Prevalence of Tobacco mosaic virus in Iran and Evolutionary Analyses of the Coat Protein Gene.

The incidence and distribution of Tobacco mosaic virus (TMV) and related tobamoviruses was determined using an enzyme-linked immunosorbent assay on 1,926 symptomatic horticultural crops and 107 asymptomatic weed samples collected from 78 highly infected fields in the major horticultural crop-producing areas in 17 provinces throughout Iran. The results were confirmed by host range studies and reverse transcription-polymerase chain reaction. The overall incidence of infection by these viruses in symptomatic plants was 11.3%. The coat protein (CP) gene sequences of a number of isolates were determined and disclosed to be a high identity (up to 100%) among the Iranian isolates. Phylogenetic analysis of all known TMV CP genes showed three clades on the basis of nucleotide sequences with all Iranian isolates distinctly clustered in clade II. Analysis using the complete CP amino acid sequence showed one clade with two subgroups, IA and IB, with Iranian isolates in both subgroups. The nucleotide diversity within each sub-group was very low, but higher between the two clades. No correlation was found between genetic distance and geographical origin or host species of isolation. Statistical analyses suggested a negative selection and demonstrated the occurrence of gene flow from the isolates in other clades to the Iranian population.

Pathogenicity of Pochonia species on eggs of Meloidogyne javanica.

Among fungi, species of the genus Pochonia Batista & O.M. Fonseca are considered as promising biological control agents with high potential to reduce root-knot nematode (RKN) and nematode populations. In this research we investigated Fars province of Iran for the presence of Pochonia spp., compared pathogenicity of different Pochonia species on eggs of RKN in vitro, and selected the best isolates for further studies. During 2004-2006, 128 soil samples of fields infested with cyst nematodes and 18 soil samples infested with RKN were collected from Fars province of Iran. In vitro pathogenicity tests were carried out on 36 isolates of Pochonia spp. obtained from CBS and IRAN culture collections. The seven best isolates of this experiment were selected for greenhouse test and their ability in controlling RKN was examined in natural soil. In greenhouse test fresh weight of plant's tops and roots, gall index, nematode multiplication, second-stage juveniles' population in soil, reproduction rate (P(f)/P(i)), proportion of infected eggs, control efficacy, root colonization and soil colony forming units were determined. In vitro pathogenicity of Pochonia on RKN eggs varied between 39% and 95% eggs infected. In greenhouse experiment, three isolates are promising for control of RKN and selected isolates are subjected to more extensive testing to determine their effectiveness in a range of conditions before being developed as commercial biological control agents.

Effect of Salvia officinalis L. leaves on serum glucose and insulin in healthy and streptozotocin-induced diabetic rats.

The leaves of sage (Salvia officinalis L., Lamiaceae) are reported to have a wide range of biological activities, such as anti-bacterial, fungistatic, virustatic, astringent, eupeptic and anti-hydrotic effects. To determine the hypoglycaemic effect of sage leaves, we investigated the effects of essential oil and methanolic effect of the plant on healthy and streptozotocin-induced diabetic rats. The animals were made diabetic using by streptozotocin (70 mg/kg, i.p.). The methanolic extract (100, 250, 400 and 500 mg/kg) and essential oil (0.042, 0.125, 0.2 and 0.4 ml/kg) were injected intraperitoneally. The control groups were administered water and sunflower oil as vehicles of methanolic extract and essential oil, respectively. Blood samples were obtained from retro-orbital sinus before administration and 1, 3 and 5 h after administrations. The serum glucose was measured by the enzymatic method of glucose oxidase. The results showed that the essential oil of sage did not change serum glucose, while the plant extract significantly decreased serum glucose in diabetic rats in 3h without effect on insulin releasing from the pancreas but not in healthy rats. Also, the LD(50) of the methanolic extract is measured (4000 mg/kg, i.p.). The present data indicate that sage extract has hypoglycaemic effect on diabetic animals and the plant should be considered in future therapeutic researches.