Project description:Epidemics of coffee leaf rust (CLR) lead to great yield losses and huge depreciation of coffee marketing values, if no control measures are applied. Societal expectations of a more sustainable coffee production are increasingly imposing the replacement of pesticide treatments by alternative solutions. A good protection strategy is to take advantage of the plant immune system by eliciting its constitutive defenses. Based on such concept, plant resistance inducers (PRIs) have been developed. The Greenforce CuCa formulation made by UFLA (Brazil) is, in addition to acibenzolar-S-methyl (ASM), showing promising results in the control of CLR (Hemileia vastatrix) in Coffea arabica. In order to improve our understanding of the molecular mechanisms of the PRIs, proteomic (2DE-MALDI/TOF/TOF-MS/MS), physiological (leaf gas-exchange) and biochemical (enzymatic) analyses of coffee leaves treated with Greenforce CuCa and ASM and inoculation with H. vastatrix were performed. Proteomic data showed metabolic adjustments mainly related with photosynthesis, protein metabolism and stress responses but, the proteins modulated by the two PRIs were different. Greenforce CuCa, on its own, increased photosynthesis and stomatal conductance, while ASM caused a decrease in these parameters. Upon H. vastratix infection, the Greenforce CuCa showed a higher protective effect on the leaf physiology than ASM. The enzymatic analyses indicated that Greenforce CuCa reinforces the redox homeostasis of the leaf, while ASM seems to increase the involvement of secondary metabolism. So, the PRIs prepare the plant to resist CLR but, inducing different defense mechanisms upon pathogen infection. The data also evidenced the existence of a link between the primary metabolism and defense responses. Furthermore, Greenforce CuCa emerged as a significant agent for CLR management. The identification of components of the plant primary metabolism, essential for plant growth and development that, simultaneously, participate in the plant defense responses can open new perspectives for plant breeding programs.
Project description:The green algal Botryococcus braunii (Chlorophyte) is known for accumulating high levels of hydrocarbons that are a useful alternative to fossil fuels. B. braunii is categorized into three groups based on types of their accumulated hydrocarbons: alkadiene/triene in race A, botryococcenes in race B, and lycopadiene in race L. Transcriptomic studies in race A and race B have discovered tremendous information related to the genes encoding proteins involved in hydrocarbon biosynthesis. However, transcriptome of race L has not been reported. In this study, we report a transcriptome of race L B. braunii AC768 through the de novo assembly using Hiseq platform. Our analyses indicate that photosynthesis and protein biosynthesis are the most abundantly transcribed in actively growing race L B. braunii. We show that the transcriptome of race L shares similar amounts (~20%) of mutual best-hits with that of race A or race B. Sequence homologous analyses indicate that enzymes involved in squalene and phytoene biosynthesis are well separated into geranyl-diphosphate synthase, farnesyl-diphosphate synthase, geranylgeranyl-diphosphate synthase, phytoene synthase, and squalene synthase. Both B. braunii specific enzymes botryococcene synthase SSL3 and lycopaoctaene synthase LOS are found to form distinctive subgroups in the group of squalene synthase. One of the ESTs in AC768 transcriptome that falls into the subgroup with LOS and shares >88% identity with that of LOS. Together, our results show that SSL and LOS are unique to race B and race L B. braunii subspecies, respectively. We propose that phytoene synthase in race L shares higher homolog to squalene synthase than phytoene synthase in other algae.
Project description:Coffee leaf rust (CLR), caused by the fungal pathogen Hemileia vastatrix, has plagued coffee production worldwide for over 150 years. Hemileia vastatrix produces urediniospores, teliospores, and the sexual basidiospores. Infection of coffee by basidiospores of H. vastatrix has never been reported and thus far, no alternate host, capable of supporting an aecial stage in the disease cycle, has been found. Due to this, some argue that an alternate host of H. vastatrix does not exist. Yet, to date, the plant pathology community has been puzzled by the ability of H. vastatrix to overcome resistance in coffee cultivars despite the apparent lack of sexual reproduction and an aecidial stage. The purpose of this study was to introduce a new method to search for the alternate host(s) of H. vastatrix. To do this, we present the novel hypothetical alternate host ranking (HAHR) method and an automated text mining (ATM) procedure, utilizing comprehensive biogeographical botanical data from the designated sites of interests (Ethiopia, Kenya and Sri Lanka) and plant pathology insights. With the HAHR/ATM methods, we produced prioritized lists of potential alternate hosts plant of coffee leaf rust. This is a first attempt to seek out an alternate plant host of a pathogenic fungus in this manner. The HAHR method showed the highest-ranking probable alternate host as Psychotria mahonii, Rubus apetalus, and Rhamnus prinoides. The cross-referenced results by the two methods suggest that plant genera of interest are Croton, Euphorbia, and Rubus. The HAHR and ATM methods may also be applied to other plant-rust interactions that include an unknown alternate host or any other biological system, which rely on data mining of published data.