Two different species, Trichoderma viride TV10 and Trichoderma harzianum TH12 from 30 Trichoderma isolates were selected out based on their high growth inhibition of the phytopathogen Sclerotinia sclerotiorum (Lib) de...Two different species, Trichoderma viride TV10 and Trichoderma harzianum TH12 from 30 Trichoderma isolates were selected out based on their high growth inhibition of the phytopathogen Sclerotinia sclerotiorum (Lib) de Bary, which reached 84.44% and 100%, respectively. Their untreated culture filtrates (CF) and culture filtrates treated with heat (CFH) also were tested for growth inhibition of the pathogen in potato dextrose agar (PDA). Morphological and molecular characterisation by internal transcribed spacer (ITS) PCR provided consistent identification of these isolates. The degree of infection and disease index (DI) of S. sclerotiorum were examined in Brassica napus (AACC) and Raphanus alboglabra (RR) and Brassica alboglabra (CC). The results revealed that Raphanus alboglabra showed higher disease resistance than that of B. napus. Biotic elecitors T. harzianum TH12 and T. viride TV10 and their CF and CFH demonstrated the ability to cause induced systemic resistance (ISR) in B. napus and Raphanus alboglabra against sclerotinia stem rot (SSR) disease. Furthermore, a high ability to reduce the degree of infection and DI in B. napus with the biotic elicitors T. harzianum TH12 and T. viride TV10 was observed, with numbers reaching 7.22% to 6.67% and 17.78% to 11.67%, respectively. When CF were used, reached 20.00% to 16.67% and 33.33% to 23.33%, respectively;with CFH, values reached 35.00% to 21.67% and 37.78% to 28.33%, respectively. While in Raphanus alboglabra the degree of infection and DI reached 0.00% and 0.00% with all biotic elicitors treatments. These results show that biotic elicitor treatments significantly (P B. napus and Raphanus alboglabra ranked as most effective. This study showed for the first time the ability of genotype Raphanus alboglabra (RRCC) to demonstrate resistance against S. sclerotiorum with or without treatment by biotic elicitors and the ability of genotype B. napus (AACC) to demonstrate resistance to the pathogen after treatment with biotic elicitors.展开更多
The beneficial applications of Trichoderma spp. in agriculture include not only the control of plant pathogens, but also the improvement of plant growth, micronutrient availability, and plant tolerance to abiotic stre...The beneficial applications of Trichoderma spp. in agriculture include not only the control of plant pathogens, but also the improvement of plant growth, micronutrient availability, and plant tolerance to abiotic stress. In addition, it has been suggested that these fungi are able to increase plant disease resistance by activating induced systemic resistance (ISR) . The mode of action of these beneficial fungi in the Trichoderma -plant-pathogen interaction are many, complex and not completely understood. Numerous lytic enzymes have been characterized, the encoding genes (ech42 gluc78, nag1 from T. atroviride strain P1) cloned, and their role in biocontrol demonstrated. The corresponding biocontrol-related inducible promoters have been used in a reporter system based on the Aspergillus niger glucose oxidase gene (goxA) to monitor biocontrol activity. Glucose oxidase catalyzes the oxygen-dependent oxidation of D-glucose to D-glucono-1,5-lactone and hydrogen peroxide; this latter compound is known to have an antifungal effect and activate the plant defence cascade, thus increasing resistance to pathogen attack. T. atroviride P1 transformants with various promoters gox were tested as seed coating treatments on bean seeds planted in soil infested with a soilborne fungal pathogen. Successively, the emergent leaves were inoculated with a foliar pathogen to determine the effect of the GOX transformants on biocontrol and resistance to pathogen attack. Inoculations with the P1-GOX transformants not only reduced disease symptoms caused by a soil pathogen, but also the lesions of various foliar pathogens applied far from the Trichoderma colonization, thus activating ISR. A similar approach is being use to genetically improve T. harzianum T22, a rhizosphere competent and commercially marketed strain not transformed yet, by using four different gox gene constructs under the control of constitutive and inducible promoters. Plasmids have been introduced in Trichoderma by protoplasts co-transformation. hygromicin resistant progeny selected, and mitotically stable transformants analysed to confirm the presence of the novel enzyme activity. Progenies are being tested for biocontrol ISR inducing activity.展开更多
