Infection process was similar on the surface of the lemma, palea and glume. Growth of the fungus in the epidermal and parenchyma cells was found predominantly in the cell walls, and hyphae also extended intercellularly and intracellularly. Infection of seeds appeared to occur via two ways: (i) direct infection of the outer layers of the cell walls of the pericarp and (ii) through entering the stigma into the pericarp cells. Secretion of host cell wall hydrolytic enzymes at the apex of the penetrating hyphae

may facilitate the spread of the fungus. In addition, toxins secreted by the fungus might explain the rapid death of host cells in contact with or distant to fungal cells. A host response to fungal infection involved NVP-LDE225 mouse the development of appositions between cell wall and plasma membrane in cells adjacent to fungal cells. Fungal hyphae were sometimes also surrounded by electron dense material. “
“The genome of Potato virus Y is a single-stranded, positive-sense RNA molecule that encodes a single large polypeptide that is cleaved by self-encoded proteases into 10 functional proteins. Using specific primers designed based on the cloned genome sequence of the necrotic strain of Potato virus Y (PVYN), we amplified 400 bp and 500 bp cDNA fragments from the 3′ ends of P1, HC-Pro, P3, CI, Vpg, NIa, NIb and CP genes. These cDNA fragments were then inserted into the binary vector pROKII

to construct the vectors pROK-P1, pROK-HC-Pro, pROK-P3, pROK-CI, pROK-NIa-Vpg, pROK-NIa-Pro, pROK-NIb and pROK-CP, all of which contained hairpin RNAs (hpRNAs). These recombinant binary vectors were introduced into Agrobacterium tumefaciens strain Rapamycin chemical structure LBA4404 and then into Nicotiana tabacum L. var. NC89 plants, respectively. Virus challenge inoculation indicated that the plants transformed with each construct were resistant to PVY infection, and the percentage

MCE公司 of resistant plants obtained ranged from 33–64%. Northern blot showed an inverse correlation between transgenic transcript accumulation and virus resistance. siRNAs could be detected in all the resistant plants. We also studied the relationship between the secondary structure and the gene-silencing efficiency and found a positive correlation between local free energies (ΔGloc) and the virus-resistance ratio. For each construct, one line of progeny T1 was randomly selected to analyse the inheritance of the transgene and the resistance. All transgenic single locus lines were completely resistant, and this resistance could be stably inherited. “
“Fungi (17 species), oomycetous organisms (four species of Pythium) and a plasmodiophorid (Polymyxa graminis) were recorded in wheat roots analysed by cloning of the total ITS1/2 rDNA and sequencing of representative clones. Roots of a fourth successive wheat crop were inhabited mostly by fungal pathogens including Gaeumannomyces graminis var. tritici, Monographella nivalis var. nivalis, Ophiosphaerella sp. and Helgardia anguioides.