Growth-defense tradeoffs are thought to occur in plants due to resource restrictions, which demand prior- itization towards either growth or defense, depending on external and internal factors. These tradeoffs have pr...Growth-defense tradeoffs are thought to occur in plants due to resource restrictions, which demand prior- itization towards either growth or defense, depending on external and internal factors. These tradeoffs have profound implications in agriculture and natural ecosystems, as both processes are vital for plant survival, reproduction, and, ulti- mately, plant fitness. While many of the molecular mechanisms underlying growth and defense tradeoffs remain to be elucidated, hormone crosstalk has emerged as a major player in regulating tradeoffs needed to achieve a balance. In this review, we cover recent advances in understanding growth-defense tradeoffs in plants as well as what is known regard- ing the underlying molecular mechanisms. Specifically, we address evidence supporting the growth-defense tradeoff concept, as well as known interactions between defense signaling and growth signaling. Understanding the molecular basis of these tradeoffs in plants should provide a foundation for the development of breeding strategies that optimize the growth-defense balance to maximize crop yield to meet rising global food and biofuel demands.展开更多
In nature, plants constantly have to face pathogen attacks. However, plant disease rarely occurs due to efficient immune systems possessed by the host plants. Pathogens are perceived by two different recognition syste...In nature, plants constantly have to face pathogen attacks. However, plant disease rarely occurs due to efficient immune systems possessed by the host plants. Pathogens are perceived by two different recognition systems that initiate the so-called pattern-triggered immunity （PTI） and effector-triggered immunity （ETI）, both of which are accompanied by a set of induced defenses that usually repel pathogen attacks. Here we discuss the complex network of signaling pathways occurring during PTI, focusing on the involvement of mitogen-activated protein kinases.展开更多
Since the first plant cyclic nucleotide-gated ion channel （CNGC）, HvCBT1, was identified as a calmodulin bind- ing protein, more than a decade has passed and a substantial amount of work has been done to understand ...Since the first plant cyclic nucleotide-gated ion channel （CNGC）, HvCBT1, was identified as a calmodulin bind- ing protein, more than a decade has passed and a substantial amount of work has been done to understand the molecular nature and function of these channel proteins. Based on electrophysiological and heterologous expression analyses, plant CNGCs function as non-selective cation channels and, so far, their biological roles have been reported in defense responses, development, and ion homeostasis. Forward genetic approaches identified four AtCNGCs （AtCNGC2, 4, 11, and 12） to be involved in plant immunity, as null mutants for AtCNGC2, 4, 11, and 12 as well as a gain-of- function mutant for AtCNGC11 and 12 exhibited alterations in defense responses. Since ion flux changes have been reported as one of the early events upon pathogen recognition and also are an essential component for the activation of defense responses, the involvement of CNGCs in these ion flux changes has been suggested. However, the recent detailed characterization of null mutants suggested a more complex involvement of this channel family. In this review, we focus on the discoveries and character- ization of these CNGC mutants and discuss possible roles of CNGCs as components in plant immunity.展开更多
Light and chloroplast function is known to affect the plant immune response; however, the underlying mechanism remains elusive. We previously demonstrated that two light signaling factors, FAR-RED ELONGATED HYPOCOTYL ...Light and chloroplast function is known to affect the plant immune response; however, the underlying mechanism remains elusive. We previously demonstrated that two light signaling factors, FAR-RED ELONGATED HYPOCOTYL 3（FHY3）and FAR-RED IMPAIRED RESPONSE 1（FAR1）, regulate chlorophyll biosynthesis and seedling growth via controlling HEMB1 expression in Arabidopsis thaliana. In this study, we reveal that FHY3 and FAR1 are involved in modulating plant immunity. We showed that the fhy3 far1 double null mutant displayed high levels of reactive oxygen species and salicylic acid（SA） and increased resistance to Pseudomonas syringae pathogen infection. Microarray analysis revealed that a large proportion of pathogen-related genes, particularly genes encoding nucleotide-binding and leucine-rich repeat domain resistant proteins, are highly induced in fhy3 far1. Genetic studies indicated that the defects of fhy3 far1 can be largely rescued by reducing SA signaling or blocking SA accumulation, and by overexpression of HEMB1, which encodes a 5-aminolevulinic acid dehydratase in the chlorophyll biosynthetic pathway.Furthermore, we found that transgenic plants with reduced expression of HEMB1 exhibit a phenotype similar to fhy3 far1.Taken together, this study demonstrates an important role of FHY3 and FAR1 in regulating plant immunity, through integrating chlorophyll biosynthesis and the SA signaling pathway.展开更多
