Helminthosporium:  secondary metabolites, southern leaf blight of corn, and biology

Hesseltine, C. W.; Ellis, J. J.; Shotwell, Odette L.

doi:10.1021/jf60176a020

Cited by 22 publications

(9 citation statements)

References 53 publications

(65 reference statements)

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“…After repeated recrystallization, TLC revealed a major component with an RF (0.5) identical to that of authentic ophn A and a small amount of a second component with higher mobility. Nuclear magnetic resonance and low resolution mass spectra of this material corresponded to published data (6,12). Plant Material.…”

supporting

confidence: 66%

“…Further investigation suggests that the carbohydrate leakage can be ascribed to the presence, in crude toxin preparations, of ophn A. Ophiobolin A (Fig. 1) is a sesterterpene compound originally isolated from Helminthosporium oryzae (Cochliobolus miyabeanus) (11,15) and also produced by several related fungal species including H. maydis (6,19). The chemical properties have been investigated thoroughly (ref.…”

mentioning

confidence: 99%

“…The chemical properties have been investigated thoroughly (ref. 6 and references therein), but the phytotoxicity has been characterized incompletely. Orsenigo (15) showed that ophn A at concentrations as low as 30 ,g/ml inhibited the elongation of rice coleoptiles and seedling roots and of oat coleoptiles.…”

mentioning

confidence: 99%

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Effects of Ophiobolin A on Ion Leakage and Hexose Uptake by Maize Roots

Tipton¹,

Paulsen²,

Betts³

1977

Plant Physiol.

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Ophiobolin A, a sesterterpene metaboHte ofHelminthosporium maydis, Nisikado and Miyake, stimulates net leakage of electrolytes and glucose from maize (Zea mays L.) seedlng roots. Treatmnent of the roots with ophiobolin A at a concentration of 10 ag/nd (25 jAm) inhbits uptake of 10 mM 2-deoxyglucose by 50% and of 0.5 mM 2-deoxyglucose by 85%. Compartmental (15) showed that ophn A at concentrations as low as 30 ,g/ml inhibited the elongation of rice coleoptiles and seedling roots and of oat coleoptiles. Treatment of beet root slices with ophn A caused leakage of anthocyanin. In a later report (16), leakage of phosphate and organic compounds from corn seedling roots and from potato tuber discs was mentioned. The inhibition of rice seedling growth was confirmed by Ohkawa and Tamura (13) and it was shown by Oku (14) that ophn A could be isolated from infected rice leaves, suggesting that ophiobolin toxicity may play a role in disease development.In this paper, we report that ophn A is an effective inhibitor, at low concentrations, of hexose uptake in maize and carrot roots and stimulates ion leakage from these tissues. (10) with the addition of 0.02 g FeSO4 7H20 and 1 g yeast extract/l; pH of the medium was 5.6. Spore suspensions were used to inoculate 200-ml portions of medium in 2,800-ml Fernbach flasks, and the flasks were incubated at 25 ± 1 C in a growth chamber with approximately 1200 ft-c of continuous light.After 10 days, the growth medium was separated from the mycelial mats by straining through four layers of cheesecloth and filtering through Whatman No. 1 filter paper. The combined filtrate (12 liters) was transferred to a liquid-liquid extractor and extracted with diethyl ether for a total of 12 hr. The ether extract was dried with sodium sulfate and taken to an orange, nondrying oil by evaporation under vacuum at 45 C. The oil was dissolved in methylene chloride and crystallized by the addition of heptane. Washing with cold diethyl ether yielded 283 mg of white, needle-shaped crystals. Progress of the purification was monitored by TLC on Silica Gel GF254 plates developed with chloroform-methanol (100:2, v/v), and visualized by spraying with 1 % phosphomolybdic acid in methanol followed by heating at 100 C for 2 min. After repeated recrystallization, TLC revealed a major component with an RF (0.5) identical to that of authentic ophn A and a small amount of a second component with higher mobility. Nuclear magnetic resonance and low resolution mass spectra of this material corresponded to published data (6, 12).Plant Material. Corn seeds (Zea mays L., W64A, N or T cytoplasm) were washed with water and placed in 20% H202 for 30 min. The seeds were washed three times with sterile distilled H20 and transferred aseptically into sterile Petri dishes lined with two filter paper discs and moistened with 5 ml of 0.1 mm CaCl2. Ten seeds were placed in each dish. The seeds were incubated for 3 days at 30 C in the dark. The root tips (approximately 2.5 cm) of the germinated seeds were removed for use in 90...

