Effects of <i>Helminthosporium maydis</i> race T toxin on protoplasts of resistant and susceptible corn (<i>Zea mays</i>)

Pelcher, Lawrence E.; Kao, K. N.; Gamborg, O. L.; Yoder, O. C.; Gracen, Vernon

doi:10.1139/b75-052

Cited by 32 publications

(6 citation statements)

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“…3b and 5). These results are consistent with the observations that N versions of maize are partially toxin-sensitive in the root elongation bioassay (7,20), as well as in other physiological phenomena (4,8,9,22 Root elongation, and thus the physiological age of cells, was found to be an important factor in demonstrating the sensitivity of maize roots to the toxin complex. This was found for both the basal (Fig.…”

Section: Discussionsupporting

confidence: 90%

Influence of Helminthosporium maydis, Race T, Toxin on Potassium Uptake in Maize Roots

Frick¹,

Nicholson²,

Hodges³

et al. 1976

Plant Physiol.

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The effect of a toxin extract of Helminthosporium maydis, race T on K + (86Rb) uptake by excised root segments of normal (N) and Texas cytoplasmic male-sterile (T) versions of corn inbred W64A was investigated. The uptake of K+ was inhibited in both N and T roots by the toxin. This was true for both basal (freshly excised) and augmented (pretreated with aeration) K+ uptake. Augmented uptake was more toxin-sensitive than basal uptake (irrespective of cytoplasm type), and the augmented uptake in T roots was seven to eight times more toxin-sensitive than in N roots.Specific zones of roots differed in their basal and augmented K+ uptake rates as well as their toxin sensitivities. The root apex of T was more sensitive to toxin than the apex of N roots when basal K+ uptake was measured. In mature zones of the root, T was more sensitive than N when augmented rates were measured. During the development of the augmented K+ uptake capacity in either N or T roots, the sensitivity to the toxin did not change; uptake in N roots was inhibited by 10 to 25% and uptake in T roots was inhibited by 70 to 80%. The difference in toxin sensitivity of K+ uptake between N and T roots may be due to N possessing a protective mechanism which is deficient in T.The extreme susceptibility of Texas cytoplasmic male-sterile (T) maize to Southern Corn Leaf Blight is cytoplasmically conditioned and inherited in association with the non-Mendelian determinant of male sterility (12,18). T versions of a given maize inbred are more susceptible to Helminthosporium maydis, race T than normal cytoplasmic (N) versions (7, 10). The fungal pathogen synthesizes a toxin complex which accounts for this difference in levels of susceptibility of the host cytoplasmic types (7,8 Table I and Figure 1, the absorption period was 60 min during which time some augmentation occurred. The segments were exposed to label and toxin simultaneously. Labeled segments were washed for 20 min in 40 ml of cold I mM CaSO4, weighed, and assayed for " Rb content by liquid scintillation spectrometry. Transfer of segments between solutions was by filtration on a Buchner funnel. Influx of K+ and 86Rb were taken to be equivalent using tissue grown in the absence of exogenous K+ (17).Basal rates of K+ uptake were measured in freshly cut root segments, whereas augmented rates were measured after aeration of segments in distilled H20. This augmented uptake potential has been referred to as in "induced" ion uptake (19), or as "aging" (1, 16) and may be an important feature of the transport process.Helminthosporium maydis Nisikado and Miyake, race T, was grown for 8 to 10 days in shake culture (100 rpm, 24 C) on Fries medium (26), without micronutrients. The culture fluid was filtered through cheesecloth, concentrated to one-tenth volume by flash evaporation at 45 C, and precipitated (12 hr, 4 C) with two volumes of cold methyl alcohol. The precipitate was removed by centrifugation and the methyl alcohol was removed from the aqueous-methyl alcohol phase by flash evaporation. The rema...

