Anthracnose disease is one of the major economic constraints to chilli production worldwide, especially in tropical and subtropical regions. Accurate taxonomic information is necessary for effective disease control ma...Anthracnose disease is one of the major economic constraints to chilli production worldwide, especially in tropical and subtropical regions. Accurate taxonomic information is necessary for effective disease control management. In the Colletotrichum patho-system, different Colletotrichum species can be associated with anthracnose of the same host. Little information is known concerning the interactions of the species associated with the chilli anthracnose although several Colletotrichum species have been reported as causal agents of chilli anthracnose disease worldwide. The ambiguous taxonomic status of Colletotrichum species has resulted in inaccurate identification which may cause practical problems in plant breeding and disease management. Although the management and control of anthracnose disease are still being extensively researched, commercial cultivars of Capsicum annuum that are resistant to the pathogens that cause chilli anthracnose have not yet been developed. This paper reviews the causal agents of chilli anthracnose, the disease cycle, conventional methods in identification of the pathogen and molecular approaches that have been used for the identification of Colletotrichum species. Pathogenetic variation and population structure of the causal agents of chilli anthracnose along with the current taxonomic status of Colletotrichum species are discussed. Future developments leading to the disease management strategies are suggested.展开更多
To assesse the genetic diversity among wild and cultivated accessions of 8 taxonomic groups in 2 species, and 5 subspecies under Pisum genus, and to analyze population structure and their genetic relationships among v...To assesse the genetic diversity among wild and cultivated accessions of 8 taxonomic groups in 2 species, and 5 subspecies under Pisum genus, and to analyze population structure and their genetic relationships among various groups of taxonomy, the study tried to verify the fitness of traditionally botanical taxonomic system under Pisum genus and to provide essential information for the exploration and utilization of wild relatives of pea genetic resources. 197 Pisum accessions from 62 counties of 5 continents were employed for SSR analysis using 21 polymorphic primer pairs in this study. Except for cultivated field pea Pisum sativum ssp. sativum var. sativum （94 genotypes）, also included were wild relative genotypes that were classified as belonging to P. fulvum, P. sativum ssp.abyssinicum, P. sativum ssp. asiaticum, P. sativum ssp. transcaucasicum, P. sativum ssp. elatius var. elatius, P. sativum ssp. elatius var. pumilio and P. sativum ssp. sativum var. arvense （103 genotypes）. The PCA analyses and 3-dimension PCA graphs were conducted and drawn by NTSYSpc 2.2d statistical package. Nei78 genetic distances among groups of genetic resources were calculated, and cluster analysis using UPGMA method was carried out by using Popgene V1.32 statistical package, the dendrogram was drawn by MEGA3.1 statistical package. Allelic statistics were carried out by Popgene V1.32. The significance test between groups of genotypes was carried out by Fstat V2.9.3.2 statistical package. 104 polymorphic bands were amplified using 21 SSR primer pairs with unambiguous unique polymorphic bands. 4.95 alleles were detected by each SSR primer pair in average, of which 65.56% were effective alleles for diversity. PSAD270, PSAC58, PSAA18, PSAC75, PSAA175 and PSAB72 were the most effective SSR pairs. SSR alleles were uniformly distributed among botanical taxon units under Pisum genus, but significant difference appeared in most pairwise comparisons for genetic diversity between taxon unit based groups of genetic resources. Genetic diversity level of wild species P. fulvum was much lower than the cultivated species P. sativum. Under species P. sativum, P. sativum ssp. sativum var. sativum and P. sativum ssp. asiaticum were the highest in gentic diversity, followed by P. sativum ssp. elatius var. elatius and P. sativum ssp. transcaucasicum, P. sativum ssp. elatius var. pumilio, P. sativum ssp. sativum vat. arvense and P. sativum ssp. abyssinicum were the lowest. Four gene pool clusters were detected under Pisum genus by using PCA analysis. Gene pool ＂fulvum＂ mainly consisted of wild species Pisum fulvum, gene pool ＂abyssinicum＂ mainly consisted of P. sativum ssp. abyssinicum, and gene pool ＂arvense＂ mainly consisted of P. sativum ssp. sativum var. arvense. While gene pool ＂sativum＂ were composed by 5 botanical taxon units, they are P. sativum ssp. asiaticum, P. sativum ssp. elatius var. elatius, P. sativum ssp. transcaucasicum, P. sativum ssp. elatius var. pumilio and P. sativum ssp. sativum var. sativum. ＂sativum＂ gene pool constructed the primary gene pool of cultivated genetic resources; ＂fulvum＂ gene pool, ＂abyssinicum＂ gene pool and ＂arvense＂ gene pool together constructed the secondary gene pool of cultivated genetic resources. Pairwise Nei78 genetic distance among botanical taxon based groups of pea genetic resources ranged from 7.531 to 35.956, 3 large cluster groups were identified based on the UPGMA dendrogram. Group Ⅰ equals to ＂sativum＂ and ＂arvense＂ gene pools, Group Ⅱ equals to ＂abyssinicum＂ gene pool, and Group Ⅲ equals to ＂fulvum＂ gene pool. The UPGMA clustering results generally supporting the PCA clusting results. There were significant differences among most botanical groups under Pisum genus, with clear separation of four gene pools for genetic diversity structure. The research results partially support the traditional botanical taxonomy under Pisum genus, and pointed out its advantage and shortcoming. In order to broaden the genetic bases of pea varieties, the genetic potentials in the four gene pools should be thoroughly exploited.展开更多
文摘Anthracnose disease is one of the major economic constraints to chilli production worldwide, especially in tropical and subtropical regions. Accurate taxonomic information is necessary for effective disease control management. In the Colletotrichum patho-system, different Colletotrichum species can be associated with anthracnose of the same host. Little information is known concerning the interactions of the species associated with the chilli anthracnose although several Colletotrichum species have been reported as causal agents of chilli anthracnose disease worldwide. The ambiguous taxonomic status of Colletotrichum species has resulted in inaccurate identification which may cause practical problems in plant breeding and disease management. Although the management and control of anthracnose disease are still being extensively researched, commercial cultivars of Capsicum annuum that are resistant to the pathogens that cause chilli anthracnose have not yet been developed. This paper reviews the causal agents of chilli anthracnose, the disease cycle, conventional methods in identification of the pathogen and molecular approaches that have been used for the identification of Colletotrichum species. Pathogenetic variation and population structure of the causal agents of chilli anthracnose along with the current taxonomic status of Colletotrichum species are discussed. Future developments leading to the disease management strategies are suggested.
