Gray leaf spot(GLS),caused by Cercospora zeae-maydis,is an important foliar disease of maize(Zea mays L.)worldwide,resistance to which is controlled by multiple quantitative trait loci(QTL).To gain insights into the g...Gray leaf spot(GLS),caused by Cercospora zeae-maydis,is an important foliar disease of maize(Zea mays L.)worldwide,resistance to which is controlled by multiple quantitative trait loci(QTL).To gain insights into the genetic architecture underlying the resistance to this disease,an association mapping population consisting of 161 inbred lines was evaluated for resistance to GLS in a plant pathology nursery at Shenyang in 2010 and 2011.Subsequently,a genome-wide association study,using 41,101 single-nucleotide polymorphisms(SNPs),identified 51 SNPs significantly(P<0.001)associated with GLS resistance,which could be converted into 31 QTL.In addition,three candidate genes related to plant defense were identified,including nucleotidebinding-site/leucine-rich repeat,receptor-like kinase genes similar to those involved in basal defense.Two genic SNPs,PZE-103142893 and PZE-109119001,associated with GLS resistance in chromosome bins 3.07 and 9.07,can be used for marker-assisted selection(MAS)of GLS resistance.These results provide an important resource for developing molecular markers closely linked with the target trait,enhancing breeding efficiency.展开更多
Two fragments SCS362o and SCS3580 of the co-dominant marker OPS0362o&580 that were linked to the resistance gene of soybean frog-eye leaf spot have been completely sequenced. A significant insertion of 30 bp is th...Two fragments SCS362o and SCS3580 of the co-dominant marker OPS0362o&580 that were linked to the resistance gene of soybean frog-eye leaf spot have been completely sequenced. A significant insertion of 30 bp is the main reason of the polymorphism between the two fragments. The results of Southern hybridization indicate that SCS362o derives from a single- or low-copy sequence and can be used as an RFLP probe. A co-dominant SCAR marker SCSSeao&sao has been developed based on the sequences. The segregation of SCS362o&58o is similar to that of RAPD marker OPS03620&580. Significant polymorphism has been shown between resistant and susceptible genotypes when 62 soybean genotypes were surveyed for the SCAR marker. Therefore, the marker can be used in the resistance breeding of soybean frog-eye leaf spot by marker-assisted selection.展开更多
Cercospora leaf spot is fast turning into a critically important disease in Zimbabwe.The disease is caused by Cercospora coffeicola which significantly reduces productivity and quality of coffee.Disturbingly,optimum s...Cercospora leaf spot is fast turning into a critically important disease in Zimbabwe.The disease is caused by Cercospora coffeicola which significantly reduces productivity and quality of coffee.Disturbingly,optimum sporulation of Cercospora coffeicola in culture remains a limiting factor for microbial analysis and quantitative studies of Cercospora leaf spot.Faced with this challenge,an in-vitro study was conducted at Coffee Research Institute,Manicaland,Zimbabwe to examine growth of Cercospora coffeicola in different nutrient media and to determine the best media for Cercospora coffeicola analysis.Six nutrient media were assessed(corn meal agar,oat meal agar,Czapek Dox agar,malt extract agar,yeast extract agar and potato dextrose agar)for the growth of Cercospora coffeicola.The laboratory-based experiment was duplicated,laid out in a Completely Randomized Design,replicated three times and based on Cercospora coffeicola nutrient inoculation.Data were collected on radial growth,colour and texture of mycelium at 3 and 6 days after inoculation.There were significant differences(p<0.05)in the growth of Cercospora coffeicola in media after 3 and 6 days.Malt extract agar had the greatest radial growth(34 mm and 32 mm)of Cercospora coffeicola for trials 1 and 2 respectively,whilst the least growth was in the oat meal agar(14.2 mm and 15.7 mm)for trials 1 and 2 respectively.There were variations in colour and texture of mycelium with malt extract agar,potato dextrose agar and oat meal agar associated with darker colours and rough texture while smooth white mycelia were found in corn meal agar.After considering all nutrient media,malt extract agar was found to be the best media for the growth of Cercospora coffeicola in-vitro.On the basis of our findings,the authors recommend the use of malt extract agar as the primary media for identification and characterisation of Cercospora coffeicola.展开更多