Plants have evolved a large number of receptor-like cytoplasmic kinases （RLCKs） that often functionally and physically associate with receptor-like kinases （RLKs） to modulate plant growth, development and immune r...Plants have evolved a large number of receptor-like cytoplasmic kinases （RLCKs） that often functionally and physically associate with receptor-like kinases （RLKs） to modulate plant growth, development and immune responses. Without any apparent extracellular domain, RLCKs relay intracellular signaling often via RLK complex-mediated transphosphorylation events. Recent advances have suggested essential roles of diverse RLCKs in concert with RLKs in regulating various cellular and physiological responses. We summarize here the complex roles of RLCKs in mediating plant immune responses and growth regulation, and discuss specific and overlapping functions of RLCKs in transducing diverse signaling pathways.展开更多
Plant immune receptors belonging to the receptor-like kinase （RLK） family play important roles in the recog- nition of microbial pathogens and activation of downstream defense responses. The Arabidopsis mutant snc4-...Plant immune receptors belonging to the receptor-like kinase （RLK） family play important roles in the recog- nition of microbial pathogens and activation of downstream defense responses. The Arabidopsis mutant snc4-1D con- tains a gain-of-function mutation in the RLK SNC4 （SUPPRESSOR OF NPRI-1, CONSTITUTIVE4）, which leads to constitutive activation of defense responses. Analysis of suppressor mutants of snc4-1D identified two conserved splicing factors, SUA （SUPPRESSOR OF ABI3-5） and RSN2 （REQUIRED FOR SNC4-1D 2）, that are required for the constitutive defense responses in snc4-1D. In sua and rsn2 mutants, SNC4 splicing is altered and the amount of 5NC4 transcripts is reduced. Further analysis showed that SUA and RSN2 are also required for the proper splicing of CERK1 （CHITIN ELICITOR RECEPTOR KINASE1）, which encodes another RLK that functions as a receptor for chitin. In sua and rsn2 mutants, induction of reactive oxygen species by chitin is reduced and the non-pathogenic bacteria Pseudomonas syringae pv. tomato DC3OOOhrcC grows to higher titers than in wild-type plants. Our study suggests that pre-mRNA splicing plays important roles in the regulation of plant immunity mediated by the RLKs SNC4 and CERK1.展开更多
The Arabidopsis heterotrimeric G-protein controls defense responses to necrotrophic and vascular fungi. The agbl mutant impaired in the Gβ subunit displays enhanced susceptibility to these pathogens. Gβ/AGB1 forms a...The Arabidopsis heterotrimeric G-protein controls defense responses to necrotrophic and vascular fungi. The agbl mutant impaired in the Gβ subunit displays enhanced susceptibility to these pathogens. Gβ/AGB1 forms an obligate dimer with either one of the Arabidopsis Gγsubunits （γ1/AGG1 and γ2/AGG2）. Accordingly, we now demonstrate that the aggl agg2 double mutant is as susceptible as agbl plants to the necrotrophic fungus Plectosphaerella cucumerina. To elucidate the molecular basis of heterotrimeric G-protein-mediated resistance, we performed a comparative transcriptomic analysis of agbl-1 mutant and wild-type plants upon inoculation with P cucumerina. This analysis, together with metab- olomic studies, demonstrated that G-protein-mediated resistance was independent of defensive pathways required for resistance to necrotrophic fungi, such as the salicylic acid, jasmonic acid, ethylene, abscisic acid, and tryptophan-derived metabolites signaling, as these pathways were not impaired in agbl and aggl agg2 mutants. Notably, many mis-reguiated genes in agbl plants were related with cell wall functions, which was also the case in aggl agg2 mutant. Biochemical analyses and Fourier Transform InfraRed （FTIR） spectroscopy of cell walls from G-protein mutants revealed that the xylose content was lower in agbl and aggl agg2 mutants than in wild-type plants, and that mutant walls had similar FTIR spec-tratypes, which differed from that of wild-type plants. The data presented here suggest a canonical functionality of the Gβ and Gγ1/γ2 subunits in the control of Arabidopsis immune responses and the regulation of cell wall composition.展开更多
