Variabilidade genética entre isolados de Colletotrichum gossypii do algodoeiro

Abstract

Cott on is a t ta ck ed by Co l le to tr ic h u m g o ssy p ii (CG) a nd C . g o ssy p ii va r. c e p h a lo sp o rio id e s (CGC). Both the pa thogens a re t r a n sm i tt e d by se e d a n d t h e i r m o r ph o l o gi c a l di st i nc t i o n i s extremely difficult and inconsistent. In the present study, attempts were ma de to verify the genetic va ria bility among 5 3 isola tes of CG and CGC u sing RAPD-PCR, ERIC-a nd REP-PCR, a s well a s PCR-RFLP of the ITS rDNA region. Ba sed on pathogenicity tests, 21 isolates were cla ssified as CG and 32 as CGC. RAPD analysis wa s pe rformed u sing eight primers a n d the resu lts revea l ed two m a jo r g ro u p s. T h e fi r st g r o u p c o n t a i n e d 9 4 % of t h e i so l a t e s originated from seeds and the second conta ined 95% of the isolates Mehta, Y.R.; Mehta, A. Genetic variability among the isolates of Colletotrichum gossypii of cotton. Summa Phytopathologica, v.36, n.1, p.40-44, 2010.Keywords: Gossypium hirsutum, ramulosis, genetic variability, molecular analysis Palavras-chave adicionais: Gossypium hirsutum, ramulose, variabilidade genética, análise molecular RESUMOO algodoeiro é atacado por Colletotrichum gossyp ii (CG) e C. g ossy p ii va r. c ep h a lo spo rio id es (CGC). Ambos os pa tógenos sã o t r a n sm i t id o s pe l a se m e n t e e su a d i sti n ç ã o m o r fo l ó g i ca é extr ema ment e difíc il e in consist ente. Tenta tiv a s fora m feita s no presente tra ba lho pa ra verificar a varia bilida de genética entre CG e CGC a través de RAPD-PCR, ERIC-e REP-PCR e PCR-RFLP da r e gi ã o IT S r DN A. por 94% dos isolados de sementes e o segundo por 95% dos isolados de folha s. Na análise de ERIC-e REP-PCR, resultados semelhantes a RAPD fora m obtidos, sendo que o primeiro gru po foi forma do por 93 % dos isola dos provenientes da s sementes e o segu ndo por 7 8 % dos isola dos provenientes da s folha s. Qu ando o produ to de a mplifica çã o da regiã o IT S rDNA foi digerido com oito enzima s de restrição, um perfil de bandas semelhante para todos os isolados foi obtido. Resu ltados de RAPD, ERIC-e REP-PCR demonstraram qu e existem difer ença s gené tica s ent re os isol a dos prov enien tes da s sementes e aqu eles provenientes de pa rte a érea , e esses dois g ru p os fo r a m cl a ra m en t e d ist in to s. E st u do s fu tu r os de v em se r rea lizados utiliza ndo ou tras técnica s molecu la res pa ra a obtençã o de ma rcadores capa zes de distinguir entre isolados de CG e CGC. orig ina ted from l ea ves. Simila r resu lt s were obta in ed by E RICand REP-PCR, where the first group conta ined 93% of the isola tes originated from seeds and the second conta ined 78% of the isolates or igin a te d fr om lea v es. Whe n th e a mpli fie d pr odu ct o f t he I T S rDNA region was digested with eight restriction enzymes, simila r ba nding pa tterns were observed for a ll isola tes. Resu lts of RAPD, E R IC -a n d R E P -P C R de m o n str a t e d t h e ex i st en c e of g e n et i c varia bility among the seed and lea f isolates and th...

Response of cotton genotypes to the incidence of Alternaria leaf spot

“…Diferenças quanto Cia Alternaria leaf spot, known and described for more than one century (20), is caused by at least three pathogens: Alternaria macrospora, A. alternata and A. gossypina. The first one is most widespread in the world and has been identified in Brazil (14,15,17,19). Its importance for the cotton crop has been emphasized, especially due to the focus on cultivars of Gossypium barbadense L. causing yield losses of up to 20% (11,12,13,20) and due to seed transmission (2).…”

Caracterização morfofisiológica de isolados do gênero Cylindrocladium

“…Quando cultivado em meio artificial, Cylindrocladium apresenta colônias de coloração marrom-castanha e de crescimento rápido, sob temperaturas elevadas (20). Atualmente, também a seqüência do DNA tem auxiliado nesta identificação (16,29).…”

Specificity and sensibility of primer pair in the detection of Colletotrichum gossypii var. cephalosporioides in cotton seeds by PCR technique

“…cephalosporioides and C. gossypii) belong to the Ascomycota phylum, having as main feature the production of conidial mass with orange color in acervuli and conidia morphologically similar (Bailey et al, 1996). Both pathogens are transmitted by seeds and cause damages in cotton plants (Silva-Mann et al, 2005;Mehta and Mehta, 2010).…”

“…cephalosporioides and C. gossypii were carried out by using the "blotter" method, in which the assessment is based on mycelial growth habit of fungi developed in seeds after an incubation period (Tanaka et al, 1996). In this case, the high morphological similarities and isolate variability of these fungi make the results of such analysis questionable and not always consistent (Silva-Mann et al, 2002;Mehta and Mehta, 2010), determining the need to develop more accurate and reliable methods for this task.…”