Phosphite and mycorrhizal formation in seedlings of three Australian Myrtaceae

Howard, K.; Dell, B.; Hardy, G.

doi:10.1071/bt00007

Cited by 22 publications

(12 citation statements)

References 23 publications

(23 reference statements)

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“…Such phosphorus accumulation may have negative impacts in ecosystems adapted to low phosphorus availability as is the case with various Australian plant communities (Saunders , Chen et al ). Long‐term studies are therefore needed to examine potential cumulative effects on ecosystem functioning and species diversity above‐ and below‐ground (Howard et al , Fairbanks et al ).…”

Section: Discussionmentioning

confidence: 99%

Foliar phosphite application has minor phytotoxic impacts across a diverse range of conifers and woody angiosperms

Scott

Bader

Williams

2016

Physiologia Plantarum

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Phytophthora plant pathogens cause tremendous damage in planted and natural systems worldwide. Phosphite is one of the only effective chemicals to control broad-scale Phytophthora disease. Little work has been done on the phytotoxic effects of phosphite application on plant communities especially in combination with plant physiological impacts. Here, we tested the phytotoxic impact of phosphite applied as foliar spray at 0, 12, 24 and 48 kg a.i. ha(-1) . Eighteen-month-old saplings of 13 conifer and angiosperm species native to New Zealand, and two exotic coniferous species were treated and the development of necrotic tissue and chlorophyll-a-fluorescence parameters (optimal quantum yield, Fv /Fm ; effective quantum yield of photosystem II, ΦPSII ) were assessed. In addition, stomatal conductance (gs ) was measured on a subset of six species. Significant necrosis assessed by digital image analysis occurred in only three species: in the lauraceous canopy tree Beilschmiedia tawa (8-14%) and the understory shrub Dodonaea viscosa (5-7%) across phosphite concentrations and solely at the highest concentration in the myrtaceous pioneer shrub Leptospermum scoparium (66%). In non-necrotic tissue, Fv /Fm , ΦPSII and gs remained unaffected by the phosphite treatment. Overall, our findings suggest minor phytotoxic effects resulting from foliar phosphite application across diverse taxa and regardless of concentration. This study supports the large-scale use of phosphite as a management tool to control plant diseases caused by Phytophthora pathogens in plantations and natural ecosystems. Long-term studies are required to ascertain potential ecological impacts of repeated phosphite applications.

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Section: Discussionmentioning

confidence: 99%

Foliar phosphite application has minor phytotoxic impacts across a diverse range of conifers and woody angiosperms

Scott

Bader

Williams

2016

Physiologia Plantarum

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“…Although phosphonates fall under the category of natural products, they are currently not registered for organic crop production. Phosphonates have been known to stimulate symbiotic infections by mycorrhizal fungi (Jabaji-Hare & Kendrick, 1987;Howard et al, 2000); however, their compatibility with microbial-based biopesticides has not been investigated. We have been working with liquid formulation of AG3 phosphonate for the past several years to determine its effectiveness in suppressing some common soilborne diseases of vegetable crops.…”

Section: Effect Of Ag3 Phosphonate On Phytophthora Damping-off and Romentioning

confidence: 99%

Effectiveness of AG3 phosphonate formulation in suppressing phytophthora blight in cucumber and bell pepper plants under growth room conditions

