University of Illinois, USA
Xanthomonas spot of cucurbits, caused by Xanthomonas cucurbitae, is an emerging disease in the United States (US) and other cucurbit growing areas of the world. The pathogen can infect all cucurbit crops, but its major hosts are pumpkins and winter squash. Leaves and fruits of cucurbits are infected by X. cucurbitae at all growth stages. Infected fruits are usually colonized by opportunistic fungi and bacteria and rot. Our surveys in the North Central Region of the US showed that 159 of 180 and 71 of 79 of pumpkin and squash fields, respectively, had fruits infected with X. cucurbitae. The average incidence of fruits with bacterial spot in all pumpkin and squash fields surveyed was 25 and 19%, respectively. We identify the pathogen based on the colony morphology on yeast dextrose agar (YDC), polymerase chain reaction (PCR) test using RST2/RST3 primers, and pathogenicity test on susceptible pumpkin ‘Howden’. X. cucurbitae survived in infected leaves and fruits in the field for more than 24 months. Also, X. cucurbitae survived longer than 18 months in the seeds at 4 and 22°C and remained viable. We eradicated the pathogen in the naturally-infected and artificially infested seeds by hot-water treatment at 55°C for 15 min and HCl treatment at 0.5% concentration for 40 min. Also, in our field trials, copper oxychloride + copper hydroxide (Badge X2 DF), copper sulfate (Cuprofix Ultra 40 DF), copper sulfate pentahydrate (Phyton-016B), copper hydroxide (Kocide-3000 46.1 DF) plus acibenzolar-s-methyl (ActiGard 50 WG), Kocide-3000 46.1 DF plus famoxadone + cymoxanil (Tanos 50D WG), an extract from Reynoutria sachalinensis (Regalia), and B. subtilis (Serenade ASO) were effective in reducing incidence and severity of bacterial spot on both leaves and fruits compared to controls. Currently, we are evaluation cultivar resistance of cucurbits to X. cucurbitae, and effects of cropping rotation and a newly identified biocontrol agents for managing Xanthomonas spot of cucurbits.
Mohammad Babadoost received his M.S. in plant pathology from Washington State University and Ph.D. in plant pathology from North Carolina State University. In 1999, he joined the faculty of the University of Illinois at Urbana-Champaign, and he is now a Professor of Plant Pathology and Extension Specialist. Mohammad conducts research and extension programs on the biology and management of vegetable and fruit crops diseases, and teaches “Plant Disease Diagnosis and Management” and “Outreach Education Skills.” He has served as an editor of the APS-FNT and ASHS HortTechnology and as a reviewer for more than 20 journals. He has published 1 books, 4 book chapter, 1 monograph, 10 bulletins, 58 refereed articles, 88 articles in proceedings, 97 abstracts, and 182 article in newsletters. Dr. Babadoost has developed a profound commitment to sharing his expertise in developing countries to advance the science of plant pathology and establishing food security in the world.
Aligarh Muslim University, India
Nitric oxide acts as gasotransmitter-diffusible plant growth regulator and play an important role in growth and development of plant. Therefore, in present study mustard plants were sprayed with different concentrations of sodium nitroprusside (0, 10-4 M, 10-5 M and 10-6 M SNP) at 25 days after sowing (DAS) to assess different physiological parameters. The results indicate that foliar application of SNP up-regulate chlorophyll content, photosynthetic efficiency along with gaseous exchange parameters and ultimately leads to increase in overall photosynthetic machinery. Compound and scanning electron microscopic studies also revealed a remarkable increase in stomatal aperture. Further, a gradual increase in carbon metabolism (total reducing sugars, total carbohydrate content, glucose, fructose and sucrose content) was also observed in SNP-treated plants as compared to control. Nutrient status (carbon, nitrogen, phosphorus, sulfur, potassium and magnesium) of leaves also showed a significant increase. The activity of various enzymes associated with nitrogen metabolism, CO2/HCO3- homeostasis, glycolysis, Calvin cycle and Krebs cycle (nitrate reductase, carbonic anhydrase, hexokinase, rubisco, fumarase and succinate dehydrogenase) were also increased. It was also reported that superoxide, hydrogen peroxide and malondialdehyde content was decreased in SNP-treated samples. SNP application also up-regulate antioxidative defense system by increasing the activity of antioxidant enzymes, i.e., catalase, peroxidase and superoxide dismutase. Thus, it can be concluded from the present observation that SNP at lower concentration proved beneficial and alter most of the parameters studied which ultimately leads to increase the efficiency of photosynthesis in mustard plants.