基金supported by the National Key Technologies R&D Program of China (2006BAD13B05,2006BAD02B08)the National Program for Crop Germplasm Protection of China (NB07-2130135-(25-30)-13)+1 种基金the National Science and Technology Plat-form R&D Program of China (2005DKA21001-6)the China-ACIAR Project (ACIAR:CS1/2000/035).
文摘To assesse the genetic diversity among wild and cultivated accessions of 8 taxonomic groups in 2 species, and 5 subspecies under Pisum genus, and to analyze population structure and their genetic relationships among various groups of taxonomy, the study tried to verify the fitness of traditionally botanical taxonomic system under Pisum genus and to provide essential information for the exploration and utilization of wild relatives of pea genetic resources. 197 Pisum accessions from 62 counties of 5 continents were employed for SSR analysis using 21 polymorphic primer pairs in this study. Except for cultivated field pea Pisum sativum ssp. sativum var. sativum （94 genotypes）, also included were wild relative genotypes that were classified as belonging to P. fulvum, P. sativum ssp.abyssinicum, P. sativum ssp. asiaticum, P. sativum ssp. transcaucasicum, P. sativum ssp. elatius var. elatius, P. sativum ssp. elatius var. pumilio and P. sativum ssp. sativum var. arvense （103 genotypes）. The PCA analyses and 3-dimension PCA graphs were conducted and drawn by NTSYSpc 2.2d statistical package. Nei78 genetic distances among groups of genetic resources were calculated, and cluster analysis using UPGMA method was carried out by using Popgene V1.32 statistical package, the dendrogram was drawn by MEGA3.1 statistical package. Allelic statistics were carried out by Popgene V1.32. The significance test between groups of genotypes was carried out by Fstat V2.9.3.2 statistical package. 104 polymorphic bands were amplified using 21 SSR primer pairs with unambiguous unique polymorphic bands. 4.95 alleles were detected by each SSR primer pair in average, of which 65.56% were effective alleles for diversity. PSAD270, PSAC58, PSAA18, PSAC75, PSAA175 and PSAB72 were the most effective SSR pairs. SSR alleles were uniformly distributed among botanical taxon units under Pisum genus, but significant difference appeared in most pairwise comparisons for genetic diversity between taxon unit based groups of genetic resources. Genetic diversity level of wild species P. fulvum was much lower than the cultivated species P. sativum. Under species P. sativum, P. sativum ssp. sativum var. sativum and P. sativum ssp. asiaticum were the highest in gentic diversity, followed by P. sativum ssp. elatius var. elatius and P. sativum ssp. transcaucasicum, P. sativum ssp. elatius var. pumilio, P. sativum ssp. sativum vat. arvense and P. sativum ssp. abyssinicum were the lowest. Four gene pool clusters were detected under Pisum genus by using PCA analysis. Gene pool ＂fulvum＂ mainly consisted of wild species Pisum fulvum, gene pool ＂abyssinicum＂ mainly consisted of P. sativum ssp. abyssinicum, and gene pool ＂arvense＂ mainly consisted of P. sativum ssp. sativum var. arvense. While gene pool ＂sativum＂ were composed by 5 botanical taxon units, they are P. sativum ssp. asiaticum, P. sativum ssp. elatius var. elatius, P. sativum ssp. transcaucasicum, P. sativum ssp. elatius var. pumilio and P. sativum ssp. sativum var. sativum. ＂sativum＂ gene pool constructed the primary gene pool of cultivated genetic resources; ＂fulvum＂ gene pool, ＂abyssinicum＂ gene pool and ＂arvense＂ gene pool together constructed the secondary gene pool of cultivated genetic resources. Pairwise Nei78 genetic distance among botanical taxon based groups of pea genetic resources ranged from 7.531 to 35.956, 3 large cluster groups were identified based on the UPGMA dendrogram. Group Ⅰ equals to ＂sativum＂ and ＂arvense＂ gene pools, Group Ⅱ equals to ＂abyssinicum＂ gene pool, and Group Ⅲ equals to ＂fulvum＂ gene pool. The UPGMA clustering results generally supporting the PCA clusting results. There were significant differences among most botanical groups under Pisum genus, with clear separation of four gene pools for genetic diversity structure. The research results partially support the traditional botanical taxonomy under Pisum genus, and pointed out its advantage and shortcoming. In order to broaden the genetic bases of pea varieties, the genetic potentials in the four gene pools should be thoroughly exploited.