Abbasi

Lazarovits

Weselowski

2011

Canadian Journal of Plant Pathology

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Phytophthora blight or crown or root rot (Phytophthora capsici Leonian) is an important disease of a wide range of plant species including peppers, tomatoes, cucumbers and other cucurbits in Canada and worldwide. We have previously demonstrated the effectiveness of a new liquid formulation of AG3 phosphonate (Calirus 150, Bromine Compounds Ltd., Beer Sheva, Israel) in suppressing pythium damping-off of cucumbers and clubroot of bok choy and cabbage. In this study, the effectiveness of AG3 phosphonate formulation to suppress phytophthora damping-off and root rot of cucumber (Cucumis sativus L.) seedlings or phytophthora blight of bell pepper (Capsicum annuum L.) plants was determined in a peat-based mix or sandy-loam soil artificially infested with soil inoculum of P. capsici under growth room conditions. In an infested peat-based mix, AG3 phosphonate preplanting amendment or postplanting drench treatments (0.05%, 0.1% and 0.2% a.i.) and a 10-min seed-soak treatment (10.45% a.i.) significantly increased the percentage of healthy cucumber seedlings and reduced damping-off and root rot severity. The seed-soak and 0.2% treatments were the most effective treatments that consistently suppressed damping-off and root rot of cucumber even in a peat-based mix infested with high inoculum levels of P. capsici. Disease severity on cucumber plants was also significantly less in the AG3 phosphonate treatments. The single drench applications of AG3 phosphonate (0.05%, 0.1% and 0.2% a.i.) significantly reduced the incidence and severity of phytophthora blight of bell pepper plants in an infested peat-based mix or a sandy-loam soil compared with the control plants receiving no treatment. The best control of phytophthora blight of bell pepper was achieved with the higher rate (0.2% a.i.) in both peat-based mix and soil with 90% of the plants remaining healthy compared with none in the control. The disease protection increased with increasing concentrations of AG3 phosphonate in both bell peppers and cucumbers without any phytotoxicity.Résumé: La brûlure phytophtoréenne, ou pourriture phytophtoréenne des tiges et du collet (Phytophthora capsici Leonian), est une grave maladie qui, au Canada comme partout dans le monde, touche une grande variété d'espèces dont les poivrons, les tomates, les concombres et d'autres cucurbitacées. Nous avons auparavant démontré l'efficacité d'une nouvelle formulation liquide de phosphonate AG3 (Calirus 150, Bromine Compounds Ltd., Beer Sheva, Israël) quant à l'inhibition de la fonte des semis chez le concombre et de la hernie chez le chou et le pak-choï. Dans cette étude, l'efficacité de la formulation de phosphonate AG3 quant à l'inhibition de la fonte phytophtoréenne des semis et de la pourriture des tiges et du collet chez les jeunes plants de concombre (Cucumis sativus), ou de la pourriture des fruits chez le poivron (Capsicum annuum L.), a été démontrée, en chambre de culture, dans un mélange à base de tourbe ou dans un terreau sableux infectés artificiellement avec un inoculum de P. capsici. Dans ...

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“…Analyses of various hormone signaling mutants in Arabidopsis suggested a role for Phi in priming SA-mediated defense signaling, but not jasmonic acid (JA), ethylene or abscisic acid signaling (Massoud et al, 2012). Despite its oomycetecidal properties, no adverse effect of Phi on soil mycorrhizae was reported (Howard et al, 2000). Additionally, in soybean, a positive impact of manganese phosphite application (used to control the fungal pathogen Macrophomina phaseolina) on the plant growth-promoting rhizobacteria Pseudomonas fluorescens and Bacillus subtilis was observed (Simonetti et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Transcriptome‐based analyses of phosphite‐mediated suppression of rust pathogens Puccinia emaculata and Phakopsora pachyrhizi and functional characterization of selected fungal target genes

et al. 2018

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Phosphite (Phi) is used commercially to manage diseases mainly caused by oomycetes, primarily due to its low cost compared with other fungicides and its persistent control of oomycetous pathogens. We explored the use of Phi in controlling the fungal pathogens Puccinia emaculata and Phakopsora pachyrhizi, the causal agents of switchgrass rust and Asian soybean rust, respectively. Phi primes host defenses and efficiently inhibits the growth of P. emaculata, P. pachyrhizi and several other fungal pathogens tested. To understand these Phi-mediated effects, a detailed molecular analysis was undertaken in both the host and the pathogen. Transcriptomic studies in switchgrass revealed that Phi activates plant defense signaling as early as 1 h after application by increasing the expression of several cytoplasmic and membrane receptor-like kinases and defense-related genes within 24 h of application. Unlike in oomycetes, RNA sequencing of P. emaculata and P. pachyrhizi did not exhibit Phi-mediated retardation of cell wall biosynthesis. The genes with reduced expression in either or both rust fungi belonged to functional categories such as ribosomal protein, actin, RNA-dependent RNA polymerase, and aldehyde dehydrogenase. A few P. emaculata genes that had reduced expression upon Phi treatment were further characterized. Application of double-stranded RNAs specific to P. emaculata genes encoding glutamate N-acetyltransferase and cystathionine gamma-synthase to switchgrass leaves resulted in reduced disease severity upon P. emaculata inoculation, suggesting their role in pathogen survival and/or pathogenesis.

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Phosphite and mycorrhizal formation in seedlings of three Australian Myrtaceae

Cited by 22 publications

References 23 publications

Foliar phosphite application has minor phytotoxic impacts across a diverse range of conifers and woody angiosperms

Foliar phosphite application has minor phytotoxic impacts across a diverse range of conifers and woody angiosperms

Effectiveness of AG3 phosphonate formulation in suppressing phytophthora blight in cucumber and bell pepper plants under growth room conditions

Transcriptome‐based analyses of phosphite‐mediated suppression of rust pathogens Puccinia emaculata and Phakopsora pachyrhizi and functional characterization of selected fungal target genes

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