[ Objective ] The paper was to explore the induced resistance of tomato against gray mold （Botrytis cinerea） by salicylic acid. [ Method ] SA was used as an inducer to treat tomato seedlings, the effects of SA on my...[ Objective ] The paper was to explore the induced resistance of tomato against gray mold （Botrytis cinerea） by salicylic acid. [ Method ] SA was used as an inducer to treat tomato seedlings, the effects of SA on mycelial diameter and spore germination of B. cinerea were studied, and the changes of 4 defense enzyme activities containing catalase （CAT）, peroxidase （POD）, polyphenol oxidase （PPO） and phenylalanine ammonia lyase （PAL）, as well as malondialdehyde （MDA） content during the production process of induced resistance were also measured. [ Result] SA had no inhibitory effect against spore germination and myce- lial growth of B. cinerea within the concentration range, and the relative induced effect had different degrees of improvement after treatment. The induced effect was the best as B. cinerea was challenged to inoculate at the third day after using 150 mg/L SA in tomato plants, and the duration of resistance was 10 -15 d. After treated by SA, CAT, POD, PPO and PAL first increased and then decreased in systemic induced resistance against B. cinerea, which were significantly higher than control. Meanwhile, MDA content showed ascendant trend in wavy line form. [ Conclusion ] The use of SA within a certain concentration range is safe; CAT, POD, PPO and PAL activities have positive correlation with induced resistance against B. cinerea, the increase of MDA content also has close relationship with the imvrovement of disease resistance.展开更多
Oligosaccharins are potent biomolecules which activate defense responses and resistance in tobacco plants. However, it is not known the systemic behavior of defensive enzymes activated by these elicitors. In this work...Oligosaccharins are potent biomolecules which activate defense responses and resistance in tobacco plants. However, it is not known the systemic behavior of defensive enzymes activated by these elicitors. In this work, the dynamic behavior of key defensive enzymes was evaluated in tobacco plant leaves previously treated through the roots with chitosan polymer (CH), chitosan (COS) and pectic (OGAS) oligosaccharides and Spermine (Sp). All macromolecules tested activated protein levels and defense enzymatic activity in tobacco leaves but with different response dynamics among them and depending on the biochemical variable evaluated. Defense response above control levels were detected since 12 hours after treatments and it consisted in a biphasic behavior with two peaks for PAL (EC 4.3.1.5) and β 1 - 3 glucanase (EC 3.2.1.6) enzymatic activities. The highest enzymatic levels for these enzymes were achieved at 48 hours in plantlets elicited with COS and at 72 hours for those plants treated with chitosan polymer, while the highest POD (EC 1.11.1.6) activity was detected with CH between 48 and 72 hours. These results demonstrated systemic defense activation by oligosaccharins in tobacco whose dynamic of defense response is affected by the kind of oligosaccharins tested. When applying OGAS by foliar spray on tobacco, systemic resistance against Phytoththora nicotianae was induced and plantlets were protected with the low concentration tested by 46% under the bioassays conditions performed. Moreover, enzymatic determinations on roots and leaves previous to plant-pathogen interaction showed increments above 30% of control levels for PAL and POD activities. It means that oligosaccharins activate local and systemic defense responses in plants in the absent of pathogen infection.展开更多
