Rice false smut has become an increasingly serious disease in rice （Oryza sativa L.） production worldwide. The typical feature of this disease is that the fungal pathogen Ustilaginoidea virens （Uv） specifical y in...Rice false smut has become an increasingly serious disease in rice （Oryza sativa L.） production worldwide. The typical feature of this disease is that the fungal pathogen Ustilaginoidea virens （Uv） specifical y infects rice flower and forms false smut bal , the ustiloxin-containing bal-like fungal colony, of which the size is usual y several times larger than that of a mature rice seed. However, the underlying mechanisms of Uv-rice interac-tion are poorly understood. Here, we applied time-course microscopic and transcriptional approaches to investigate rice responses to Uv infection. The results demonstrated that the flower-opening process and expression of associated transcription factors, including ARF6 and ARF8, were inhibited in Uv-infected spikelets. The ovaries in infected spikelets were interrupted in fertilization and thus were unable to set seeds. However, a number of grain-fil ing-related genes, including seed storage protein genes, starch anabolism genes and endosperm-specific transcription factors （RISBZ1 and RPBF）, were highly transcribed as if the ovaries were fertilized. In addition, critical defense-related genes like NPR1 and PR1 were downregulated by;Uv infection. Our data imply that Uv may hijack host nutrient reservoir by activation of the grain-fil ing network because of growth and formation of false smut bal s.展开更多
Study on the regulation of broad-spectrum resistance is an active area in plant biology. RESISTANCE TO POWDERY MILDEW 8.1(RPW8.1)is one of a few broad-spectrum resistance genes triggering the hypersensitive response(H...Study on the regulation of broad-spectrum resistance is an active area in plant biology. RESISTANCE TO POWDERY MILDEW 8.1(RPW8.1)is one of a few broad-spectrum resistance genes triggering the hypersensitive response(HR) to restrict multiple pathogenic infections. To address the question how RPW8.1 signaling is regulated,we performed a genetic screen and tried to identify mutations enhancing RPW8.1-mediated HR.Here, we provided evidence to connect an annexin protein with RPW8.1-mediated resistance in Arabidopsis against powdery mildew. We isolated and characterized Arabidopsis b7-6 mutant.A point mutation in b7-6 at the At5 g12380 locus resulted in an amino acid substitution in ANNEXIN8(AtANN8). Loss-of-function or RNA-silencing of AtANN8 led to enhanced expression of RPW8.1,RPW8.1-dependent necrotic lesions in leaves, and defense against powdery mildew. Conversely,over-expression of AtANN8 compromised RPW8.1-mediated disease resistance and cell death. Interestingly, the mutation in AtANN8 enhanced RPW8.1-triggered H2O2. In addition, mutation in AtANN8 led to hypersensitivity to salt stress. Together, our data indicate that AtANN8 is involved in multiple stress signaling pathways and negatively regulates RPW8.1-mediated resistance against powdery mildew and cell death, thus linking ANNEXIN’s function with plant immunity.展开更多
Plants have evolved a sophisticated immune system to fight against pathogenic microbes. Upon detection of pathogen invasion by immune receptors, the immune system is turned on, resulting in production of antimicrobial...Plants have evolved a sophisticated immune system to fight against pathogenic microbes. Upon detection of pathogen invasion by immune receptors, the immune system is turned on, resulting in production of antimicrobial molecules including pathogenesis-related（PR） proteins.Conceivably, an efficient immune response depends on the capacity of the plant cell＇s protein/membrane trafficking network to deploy the right defense-associated molecules in the right place at the right time. Recent research in this area shows that while the abundance of cell surface immune receptors is regulated by endocytosis, many intracellular immune receptors, when activated, are partitioned between the cytoplasm and the nucleus for induction of defense genes and activation of programmed cell death, respectively. Vesicle transport is an essential process for secretion of PR proteins to the apoplastic space and targeting of defense-related proteins to the plasma membrane or other endomembrane compartments. In this review, we discuss the various aspects of protein trafficking during plant immunity, with a focus on the immunity proteins on the move and the major components of the trafficking machineries engaged.展开更多
基金supported by Sichuan Agricultural University start-up packages awarded to W.-M.W.and J.F.grants from the China Postdoctoral Science Foundation (2012M521679 to J.F.)grants from the Special Fund for Agro-Scientific Research in the Public Interest (200903039 to F.H.and W.-X.S.)
