Nep1 Protein from Fusarium oxysporum Enhances Biological Control of Opium Poppy by Pleospora papaveracea

Abstract

The fungus Pleospora papaveracea and Nep1, a phytotoxic protein from Fusarium oxysporum, were evaluated for their biocontrol potential on opium poppy (Papaver somniferum). Four treatments consisting of a control, P. papaveracea conidia, Nep1 (5 mug/ml), and P. papaveracea conidia plus Nep1 (5 mug/ml) were used in detached-leaf and whole-plant studies. Conidia of P. papaveracea remained viable for 38 days when stored at 20 or 4 degrees C. Nep1 was stable in the presence of conidia for 38 days when stored at 4 degrees C or for 28 days at 20 degrees C. The presence of Nep1 did not affect conidia germination or appressoria formation. Nep1 was recovered from drops applied to opium poppy leaves in greenhouse and field studies 24 h after treatment. Opium poppy treated with the combination of Nep1 and P. papaveracea had higher necrosis ratings than the other treatments. There were changes in the intercellular protein profiles, determined by sodium dodecyl sulfate gel electrophoresis and silver staining, due to application of treatments; the most intense occurred in response to the combination of Nep1 and P. papaveracea. The combination of Nep1 and P. papaveracea enhanced the damage caused to opium poppy more than either component alone.

Induction of defense responses in tobacco by the protein Nep1 from Fusarium oxysporum

“…Critical to the response of plants to foliar sprays with Nep1 is the inclusion of surfactants (Silwet-L77) which appears to allow penetration of the leaf epidermal layer through stomata [15,16]. Nep1 promotes disease in at least one plantpathogen interaction [17] and is compatible with some herbicides [16]. Based on results presented here, it is difficult to distinguish the response of plants to Nep1 from the response of plants to necrosis-inducing elicitors at the cellular level.…”

“…Harpins are capable of inducing systemic acquired resistance that protects plants against multiple diseases and even insects [25][26][27]. In contrast, Nep1 has been shown to promote disease development in at least one plantpathogen interaction [17] supporting evidence that AOS may function to promote disease depending upon the pathogen and plant involved [58]. Active oxygen is likely to be produced at some point in the process of cell death regardless of the cause [59].…”

“…In addition, it has been demonstrated that Nep1 remains active when co-applied with the chemical herbicides 2,4-D and glyphosate [16]. Nep1 has also been found to enhance disease development when co-applied with the bioherbicidal fungus Pleospora papa6eracea to Papa6er somniferum [17]. Although it is well established that Nep1 causes necrosis and induces ethylene in many plant species, the response of plants to Nep1 at the cellular level has not been detailed.…”

Developmental expression of stress response genes in Theobroma cacao leaves and their response to Nep1 treatment and a compatible infection by Phytophthora megakarya

“…PaNie from P. aphanidermatum induces DNA laddering in carrot (Daucus carota L.), a primary measure for programmed cell death, in addition to production of the phytoalexin 4-hydroxybenzoic acid [54]. Foliar application of the combination of Nep1 with the plant pathogen Pleospora papaveracea enhances disease development on opium poppy (Papaver somniferum L.) [11].…”

Phytophthora parasitica transcriptome, a new concept in the understanding of the citrus gummosis

“…The inhibition of this enzyme is an effective therapy in the treatment of Trypanosomiasis and also other diseases caused by Plasmodia, Giardia, and Leishmania and in Stagonospora (Septoria) nodorum, a phytopathogenic fungi. This is probably a target for chemical control because of the need for this enzyme in virulence and growth (Bailey et al, 2000).…”