RESUMO
Association of Chrysanthemum stunt viroid (CSVd) and Chrysanthemum chlorotic mottle viroid (CChMVd) with the Chrysanthemum plants exhibiting severe stunting, distinct yellow leaf mottling, and chlorosis was detected in the main chrysanthemum-growing regions of India. Sequence analysis of 90 cDNA clones obtained for CSVd and CChMVd, representing the chrysanthemum-growing regions of India, revealed the high degree of sequence variation throughout the genome under natural conditions. Additionally, all the analyzed CChMVd clones revealed the presence of UUUC in the tetraloop, a signature of symptomatic variants in susceptible cultivars. Phylogenetic analysis revealed that Indian CSVd is closely related to European isolates from ornamentals, whereas CChMVd clustered along with the isolates reported from the East Asian countries.
Assuntos
Chrysanthemum/virologia , Variação Genética , Doenças das Plantas/virologia , Viroides/genética , Viroides/isolamento & purificação , Sequência de Bases , Índia , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Filogenia , RNA Viral/química , RNA Viral/genética , Viroides/química , Viroides/classificaçãoRESUMO
A specific and sensitive reverse transcriptase-nested polymerase chain reaction assay (RT-nPCR) was developed for the detection of Citrus tristeza virus (CTV) from naturally infected citrus samples. Two sets of primer pairs were designed by alignment of nucleotide sequences available in GenBank database for different genotypes of CTV. RT-nPCR reaction components and thermal cycling parameters were optimized and reaction conditions were standardized. Sequencing of the PCR products from direct and nested-PCR reactions confirmed the specificity of both primer pairs. Presence of CTV specific amplicons in asymptomatic samples which were collected from diseased orchards indicated the sensitivity of the test. As RT-nPCR technique, developed in the present study, is specific and efficient in detecting CTV, this could be envisioned for diagnostic applications and surveillance.
Assuntos
Citrus/virologia , Closterovirus/isolamento & purificação , Doenças das Plantas/virologia , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Closterovirus/genética , Primers do DNA/genéticaRESUMO
The study reports the occurrence of fumonisin producing Fusarium verticillioides in 90 samples of stored paddy (Oryza sativa L.) collected from different geographical regions of Karnataka, India. Fumonisin producing F. verticillioides was identified based on micromorphological characteristics and PCR using two sets of primers. One set of primers was F. verticillioides species specific, which selectively amplified the intergenic space region of rDNA. The other set of primers was specific to fumonisin producing F. verticillioides. Eight paddy samples were positive for F. verticillioides. Eleven isolates obtained from these samples were capable of producing fumonisin.
RESUMO
The study reports the occurrence of fumonisin producing Fusarium verticillioides in 90 samples of stored paddy (Oryza sativa L.)collected from different geographical regions ofKarnataka, India. Fumonisin producing F. verticillioides was identified based on micromorphological characteristics and PCR using two sets of primers. One set of primers was F. verticillioides species specific, which selectively amplified the intergenic space region of rDNA. The other set of primers was specific to fumonisin producing F. verticillioides. Eight paddy samples were positive for F. verticillioides. Eleven isolates obtained from these samples were capable of producing fumonisin.
O estudo relata a ocorrência de Fusarium verticillioides produtor de fumonisina em 90 amostras de arroz armazenado, coletado de diferentes regiões geográficas de Karnataka, Índia. F. verticillioides produtor de fumonisina foi identificado baseado em características micromorfológicas e PCR empregando dois sets de primers. Um dos sets era F. verticillioides especie-específico, que amplificava seletivamente a região do espaço intergênico do rDNA. O outro set de primers era especifico para F. verticillioides produtor de fumonisina. Oito amostras de arroz foram positivas para F. verticillioides. Onze isolados obtidos dessas amostras foram produtores de fumonisina.