Evaluation of the efficacy of different concentrations of nano-capsules containing Talaromyces flavus with two forms of powder and suspension in reducing the incidence of cotton Verticillium wilt.

Previous domestic and foreign studies have shown the significant effect of Talaromyces flavus on growth inhibition of some important plant pathogens including Verticillium dahliae, Fusarium oxysporum f. sp. lycopersici and Fusarium oxysporum f. sp. cucumerinum. In Iran, it is necessary to produce new formulations of this fungus based on modern technologies given the importance of attracting companies producing biological control agents and transferring the technical knowledge of mass production of formulations of these agents to them. In the present study, based on the method presented in the Pesticide Research Department of the Iranian Plant Protection Research Institute, two types of T. flavus formulations in the form of nano-capsules containing Talaromyces flavus with two forms of powder and suspension were prepared using nanotechnology. In the next step, during the greenhouse examination, the efficiency of each of these new formulations in concentrations of one to five per thousand for soil addition method and concentration of five per thousand for seed impregnation method (six treatments for each of the two new formulations) was compared with the registered formulation of Talaromin in two methods of seed impregnation and soil addition with healthy control and infected control to control cotton Verticillium wilt disease, in the form of a randomized complete block design with 16 treatments and 5 replications. After statistical analysis of the data obtained by Duncan's Multiple Range Test by MS TAT C software, the results showed that in terms of disease severity among treatments with the previous formulation (Talaromin) with each of the methods of soil addition and seed impregnation, there was no statistically significant difference between nano-suspension with each of the concentrations of one, four and five per thousand by the soil addition method and nano-powder with each of the concentrations of two and three per thousand by soil addition method, and the mentioned treatments were included in one statistical group in terms of disease severity with healthy control.

Development of EST-SSR markers related to disease resistance and their application in genetic diversity and evolution analysis in Gossypium.

Cotton (Gossypium spp) is one of the most economically important crops that provide the world's most widely used natural fiber. Diseases such as Fusarium wilt and particularly Verticillium wilt seriously affect cotton production, and thus breeding for disease resistance is one of the most important goals of cotton breeding programs. Currently, potential exists to improve disease resistance in cultivated cotton. Increasing the understanding of the distribution, structure, and organization of genes or quantitative trait loci for disease resistance will help the breeders improve crop yield even in the event of disease. To facilitate the mapping of disease-resistance quantitative trait loci to achieve disease-resistant molecular breeding in cotton, it is necessary to develop polymorphic molecular markers. The objective of this study was to develop simple sequence repeat markers based on cotton expressed sequence tags for disease resistance. The efficacy of these simple sequence repeat markers, their polymorphisms, and cross-species transferability were evaluated. Their value was further investigated based on genetic diversity and evolution analysis. In this study, the unique sequences used to develop markers were compared with the G. arboretum and G. raimondii genome sequences to investigate their position, homology, and collinearity between G. arboretum and G. raimondii.

Effects of nitric oxide on sunflower seedlings: A balance between defense and development.

Nitric oxide (NO) is a major plant signaling molecule that plays key roles during plant-pathogen interactions and plant development. Previous work showed the participation of NO in the development and lignin composition of sunflower roots. Thereby, we have hypothesized that NO applications could control the attack of the fungal pathogen Verticillium dahliae in sunflowers. Seedlings growing hydroponically were pretreated with NO donors and further inoculated with the fungus. Evaluation of disease symptoms showed that NO pretreatments could not reduce Verticillium wilt. Strikingly, NO donors appear to promote the fungal infection. These results indicate that NO applications were unable to protect sunflowers from Verticillium attack and highlight the role played by the fine tuning regulation of NO levels required to balance plant responses between development and defense.

Sources of Verticillium dahliae affecting lettuce.

ABSTRACT Since 1995, lettuce in coastal California, where more than half of the crop in North America is grown, has consistently suffered from severe outbreaks of Verticillium wilt. The disease is confined to this region, although the pathogen (Verticillium dahliae) and the host are present in other crop production regions in California. Migration of the pathogen with infested spinach seed was previously documented, but the geographic sources of the pathogen, as well as the impact of lettuce seed sparsely infested with V. dahliae produced outside coastal California on the pathogen population in coastal California remain unclear. Population analyses of V. dahliae were completed using 16 microsatellite markers on isolates from lettuce plants in coastal California, infested lettuce seed produced in the neighboring Santa Clara Valley of California, and spinach seed produced in four major spinach seed production regions: Chile, Denmark, the Netherlands, and the United States (Washington State). California produces 80% of spinach in the United States and all seed planted with the majority infested by V. dahliae comes from the above four sources. Three globally distributed genetic populations were identified, indicating sustained migration among these distinct geographic regions with multiple spinach crops produced each year and repeated every year in coastal California. The population structure of V. dahliae from coastal California lettuce plants was heavily influenced by migration from spinach seed imported from Denmark and Washington. Conversely, the sparsely infested lettuce seed had limited or no contribution to the Verticillium wilt epidemic in coastal California. The global trade in plant and seed material is likely contributing to sustained shifts in the population structure of V. dahliae, affecting the equilibrium of native populations, and likely affecting disease epidemiology.