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Section: Discussionsupporting

confidence: 90%

Influence of Helminthosporium maydis, Race T, Toxin on Potassium Uptake in Maize Roots

Frick¹,

Nicholson²,

Hodges³

et al. 1976

Plant Physiol.

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“…Wolf and Earle (1990) also found that after HC toxin treatment the number of surviving maize calli varied depending on the genotype . Similar observations have been made by various authors also on different species (Pelcher et al ., 1975 ;Arcioni et al ., 1987 ;Chawla & Wenzel, 1987 ;Binarova et al ., 1990 ;Liu et al ., 1991) . The 2% to 8% regeneration frequency of calli selected on MST medium was approximately ten times lower in average as compared to that under non-toxic conditions .…”

Section: Response Of Wheat Genotypes To In Vitro Selection and Plant supporting

confidence: 93%

In vitro techniques for selecting wheat (Triticum aestivum L.) for Fusarium-resistance. II. Culture filtrate technique and inheritance of Fusarium-resistance in the somaclones

et al. 1996

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Calli of resistant, intermediary and susceptible wheat (Triticum aestivum L .) varieties were selected using culture filtrates of Fusarium graminearum and F culmorum and the regenerants were evaluated for resistance up to R3 .Czapek-Dox broth medium was inoculated with mycelia of Fusarium isolates and incubated for 2-6 weeks . Filtrates were added to MS callus growing medium, then 5 weeks-old calli were transferred onto this medium (MST) for 4-5 weeks . MST containing 30% filtrate was found to be suitable for selection . Resistant calli were transferred again to fresh MST for further two selection cycles. The surviving calli produced less fertile regenerated lines (Ro) than the non-selected ones . Among 18 R, lines tested for Fusarium-resistance in the seedling stage by artificial inoculation in the greenhouse, two (11 .1%) were significantly more resistant, one (5 .6%) was more susceptible than the original cultivar and the rest (83 .3%) behaved similarly to the donor plants. Among unselected R3 lines of three varieties, practically the same number of resistant plants were found as among the related selected ones .When the R3 selfed generations obtained through double-layer and culture filtrate selection techniques were tested for Fusarium-resistance, 35 .7% of the lines were found to be more resistant than the original cultivars, none was more susceptible and 64 .3% had a reaction similar to that of the source materials . Thus, inheritance of the disease reaction was not stable in all cases . Success of in vitro selection for Fusarium-resistance depended also on the genotype, and toxin analysis showed that although being effective, the selective media contained deoxynivalenol only exceptionally. In selecting wheat for Fusarium-resistance in vitro, the culture filtrate technique proved better than the double-layer procedure .

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“…several Helminthosporiurn toxins (Gengenbach et al, 1977;Ling et al, 1985;Rines & Luke, 1985;Chawla & Wenzel, 1987b). For many host-specific toxins an excellent correlation has been demonstrated between resistance to the pathogen at the plant level and insensitivity to the toxin at the cellular level (Strobel, 1975;Pelcher et al, 1975;Earle, 1982;Gendloff et al, 1987;Ishida & Kumashiro, 1988). However, examples showing that resistance to host-specific toxins was not expressed at the cellular level are also known, e.g.…”

Section: Selection With Phytotoxinsmentioning

confidence: 99%

Application of cell and tissue culture and in vitro selection for disease resistance breeding — a review

Bulk

1991

Euphytica

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Effects of Helminthosporium maydis race T toxin on protoplasts of resistant and susceptible corn (Zea mays)

Cited by 32 publications

References 0 publications

Influence of Helminthosporium maydis, Race T, Toxin on Potassium Uptake in Maize Roots

Influence of Helminthosporium maydis, Race T, Toxin on Potassium Uptake in Maize Roots

In vitro techniques for selecting wheat (Triticum aestivum L.) for Fusarium-resistance. II. Culture filtrate technique and inheritance of Fusarium-resistance in the somaclones

Application of cell and tissue culture and in vitro selection for disease resistance breeding — a review

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