Environmental factors limiting growth of Sporobolomyces roseus, an antagonist of Cochliobolus sativus, on wheat leaves

Bashi, Esther; Fokkema, N. J.

doi:10.1016/s0007-1536(77)80146-0

Cited by 77 publications

(39 citation statements)

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“…4) might suggest parasitism, although we could not demonstrate this in vitro ( Supplemental Fig. S4); however, it might also suggest competition for nutrients because conidial germination in many B. cinerea isolates is nutrient dependent and P. aphidis outcompeting B. cinerea conidia for available nutrients would reduce disease severity (Bashi and Fokkema, 1977;Fokkema et al, 1979;Dik et al, 1991Dik et al, , 1992Filonow et al, 1996;Barnett et al, 2000).…”

Section: Discussionmentioning

confidence: 74%

The Epiphytic Fungus Pseudozyma aphidis Induces Jasmonic Acid- and Salicylic Acid/Nonexpressor of PR1-Independent Local and Systemic Resistance

et al. 2013

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Pseudozyma spp. are yeast-like fungi, classified in the Ustilaginales, which are mostly epiphytic or saprophytic and are not pathogenic to plants. Several Pseudozyma species have been reported to exhibit biological activity against powdery mildews. However, previous studies have reported that Pseudozyma aphidis, which can colonize plant surfaces, is not associated with the collapse of powdery mildew colonies. In this report, we describe a novel P. aphidis strain and study its interactions with its plant host and the plant pathogen Botrytis cinerea. This isolate was found to secrete extracellular metabolites that inhibit various fungal pathogens in vitro and significantly reduce B. cinerea infection in vivo. Moreover, P. aphidis sensitized Arabidopsis (Arabidopsis thaliana) plants' defense machinery via local and systemic induction of PATHOGENESIS-RELATED1 (PR1) and PLANT DEFENSIN1.2 (PDF1.2) expression. P. aphidis also reduced B. cinerea infection, locally and systemically, in Arabidopsis mutants impaired in jasmonic acid (JA) or salicylic acid (SA) signaling. Thus, in addition to direct inhibition, P. aphidis may inhibit B. cinerea infection via induced resistance in a manner independent of SA, JA, and Nonexpressor of PR1 (NPR1). P. aphidis primed the plant defense machinery and induced stronger activation of PDF1.2 after B. cinerea infection. Finally, P. aphidis fully or partially reconstituted PR1 and PDF1.2 expression in npr1-1 mutant and in plants with the SA hydroxylase NahG transgene, but not in a jasmonate resistant1-1 mutant, after B. cinerea infection, suggesting that P. aphidis can bypass the SA/NPR1, but not JA, pathway to activate PR genes. Thus, either partial gene activation is sufficient to induce resistance, or the resistance is not directed solely through PR1 and PDF1.2 but probably through other pathogen-resistance genes or pathways as well.

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Section: Discussionmentioning

confidence: 74%

The Epiphytic Fungus Pseudozyma aphidis Induces Jasmonic Acid- and Salicylic Acid/Nonexpressor of PR1-Independent Local and Systemic Resistance

et al. 2013

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“…The differences can be ascribed to differences in environmental conditions. In 1986, high temperature and low relative humidity caused crystallization of honeydew substitute and most likely reduced the growth of the phyllosphere mycoflora (Bashi and Fokkema, 1977). Therefore, the effects found were probably caused by honeydew per se, whereas the moderate temperatures and the occurrence of dew in 1987 were conducive to growth of saprophytic micro-organisms, which confounded the effects of honeydew.…”

Section: ) C ( ---------) D ( ---) and E ( ----)mentioning

confidence: 99%

Simulation of damage in winter wheat caused by the grain aphid Sitobion avenae. 1. Quantification of the effects of honeydew on gas exchange of leaves and aphid populations of different size on crop growth