Induced systemic resistance(ISR)is a mechanism by which certain plant beneficial rhizobacteria and fungi produce immunity,which can stimulate crop growth and resilience against various phytopathogens,insects,and paras...Induced systemic resistance(ISR)is a mechanism by which certain plant beneficial rhizobacteria and fungi produce immunity,which can stimulate crop growth and resilience against various phytopathogens,insects,and parasites.These beneficial rhizobacteria and fungi improve plant performance by regulating hormone signaling,including salicylic acid(SA),jasmonic acid(JA),prosystemin,pathogenesis-related gene 1,and ethylene(ET)pathways,which activate the gene expression of ISR,the synthesis of secondary metabolites,various enzymes,and volatile compounds that ultimately induce defense mechanisms in plant.To protect themselves from disease,plants have various advanced defense mechanisms in which local acquired resistance,systemic gene silencing,systemic wound response,systemic acquired resistance(SAR),and ISR are involved.Several rhizobacteria activate the SA-dependent SAR pathway by producing SA at the root’s surface.In contrast,other rhizobacteria can activate different signaling pathways independent of SA(SA-independent ISR pathways)such as those dependent on JA and ET signaling.The main objective of this review is to provide insight into the types of induced resistance utilized for plant defense.Further to this,the genetic approaches used to suppress disease-causing genes,i.e.,RNA interference and antisense RNA,which are still underutilized in sustainable agriculture,along with the current vision for virus-induced gene silencing are also discussed.展开更多
Small RNAs play an important role in plant immune responses. However, their regulatory function in induced systemic resistance（ISR） is nascent. Bacillus cereus AR156 is a plant growth-promoting rhizobacterium that i...Small RNAs play an important role in plant immune responses. However, their regulatory function in induced systemic resistance（ISR） is nascent. Bacillus cereus AR156 is a plant growth-promoting rhizobacterium that induces ISR in Arabidopsis against bacterial infection. Here,by comparing small RNA profiles of Pseudomonas syringae pv. tomato（Pst） DC3000-infected Arabidopsis with and without AR156 pretreatment, we identified a group of Arabidopsis micro RNAs（mi RNAs） that are differentially regulated by AR156 pretreatment. mi R825 and mi R825 are two mi RNA generated from a single mi RNA gene.Northern blot analysis indicated that they were significantly downregulated in Pst DC3000-infected plants pretreated with AR156, in contrast to the plants without AR156 pretreatment. mi R825 targets two ubiquitin-protein ligases,while mi R825 targets toll-interleukin-like receptor（TIR）-nucleotide binding site（NBS） and leucine-rich repeat（LRR）type resistance（R） genes. The expression of these target genes negatively correlated with the expression of mi R825 and mi R825. Moreover, transgenic plants showing reduced expression of mi R825 and mi R825 displayed enhanced resistance to Pst DC3000 infection, whereas transgenic plants overexpressing mi R825 and mi R825 were more susceptible. Taken together, our data indicates that Bacillus cereus AR156 pretreatment primes ISR to Pst infection by suppressing mi R825 and mi R825 and activating the defense related genes they targeted.展开更多
Brassica napus(cv.Madrigal)seedlings pre-treated with ascospores of Leptosphaeria biglobosa or foliar sprays of either acibenzolar-S-methyl(ASM)or menadione sodium bisulphite(MSB)were chal- lenge inoculated with L.mac...Brassica napus(cv.Madrigal)seedlings pre-treated with ascospores of Leptosphaeria biglobosa or foliar sprays of either acibenzolar-S-methyl(ASM)or menadione sodium bisulphite(MSB)were chal- lenge inoculated with L.maculans ascospores and assessed for phoma leaf spot development and tissue morphology and gene expression responses to infection.Rates of increase in phoma leaf spot area 8―21 d after challenge inoculation were significantly greater on water pre-treated plants than on plants pre-treated with L.biglobosa,ASM or MSB on both pre-treated leaves(local effect)and younger leaves without pre-treatment(systemic effect).Ninety-six h after challenge inoculation,the invasive hyphae of L.maculans were encircled by rings of necrotic mesophyll cells on leaves pre-treated with L. biglobosa,ASM or MSB but not those pre-treated with water.Quantification of transcript levels of genes commonly used as markers of the major defence signalling pathways(PDF1.2,PR-1,NPR1,APX, CHB4)0–96 h after L.maculans challenge inoculation showed expression patterns indicating prefer- ential activation of the jasmonate/ethylene pathway and involved induction of NPR1 locally and sys- temically in leaves of plants pre-treated with L.biglobosa ascospores.展开更多