文摘Growth-defense tradeoffs are thought to occur in plants due to resource restrictions, which demand prior- itization towards either growth or defense, depending on external and internal factors. These tradeoffs have profound implications in agriculture and natural ecosystems, as both processes are vital for plant survival, reproduction, and, ulti- mately, plant fitness. While many of the molecular mechanisms underlying growth and defense tradeoffs remain to be elucidated, hormone crosstalk has emerged as a major player in regulating tradeoffs needed to achieve a balance. In this review, we cover recent advances in understanding growth-defense tradeoffs in plants as well as what is known regard- ing the underlying molecular mechanisms. Specifically, we address evidence supporting the growth-defense tradeoff concept, as well as known interactions between defense signaling and growth signaling. Understanding the molecular basis of these tradeoffs in plants should provide a foundation for the development of breeding strategies that optimize the growth-defense balance to maximize crop yield to meet rising global food and biofuel demands.
文摘In nature, plants constantly have to face pathogen attacks. However, plant disease rarely occurs due to efficient immune systems possessed by the host plants. Pathogens are perceived by two different recognition systems that initiate the so-called pattern-triggered immunity （PTI） and effector-triggered immunity （ETI）, both of which are accompanied by a set of induced defenses that usually repel pathogen attacks. Here we discuss the complex network of signaling pathways occurring during PTI, focusing on the involvement of mitogen-activated protein kinases.
文摘Since the first plant cyclic nucleotide-gated ion channel （CNGC）, HvCBT1, was identified as a calmodulin bind- ing protein, more than a decade has passed and a substantial amount of work has been done to understand the molecular nature and function of these channel proteins. Based on electrophysiological and heterologous expression analyses, plant CNGCs function as non-selective cation channels and, so far, their biological roles have been reported in defense responses, development, and ion homeostasis. Forward genetic approaches identified four AtCNGCs （AtCNGC2, 4, 11, and 12） to be involved in plant immunity, as null mutants for AtCNGC2, 4, 11, and 12 as well as a gain-of- function mutant for AtCNGC11 and 12 exhibited alterations in defense responses. Since ion flux changes have been reported as one of the early events upon pathogen recognition and also are an essential component for the activation of defense responses, the involvement of CNGCs in these ion flux changes has been suggested. However, the recent detailed characterization of null mutants suggested a more complex involvement of this channel family. In this review, we focus on the discoveries and character- ization of these CNGC mutants and discuss possible roles of CNGCs as components in plant immunity.
基金supported by grants from the National Natural Science Foundation of China(31170221,31325002 and 31300206)the Ministry of Agriculture of China(2014ZX08009-003)
文摘Light and chloroplast function is known to affect the plant immune response; however, the underlying mechanism remains elusive. We previously demonstrated that two light signaling factors, FAR-RED ELONGATED HYPOCOTYL 3（FHY3）and FAR-RED IMPAIRED RESPONSE 1（FAR1）, regulate chlorophyll biosynthesis and seedling growth via controlling HEMB1 expression in Arabidopsis thaliana. In this study, we reveal that FHY3 and FAR1 are involved in modulating plant immunity. We showed that the fhy3 far1 double null mutant displayed high levels of reactive oxygen species and salicylic acid（SA） and increased resistance to Pseudomonas syringae pathogen infection. Microarray analysis revealed that a large proportion of pathogen-related genes, particularly genes encoding nucleotide-binding and leucine-rich repeat domain resistant proteins, are highly induced in fhy3 far1. Genetic studies indicated that the defects of fhy3 far1 can be largely rescued by reducing SA signaling or blocking SA accumulation, and by overexpression of HEMB1, which encodes a 5-aminolevulinic acid dehydratase in the chlorophyll biosynthetic pathway.Furthermore, we found that transgenic plants with reduced expression of HEMB1 exhibit a phenotype similar to fhy3 far1.Taken together, this study demonstrates an important role of FHY3 and FAR1 in regulating plant immunity, through integrating chlorophyll biosynthesis and the SA signaling pathway.