Rossing

Wiel

1990

Netherlands Journal of Plant Pathology

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Damage in winter wheat caused by the grain aphid Sitobion avenae F., was studied in the laboratory and at field level.Honeydew substitute solution was applied to flag leaves of winter wheat plants. One and fifteen days after application, the rates of net carbon dioxide assimilation and transpiration were measured. The rate of dark respiration was significantly higher one day after application of honeydew substitute as compared to the control. Other parameters describing the carbon dioxide -light response were not significantly affected. Fifteen days after honeydew substitute application, the two experimental years yielded different results. Under hot and dry conditions, the rate of dark respiration was higher while the rate of carbon dioxide assimilation at high irradiance, the mesophyll conductance and the leaf nitrogen content were lower than for the untreated control. In addition, chlorotic symptoms were visible. At moderate temperature and relative humidity, the initial light use efficiency was significantly lower fifteen days after treatment with honeydew substitute whereas other parameters were not significantly affected.In field experiments at two locations natural aphid populations consisting of mainly S. ave11ae were treated weekly with an aphicide from crop development stages DC 71, 73, 75 and 77, respectively, to create infestations of different size and duration. In the unsprayed controls densities reached 15.8 and 44.4 aphids per tiller, amounting to 182 and 544 aphid-days, respectively. Crop samples were analysed weekly, starting at flowering. At the smaller natural infestation, no significant effect on any yield component nor on yield was found at any treatment. The larger infestation caused a significant reduction of leaf area index, leaf weight, amount of water-soluble carbohydrates and grain weight on various sample dates when the infestation was not sprayed before DC 75. No effects were found on tiller and grain density nor on nitrogen content of plant parts at harvest.

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“…The factors that lead to such great differences in epiphytic population sizes have not been elucidated. If epiphytic bacterial communities are limited in size by the presence of available and utilizable carbon and/or nitrogen sources, as suggested by recent studies (2,9,(43)(44)(45), then it might be expected that the availability of utilizable nutrient sources would vary greatly among leaves of the same plant and also among leaves of different plant species. There has been no detailed examination of the variation in leaf surface nutrient availability among leaves that would enable us to determine its contribution to epiphytic bacterial populations.…”

mentioning

confidence: 98%

“…This suggests that microorganisms growing on plant surfaces could be competing for a limited amount of nutrients, which in turn would determine the microbial carrying capacity of the leaf. Depending on the system studied, carbon compounds alone or both carbon and nitrogen compounds were shown to be limiting factors for bacterial and yeast populations on leaves (2,9,44,45). Furthermore, Wilson et al (43) have shown that plants genetically modified to produce opines supported higher population sizes of opine-utilizing microorganisms than nonmodified plants.…”

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confidence: 99%

Role of Leaf Surface Sugars in Colonization of Plants by Bacterial Epiphytes

Mercier

Lindow

2000

Appl Environ Microbiol

331

204

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The relationship between nutrients leached onto the leaf surface and the colonization of plants by bacteria was studied by measuring both the abundance of simple sugars and the growth of Pseudomonas fluorescens on individual bean leaves. Data obtained in this study indicate that the population size of epiphytic bacteria on plants under environmentally favorable conditions is limited by the abundance of carbon sources on the leaf surface. Sugars were depleted during the course of bacterial colonization of the leaf surface. However, about 20% of readily utilizable sugar, such as glucose, present initially remained on fully colonized leaves. The amounts of sugars on a population of apparently identical individual bean leaves before and after microbial colonization exhibited a similar right-hand-skewed distribution and varied by about 25-fold from leaf to leaf. Total bacterial population sizes on inoculated leaves under conditions favorable for bacterial growth also varied by about 29-fold and exhibited a right-hand-skewed distribution. The amounts of sugars on leaves of different plant species were directly correlated with the maximum bacterial population sizes that could be attained on those species. The capacity of bacteria to deplete leaf surface sugars varied greatly among plant species. Plants capable of supporting high bacterial population sizes were proportionally more depleted of leaf surface nutrients than plants with low epiphytic populations. Even in species with a high epiphytic bacterial population, a substantial amount of sugar remained after bacterial colonization. It is hypothesized that residual sugars on colonized leaves may not be physically accessible to the bacteria due to limitations in wettability and/or diffusion of nutrients across the leaf surface.

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Environmental factors limiting growth of Sporobolomyces roseus, an antagonist of Cochliobolus sativus, on wheat leaves

Cited by 77 publications

References 10 publications

The Epiphytic Fungus Pseudozyma aphidis Induces Jasmonic Acid- and Salicylic Acid/Nonexpressor of PR1-Independent Local and Systemic Resistance

The Epiphytic Fungus Pseudozyma aphidis Induces Jasmonic Acid- and Salicylic Acid/Nonexpressor of PR1-Independent Local and Systemic Resistance

Simulation of damage in winter wheat caused by the grain aphid Sitobion avenae. 1. Quantification of the effects of honeydew on gas exchange of leaves and aphid populations of different size on crop growth

Role of Leaf Surface Sugars in Colonization of Plants by Bacterial Epiphytes

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