文摘Two different species, Trichoderma viride TV10 and Trichoderma harzianum TH12 from 30 Trichoderma isolates were selected out based on their high growth inhibition of the phytopathogen Sclerotinia sclerotiorum (Lib) de Bary, which reached 84.44% and 100%, respectively. Their untreated culture filtrates (CF) and culture filtrates treated with heat (CFH) also were tested for growth inhibition of the pathogen in potato dextrose agar (PDA). Morphological and molecular characterisation by internal transcribed spacer (ITS) PCR provided consistent identification of these isolates. The degree of infection and disease index (DI) of S. sclerotiorum were examined in Brassica napus (AACC) and Raphanus alboglabra (RR) and Brassica alboglabra (CC). The results revealed that Raphanus alboglabra showed higher disease resistance than that of B. napus. Biotic elecitors T. harzianum TH12 and T. viride TV10 and their CF and CFH demonstrated the ability to cause induced systemic resistance (ISR) in B. napus and Raphanus alboglabra against sclerotinia stem rot (SSR) disease. Furthermore, a high ability to reduce the degree of infection and DI in B. napus with the biotic elicitors T. harzianum TH12 and T. viride TV10 was observed, with numbers reaching 7.22% to 6.67% and 17.78% to 11.67%, respectively. When CF were used, reached 20.00% to 16.67% and 33.33% to 23.33%, respectively;with CFH, values reached 35.00% to 21.67% and 37.78% to 28.33%, respectively. While in Raphanus alboglabra the degree of infection and DI reached 0.00% and 0.00% with all biotic elicitors treatments. These results show that biotic elicitor treatments significantly (P B. napus and Raphanus alboglabra ranked as most effective. This study showed for the first time the ability of genotype Raphanus alboglabra (RRCC) to demonstrate resistance against S. sclerotiorum with or without treatment by biotic elicitors and the ability of genotype B. napus (AACC) to demonstrate resistance to the pathogen after treatment with biotic elicitors.
文摘The beneficial applications of Trichoderma spp. in agriculture include not only the control of plant pathogens, but also the improvement of plant growth, micronutrient availability, and plant tolerance to abiotic stress. In addition, it has been suggested that these fungi are able to increase plant disease resistance by activating induced systemic resistance (ISR) . The mode of action of these beneficial fungi in the Trichoderma -plant-pathogen interaction are many, complex and not completely understood. Numerous lytic enzymes have been characterized, the encoding genes (ech42 gluc78, nag1 from T. atroviride strain P1) cloned, and their role in biocontrol demonstrated. The corresponding biocontrol-related inducible promoters have been used in a reporter system based on the Aspergillus niger glucose oxidase gene (goxA) to monitor biocontrol activity. Glucose oxidase catalyzes the oxygen-dependent oxidation of D-glucose to D-glucono-1,5-lactone and hydrogen peroxide; this latter compound is known to have an antifungal effect and activate the plant defence cascade, thus increasing resistance to pathogen attack. T. atroviride P1 transformants with various promoters gox were tested as seed coating treatments on bean seeds planted in soil infested with a soilborne fungal pathogen. Successively, the emergent leaves were inoculated with a foliar pathogen to determine the effect of the GOX transformants on biocontrol and resistance to pathogen attack. Inoculations with the P1-GOX transformants not only reduced disease symptoms caused by a soil pathogen, but also the lesions of various foliar pathogens applied far from the Trichoderma colonization, thus activating ISR. A similar approach is being use to genetically improve T. harzianum T22, a rhizosphere competent and commercially marketed strain not transformed yet, by using four different gox gene constructs under the control of constitutive and inducible promoters. Plasmids have been introduced in Trichoderma by protoplasts co-transformation. hygromicin resistant progeny selected, and mitotically stable transformants analysed to confirm the presence of the novel enzyme activity. Progenies are being tested for biocontrol ISR inducing activity.