Frog-eye leaf spot of soybean caused by Cercospora sojina Hara is a kind of worldwide disease. Resistance to race 7 of C. sojina was found to be due to a single dominant gene through analyzing resistant behavior of th...Frog-eye leaf spot of soybean caused by Cercospora sojina Hara is a kind of worldwide disease. Resistance to race 7 of C. sojina was found to be due to a single dominant gene through analyzing resistant behavior of the cross NEAU91212 （susceptible to race 7）× NEAU9674 （resistant to all races）. 3 RAPD markers linked to the resistant gene Rcsc 7 were identified using the BSA method. 2 fragments of OPS03<sub>620</sub> and OPS03<sub>580</sub> amplified with primer OPS03 co-dominantly segregated in the F<sub>2</sub> individuals. The genetic distance between OPS03<sub>620</sub> and the resistant gene is 8.7 cM. According to the co-dominant marker, the accuracy of predicting the homozygous and heterozygous resistant F<sub>2</sub> individuals were 100% and 97.6%, respectively.展开更多
The gray leaf spot caused by Cercospora zeina has become a serious disease in maize in China.The isolates of C.zeina from Yunnan,Sichuan,Guizhou,Hubei,Chongqing,Gansu,and Shaanxi were collected.From those,127 samples ...The gray leaf spot caused by Cercospora zeina has become a serious disease in maize in China.The isolates of C.zeina from Yunnan,Sichuan,Guizhou,Hubei,Chongqing,Gansu,and Shaanxi were collected.From those,127 samples were used for genetic diversity analysis based on inter-simple sequence repeat(ISSR)and 108 samples were used for multi-gene sequence analysis based on five gene fragments.The results indicated that populations of C.zeina were differentiated with a relatively high genetic level and were classified into two major groups and seven subgroups.The intra-population genetic differentiation of C.zeina is the leading cause of population variation in China,and interpopulation genetic similarity is closely related to the colonization time and spread direction.The multi-gene sequence analysis of C.zeina isolates demonstrated that there were nine haplotypes.Genetic diversity and multi-gene sequence revealed that Yunnan population of C.zeina,the earliest colonizing in China,had the highest genetic and haplotype diversity and had experienced an expansion event.With the influence of the southwest monsoon in the Indian Ocean,C.zeina from Yunnan gradually moved to Sichuan,Guizhou,Shaanxi,Gansu,and Chongqing.Meanwhile,C.zeina was transferred directly from the Yunnan into the Hubei Province via seed and then came into Shaanxi,Henan,and Chongqing along with the wind from Hubei.展开更多
Groundnut leaf spot is one of the important factors limiting groundnut productivity in Africa particularly in the Democratic Republic of Congo (DR Congo). Early and late leaf spot disease of groundnut caused by Cercos...Groundnut leaf spot is one of the important factors limiting groundnut productivity in Africa particularly in the Democratic Republic of Congo (DR Congo). Early and late leaf spot disease of groundnut caused by Cercospora arachidicola Hori and Cercosporidium personatum (Berk & Curt.) Deighton, respectively, can cause considerable yield losses without fungicide management. The main objectives of this research were to analyze plant and disease developmental cycles. Significant differences were observed among the groundnut varieties evaluated for resistance to the leaf spot disease. The results show that plant development cycle can be divided into three developmental stages. A first stage characterized by a low production of leaves, a second stage with a significant leaf development and finally a third stage with a reduction of leaves. Interestingly, the leaf spot disease cycle was also divided in three stages. The disease stage characterized by the highest level of symptom expression was not associated with the plant phase with the highest emerged leaves. Disease symptoms reached the highest pick only after the phase of intense leaf development. The molecular analysis revealed that all the groundnut varieties analyzed were genetically closely related even though they showed different reactions to the leaf spot disease.展开更多
Late-cycle diseases (LCD) cause a significant deterioration in quality and reduce yields in soybean crops. In Argentina, in particular, leaf blight and purple seed stain, caused by the agent Cercospora kikuchii, and f...Late-cycle diseases (LCD) cause a significant deterioration in quality and reduce yields in soybean crops. In Argentina, in particular, leaf blight and purple seed stain, caused by the agent Cercospora kikuchii, and frog eye spot, caused by C. sojina, are the prevailing sources of diseases. The early, rapid and accurate detection of these phytopathogens becomes essential, and would contribute to preserving both the environment and the health of humans and animals by preventing the wasteful or improper use of chemicals such as pesticides. In order to detect Cercospora species in soybean plants at an early stage, immunochemical and molecular techniques were developed in this work. Strains from the NITE Biological Resource Center collection (Japan): Cercospora