文摘Plants have evolved a large number of receptor-like cytoplasmic kinases （RLCKs） that often functionally and physically associate with receptor-like kinases （RLKs） to modulate plant growth, development and immune responses. Without any apparent extracellular domain, RLCKs relay intracellular signaling often via RLK complex-mediated transphosphorylation events. Recent advances have suggested essential roles of diverse RLCKs in concert with RLKs in regulating various cellular and physiological responses. We summarize here the complex roles of RLCKs in mediating plant immune responses and growth regulation, and discuss specific and overlapping functions of RLCKs in transducing diverse signaling pathways.
文摘Plant immune receptors belonging to the receptor-like kinase （RLK） family play important roles in the recog- nition of microbial pathogens and activation of downstream defense responses. The Arabidopsis mutant snc4-1D con- tains a gain-of-function mutation in the RLK SNC4 （SUPPRESSOR OF NPRI-1, CONSTITUTIVE4）, which leads to constitutive activation of defense responses. Analysis of suppressor mutants of snc4-1D identified two conserved splicing factors, SUA （SUPPRESSOR OF ABI3-5） and RSN2 （REQUIRED FOR SNC4-1D 2）, that are required for the constitutive defense responses in snc4-1D. In sua and rsn2 mutants, SNC4 splicing is altered and the amount of 5NC4 transcripts is reduced. Further analysis showed that SUA and RSN2 are also required for the proper splicing of CERK1 （CHITIN ELICITOR RECEPTOR KINASE1）, which encodes another RLK that functions as a receptor for chitin. In sua and rsn2 mutants, induction of reactive oxygen species by chitin is reduced and the non-pathogenic bacteria Pseudomonas syringae pv. tomato DC3OOOhrcC grows to higher titers than in wild-type plants. Our study suggests that pre-mRNA splicing plays important roles in the regulation of plant immunity mediated by the RLKs SNC4 and CERK1.
文摘The Arabidopsis heterotrimeric G-protein controls defense responses to necrotrophic and vascular fungi. The agbl mutant impaired in the Gβ subunit displays enhanced susceptibility to these pathogens. Gβ/AGB1 forms an obligate dimer with either one of the Arabidopsis Gγsubunits （γ1/AGG1 and γ2/AGG2）. Accordingly, we now demonstrate that the aggl agg2 double mutant is as susceptible as agbl plants to the necrotrophic fungus Plectosphaerella cucumerina. To elucidate the molecular basis of heterotrimeric G-protein-mediated resistance, we performed a comparative transcriptomic analysis of agbl-1 mutant and wild-type plants upon inoculation with P cucumerina. This analysis, together with metab- olomic studies, demonstrated that G-protein-mediated resistance was independent of defensive pathways required for resistance to necrotrophic fungi, such as the salicylic acid, jasmonic acid, ethylene, abscisic acid, and tryptophan-derived metabolites signaling, as these pathways were not impaired in agbl and aggl agg2 mutants. Notably, many mis-reguiated genes in agbl plants were related with cell wall functions, which was also the case in aggl agg2 mutant. Biochemical analyses and Fourier Transform InfraRed （FTIR） spectroscopy of cell walls from G-protein mutants revealed that the xylose content was lower in agbl and aggl agg2 mutants than in wild-type plants, and that mutant walls had similar FTIR spec-tratypes, which differed from that of wild-type plants. The data presented here suggest a canonical functionality of the Gβ and Gγ1/γ2 subunits in the control of Arabidopsis immune responses and the regulation of cell wall composition.
基金Supported by National Natural Science Foundation of China(No.32072444)National Natural Science Foundation of China(No.32060429)the key Project of Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2022D01D44).