文摘[ Objective ] The paper was to explore the induced resistance of tomato against gray mold （Botrytis cinerea） by salicylic acid. [ Method ] SA was used as an inducer to treat tomato seedlings, the effects of SA on mycelial diameter and spore germination of B. cinerea were studied, and the changes of 4 defense enzyme activities containing catalase （CAT）, peroxidase （POD）, polyphenol oxidase （PPO） and phenylalanine ammonia lyase （PAL）, as well as malondialdehyde （MDA） content during the production process of induced resistance were also measured. [ Result] SA had no inhibitory effect against spore germination and myce- lial growth of B. cinerea within the concentration range, and the relative induced effect had different degrees of improvement after treatment. The induced effect was the best as B. cinerea was challenged to inoculate at the third day after using 150 mg/L SA in tomato plants, and the duration of resistance was 10 -15 d. After treated by SA, CAT, POD, PPO and PAL first increased and then decreased in systemic induced resistance against B. cinerea, which were significantly higher than control. Meanwhile, MDA content showed ascendant trend in wavy line form. [ Conclusion ] The use of SA within a certain concentration range is safe; CAT, POD, PPO and PAL activities have positive correlation with induced resistance against B. cinerea, the increase of MDA content also has close relationship with the imvrovement of disease resistance.
文摘Oligosaccharins are potent biomolecules which activate defense responses and resistance in tobacco plants. However, it is not known the systemic behavior of defensive enzymes activated by these elicitors. In this work, the dynamic behavior of key defensive enzymes was evaluated in tobacco plant leaves previously treated through the roots with chitosan polymer (CH), chitosan (COS) and pectic (OGAS) oligosaccharides and Spermine (Sp). All macromolecules tested activated protein levels and defense enzymatic activity in tobacco leaves but with different response dynamics among them and depending on the biochemical variable evaluated. Defense response above control levels were detected since 12 hours after treatments and it consisted in a biphasic behavior with two peaks for PAL (EC 4.3.1.5) and β 1 - 3 glucanase (EC 3.2.1.6) enzymatic activities. The highest enzymatic levels for these enzymes were achieved at 48 hours in plantlets elicited with COS and at 72 hours for those plants treated with chitosan polymer, while the highest POD (EC 1.11.1.6) activity was detected with CH between 48 and 72 hours. These results demonstrated systemic defense activation by oligosaccharins in tobacco whose dynamic of defense response is affected by the kind of oligosaccharins tested. When applying OGAS by foliar spray on tobacco, systemic resistance against Phytoththora nicotianae was induced and plantlets were protected with the low concentration tested by 46% under the bioassays conditions performed. Moreover, enzymatic determinations on roots and leaves previous to plant-pathogen interaction showed increments above 30% of control levels for PAL and POD activities. It means that oligosaccharins activate local and systemic defense responses in plants in the absent of pathogen infection.
基金Gujarat Arts and Science College,India and Raiganj University,India for their support
文摘Induced systemic resistance(ISR)is a mechanism by which certain plant beneficial rhizobacteria and fungi produce immunity,which can stimulate crop growth and resilience against various phytopathogens,insects,and parasites.These beneficial rhizobacteria and fungi improve plant performance by regulating hormone signaling,including salicylic acid(SA),jasmonic acid(JA),prosystemin,pathogenesis-related gene 1,and ethylene(ET)pathways,which activate the gene expression of ISR,the synthesis of secondary metabolites,various enzymes,and volatile compounds that ultimately induce defense mechanisms in plant.To protect themselves from disease,plants have various advanced defense mechanisms in which local acquired resistance,systemic gene silencing,systemic wound response,systemic acquired resistance(SAR),and ISR are involved.Several rhizobacteria activate the SA-dependent SAR pathway by producing SA at the root’s surface.In contrast,other rhizobacteria can activate different signaling pathways independent of SA(SA-independent ISR pathways)such as those dependent on JA and ET signaling.The main objective of this review is to provide insight into the types of induced resistance utilized for plant defense.Further to this,the genetic approaches used to suppress disease-causing genes,i.e.,RNA interference and antisense RNA,which are still underutilized in sustainable agriculture,along with the current vision for virus-induced gene silencing are also discussed.
