The cereal cyst nematode（CCN, Heteroder aavenae） causes serious yield loss on cereal crops, especially wheat, worldwide. Daxing population in Beijing City and Huangyuan population in Qinghai Province, China, are two...The cereal cyst nematode（CCN, Heteroder aavenae） causes serious yield loss on cereal crops, especially wheat, worldwide. Daxing population in Beijing City and Huangyuan population in Qinghai Province, China, are two CCN populations. In this study, the CCN pathotypes of Daxing and Huangyuan populations were characterized by tests on 23 standard ＂International Test Assortment＂ with the local species Wenmai 19 as the susceptible control. Tested materials were grouped by three nematode populations＇ virulence on resistant genes（Rha1, Rha2, Rha3, Cre1） and nonresistant genes, varieties and lines. Both Daxing and Huangyuan populations were avirulent to Ortolan（Ha1）. Barley cvs. Ortolan, Siri, Morocco, Bajo Aragon 1-1, and Martin 403-2 were all resistant to both populations. Cultivars Herta, Harlan 43 and wheat Iskamish-K-2-light were all susceptible to Huangyuan population, all of them, however, were resistant to Daxing population. The other five oats were all resistant to the two tested CCN populations. Except Iskamisch K-2-light, all the other wheat cultivars（Capa, Loros×Koga, AUS 10894, and Psathias） were susceptible to Daxing population. Because the pathotypes of the two tested CCN populations in Beijing and Qinghai were not identical to any of the 13 pathotypes previously characterized by the test assortment, we classified Daxing and Huangyuan populations as the new pathotypes, named Ha91.展开更多
The root-knot nematode Meloidogyne graminicola, which is distributed worldwide, is considered a major constraint on rice production in Asia. The present study used the root gall index and number of nematodes inside th...The root-knot nematode Meloidogyne graminicola, which is distributed worldwide, is considered a major constraint on rice production in Asia. The present study used the root gall index and number of nematodes inside the roots to evaluate resistance/susceptibility to M. graminicola in different subpopulations of Oryza sativa （aus, hybrid aus, indica, hybrid indica, temperate japonica, tropical japonica）. Nematode development in highly resistant varieties was also evaluated. Analyses of randomly selected 35 varieties showed the number of M. graminicola nematodes inside the roots correlated very strongly （r=0.87, P≤0.05） with the nematode gall index, and the results from pot and field experiments revealed similar rankings of the varieties for resistance/susceptibility. Among the 136 tested varieties, temperate japonica displayed the highest gall index, followed by tropical japonica, indica, hybrid indica, aus, and hybrid aus. Zhonghua 11 （aus）, Shenliangyou 1 （hybrid aus） and Cliangyou 4418 （hybrid indica） were highly resistant to M. graminicola under both pot and field conditions. Further examination of nematode development suggested that compared to susceptible rice, M. graminicola penetrated less often into highly resistant varieties and more frequently failed to develop into females. The promising varieties found in the present research might be useful for the breeding of hybrid rice in China and for the further development of practical nematode management measures.展开更多
The potato cyst nematodes(PCN) Globodera rostochiensis(Wollenweber) Skarbilovich,1959 is considered the most damaging nematode pest of potato worldwide that causes significant yield losses,and this nematode is recogni...The potato cyst nematodes(PCN) Globodera rostochiensis(Wollenweber) Skarbilovich,1959 is considered the most damaging nematode pest of potato worldwide that causes significant yield losses,and this nematode is recognized and listed as a quarantine nematode in many countries(EPPO 2017).China is currently the largest producer of potato in the world.展开更多
The resistance of soybean(Glycine max(L.) Merr.) to soybean cyst nematode(SCN, Heterodera glycines Ichinohe), which is a devastating pathogen in soybean production and causes a large quantity of annual yield loss worl...The resistance of soybean(Glycine max(L.) Merr.) to soybean cyst nematode(SCN, Heterodera glycines Ichinohe), which is a devastating pathogen in soybean production and causes a large quantity of annual yield loss worldwide, can shift during the long-term interaction and domestication. It is vital to identify more new resistance genetic sources for identification of novel genes underlying resistance to SCN for management of this pathogen. In the present study, first, two ethane methylsulfonate-mutagenesis soybean M2 populations of PI 437654, which shows a broad resistance to almost all of SCN races, and Zhonghuang 13, which is a soybean cultivar in China conferring strong resistance to lodging, were developed. Many types of morphological phenotypes such as four-and five-leaflet