Fungal saprobes and pathogens as endophytes of rice (Oryza sativaL.)

Abstract

SUMMARYFungal endophytes have been isolated from inside the leaf blades, leaf sheaths, and roots of six-week-old plants as well as from seeds and ten-day-old seedlings of Orysa sativa (E.). The fungi isolated can be grouped in two categories; one containing organisms known mainly to be saprotrophic and the other comprising potential pathogens. Of the former Alternaria alternata (Fr,) Keissler and Epicoccum purpurascens Ehrenb. ex. Schlecht preferentially colonize the leaf blades of their host, whereas Cladosporium tenuissimum Cooke seems more generally distributed between leaf blades and leaf sheaths. Fusarium equiseti (Corda) Saec., F. oxysporum Schecht and Phoma sorghina (Sacc. Boerema) are latent in their hosts without causing disease symptoms. A. alternata, E. purpurascens, F. equiseti, and Nigrospora oryzae have also been frequenth-isolated from seeds and young seedlings and can be considered seed-borne. Prineipal components analysis has shown a marked tissue specificity among riee endophytes. Leaf sheaths of the rice varieties grown under dry conditions are colonized by endophyte communities different from those of the wet cultivars.

First characterization of endophytic Corynespora cassiicola isolates with variant cassiicolin genes recovered from rubber trees in Brazil

“…However, these experiments were conducted on detached leaves kept alive under moist environment for up to nine days, which cannot reflect exactly the field conditions. The initiation of the senescence process may have induced a lifestyle transition from endophyte to pathogen, in agreement with previous works showing that some endophytes may become pathogenic when the host plant is stressed (Fisher and Petrini 1992). However, a more probable interpretation would be that the observed symptoms reflect a saprotrophic process rather than parasitism.…”

Influence of hydrodynamics and nutrients on biofilm structure

“…The flow meter was sterilised using a method adapted from Fisher and Petrini (1992) in which it was exposed to 70 % ethanol for 15 minutes, 40% NaOCl solution (approx. 12% available chlorine when undiluted) for 15 minutes, and 70 % ethanol for 15 minutes.…”

Natural occurrence of fungal egg parasites of root-knot nematodes, Meloidogyne spp. in organic and integrated vegetable production systems in Spain

“…d F-values, degrees of freedom, and P values to compare parasitism, richness, H 0 , and J 0 between organic and integrated production consider a parasite. Three out the four remaining fungi, Cladosporium tenuissimum, Penicillium citrinum, and P. olsonii, have been reported as endophytes (Fisher and Petrini 1992;Vega et al 2006;Maciá-Vicente et al 2008), and F. verticillioides as a plant pathogen, but as far as we know, their capacity to parasitize nematode eggs has not been investigated. Higher levels of parasitism were found in organic than integrated production.…”