文摘Rice false smut has become an increasingly serious disease in rice （Oryza sativa L.） production worldwide. The typical feature of this disease is that the fungal pathogen Ustilaginoidea virens （Uv） specifical y infects rice flower and forms false smut bal , the ustiloxin-containing bal-like fungal colony, of which the size is usual y several times larger than that of a mature rice seed. However, the underlying mechanisms of Uv-rice interac-tion are poorly understood. Here, we applied time-course microscopic and transcriptional approaches to investigate rice responses to Uv infection. The results demonstrated that the flower-opening process and expression of associated transcription factors, including ARF6 and ARF8, were inhibited in Uv-infected spikelets. The ovaries in infected spikelets were interrupted in fertilization and thus were unable to set seeds. However, a number of grain-fil ing-related genes, including seed storage protein genes, starch anabolism genes and endosperm-specific transcription factors （RISBZ1 and RPBF）, were highly transcribed as if the ovaries were fertilized. In addition, critical defense-related genes like NPR1 and PR1 were downregulated by;Uv infection. Our data imply that Uv may hijack host nutrient reservoir by activation of the grain-fil ing network because of growth and formation of false smut bal s.
基金supported by the National Natural Science Foundation of China (Grant numbers 31672090, 31430072 and 31371931 to W.-M.W.)the National Science Foundation (Grant numbers IOS-1457033 and IOS-1901566 to S. X.)。
文摘Study on the regulation of broad-spectrum resistance is an active area in plant biology. RESISTANCE TO POWDERY MILDEW 8.1(RPW8.1)is one of a few broad-spectrum resistance genes triggering the hypersensitive response(HR) to restrict multiple pathogenic infections. To address the question how RPW8.1 signaling is regulated,we performed a genetic screen and tried to identify mutations enhancing RPW8.1-mediated HR.Here, we provided evidence to connect an annexin protein with RPW8.1-mediated resistance in Arabidopsis against powdery mildew. We isolated and characterized Arabidopsis b7-6 mutant.A point mutation in b7-6 at the At5 g12380 locus resulted in an amino acid substitution in ANNEXIN8(AtANN8). Loss-of-function or RNA-silencing of AtANN8 led to enhanced expression of RPW8.1,RPW8.1-dependent necrotic lesions in leaves, and defense against powdery mildew. Conversely,over-expression of AtANN8 compromised RPW8.1-mediated disease resistance and cell death. Interestingly, the mutation in AtANN8 enhanced RPW8.1-triggered H2O2. In addition, mutation in AtANN8 led to hypersensitivity to salt stress. Together, our data indicate that AtANN8 is involved in multiple stress signaling pathways and negatively regulates RPW8.1-mediated resistance against powdery mildew and cell death, thus linking ANNEXIN’s function with plant immunity.
基金supported by a grant from the National Science Foundation(grant number IOS-1146589)to S.X.Research in the Wang lab is supported by grants from the National Natural Science Foundation of China(grant numbers 31371931 and 31430072)to W.M.W
文摘Plants have evolved a sophisticated immune system to fight against pathogenic microbes. Upon detection of pathogen invasion by immune receptors, the immune system is turned on, resulting in production of antimicrobial molecules including pathogenesis-related（PR） proteins.Conceivably, an efficient immune response depends on the capacity of the plant cell＇s protein/membrane trafficking network to deploy the right defense-associated molecules in the right place at the right time. Recent research in this area shows that while the abundance of cell surface immune receptors is regulated by endocytosis, many intracellular immune receptors, when activated, are partitioned between the cytoplasm and the nucleus for induction of defense genes and activation of programmed cell death, respectively. Vesicle transport is an essential process for secretion of PR proteins to the apoplastic space and targeting of defense-related proteins to the plasma membrane or other endomembrane compartments. In this review, we discuss the various aspects of protein trafficking during plant immunity, with a focus on the immunity proteins on the move and the major components of the trafficking machineries engaged.
