A microarray analysis highlights the role of tetrapyrrole pathways in grapevine responses to "stolbur" phytoplasma, phloem virus infections and recovered status.

After providing a picture of the global transcriptomic changes of grapevine responses to \u201cstolbur\u201d phytoplasma, the recovery status and molecular responses to the phytoplasma and virus co-presence were analyzed. NimbleGen\uae Vitis vinifera genome arrays were used. Lower transcript abundance of the genes involved in photosynthesis, trehalose, phospholipids was observed in response to the presence of \u201cstolbur\u201d phytoplasma. The expression of the genes involved in tetrapyrrole increased. The recovered plants showed that the transcripts involved in ATP synthesis and amino acid metabolism, secondary metabolism and biotic stress-related pathways increased. Recovery was associated with tetrapyrrole pathway repression. Co-infection with viruses induced the genes involved in the hormone categories (cytokinin, gibberellin, salicylic acid and jasmonates)

Defence mechanisms against insecticides temephos and diflubenzuron in the mosquito Aedes caspius: the P-glycoprotein efflux pumps

P-glycoproteins (P-gps) are efflux transporters found in cells of a broad range of both procaryotic and eukaryotic taxa, whose action is to relieve the cells of multiple, structurally dissimilar, toxic compounds. The possible role of P-gps in defence against the insecticides temephos and diflubenzuron was investigated in the mosquito Aedes caspius (Pallas), also known as Ochlerotatus (Aedes) caspius (Diptera: Culicidae), and the genomic DNA sequences encoding for P-gp transporters were isolated to provide molecular instruments for future research into the expression and characterization of genes codifying for P-gps in this mosquito species. Mosquito larvae were treated with insecticides alone and in conjunction with a sublethal dose of the P-gp inhibitor verapamil. The inhibition of P-gps reduced the LD 50 values of temephos and diflubenzuron by factors of 3.5 and 16.4, respectively, suggesting the potential involvement of P-gps in insecticide defence. Using a polymerase chain reaction (PCR)-based approach, a 481-bp sequence was isolated. The inferred nucleotide sequence shows high homology with the C-terminal sequence of known P-gps. The isolation and characterization of a putative P-gp sequence from Ae. caspius is the first step towards a better molecular understanding of the role played by multidrug transporters in the defence against insecticides in this species. This knowledge may open the way to a novel control strategy based on the inhibition of pest defences. The beneficial consequences of the inhibition of efflux pumps in improving insecticide performance are discussed

Molecular characterization of the laccase isoforms in fungi of Pleurotus genus.

Denmar

DNA-fingerprinting (AFLP and RFLP) for genotypic identification in species of the Pleurotus eryngii complex

Wild populations of edible species are important source of genetic variability for cultivated lines that can undergo a drastic loss of diversity resulting from man's selection. The development of tools aimed at the clear-cut and safe identification and assessment of genetic variability of the wild and cultivated strains is thus a fundamental goal of molecular genetic research. In this study, we used two polymerase chain reaction (PCR)-based fingerprinting methods-amplified fragment length polymorphism (AFLP) and restriction fragment length polymorphism (RFLP) of laccase and manganese peroxidase genes-to assess genetic differences among strains and independently evolving lineages belonging to the Pleurotus eryngii complex. Both laccase RFLP and AFLP have been proved to distinguish unambiguously the three taxa studied: Pleurotus ferulae, P. eryngii, and P. eryngii var. nebrodensis. AFLP also showed enough sensitivity to detect polymorphisms among the strains, proving to be an efficient DNA fingerprinting tool in studies of strain assignment. The divergent RFLP laccase and manganese peroxidase patterns are also discussed in relation to the role played by these genes in the interaction between these fungi and their host plants