leaves were observed from these two soybean M2 populations. Second, 13 mutants were identified and confirmed to exhibit alteration of resistance to SCN race 4 through the forward genetic screening of 400 mutants of the PI 437654 M2 population, the rate of mutants with alteration of SCNinfection phenotype is 3.25%. Third, these identified mutants were further verified not to show any changes in the genomic sequences of the three known SCN-resistant genes, GmSHMT08, GmSNAP18 and GmSANP11, compared to the wildtype soybean; and all of them were still resistant to SCN race 3 similar to the wild-type soybean. Taken together, we can conclude that the 13 mutants identified in the present study carry the mutations of the new gene(s) which contribute(s) to the resistance to SCN race 4 in PI 437654 and can be potentially used as the genetic soybean sources to further identify the novel SCN-resistant gene(s).展开更多
The potato rot nematode(Ditylenchus destructor) is a very economically important nematode in agronomic and horticultural plants worldwide. In this study, 43 populations of D. destructor were collected from different h...The potato rot nematode(Ditylenchus destructor) is a very economically important nematode in agronomic and horticultural plants worldwide. In this study, 43 populations of D. destructor were collected from different hosts across China, including 37 populations from Chinese herbal medicine plants. Obtained sequences of ITS-rDNA and D2–D3of 28S-rDNA genes of D. destructor were compared and analyzed. Nine types of significant length variations in ITS sequences were observed among all populations. The differences in ITS1 length were mainly caused by the presence of repetitive elements with substantial base substitutions. Reconstructions of ITS1 secondary structures showed that the minisatellites formed a stem structure. Ten haplotypes were observed in all populations based on mutations and variations of helix H9. Among them, 3 known haplotypes(A–C) were found in 7 populations isolated from potato,sweet potato, and Codonopsis pilosula, and 7 unique haplotypes were found in other 36 populations collected from C. pilosula and Angelica sinensis compared with 7 haplotypes(A–G) according to Subbotin' system. These unique haplotypes were different from haplotypes A–G, and we named them as haplotypes H–N. The present results showed that a total of 14 haplotypes(A–N) of ITS-rDNA have been found in D. destructor. Phylogenetic analyses of ITSrDNA and D2–D3 showed that all populations of D. destructor were clustered into two major clades: one clade only containing haplotype A from sweet potato and the other containing haplotypes B–N from other plants. For further verification, PCR-ITS-RFLP profiles were conducted on 7 new haplotypes. Collectively, our study suggests that D. destructor populations on Chinese medicinal materials are very different from those on other hosts and this work provides a paradigm for relevant researches.展开更多
The sugar beet cyst nematode,Heterodera schachtii,is a major parasite of sugar beet which has been recognized and listed as a quarantine nematode in China and more than 20 countries and regions worldwide.A survey for ...The sugar beet cyst nematode,Heterodera schachtii,is a major parasite of sugar beet which has been recognized and listed as a quarantine nematode in China and more than 20 countries and regions worldwide.A survey for important nematodes was undertaken in the sugar beet planting area of China during 2015-2018,and numerous cysts were collected from sugar beet fields in Xinyuan County,Xinjiang Uygur Autonomous Region of China.The observations of morphological and morphometric characteristics revealed that cysts,vulval cones and second-stage juveniles of the Xinjiang population were in the same range of each other and within those of other reported H.schachtii populations.Molecular analysis of rDNA-ITS,28S-D2/D3 and mtDNA cytochrome c oxidase subunit 1(COI)gene sequences suggested that the Xinjiang population clustered in a branch with those foreign populations,and the sequence similarity was as high as 99.81-100%.Moreover,this result was confirmed by PCR assay with species-specific primer SHF6 and rDNA2 of H.schachtii,and the pathogenicity test confirmed successful Xinjiang population reproduction in both plant hosts.In conclusion,based on morphological and molecular characterization,this study confirmed that the cyst nematode population collected from sugar beet fields in Xinjiang is H.schachtii.As far as we know,this is the first report of H.schachtii on sugar beets in Xinjiang,China.展开更多
