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Asiatic citrus canker is a devastating disease resulting in drastic economic losses in citriculture worldwide. Amongst three different types of the disease, i.e. A, A* and A^w, the A* type is genetically less known. In order to comprehend the behavior of the Asiatic citrus canker A*-type strain (Xanthomonas citri subsp. citri) in the vicinity of the host cells, a targeted semi-quantitative transcript analysis approach via RT-PCR was carried out. A subset of sixteen genes, as representative of different steps involved in phytopathogencity, was analyzed on the culture medium (as uninduced) and compared with the subset isolated from the infected Mexican lime (Citrus auarntifolia L.) plants (as induced). The results showed that certain genes were up-regulated in induced condition, suggesting a putative role in bacteria-host interaction. Furthermore, the transcripts in induced condition could be classified into constitutive, early- and late-responsive genes, demonstrating their functional relevance during the host-pathogen interaction.    

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Citrus canker has worldwide distribution and is still a devastating disease caused by the bacteria Xanthomonas citri subsp. citri (Xcc). With the aim of evaluating C. aurantifolia response mechanism, plant leaves non-inoculated and inoculated with the bacteria were collected in 1, 4, and 7 days post-inoculation. Consequently, the chlorophyll pigment content and fluorescence were determined, and proteomics study was conducted. Results indicated that pathogen infection, despite the negative effect on chlorophyll pigment content, improved the physiological condition. The maximum efficiency of PSII photochemistry and PSII quantum Yield (YPSII) as well as photochemical quenching increase were observed in infected plants compared to the control, whilst non-photochemical quantum decreased during infection. Judging by the results, the proteomic analysis revealed that these responses were mirrored by rapid changes in the host proteome that included the up-regulation of carbohydrate metabolism proteins and down-regulation of the ATP generating proteins during pathogen infection. The results indicated that the pathogen manipulates the host homeostasis by its effector proteins to exploit in its favor.

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Developing high-yielding varieties of sunflower as oilseed staple crops requires knowledge of physiological and molecular mechanisms involved in yield formation. Source strength, sink demand, and their interactions play crucial roles in the yield formation of sunflowers. The persistence of assimilate flux to the developing grains mainly determines sink demand. There was no information on the molecular mechanism for assimilate flux to the sink organ of sunflowers. To shed light on molecular events engaging in assimilate flux to sink organs, two experiments were carried out on five sunflower inbred lines differing in their grain yields. Source-related parameters (such as leaf biomass, area, and number) and sink-associated attributes (such as floret number at the first anthesis and capitulum biomass and diameter, in addition to changes in biomass of capitulum and stem, at the first anthesis with those at physiological maturity) were evaluated across all the inbred lines. The Invertase gene expression level was measured on the receptacle base of three inbred lines, showing discrepancies in the source, sink, and grain yield performances. While no significant correlation was found between source strength and sink demand with grain yield, the results showed that higher grain yield was likely attributed to the persistence of assimilate flux to the capitulum base during grain filling. This phenomenon is discussed to be due to higher Invertase activity in the receptacle base.