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Citrus greening or Huanglongbing (HLB), a destructive disease of citrus worldwide, was reported from south of Iran in 2007. The molecular basis of compatibility and disease development in this system is poorly understood. We have carried out a cDNA-AFLP analysis to analyse gene expression of grapefruit infected by Candidatus Leiberibacter asiaticus in the late infection stage. We have applied a cDNA-AFLP approach on grafted infected grapefruit trees at the representing symptoms stage in susceptible host. Selective amplifications with 10 primer combinations allowed the visualization of approximately 24 transcript-derived fragments (TDFs) in the leaves of graft-inoculated trees, which were differentially expressed. We sequenced 14 fragments, which were identified as grapefruit transcripts after homology searching, whereas 12 were not homologous to sequences in NCBI databases. Many grapefruit genes spanning almost all functional categories were upregulated during infection, especially genes involved in ATP synthesize, cytochrome P450 synthesize, isoflavone 2'-hydroxylase, zeaxanthin epoxidase, cellulose synthase, DNA repair protein, aconitate hydratase 2 and citrus tristeza virus resistance gene. This study provides the first global catalogue of grapefruit genes expressed during inoculation, together with their functional annotations. This will help to elucidate the molecular basis of the resistance process and identify genes and chemicals that could help to inhibit the pathogen.

Plasma electrolytic boriding (PEB) is a kind of plasma electrolytic saturation (PES) which is a relatively new surface engineering treatment to produce nanocrystalline coatings. This method of treatment provides high abrasion and corrosion resistance because of the nanocrystalline interlayer formation. In this study, PEB was applied on low alloy steel substrates, and the surface morphology and phase composition of the internal nanocrystalline layer formed has been studied using X-ray diffraction and scanning electron microscopy. Coating wear properties were assessed by conducting pin-on-disk wear tests. The corrosion resistance and electrochemical properties of the nanocrystalline coating were investigated by measuring the linear polarization resistance and also electrochemical impedance spectroscopy (EIS).

In present study, the feasibility of improving tribological performance of low carbon chromium steel by applying complex surface treatments which combines the method of Plasma electrolytic saturation (PES) is investigated. The different regimes of diffusion treatments on the surface affect the mechanical and tribological characteristics of the steel substrates by production of nanocrystalline interlayers. The major advantage of the PES technique was shown to be the extremely high nanocrystalline coating growth rate by the aggressive ionized particles. The combination of characteristics far exceeds the capabilities of the diffusion procedure by means of PES technique. It was found that the different compositions of interlayers produced by means of complex diffusion treatments eliminate the sharp slope of the microhardness profile. The gradual decrease of microhardness with distance from the surface, provides a good tribological performance. The boride layer reveals the highest value of microhardness among the produced interlayers. In the case of tribological performance, the boronitrided sample shows the best characteristics which are related to the formation of nanocrystalline nitride layer beneath the top boride layer.