The root-knot nematode Meloidogyne graminicola is considered one of the most devastating pests in rice-producing areas,and nematicides are neither ecofriendly nor cost effective.More acceptable biological agents are r...The root-knot nematode Meloidogyne graminicola is considered one of the most devastating pests in rice-producing areas,and nematicides are neither ecofriendly nor cost effective.More acceptable biological agents are required for controlling this destructive pathogen.In this study,the biocontrol potential of Aspergillus welwitschiae AW2017 was investigated in laboratory and greenhouse experiments.The in vitro ovicidal and larvicidal activities of A.welwitschiae metabolites were tested on M.graminicola in laboratory experiments.The effect of A.welwitschiae on the attraction of M.graminicola to rice and the infection of rice by M.graminicola was evaluated in a greenhouse.The bioagent AW2017 displayed good nematicidal potential via its ovicidal and larvicidal action.The best larvicidal activity was observed at a concentration of 5×AW2017,which caused an 86.2%mortality rate at 48 h post inoculation.The highest ovicidal activity was recorded at a concentration of 5×AW2017,which resulted in an approximately 47.3%reduction in egg hatching after 8 d compared to the control.Under greenhouse conditions,the application of A.welwitschiae significantly reduced the root galls and nematodes in rice roots compared to the control.At a concentration of 5×AW2017,juveniles and root galls in rice roots at 14 d post inoculation(dpi)were reduced by 24.5 and 40.5%,respectively.In addition,the attraction of M.graminicola to rice roots was significantly decreased in the AW2017 treatment,and the development of nematodes in the AW2017-treated plants was slightly delayed compared with that in the PDB-treated control plants.The results indicate that A.welwitschiae is a potential biological control agent against M.graminicola in rice.展开更多
Potassium(K),an important nutrient element,can improve the stress resistance/tolerance of crops.The application of K in resisting plant-parasitic nematodes shows that the K treatment can reduce the occurrence of nemat...Potassium(K),an important nutrient element,can improve the stress resistance/tolerance of crops.The application of K in resisting plant-parasitic nematodes shows that the K treatment can reduce the occurrence of nematode diseases and increase crop yield.However,data on K_(2)SO_(4)induced rice resistance against the root-knot nematode Meloidogyne graminicola are still lacking.In this work,K_(2)SO_(4)treatment reduced galls and nematodes in rice plants and delayed the development of nematodes.Rather than affecting the attractiveness of roots to nematodes and the morphological phenotype of giant cells at feeding sites,such an effect is achieved by rapidly priming hydrogen peroxide(H_(2)O_(2))accumulation and increasing callose deposition.Meanwhile,galls and nematodes in rice roots were more in the potassium channel OsAKT11 and transporter OsHAK5 gene-deficient plants than in wild-type,while the K_(2)SO_(4)-induced resistance showed weaker in the defective plants.In addition,during the process of nematode infection,the expression of jasmonic acid(JA)/ethylene(ET)/brassinolide(BR)signaling pathway-related genes and pathogenesis-related(PR)genes OsPR1 a/OsPR1 b was up-regulated in rice after K_(2)SO_(4)treatment.In conclusion,K_(2)SO_(4)induced rice resistance against M.graminicola.The mechanism of inducing resistance was to prime the basal defense and required the participation of the K^(+)channel and transporter in rice.These laid a foundation for further study on the mechanism of rice defense against nematodes and the rational use of potassium fertilizer on improving rice resistance against nematodes in the field.展开更多
Heterodera avenae （cereal cyst nematode, CCN） infects many cereal crops and causes serious yield losses worldwide. Interaction studies investigating H. avenae and its hosts are still in their infancy. In this study,...Heterodera avenae （cereal cyst nematode, CCN） infects many cereal crops and causes serious yield losses worldwide. Interaction studies investigating H. avenae and its hosts are still in their infancy. In this study, a barley model plant, the Hordeum vulgare cultivar Golden Promise, was investigated for its potential as a candidate model host to study its inter- action with H. avenae. CCN-infective juveniles were attracted by the root tips and gathered around the root elongation zones of Golden Promise on 0.7% water agar plates. The juveniles invaded the roots and developed successfully until maturation at 40 days after inoculation in sterile sand soil. The cryotomy and syncytium measurements indicated that the syncytia enlarged gradually throughout the development of the nematodes and caused the corresponding root regions to swell obviously. Quantitative real-time PCR analysis showed that the down-regulation of defence-related barley genes and up-regulation Of development-related barley ger^es contribute to the understanding of compatible interaction between H. avenae and Golden Promise. Barley stripe mosaic virus （BSMV） virus-induced gene silencing （VIGS） can be used in the roots of Golden Promise. In conclusion, the Hordeum vulgare cultivar Golden Promise is a suitable candidate model host for interaction studies with Heterodera avenae. The studies presented above document the first CCN host that no.t only has published genome context but also be compatible to BSMV VIGS.展开更多
