Enhancement of Defence Responses against Bayoud Disease by Treatment of Date Palm Seedlings with an Hypoaggressive Fusarium oxysporum Isolate

Abstract

Pretreatment of date palm seedlings with an hypoaggressive Fusarium isolate (AHD) protected them partially from further infection by Fusarium oxysporum f.sp. albedinis (Foa), the Bayoud disease pathogen. No mortality occurred during 2-3 months of incubation in plants pretreated with AHD, as opposed to aggressive isolate (ZAG) inoculated controls where up to 100% mortality was observed 15-30 days after inoculation. Such protection involved biochemical interactions between the host plant and AHD since no direct competition or antagonism was revealed between AHD and ZAG. The examination of the accumulation of phenolics and peroxidase activity, two parameters previously reported to be involved in date palm resistance to Foa, indicated that the response to AHD was correlated with the ability of pretreated date palm tissues to establish a faster defence response in the roots of both susceptible and resistant cultivars. Plants pretreated with AHD accumulated higher amounts of phenolics, mainly nonconstitutive hydroxycinnamic acid derivatives, which play a crucial role in date palm defence against Foa, as previously described by our group. These compounds were accumulated along with the constitutive caffeoylshikimic acids. A faster induction of peroxidase activity in response to Foa was also recorded in plants pretreated with AHD. Given the multi-component nature of these induced responses, AHD could be part of integrated disease management strategies for a sustainable control of the palm tree Bayoud disease.U. S.

Protein extraction from Phoenix dactylifera L. leaves, a recalcitrant material, for two‐dimensional electrophoresis

“…Date palm leaf is a recalcitrant material which requires special treatments for obtaining extracts with adequate amounts of protein free from electrophoresis interfering compounds. As examples of such compounds, date palm tissue contains high levels of tannins and various other phenolic compounds (e.g., ferulic, p-coumaric, p-hydroxybenzoic and caffeoylshikimic acids, quercetin and isorhamnetin heterosides, and (1)-catechin and (2)-epicatechin flavanols [17][18][19]), carbohydrates (e.g., abundant starch grains in parenchymatic tissue [9]), and certain oxidative enzymes (e.g., polyphenol oxidase [20]). We have consequently tested two main procedures for optimizing protein extraction.…”

Benzo-(1,2,3)-thiadiazole-7-carbothioic S-methyl ester (BTH) stimulates defense reactions in Xanthosoma sagittifolium

“…The importance of PPO activity is the oxidation of phenolic compounds to quinones, which are often more toxic for microorganisms than the original phenols (Campos-Vargas and Saltveit 2002). Phenols play an important role in plant defense, and all classes of these compounds are involved in the resistance mechanisms Daayf et al 2003;Djocgoue et al 2007;El Hassni et al 2004).…”

Date Palm Status and Perspective in Egypt

“…Important research work has been accomplished on extraction of essential oils and polyphenols from date seeds. Three main phenolics (hydroxycinnamates; fl avonols, fl avan-3-ols, fl avan-3,4-diols, and proanthocyanidins) have been detected in dates (El-Hassni et al 2004 ). In this respect, the nonpolar and polar successive extracts of the seeds of date palm, which is widely distributed in El-Dakhla Oases, were tested for the antioxidant activity by an in vitro bioassay technique according to the b-carotene bleaching method, as well as for the estrogen-like activity (Ammar et al 2009 ).…”