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Effects of Ophiobolin A on Ion Leakage and Hexose Uptake by Maize Roots

Tipton¹,

Paulsen²,

Betts³

1977

Plant Physiol.

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“…It causes northern leaf blight, one of the dominant fungal diseases of modern maize (Borchardt et al, 1998;The CIMMYT Maize Program, 2004). Other fungal pathogens detected in both teosintes and maize are Puccinia polyspora, Puccinia sorghi, Physopella zeae (Robert, 1962), Physoderma zeae-maydis (Eddins, 1933), Sorosproium spp., Ustilago kellermanii (Borlaug, 1946), Claviceps gigantea (Fuentes et al, 1964), Gibberella fujikuroi (Steenkamp et al, 2001), and Cochliobolus heterostrophus (Hesseltine & Ellis, 1971). Another welldescribed fungal pathogen, which is also known to attack teosintes, is Ustilago maydis (Banuett, 1995).…”

Section: Pathogens Associated With Maize and Teosintesmentioning

confidence: 99%

Insect and pathogen attack and resistance in maize and its wild ancestors, the teosintes

et al. 2014

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SummaryMaize (Zea mays ssp. mays) is one of the most important crops worldwide and there are many reports in the literature on its constitutive and inducible defenses against pathogens and insects. However, research on its wild ancestors, the teosintes, with respect to resistance against these antagonists is limited. Here, we review what is known about the different arthropods and microbes that are associated with maize and teosintes in Mexico and Central America, the area of origin, and evaluate the plants' mechanisms of resistance against biotic stresses. Teosintes appear to have greater resistance against a number of pests than their cultivated counterpart. We therefore highlight the need to study the teosintes in order to identify resistance traits that can be improved in maize. As teosintes are at risk of becoming extinct, there is a need to protect their germplasm for future generations.

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“…Ophiobolin A is a fungal metabolite and a phytotoxin produced by the plant pathogen Helminthosporium maydis Nisikado and Miyake and by other members of the same genus (Hesseltine et al, 1971). In roots of maize seedlings ophiobolin A causes a leakage of electrolytes and Glc from cells (Tipton et al, 1977).…”

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Identification of the Binding and Inhibition Sites in the Calmodulin Molecule for Ophiobolin A by Site-Directed Mutagenesis

Leung

1998

Plant Physiology

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Ophiobolin A, a fungal toxin that affects maize and rice, has previously been shown to inhibit calmodulin by reacting with the lysine (Lys) residues in the calmodulin. In the present study we mutated Lys-75, Lys-77, and Lys-148 in the calmodulin molecule by site-directed mutagenesis, either by deleting them or by changing them to glutamine or arginine. We found that each of these three Lys residues could bind one molecule of ophiobolin A. Normally, only Lys-75 and Lys-148 bind ophiobolin A. Lys-77 seemed to be blocked by the binding of ophiobolin A to Lys-75. Lys-75 is the primary binding site and is responsible for all of the inhibition of ophiobolin A. When Lys-75 was removed, Lys-77 could then react with ophiobolin A to produce inhibition. Lys-148 was shown to be a binding site but not an inhibition site. The Lys-75 mutants were partially resistant to ophiobolin A. When both Lys 75 and Lys-77 or all three Lys residues were mutated, the resulting calmodulins were very resistant to ophiobolin A. Furthermore, Lys residues added in positions 86 and/or 143 (which are highly conserved in plant calmodulins) did not react with ophiobolin A. None of the mutations seemed to affect the properties of calmodulin. These results show that ophiobolin A reacts quite specifically with calmodulin.

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Helminthosporium: secondary metabolites, southern leaf blight of corn, and biology

Cited by 22 publications

References 53 publications

Effects of Ophiobolin A on Ion Leakage and Hexose Uptake by Maize Roots

Effects of Ophiobolin A on Ion Leakage and Hexose Uptake by Maize Roots

Insect and pathogen attack and resistance in maize and its wild ancestors, the teosintes

Identification of the Binding and Inhibition Sites in the Calmodulin Molecule for Ophiobolin A by Site-Directed Mutagenesis

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