For sedentary endo-parasitic nematodes, parasitism genes encoding secretory protein expressed in the subventral glands cells always play an important role during the early parasitic process. A new acid phosphatase ge...For sedentary endo-parasitic nematodes, parasitism genes encoding secretory protein expressed in the subventral glands cells always play an important role during the early parasitic process. A new acid phosphatase gene （Ha-acp1） expressed in the subventral glands of the cereal cyst nematode （Heterodera avenae） was cloned and the characteristics of the gene were analyzed. Results showed that the gene had a putative signal peptide for secretion and in situ hybridization showed that the transcripts of Ha-acp1 accumulated speciifcally in the subventral gland cells of H. avenae. Southern blot analysis suggested that Ha-acp1 belonged to a multigene family. RT-PCR analysis indicated that this transcription was strong at the pre-parasitic juveniles. Knocking down Ha-acp1 using RNA interference technology could reduce nematode infectivity by 50%, and suppress the development of cyst. Results indicated that Ha-acp1 could play an important role in destroying the defense system of host plants.展开更多
Soybean cyst nematode(SCN, Heterodera glycines(I.)) is one of the most important soil-borne pathogens for soybeans. In plant parasitic nematodes, including SCN, lysozyme plays important roles in the innate defense sys...Soybean cyst nematode(SCN, Heterodera glycines(I.)) is one of the most important soil-borne pathogens for soybeans. In plant parasitic nematodes, including SCN, lysozyme plays important roles in the innate defense system. In this study, two new lysozyme genes(Hg-lys1 and Hg-lys2) from SCN were cloned and characterized. The in situ hybridization analyses indicated that the transcripts of both Hg-lys1 and Hg-lys2 accumulated in the intestine of SCN. The q RT-PCR analyses showed that both Hg-lys1 and Hg-lys2 were upregulated after SCN second stage juveniles(J2 s) were exposed to the Grampositive bacteria Bacillus thuringiensis, Bacillus subtilis or Staphylococcus aureus. Knockdown of the identified lysozyme genes by in vitro RNA interference caused a significant decrease in the survival rate of SCN. All of the obtained results indicate that lysozyme is very important in the defense system and survival of SCN.展开更多
In recent years,Meloidogyne enterolobii has emerged as a major parasitic nematode infesting many plants in tropical or subtropical areas.However,the regions of potential distribution and the main contributing environm...In recent years,Meloidogyne enterolobii has emerged as a major parasitic nematode infesting many plants in tropical or subtropical areas.However,the regions of potential distribution and the main contributing environmental variables for this nematode are unclear.Under the current climate scenario,we predicted the potential geographic distributions of M.enterolobii worldwide and in China using a Maximum Entropy(MaxEnt)model with the occurrence data of this species.Furthermore,the potential distributions of M.enterolobii were projected under three future climate scenarios(BCC-CSM2-MR,CanESM5 and CNRM-CM6-1)for the periods 2050s and 2090s.Changes in the potential distribution were also predicted under different climate conditions.The results showed that highly suitable regions for M.enterolobii were concentrated in Africa,South America,Asia,and North America between latitudes 30°S to 30°N.Bio16(precipitation of the wettest quarter),bio10(mean temperature of the warmest quarter),and bio11(mean temperature of the coldest quarter)were the variables contributing most in predicting potential distributions of M.enterolobii.In addition,the potential suitable areas for M.enterolobii will shift toward higher latitudes under future climate scenarios.This study provides a theoretical basis for controlling and managing this nematode.展开更多
基金financially supported by the National Natural Science Foundation of China (31171827)the National Key Basic Research Program of China (973 Program,2013CB127502)