kikuchii NBRC 6711 and Cercospora sojina NBRC 6715 and regional isolates of C. kikuchii were used. To develop Dot-Blot and PCR techniques, experiments with plants undergoing different treatments were carried out: those experimentally inoculated with these fungi, those treated with sterile water and healthy plants as well. Both techniques allowed the detection, at early stages, of Cercospora species involved in two of the most frequent LCD in the country, when the cercosporin concentration produced by the fungus was higher than 3.93 ± 0.39 nmol·cyl-1 ±SD. The sensitivity between both techniques was very different. While Dot-Blot allowed the detection of the disease 4 days after inoculation, PCR detected it after 4 hours, even without visible symptoms of the disease.展开更多
基金jointly funded by the National High Technology Research and Development Program of China(2012AA101104)the Modern Agro-Industry Technology Research System of Maize(CARS-02-02)
文摘Gray leaf spot(GLS),caused by Cercospora zeae-maydis,is an important foliar disease of maize(Zea mays L.)worldwide,resistance to which is controlled by multiple quantitative trait loci(QTL).To gain insights into the genetic architecture underlying the resistance to this disease,an association mapping population consisting of 161 inbred lines was evaluated for resistance to GLS in a plant pathology nursery at Shenyang in 2010 and 2011.Subsequently,a genome-wide association study,using 41,101 single-nucleotide polymorphisms(SNPs),identified 51 SNPs significantly(P<0.001)associated with GLS resistance,which could be converted into 31 QTL.In addition,three candidate genes related to plant defense were identified,including nucleotidebinding-site/leucine-rich repeat,receptor-like kinase genes similar to those involved in basal defense.Two genic SNPs,PZE-103142893 and PZE-109119001,associated with GLS resistance in chromosome bins 3.07 and 9.07,can be used for marker-assisted selection(MAS)of GLS resistance.These results provide an important resource for developing molecular markers closely linked with the target trait,enhancing breeding efficiency.
文摘Two fragments SCS362o and SCS3580 of the co-dominant marker OPS0362o&580 that were linked to the resistance gene of soybean frog-eye leaf spot have been completely sequenced. A significant insertion of 30 bp is the main reason of the polymorphism between the two fragments. The results of Southern hybridization indicate that SCS362o derives from a single- or low-copy sequence and can be used as an RFLP probe. A co-dominant SCAR marker SCSSeao&sao has been developed based on the sequences. The segregation of SCS362o&58o is similar to that of RAPD marker OPS03620&580. Significant polymorphism has been shown between resistant and susceptible genotypes when 62 soybean genotypes were surveyed for the SCAR marker. Therefore, the marker can be used in the resistance breeding of soybean frog-eye leaf spot by marker-assisted selection.
文摘Cercospora leaf spot is fast turning into a critically important disease in Zimbabwe.The disease is caused by Cercospora coffeicola which significantly reduces productivity and quality of coffee.Disturbingly,optimum sporulation of Cercospora coffeicola in culture remains a limiting factor for microbial analysis and quantitative studies of Cercospora leaf spot.Faced with this challenge,an in-vitro study was conducted at Coffee Research Institute,Manicaland,Zimbabwe to examine growth of Cercospora coffeicola in different nutrient media and to determine the best media for Cercospora coffeicola analysis.Six nutrient media were assessed(corn meal agar,oat meal agar,Czapek Dox agar,malt extract agar,yeast extract agar and potato dextrose agar)for the growth of Cercospora coffeicola.The laboratory-based experiment was duplicated,laid out in a Completely Randomized Design,replicated three times and based on Cercospora coffeicola nutrient inoculation.Data were collected on radial growth,colour and texture of mycelium at 3 and 6 days after inoculation.There were significant differences(p<0.05)in the growth of Cercospora coffeicola in media after 3 and 6 days.Malt extract agar had the greatest radial growth(34 mm and 32 mm)of Cercospora coffeicola for trials 1 and 2 respectively,whilst the least growth was in the oat meal agar(14.2 mm and 15.7 mm)for trials 1 and 2 respectively.There were variations in colour and texture of mycelium with malt extract agar,potato dextrose agar and oat meal agar associated with darker colours and rough texture while smooth white mycelia were found in corn meal agar.After considering all nutrient media,malt extract agar was found to be the best media for the growth of Cercospora coffeicola in-vitro.On the basis of our findings,the authors recommend the use of malt extract agar as the primary media for identification and characterisation of Cercospora coffeicola.
