First Report of Fusarium sambucinum Associated on Pinus elliottii Seeds in Brazil

Abstract

An elevated incidence of the fungal genus Fusarium was ascertained during a health quality analysis of a batch of Pinus elliottii Englm. seeds obtained from the Florestas Institute for Agricultural and Forest Research (Fundação Estadual de Pesquisa Agropecuária [FEPAGRO] Florestas) in Santa Maria (29° 39′ 55″ S and 53° 54′ 45″ W), state of Rio Grande do Sul, Brazil. This genus comprised about 75% of all fungal genera observed in a blotter test. The fungus was then isolated and purified to perform pathogenicity tests. Healthy seeds of P. elliottii were inoculated by contact with fungal mycelium for 48 h (3). Forty-two days after inoculation, a reduction was observed in the germination potential of the seeds; however, those seeds that germinated developed normally until, as seedlings, they suffered damping-off. Fusarium was isolated from the affected vegetal material by transferring mycelium tips to potato dextrose agar (PDA) medium in petri dishes in order to morphologically identify the species. After 72 h, a tan mycelial pad 5.5 cm in diameter had formed. After transfer to carnation leaf agar (CLA), pale orange sporodochia that formed macroconidia could be observed. The macronidia were relatively short and narrow (40.2 × 4.7 μm), each containing a mean of 5 septa; the apical cell was pointed, while the basal one was foot-shaped (2,4). The chlamydospores formed in clusters, while the conidiogenous cells could be seen on top of monophialides. Primer pairs ITS1 and ITS4, EF1-T and EF1-567R, and βtub-F and βtub were employed to amplify the three regions ITS1.8S ITS2, elongation factor – 1α (TEF 1-α), and β-tubulin, respectively. The sequences of these three regions showed 97, 95, and 99% of similarity with Fusarium sambucinum Fückel, respectively. The pathogen was reinoculated on P. elliottii seeds in order to complete Koch's postulates. The pathogenicity test was repeated with the same conditions described before and the results were confirmed. No occurrence of damping-off was observed in the control seedlings. The inoculated seedlings showed, besides damping-off, a visible reduction in root system expansion as well as reductions in fresh and dry tissue weight. F. sambucinum has already been reported on P. radiata D. Don in New Zealand, causing root rot and dieback (1); however, in Brazil, the present study is, to the best of our knowledge, the first to report the association of this pathogen with P. elliottii. References: (1) M. A. Dick and K. Dobbie. N. Z. Plant Prot. 55:58, 2002. (2) W. Gerlach and H. Nirenberg. The Genus Fusarium – A Pictorial Atlas. Biologische Bundesanstalt für Land – und. Forstwirtschaft, Berlin, 1982. (3) M. Lazarotto et al. Summa Phytopathol. 36:134, 2010. (4) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual, 1st ed. Wiley-Blackwell, Hoboken, NJ, 2006.

CARACTERIZAÇÃO MORFOLÓGICA, MOLECULAR E PATOGENICIDADE DE <i>Fusarium acuminatum</i> E<i> Fusarium verticillioides</i> A <i>Cordia americana

“…Espécies desse gênero são amplamente distribuídas em todo o mundo, e são bem conhecidas como agentes patogênicos de viveiros, ocasionando sintomas de pré e pós-emergência, damping-off, bem como redução da germinação de sementes em viveiros de coníferas (MÁRTIN-PINTO;PAJARES;DÍEZ, 2008). No Brasil uma das principais doenças da erva-mate (Ilex paraguariensis A.…”

“…(POLETTO et al, 2012). Em plântulas de Pinus elliottii Engelm, sintomas de murcha, tombamento, apodrecimento de cotilédones e lesão seguida de ruptura do hipocótilo, foram observados devido à infecção das sementes por Fusarium sambucinum Fuckel (MACIEL et al, 2013).…”

MÉTODOS DE DETECÇÃO, TRANSMISSÃO E PATOGENICIDADE DE<i> Fusarium</i> spp. EM SEMENTES DE <i>Pinus taeda

“…em sementes de Cedrela fissilis causando danos nas raízes e, provocando posterior tombamento das plântulas. Em sementes de Pinus elliottii foi confirmada a patogenicidade de Fusarium sambucinum isolado das sementes para as plântulas, e foram constatados sintomas de apodrecimento da parte aérea (MACIEL, 2013).…”

Fusarium solani and F. oxysporum: Etiological agents of damping off in crambe

“…Some morphological characteristics can separate and group Fusarium isolates, signaling possible differences and similarities at the genetic level. The sequencing of regions such as TEF-1α (Lazarotto et al, 2014) and βtub (Maciel et al, 2013) provides reliability for the identification of complexes of Fusarium species.…”