文摘The cereal cyst nematode（CCN, Heteroder aavenae） causes serious yield loss on cereal crops, especially wheat, worldwide. Daxing population in Beijing City and Huangyuan population in Qinghai Province, China, are two CCN populations. In this study, the CCN pathotypes of Daxing and Huangyuan populations were characterized by tests on 23 standard ＂International Test Assortment＂ with the local species Wenmai 19 as the susceptible control. Tested materials were grouped by three nematode populations＇ virulence on resistant genes（Rha1, Rha2, Rha3, Cre1） and nonresistant genes, varieties and lines. Both Daxing and Huangyuan populations were avirulent to Ortolan（Ha1）. Barley cvs. Ortolan, Siri, Morocco, Bajo Aragon 1-1, and Martin 403-2 were all resistant to both populations. Cultivars Herta, Harlan 43 and wheat Iskamish-K-2-light were all susceptible to Huangyuan population, all of them, however, were resistant to Daxing population. The other five oats were all resistant to the two tested CCN populations. Except Iskamisch K-2-light, all the other wheat cultivars（Capa, Loros×Koga, AUS 10894, and Psathias） were susceptible to Daxing population. Because the pathotypes of the two tested CCN populations in Beijing and Qinghai were not identical to any of the 13 pathotypes previously characterized by the test assortment, we classified Daxing and Huangyuan populations as the new pathotypes, named Ha91.
基金supported by the grants from the National Natural Science Foundation of China (31571986)the National Basic Research Programme of China (2013CB127502)
文摘The root-knot nematode Meloidogyne graminicola, which is distributed worldwide, is considered a major constraint on rice production in Asia. The present study used the root gall index and number of nematodes inside the roots to evaluate resistance/susceptibility to M. graminicola in different subpopulations of Oryza sativa （aus, hybrid aus, indica, hybrid indica, temperate japonica, tropical japonica）. Nematode development in highly resistant varieties was also evaluated. Analyses of randomly selected 35 varieties showed the number of M. graminicola nematodes inside the roots correlated very strongly （r=0.87, P≤0.05） with the nematode gall index, and the results from pot and field experiments revealed similar rankings of the varieties for resistance/susceptibility. Among the 136 tested varieties, temperate japonica displayed the highest gall index, followed by tropical japonica, indica, hybrid indica, aus, and hybrid aus. Zhonghua 11 （aus）, Shenliangyou 1 （hybrid aus） and Cliangyou 4418 （hybrid indica） were highly resistant to M. graminicola under both pot and field conditions. Further examination of nematode development suggested that compared to susceptible rice, M. graminicola penetrated less often into highly resistant varieties and more frequently failed to develop into females. The promising varieties found in the present research might be useful for the breeding of hybrid rice in China and for the further development of practical nematode management measures.
基金supported by the National Natural Science Foundation of China (32072398)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences, China (ASTIP-02-IPP-04)。
文摘The potato cyst nematodes(PCN) Globodera rostochiensis(Wollenweber) Skarbilovich,1959 is considered the most damaging nematode pest of potato worldwide that causes significant yield losses,and this nematode is recognized and listed as a quarantine nematode in many countries(EPPO 2017).China is currently the largest producer of potato in the world.
基金financially supported by the Innovation Program and Youth elite Program of Chinese Academy of Agricultural Sciencesthe Special Fund for Agro-scientific Research in the Public Interest of China(201503114)
文摘The resistance of soybean(Glycine max(L.) Merr.) to soybean cyst nematode(SCN, Heterodera glycines Ichinohe), which is a devastating pathogen in soybean production and causes a large quantity of annual yield loss worldwide, can shift during the long-term interaction and domestication. It is vital to identify more new resistance genetic sources for identification of novel genes underlying resistance to SCN for management of this pathogen. In the present study, first, two ethane methylsulfonate-mutagenesis soybean M2 populations of PI 437654, which shows a broad resistance to almost all of SCN races, and Zhonghuang 13, which is a soybean cultivar in China conferring strong resistance to lodging, were developed. Many types of morphological phenotypes such as four-and five-leaflet leaves were observed from these two soybean M2 populations. Second, 13 mutants were identified and confirmed to exhibit alteration of resistance to SCN race 4 through the forward genetic screening of 400 mutants of the PI 437654 M2 population, the rate of mutants with alteration of SCNinfection phenotype is 3.25%. Third, these identified mutants were further verified not to show any changes in the genomic sequences of the three known SCN-resistant genes, GmSHMT08, GmSNAP18 and GmSANP11, compared to the wildtype soybean; and all of them were still resistant to SCN race 3 similar to the wild-type soybean. Taken together, we can conclude that the 13 mutants identified in the present study carry the mutations of the new gene(s) which contribute(s) to the resistance to SCN race 4 in PI 437654 and can be potentially used as the genetic soybean sources to further identify the novel SCN-resistant gene(s).
