Salt stress is a major constraint on plant growth and yield.Nitrogen(N)fertilizers are known to alleviate salt stress.However,the underlying molecular mechanisms remain unclear.Here,we show that nitratedependent salt ...Salt stress is a major constraint on plant growth and yield.Nitrogen(N)fertilizers are known to alleviate salt stress.However,the underlying molecular mechanisms remain unclear.Here,we show that nitratedependent salt tolerance is mediated by OsMADS27 in rice.The expression of OsMADS27 is specifically induced by nitrate.The salt-inducible expression of OsMADS27 is also nitrate dependent.OsMADS27 knockout mutants are more sensitive to salt stress than the wild type,whereas OsMADS27 overexpression lines are more tolerant.Transcriptomic analyses revealed that OsMADS27 upregulates the expression of a number of known stress-responsive genes as well as those involved in ion homeostasis and antioxidation.We demonstrate that OsMADS27 directly binds to the promoters of OsHKT1.1 and OsSPL7 to regulate their expression.Notably,OsMADS27-mediated salt tolerance is nitrate dependent and positively correlated with nitrate concentration.Our results reveal the role of nitrate-responsive OsMADS27 and its downstream target genes in salt tolerance,providing a molecular mechanism for the enhancement of salt tolerance by nitrogen fertilizers in rice.OsMADS27 overexpression increased grain yield under salt stress in the presence of sufficient nitrate,suggestingthatOsMADS27 is a promising candidate for the improvementof salt tolerance inrice.展开更多
Nitrogen-cycling microorganisms play key roles at the intersection of microbiology and wastewater engineering.In addition to the well-studied ammonia oxidizing bacteria,nitrite oxidizing bacteria,heterotrophic denitri...Nitrogen-cycling microorganisms play key roles at the intersection of microbiology and wastewater engineering.In addition to the well-studied ammonia oxidizing bacteria,nitrite oxidizing bacteria,heterotrophic denitrifiers,and anammox bacteria,there are some other N-cycling microorganisms that are less abundant but functionally important in wastewater nitrogen removal.These microbes include,but not limited to ammonia oxidizing archaea(AOA),complete ammonia oxidation(comammox)bacteria,dissimilatory nitrate reduction to ammonia(DNRA)bacteria,and nitrate/nitrite-dependent anaerobic methane oxidizing(NO_(x)-DAMO)microorganisms.In the past decade,the development of high-throughput molecular technologies has enabled the detection,quantification,and characterization of these minor populations.The aim of this review is therefore to synthesize the current knowledge on the distribution,ecological niche,and kinetic properties of these“overlooked”N-cycling microbes at wastewater treatment plants.Their potential applications in novel wastewater nitrogen removal processes are also discussed.A comprehensive understanding of these overlooked N-cycling microbes from microbiology,ecology,and engineering perspectives will facilitate the design and operation of more efficient and sustainable biological nitrogen removal processes.展开更多
基金The Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDA24010303 to C.B.X.).
文摘Salt stress is a major constraint on plant growth and yield.Nitrogen(N)fertilizers are known to alleviate salt stress.However,the underlying molecular mechanisms remain unclear.Here,we show that nitratedependent salt tolerance is mediated by OsMADS27 in rice.The expression of OsMADS27 is specifically induced by nitrate.The salt-inducible expression of OsMADS27 is also nitrate dependent.OsMADS27 knockout mutants are more sensitive to salt stress than the wild type,whereas OsMADS27 overexpression lines are more tolerant.Transcriptomic analyses revealed that OsMADS27 upregulates the expression of a number of known stress-responsive genes as well as those involved in ion homeostasis and antioxidation.We demonstrate that OsMADS27 directly binds to the promoters of OsHKT1.1 and OsSPL7 to regulate their expression.Notably,OsMADS27-mediated salt tolerance is nitrate dependent and positively correlated with nitrate concentration.Our results reveal the role of nitrate-responsive OsMADS27 and its downstream target genes in salt tolerance,providing a molecular mechanism for the enhancement of salt tolerance by nitrogen fertilizers in rice.OsMADS27 overexpression increased grain yield under salt stress in the presence of sufficient nitrate,suggestingthatOsMADS27 is a promising candidate for the improvementof salt tolerance inrice.
基金supported by the National Natural Science Foundation of China(Grant No.41701269)the National Key R&D Program of China(No.2019YFC0408800)the Fundamental Research Funds for the Central Universities(No.2020FZZX001-06).
文摘Nitrogen-cycling microorganisms play key roles at the intersection of microbiology and wastewater engineering.In addition to the well-studied ammonia oxidizing bacteria,nitrite oxidizing bacteria,heterotrophic denitrifiers,and anammox bacteria,there are some other N-cycling microorganisms that are less abundant but functionally important in wastewater nitrogen removal.These microbes include,but not limited to ammonia oxidizing archaea(AOA),complete ammonia oxidation(comammox)bacteria,dissimilatory nitrate reduction to ammonia(DNRA)bacteria,and nitrate/nitrite-dependent anaerobic methane oxidizing(NO_(x)-DAMO)microorganisms.In the past decade,the development of high-throughput molecular technologies has enabled the detection,quantification,and characterization of these minor populations.The aim of this review is therefore to synthesize the current knowledge on the distribution,ecological niche,and kinetic properties of these“overlooked”N-cycling microbes at wastewater treatment plants.Their potential applications in novel wastewater nitrogen removal processes are also discussed.A comprehensive understanding of these overlooked N-cycling microbes from microbiology,ecology,and engineering perspectives will facilitate the design and operation of more efficient and sustainable biological nitrogen removal processes.