文摘Frog-eye leaf spot of soybean caused by Cercospora sojina Hara is a kind of worldwide disease. Resistance to race 7 of C. sojina was found to be due to a single dominant gene through analyzing resistant behavior of the cross NEAU91212 （susceptible to race 7）× NEAU9674 （resistant to all races）. 3 RAPD markers linked to the resistant gene Rcsc 7 were identified using the BSA method. 2 fragments of OPS03<sub>620</sub> and OPS03<sub>580</sub> amplified with primer OPS03 co-dominantly segregated in the F<sub>2</sub> individuals. The genetic distance between OPS03<sub>620</sub> and the resistant gene is 8.7 cM. According to the co-dominant marker, the accuracy of predicting the homozygous and heterozygous resistant F<sub>2</sub> individuals were 100% and 97.6%, respectively.
基金supported by the China Agriculture Research System from MOAR and MOF(CARS-02)the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2017-ICS)。
文摘The gray leaf spot caused by Cercospora zeina has become a serious disease in maize in China.The isolates of C.zeina from Yunnan,Sichuan,Guizhou,Hubei,Chongqing,Gansu,and Shaanxi were collected.From those,127 samples were used for genetic diversity analysis based on inter-simple sequence repeat(ISSR)and 108 samples were used for multi-gene sequence analysis based on five gene fragments.The results indicated that populations of C.zeina were differentiated with a relatively high genetic level and were classified into two major groups and seven subgroups.The intra-population genetic differentiation of C.zeina is the leading cause of population variation in China,and interpopulation genetic similarity is closely related to the colonization time and spread direction.The multi-gene sequence analysis of C.zeina isolates demonstrated that there were nine haplotypes.Genetic diversity and multi-gene sequence revealed that Yunnan population of C.zeina,the earliest colonizing in China,had the highest genetic and haplotype diversity and had experienced an expansion event.With the influence of the southwest monsoon in the Indian Ocean,C.zeina from Yunnan gradually moved to Sichuan,Guizhou,Shaanxi,Gansu,and Chongqing.Meanwhile,C.zeina was transferred directly from the Yunnan into the Hubei Province via seed and then came into Shaanxi,Henan,and Chongqing along with the wind from Hubei.
文摘Groundnut leaf spot is one of the important factors limiting groundnut productivity in Africa particularly in the Democratic Republic of Congo (DR Congo). Early and late leaf spot disease of groundnut caused by Cercospora arachidicola Hori and Cercosporidium personatum (Berk & Curt.) Deighton, respectively, can cause considerable yield losses without fungicide management. The main objectives of this research were to analyze plant and disease developmental cycles. Significant differences were observed among the groundnut varieties evaluated for resistance to the leaf spot disease. The results show that plant development cycle can be divided into three developmental stages. A first stage characterized by a low production of leaves, a second stage with a significant leaf development and finally a third stage with a reduction of leaves. Interestingly, the leaf spot disease cycle was also divided in three stages. The disease stage characterized by the highest level of symptom expression was not associated with the plant phase with the highest emerged leaves. Disease symptoms reached the highest pick only after the phase of intense leaf development. The molecular analysis revealed that all the groundnut varieties analyzed were genetically closely related even though they showed different reactions to the leaf spot disease.
文摘Late-cycle diseases (LCD) cause a significant deterioration in quality and reduce yields in soybean crops. In Argentina, in particular, leaf blight and purple seed stain, caused by the agent Cercospora kikuchii, and frog eye spot, caused by C. sojina, are the prevailing sources of diseases. The early, rapid and accurate detection of these phytopathogens becomes essential, and would contribute to preserving both the environment and the health of humans and animals by preventing the wasteful or improper use of chemicals such as pesticides. In order to detect Cercospora species in soybean plants at an early stage, immunochemical and molecular techniques were developed in this work. Strains from the NITE Biological Resource Center collection (Japan): Cercospora kikuchii NBRC 6711 and Cercospora sojina NBRC 6715 and regional isolates of C. kikuchii were used. To develop Dot-Blot and PCR techniques, experiments with plants undergoing different treatments were carried out: those experimentally inoculated with these fungi, those treated with sterile water and healthy plants as well. Both techniques allowed the detection, at early stages, of Cercospora species involved in two of the most frequent LCD in the country, when the cercosporin concentration produced by the fungus was higher than 3.93 ± 0.39 nmol·cyl-1 ±SD. The sensitivity between both techniques was very different. While Dot-Blot allowed the detection of the disease 4 days after inoculation, PCR detected it after 4 hours, even without visible symptoms of the disease.