基金supported by the National Natural Science Foundation of China (31760507)the National Key R&D Program of China (2018YFC1706301)。
文摘The potato rot nematode(Ditylenchus destructor) is a very economically important nematode in agronomic and horticultural plants worldwide. In this study, 43 populations of D. destructor were collected from different hosts across China, including 37 populations from Chinese herbal medicine plants. Obtained sequences of ITS-rDNA and D2–D3of 28S-rDNA genes of D. destructor were compared and analyzed. Nine types of significant length variations in ITS sequences were observed among all populations. The differences in ITS1 length were mainly caused by the presence of repetitive elements with substantial base substitutions. Reconstructions of ITS1 secondary structures showed that the minisatellites formed a stem structure. Ten haplotypes were observed in all populations based on mutations and variations of helix H9. Among them, 3 known haplotypes(A–C) were found in 7 populations isolated from potato,sweet potato, and Codonopsis pilosula, and 7 unique haplotypes were found in other 36 populations collected from C. pilosula and Angelica sinensis compared with 7 haplotypes(A–G) according to Subbotin' system. These unique haplotypes were different from haplotypes A–G, and we named them as haplotypes H–N. The present results showed that a total of 14 haplotypes(A–N) of ITS-rDNA have been found in D. destructor. Phylogenetic analyses of ITSrDNA and D2–D3 showed that all populations of D. destructor were clustered into two major clades: one clade only containing haplotype A from sweet potato and the other containing haplotypes B–N from other plants. For further verification, PCR-ITS-RFLP profiles were conducted on 7 new haplotypes. Collectively, our study suggests that D. destructor populations on Chinese medicinal materials are very different from those on other hosts and this work provides a paradigm for relevant researches.
基金financially supported by the National Natural Science Foundation of China (31972247)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences (ASTIP-02-IPP-15)+1 种基金the Open Fund of Key Laboratory of Integrated Pest Management on Crop in Northwestern Oasis, Ministry of Agriculture and Rural Affairs (KFJJ202101)the China Agriculture Research System of MOF and MARA (CARS170307)
文摘The sugar beet cyst nematode,Heterodera schachtii,is a major parasite of sugar beet which has been recognized and listed as a quarantine nematode in China and more than 20 countries and regions worldwide.A survey for important nematodes was undertaken in the sugar beet planting area of China during 2015-2018,and numerous cysts were collected from sugar beet fields in Xinyuan County,Xinjiang Uygur Autonomous Region of China.The observations of morphological and morphometric characteristics revealed that cysts,vulval cones and second-stage juveniles of the Xinjiang population were in the same range of each other and within those of other reported H.schachtii populations.Molecular analysis of rDNA-ITS,28S-D2/D3 and mtDNA cytochrome c oxidase subunit 1(COI)gene sequences suggested that the Xinjiang population clustered in a branch with those foreign populations,and the sequence similarity was as high as 99.81-100%.Moreover,this result was confirmed by PCR assay with species-specific primer SHF6 and rDNA2 of H.schachtii,and the pathogenicity test confirmed successful Xinjiang population reproduction in both plant hosts.In conclusion,based on morphological and molecular characterization,this study confirmed that the cyst nematode population collected from sugar beet fields in Xinjiang is H.schachtii.As far as we know,this is the first report of H.schachtii on sugar beets in Xinjiang,China.