基金supported by a Joint Research Fund for Overseas,Hong Kong and Macao Scholars(31228018)to HJ and JGNIH grant(R01GM093008)to HJ+5 种基金NIH grant-(R01GM100364)a grant from Natural Science Foundation of Jiangsu Province of China(BK20141360)a PhD Programs Foundation of Ministry of Education of China(B0201300664)to HZan National Science Foundation grant(DBI-0743797)to WZa Talent Development Program of Wuhan,the municipal government of Wuhan,Hubei,China(2014070504020241)an internal research grant of Jianghan University,Wuhan,China to WZ
文摘Small RNAs play an important role in plant immune responses. However, their regulatory function in induced systemic resistance（ISR） is nascent. Bacillus cereus AR156 is a plant growth-promoting rhizobacterium that induces ISR in Arabidopsis against bacterial infection. Here,by comparing small RNA profiles of Pseudomonas syringae pv. tomato（Pst） DC3000-infected Arabidopsis with and without AR156 pretreatment, we identified a group of Arabidopsis micro RNAs（mi RNAs） that are differentially regulated by AR156 pretreatment. mi R825 and mi R825 are two mi RNA generated from a single mi RNA gene.Northern blot analysis indicated that they were significantly downregulated in Pst DC3000-infected plants pretreated with AR156, in contrast to the plants without AR156 pretreatment. mi R825 targets two ubiquitin-protein ligases,while mi R825 targets toll-interleukin-like receptor（TIR）-nucleotide binding site（NBS） and leucine-rich repeat（LRR）type resistance（R） genes. The expression of these target genes negatively correlated with the expression of mi R825 and mi R825. Moreover, transgenic plants showing reduced expression of mi R825 and mi R825 displayed enhanced resistance to Pst DC3000 infection, whereas transgenic plants overexpressing mi R825 and mi R825 were more susceptible. Taken together, our data indicates that Bacillus cereus AR156 pretreatment primes ISR to Pst infection by suppressing mi R825 and mi R825 and activating the defense related genes they targeted.
基金Supported by a Rothamsted International Fellowship to LIU ShengYi,a Royal Society China Fellowship to LIU RenHu,the UK Biotechnology and Biological Sciences Research Council(BBSRC),Department for Environment,Food and Rural Affairs(Defra),the Chadacre Trust,UK and the Ministry of Agriculture,P.R.China
文摘Brassica napus(cv.Madrigal)seedlings pre-treated with ascospores of Leptosphaeria biglobosa or foliar sprays of either acibenzolar-S-methyl(ASM)or menadione sodium bisulphite(MSB)were chal- lenge inoculated with L.maculans ascospores and assessed for phoma leaf spot development and tissue morphology and gene expression responses to infection.Rates of increase in phoma leaf spot area 8―21 d after challenge inoculation were significantly greater on water pre-treated plants than on plants pre-treated with L.biglobosa,ASM or MSB on both pre-treated leaves(local effect)and younger leaves without pre-treatment(systemic effect).Ninety-six h after challenge inoculation,the invasive hyphae of L.maculans were encircled by rings of necrotic mesophyll cells on leaves pre-treated with L. biglobosa,ASM or MSB but not those pre-treated with water.Quantification of transcript levels of genes commonly used as markers of the major defence signalling pathways(PDF1.2,PR-1,NPR1,APX, CHB4)0–96 h after L.maculans challenge inoculation showed expression patterns indicating prefer- ential activation of the jasmonate/ethylene pathway and involved induction of NPR1 locally and sys- temically in leaves of plants pre-treated with L.biglobosa ascospores.
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).
