Inhibiting phenylalanine ammonia lyase and cinnamyl-alcohol dehydrogenase suppresses Mla1 (HR) but not mlo5 (non-HR) barley powdery mildew resistances

1995 ◽  
Vol 47 (2) ◽  
pp. 119-140 ◽  
Author(s):  
R.J. Zeyen ◽  
W.R. Bushnell ◽  
T.L.W. Carver ◽  
M.P. Robbins ◽  
T.A. Clark ◽  
...  
2007 ◽  
Vol 97 (12) ◽  
pp. 1578-1583 ◽  
Author(s):  
E. Prats ◽  
F. Martínez ◽  
M. M. Rojas-Molina ◽  
D. Rubiales

Effects of phenylpropanoid and energetic metabolism inhibition on resistance were studied during appropriate host and nonhost cereal-rust interactions. In the appropriate barley–Puccinia hordei interaction, phenylalanine ammonia lyase (PAL) and cinnamyl alcohol dehydrogenase (CAD) inhibition reduced penetration resistance in two genotypes, suggesting a role for phenolics and lignins in resistance. Interestingly, penetration resistance of the barley genotype 17.5.16 was not affected by phenylpropanoid biosynthesis but penetration resistance was almost completely inhibited by D-mannose, which reduces the energy available in plant host cells. This suggests a parallel in the cellular basis of penetration resistance between 17.5.16 rust and mlo barleys powdery mildew interaction. Results revealed differing patterns of programmed cell death (PCD) in appropriate versus nonhost rust interactions. PAL and CAD inhibitors reduced PCD (hypersensitivity) in appropriate interactions. Conversely, they had no effect in PCD of wheat to P. hordei; whereas D-mannose dramatically reduced nonhost resistance and allowed colony establishment. The differential effects of inhibitors in the expression of the different resistances and the commonalities with the cereal-powdery mildew interaction is analyzed and discussed.


1998 ◽  
Vol 76 (7) ◽  
pp. 1282-1289 ◽  
Author(s):  
B Bucciarelli ◽  
H G Jung ◽  
M E Ostry ◽  
N A Anderson ◽  
C P Vance

Green internodal stem tissues of glasshouse grown Populus tremuloides were either wounded or wound-inoculated with Entoleuca mammata (Hypoxylon mammatum) and assayed for phenylalanine ammonia-lyase (PAL), caffeic acid - o-methyltransferase (CA-OMT), and cinnamyl - alcohol dehydrogenase (CAD) activity over a 96-h period. Lignin deposited in response to the treatments was analyzed by the Klason and the pyrolysis - gas chromatographic (GC) - mass spectroscopy (MS) methodologies. The wound-inoculated treatment resulted in a wound morphology congruent with a typical resistant and susceptible response to E. mammata. Wounding alone resulted in no morphological differences between the two genotypes. In wound-inoculated stem tissue PAL and CAD activities were substantially higher in the resistant relative to the susceptible genotype. Total Klason lignin was similar for both genotypes; however, pyrolysis-GC-MS analysis revealed a difference in the lignin monomeric composition between the two genotypes, with the susceptible genotype accumulating higher levels of hydroxyphenyl units relative to the resistant genotype. It is concluded that differences in PAL and CAD activity and the synthesis of distinct phenylpropanoid monomers distinguish the resistant from the susceptible aspen genotype. Alterations in boundary zone formation due to the differential synthesis of phenylpropanoid monomers and its effect on compartmentalization of the pathogen are discussed.Key words: aspen, Hypoxylon canker, phenylalanine ammonia-lyase, cinnamyl - alcohol dehydrogenase, caffeic acid - o-methyltransferase, disease resistance.


1998 ◽  
Vol 49 (2) ◽  
pp. 295-306 ◽  
Author(s):  
Nabila Yahiaoui, Christiane Marque ◽  
Hélène Corbière ◽  
Alain Michel Boudet

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