基金financially supported by grants from the National Key Research and Development Program (2018YFD0201202 & 2017YFD0201102)the National Natural Science Foundation of China (31571986)
文摘The root-knot nematode Meloidogyne graminicola is considered one of the most devastating pests in rice-producing areas,and nematicides are neither ecofriendly nor cost effective.More acceptable biological agents are required for controlling this destructive pathogen.In this study,the biocontrol potential of Aspergillus welwitschiae AW2017 was investigated in laboratory and greenhouse experiments.The in vitro ovicidal and larvicidal activities of A.welwitschiae metabolites were tested on M.graminicola in laboratory experiments.The effect of A.welwitschiae on the attraction of M.graminicola to rice and the infection of rice by M.graminicola was evaluated in a greenhouse.The bioagent AW2017 displayed good nematicidal potential via its ovicidal and larvicidal action.The best larvicidal activity was observed at a concentration of 5×AW2017,which caused an 86.2%mortality rate at 48 h post inoculation.The highest ovicidal activity was recorded at a concentration of 5×AW2017,which resulted in an approximately 47.3%reduction in egg hatching after 8 d compared to the control.Under greenhouse conditions,the application of A.welwitschiae significantly reduced the root galls and nematodes in rice roots compared to the control.At a concentration of 5×AW2017,juveniles and root galls in rice roots at 14 d post inoculation(dpi)were reduced by 24.5 and 40.5%,respectively.In addition,the attraction of M.graminicola to rice roots was significantly decreased in the AW2017 treatment,and the development of nematodes in the AW2017-treated plants was slightly delayed compared with that in the PDB-treated control plants.The results indicate that A.welwitschiae is a potential biological control agent against M.graminicola in rice.
基金supported by the Natural Science Foundation of China(32172382,31801716,and 31571986)the National Key Research and Development Program of China(2021YFC2600404)the Scientific Research Project of Hunan Provincial Department of Education of China(19B259)。
文摘Potassium(K),an important nutrient element,can improve the stress resistance/tolerance of crops.The application of K in resisting plant-parasitic nematodes shows that the K treatment can reduce the occurrence of nematode diseases and increase crop yield.However,data on K_(2)SO_(4)induced rice resistance against the root-knot nematode Meloidogyne graminicola are still lacking.In this work,K_(2)SO_(4)treatment reduced galls and nematodes in rice plants and delayed the development of nematodes.Rather than affecting the attractiveness of roots to nematodes and the morphological phenotype of giant cells at feeding sites,such an effect is achieved by rapidly priming hydrogen peroxide(H_(2)O_(2))accumulation and increasing callose deposition.Meanwhile,galls and nematodes in rice roots were more in the potassium channel OsAKT11 and transporter OsHAK5 gene-deficient plants than in wild-type,while the K_(2)SO_(4)-induced resistance showed weaker in the defective plants.In addition,during the process of nematode infection,the expression of jasmonic acid(JA)/ethylene(ET)/brassinolide(BR)signaling pathway-related genes and pathogenesis-related(PR)genes OsPR1 a/OsPR1 b was up-regulated in rice after K_(2)SO_(4)treatment.In conclusion,K_(2)SO_(4)induced rice resistance against M.graminicola.The mechanism of inducing resistance was to prime the basal defense and required the participation of the K^(+)channel and transporter in rice.These laid a foundation for further study on the mechanism of rice defense against nematodes and the rational use of potassium fertilizer on improving rice resistance against nematodes in the field.
基金supported by the National Natural Science Foundation of China(31571988)the Special Fund for Agro-scientific Research in the Public Interest, China (201503114)the National Key Basic Research Program of China (973 Program, 2013CB127502)
文摘Heterodera avenae （cereal cyst nematode, CCN） infects many cereal crops and causes serious yield losses worldwide. Interaction studies investigating H. avenae and its hosts are still in their infancy. In this study, a barley model plant, the Hordeum vulgare cultivar Golden Promise, was investigated for its potential as a candidate model host to study its inter- action with H. avenae. CCN-infective juveniles were attracted by the root tips and gathered around the root elongation zones of Golden Promise on 0.7% water agar plates. The juveniles invaded the roots and developed successfully until maturation at 40 days after inoculation in sterile sand soil. The cryotomy and syncytium measurements indicated that the syncytia enlarged gradually throughout the development of the nematodes and caused the corresponding root regions to swell obviously. Quantitative real-time PCR analysis showed that the down-regulation of defence-related barley genes and up-regulation Of development-related barley ger^es contribute to the understanding of compatible interaction between H. avenae and Golden Promise. Barley stripe mosaic virus （BSMV） virus-induced gene silencing （VIGS） can be used in the roots of Golden Promise. In conclusion, the Hordeum vulgare cultivar Golden Promise is a suitable candidate model host for interaction studies with Heterodera avenae. The studies presented above document the first CCN host that no.t only has published genome context but also be compatible to BSMV VIGS.
