Phenylalanine ammonia lyase mRNA accumulation, enzyme activity and cytoplasmic responses in barley isolines, differing at Ml-a and Ml-o loci, attacked by Erysiphe graminis f.sp.hordei.

摘要: Seedling leaves of two pairs near-isogenic barley lines were inoculated with conidia the powdery mildew fungus, Erysiphe graminis D.C. f.sp. hordei Marchal, race 3. One set isolines (RISO 5678-R and RISO 5678-S) differed at Ml-o locus where recessive allele ( ml-o ) confers a high degree non-specific, penetration-based papilla-associated resistance to E. , while dominant allows proportion attacking fungal germlings succeed in infecting. The second isoline (Algerian-R Algerian-S) Ml-a race-specific, epidermal cell death visible only by light microscopy. ml-a Leaf samples taken 0, 2, 4, 6, 8, 10, 12, 15, 18, 21 24 h after inoculation examine timing host cytoplasmic aggregate responses (visible microscopy) relative phenylalanine ammonia-lyase (PAL) mRNA transcript accumulation (determined quantitative northern blots), PAL enzyme activity (using radiolabellcd phenylalanine). produced primary germ-tubes (PGTs) within 2 appressorial 6–10 inoculation. In all isolines, aggregates formed subsequently dispersed beneath PGTs, between 10 h, appressoria 6 15 h. Concurrently, biphasic patterns accumulation, typified peaks 4 12 occurred isolines. Temporal roughly similar those accumulation. Fungal germ-tube contact initiated cytological common induced increased regardless Mendelian inheritance “major gene factors” sets. Thus, there was induction associated general defence infection, but no unusually strong correlation major found.