Columbia University, USA
Amaranthus is a genus of 75 species that display diverse mating strategies. Cultivar species (e.g. A. hypochondriacus) are monoecious and weedy species (e.g. A. palmeri) are dioecious. These mating strategies are influenced by genes that control the expression of sex determination and floral morphology. Sex-determining loci are highly conserved across species and often the first of genes to be mapped when constructing linkage maps of species. Here I will perform a genome-wide association studies (GWAS) to identify candidate loci of sex determination in monoecious and dioecious species of Amaranthus. The monoecious species studied include A. hypocondriacus, A. caudatus, A. cruentus, and A. retroflexus. The dioecious species studied include A. palmeri, A. tuberculatus, A. arenicola and A. canabinus. The experiment includes growing, sampling, and sequencing the genome of 800 (400 monoecious and 400 dioecious) individuals of Amaranthus. I will perform whole-genome sequencing at 1x coverage of all individuals then use a k-mer based bioinformatic approach to identify sex determination sequences. Assays will be compared across all individuals to confirm the conservation of the identified sex-specific markers. Monoecious species of Amaranthus are economically important cereal crops of interest to plant breeders for its rich nutritional content and resilience to arid environments. Dioecious Amaranthus species are aggressive weeds with successful outcrossing and adoption of herbicide resistance that is of interest to farmers. There is a hazard for selective breeding and genome editing in grain amaranths because of their potential to interbreed with wild-dioecious relatives, many of which are major yield-affecting agricultural weeds. Thus, hybridization of monoecious and dioecious species pose a threat to both breeders and farmers. Identification of sex sequences in Amaranthus provides foundational information to bioengineer sex-selective populations and understand the evolution of monoecy and dioecy in this genus.
1Institute of Agricultural Research for Development, University of Yaoundé, Cameroon
2Department of Plant Biology, Faculty of Science, University of Yaoundé, Cameroon
3Department of Molecular Biology and Biotechnology, Pan-African University, KenyaPoster
Background and Methods: Wheat is a strategic crop for most African countries food security and stability. As one of the main consumed commodity in Cameroon, its demand has increased along the years with increase in wheat consumption of 98% in urban strata and 90-91% in non-urban strata. However, 100% of the total domestic consumption is satisfied by import translating Cameroon vulnerability to food security risk. Wheat production in Cameroon is estimated at 66 tons/ha. Highly inferior to the national importation estimated at 725,000 tons in 2015. To satisfy this population demand, the government allocated an amount of 103 billion of FCFA to import approximately 518, 000 tons in 2012. Facing this situation, the Cameroon government is urge to implement appropriate strategies to reduce the wheat dependency, to minimize price fluctuation and attain a minimum threshold for self-sufficiency for this commodity. Increased temperature and degradation of soil fertility are the principal constraints affecting wheat production in Cameroon. As such, a study was conducted to determine the potential of native Carbuncular Mycorrhiza (AM) fungi in yield performance and variability of wheat genotypes cultivated in contrasted conditions of the bimodal humid forest zone of Cameroon. For this, 34 wheat genotypes were sown following an incomplete alpha-lattice design. The genotypes were evaluated on the basis of their yield potential (grain weight) and their affinity to Mycorrhiza symbiosis. The efficiency of the occurred Mycorrhiza was verified on two wheat genotypes cultivated on sterilized sand after purification of the latter. Wheat grain weight and biomass (root dry mass) were collected for this purpose.
Results: Biplot analysis revealed positive significant correlations (r=0.83 P<0.01; r=0.77, P<0.01) between the grain weight of wheat genotypes and Mycorrhiza parameters (percentage of AM colonization and number of AM spores respectively) in Mbankolo (high altitude) and positive significant correlations (r=0.56, P<0.01; r=0.57, P<0.01) between the same parameters in Nkolbisson (low altitude). The grain weight and Mycorrhiza parameters explained 90.1% and 71.3% of variance among all the wheat genotypes in high and low altitudes respectively. The following genotypes SST015, SST087, SST866 and SST88 in high altitude and the following genotypes Nd643-5, Kenya2, Babax8 and SST895 in low altitude were identified to have the highest Mycorrhiza symbiotic affinity and yield performances. The Mycorrhiza spores isolation and morphological identification revealed the presence of three species in wheat rhizosphere in both study sites: Scutellospora sp, Gigaspora sp, and Septoglomus sp. The species Scutellospora sp, was identified to be present and dominant in both study sites. The efficiency of this occurred Mycorrhiza species revealed that Scutellospora sp, had the highest positive enhancing ability on wheat yield and biomass. Thus this targeted wheat genotypes can be used to promote large scale production in both sites and vulgarize to local farmers. Also, the determination of the mechanism underpinning their symbiotic preferences will be essential in targeting the genes implicated to be used for breeding purposes. Also, this dominant Mycorrhiza species could deeply be studied and multiplied for bio-fertilizer specific to wheat production in Cameroon.