Application of cell and tissue culture and in vitro selection for disease resistance breeding — a review
ABSTRACT Somaclonal variation, i.e. the variation induced by cell and tissue culture, offers an opportunity to broaden the genetic variation of crops. As a result of somaclonal variation a wide range of plant characteristics can be altered. However, the selection of agronomically important traits, e.g. disease resistance, has many limitations. The efficiency of selection can be increased by the application of in vitro selection procedures. Selection strategies that may be applied to obtain disease resistant somaclonal variants are described. Their merits and limitations, in relation to the efficiency of the procedures, the frequency of disease resistant variants and the genetics of the resistance obtained, are discussed.
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ABSTRACT: A bioassay system using peach mesophyll cells stained with fluorochrome merocyanine 540 (MC-540) (a probe of membrane potential and other structural and functional changes in biological membranes) was developed to detect toxin activity in culture filtrates of Xanthomonas campestris pv. pruni and to compare the response of cells from bacterial leaf spot resistant and susceptible cultivars to culture filtrates of X. c. pv. pruni. Maximum changes in fluorescence intensity occurred when peach cells from susceptible cultivar Sunhigh were exposed to culture filtrates of virulent strains of X. c. pv. pruni. Smaller changes occurred when Sunhigh cells were exposed to culture filtrates of slightly virulent strains of X. c. pv. pruni and to nutrient broth. Transient changes occurred when Sunhigh cells were exposed to culture filtrates from non-pathogenic X. c. pv. pelargonii. Significantly greater changes occurred when leaf mesophyll cells from bacterial leaf spot-susceptible cultivars were exposed to culture filtrates of X. c. pv. pruni compared with cells from resistant cultivars. These results suggest that a toxic metabolite(s) present in culture filtrates of X. c. pv. pruni may play a role in bacterial spot of peach and may be an effective screening agent in a cell selection program. In addition, the peach mesophyll-merocyanine 540 bioassay system may be useful in screening peach germplasm for resistance to X. c. pv. pruni.01/1984;
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ABSTRACT: Calli derived from immature embryos of barley and wheat genotypes were screened for their resistance to purified culture filtrate produced by the fungus Helminthosporium sativum P.K. and B. Two selection methods were used: a continuous method in which four cycles of selection were performed one after another on toxic medium and a discontinuous method in which a pause on non-toxic medium was given after the second or third cycle of selection. The latter was superior as it allowed the calli to regain their regeneration ability. About 3,000 calli from two barley genotypes and 2,000 from two wheat genotypes were used for selection. The selection with the pathotoxins resulted in 6% to 17% surviving calli. Toxin tolerant callus lines of barley were characterised by protein isozymes. Zymograms showed one more isozyme than with the unselected sensitive callus. Barley and wheat plants have been regenerated from callus lines surviving the toxin treatment and in vivo testing against pathogen revealed that the majority of these plants were less sensitive.Theoretical and Applied Genetics 10/1987; 74(6):841-5. · 3.66 Impact Factor
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ABSTRACT: Plants were regenerated from callus derived from cotyledons and first true-leaves of the lettuce cultivars Salad Bowl, Lobjoits Cos and Pennlake. Sexual progeny of these regenerants were assessed under glasshouse and field conditions for variation including reaction to lettuce mosaic virus (LMV) and downy mildew (Bremia lactucae). All three cultivars exhibited somaclonal variation. Mutations detected at the seedling stage included reduced vigour, albinism and changes in chlorophyll content, with most being recessive. Variation for leaf shape and vigour was detected in mature plants. One line exhibited increased yield and chlorophyll content together with early flowering. Enhanced and reduced susceptibility to both LMV and B. lactucae were observed. Reduced susceptibility to B. lactucae was indicated by an extended latent period following inoculation in two lines. Reduced susceptibility to LMV in glasshouse trials could not be confirmed in the field although one such line exhibited an improved yield and a second line segregated 1:1 in glasshouse tests for plants which were obviously infected and those without symptoms. All variable lines were diploid.Annals of Applied Biology 02/2008; 109(2):391 - 407. · 2.15 Impact Factor