergence from Tartary buckwheat and may have contributed to its adaptation to high salinity.The L.bicolor genome resource and genetic evidence reported in this study provide profound insights into plant salt tolerance mechanisms that may facilitate the engineering of salt-tolerant crops.