基金the fund of the National Basic Research Program of China (2013CB127502)the Special Fund for Agro-Scientific Research in the Public Interest,China (200903040)the National Natural Science Foundation of China (31201493)
文摘For sedentary endo-parasitic nematodes, parasitism genes encoding secretory protein expressed in the subventral glands cells always play an important role during the early parasitic process. A new acid phosphatase gene （Ha-acp1） expressed in the subventral glands of the cereal cyst nematode （Heterodera avenae） was cloned and the characteristics of the gene were analyzed. Results showed that the gene had a putative signal peptide for secretion and in situ hybridization showed that the transcripts of Ha-acp1 accumulated speciifcally in the subventral gland cells of H. avenae. Southern blot analysis suggested that Ha-acp1 belonged to a multigene family. RT-PCR analysis indicated that this transcription was strong at the pre-parasitic juveniles. Knocking down Ha-acp1 using RNA interference technology could reduce nematode infectivity by 50%, and suppress the development of cyst. Results indicated that Ha-acp1 could play an important role in destroying the defense system of host plants.
基金supported the Central Public-Interest Scientific Institution Basal Research Fund, China (Y2019GH03)the Special Fund for Agro-Scientific Research in the Public Interest of China (210503114)SINOGRAIN Ⅱ (CHN-17/0019): Technological Innovation to Support Environmentally-Friendly Food Production and Food Safety Under a Changing Climate-Opportunities and Challenges for Norway-China Cooperation
文摘Soybean cyst nematode(SCN, Heterodera glycines(I.)) is one of the most important soil-borne pathogens for soybeans. In plant parasitic nematodes, including SCN, lysozyme plays important roles in the innate defense system. In this study, two new lysozyme genes(Hg-lys1 and Hg-lys2) from SCN were cloned and characterized. The in situ hybridization analyses indicated that the transcripts of both Hg-lys1 and Hg-lys2 accumulated in the intestine of SCN. The q RT-PCR analyses showed that both Hg-lys1 and Hg-lys2 were upregulated after SCN second stage juveniles(J2 s) were exposed to the Grampositive bacteria Bacillus thuringiensis, Bacillus subtilis or Staphylococcus aureus. Knockdown of the identified lysozyme genes by in vitro RNA interference caused a significant decrease in the survival rate of SCN. All of the obtained results indicate that lysozyme is very important in the defense system and survival of SCN.
基金supported by the Key R&D Project of Shaanxi Province,China(2020ZDLNY07-06)the Science and Technology Program of Shaanxi Academy of Sciences(2022k-11).
文摘In recent years,Meloidogyne enterolobii has emerged as a major parasitic nematode infesting many plants in tropical or subtropical areas.However,the regions of potential distribution and the main contributing environmental variables for this nematode are unclear.Under the current climate scenario,we predicted the potential geographic distributions of M.enterolobii worldwide and in China using a Maximum Entropy(MaxEnt)model with the occurrence data of this species.Furthermore,the potential distributions of M.enterolobii were projected under three future climate scenarios(BCC-CSM2-MR,CanESM5 and CNRM-CM6-1)for the periods 2050s and 2090s.Changes in the potential distribution were also predicted under different climate conditions.The results showed that highly suitable regions for M.enterolobii were concentrated in Africa,South America,Asia,and North America between latitudes 30°S to 30°N.Bio16(precipitation of the wettest quarter),bio10(mean temperature of the warmest quarter),and bio11(mean temperature of the coldest quarter)were the variables contributing most in predicting potential distributions of M.enterolobii.In addition,the potential suitable areas for M.enterolobii will shift toward higher latitudes under future climate scenarios.This study provides a theoretical basis for controlling and managing this nematode.
