Extraction of Regression Relations of Tidal Rivers by Artificial Neural Network Method

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Using a Hybrid Mapping Population to Identify Genomic Regions of Pyrenophora teres Associated With Virulence

Net blotches caused by Pyrenophora teres are important foliar fungal diseases of barley and result in significant yield losses of up to 40%. The two types of net blotch, net-form net blotch and spot-form net blotch, are caused by P. teres f. teres (Ptt) and P. teres f. maculata (Ptm), respectively. This study is the first to use a cross between Ptt and Ptm to identify quantitative trait loci (QTL) associated with virulence and leaf symptoms. A genetic map consisting of 1,965 Diversity Arrays Technology (DArT) markers was constructed using 351 progenies of the Ptt/Ptm cross. Eight barley cultivars showing differential reactions to the parental isolates were used to phenotype the hybrid progeny isolates. Five QTL associated with virulence and four QTL associated with leaf symptoms were identified across five linkage groups. Phenotypic variation explained by these QTL ranged from 6 to 16%. Further phenotyping of selected progeny isolates on 12 more barley cultivars revealed that three progeny isolates are moderately to highly virulent across these cultivars. The results of this study suggest that accumulation of QTL in hybrid isolates can result in enhanced virulence

Development of ferroelectric domains and topological defects in vacancy doped ceramics of h-LuMnO₃

Self-doping of the h-LuMnxO3±δ (0.92 ≤ x ≤ 1.12) phase and changes in the sintering time are applied to investigate the formation and annihilation of antiphase ferroelectric (FE) domains in bulk ceramics. The increase in the annealing time in sintering results in growth of FE domains, which depends on the type of vacancy, 6-fold vortices with dimensions of the order of 20 μm being observed. Interference of planar defects of the lattice with the growth of topological defects shows breaking of 6-fold symmetry in the self-doped ceramics. The role of grain boundaries in the development of topological defects has been studied. Dominance of the atypical FE domain network in very defective h-LuMnxO3±δ lattices saturated with Mn vacancies (x < 1) was also identified in the current study. After a long annealing time, scattered closed-loops of nano-dimensions are often observed isolated inside large FE domains with opposite polarization. Restoring of the polarization after alternative poling with opposite electrical fields is observed in FE domains. Stress/strain in the lattice driven by either planar defects or chemical inhomogeneity results in FE polarization switching on the nanoscale and further formation of nano-vortices, with detailed investigation being carried out by electron microscopy. Pinning of FE domains to planar defects is explored in the present microscopy analysis, and nano-scale observation of lattices is used to explain features of the ferroelectricity revealed in Piezo Force Microscopy images of the ceramics

What can we learn from population genomics studies of Curtobacterium flaccumfaciens pv. flaccumfaciens, the cause of tan spot on mungbean?

The bacterium Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) is the cause of tan spot (in some regions known as ‘wilt’) on mungbean (Vigna radiata) and other legumes worldwide. The pathogen was first reported in mungbean paddocks in Queensland in 1984, and subsequently in New South Wales in 1986, causing yield losses of up to 25% in hot and dry seasons. No chemical control is available, and disease management relies on pathogen exclusion, through the use of clean seed, and deployment of moderately susceptible varieties. Breeding programs are currently working to incorporate better resistance into new mungbean varieties. The success of breeding programs depends on a thorough understanding of the genetic diversity and evolution of the pathogen population(s). This project was designed to elucidate the genotypic diversity of Cff population(s) and investigate sources of inoculum that contribute to tan spot epidemics in the northern grains region (Queensland and northern New South Wales). Whole genome re-sequencing of 100 Cff isolates detected moderate genotypic diversity, with a narrower genetic background compared to the global Cff population. One highly adapted clonal lineage was found to dominate the population with a frequency of 45%. This study showcases how population genomics studies can be used to test hypotheses relating to disease epidemiology and provide useful information for resistance breeding programs. The results provide insights on Cff population structure and epidemiology, and have direct application for breeding programs by providing a set of Cff isolates that represent the genetic diversity of the pathogen population(s) in the northern grains region

A broad look at charcoal rot in the Northern Region broadacre crops through soil sampling and in-crop surveys

Macrophomina phaseolina (Tassi) Goid. is a generalist soil-born pathogen, which is endemic to Australia. The pathogen has a broad host-range of both monocot and dicot plant species which include numerous weed and crop plant species (1, 2). The disease is most commonly identified with summer crops, e.g. soybean, sorghum, sunflower, maize and mungbean (3) and occurs most often when hot, dry conditions occur during the growing season. Current estimates predict that north-eastern Australia will become hotter and dryer as a result of climate change (4, 5). Thus, it is likely that conditions favouring the development of this disease will become more common in the future. However, to date, no work has been done to determine the extent of the pathogen’s presence in Australian soils, in-paddock spatial variability, or the occurrence of the disease as correlated with pathogen presence and population levels. In this paper, we present findings from soil sampling and end-of-season disease assessments in sorghum paddocks across northern New South Wales (NNSW), south eastern Queensland (SEQ) and central Queensland (CQ) during the 2016/17 and 2017/18 summer cropping seasons

Evaluation of tidal bores effects of Persian Gulf on the stage-discharge curve of the Karun River

The rivers that pour to seas and oceans are known as tidal rivers. A governing factor on tidal rivers is tidal bores which are produced by the gravity of moon and sun. Reflection of waves from beaches and the shape of beaches and effects of shallow water, effect on tidal bores in the mouth of tidal rivers. These factors convert tidal bores from time periodic condition to no periodic condition. Tidal bores move to upstream of river while fluvial flows go toward downstream of river. Because of combination of Tidal bores and fluvial flows, hydraulic and hydrologic conditions are very complex in the tidal rivers. Measurement of velocity and discharge of current is impossible in the tidal limit of tidal rivers. For determination of stage-discharge curves, an especial method is needed. In this research, water surface elevation is estimated by using discharge of fluvial flow in Ahvaz and tidal height in Khoramshar in tidal limit of the Karun River (from Khoramshar to Darkhovein). Water surface elevation is shown by structural curves and regression relations. These curves and relations are suitable tools for determination of water surface elevation in the tidal limit of the Karun River by using discharge of fluvial flow in Ahvaz and tidal height of Khoramshar

Whole genome data from Curtobacterium flaccumfaciens pv. flaccumfaciens strains associated with tan spot of mungbean and soybean reveal diverse plasmid profiles

Despite the substantial economic impact of Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) on legume productions worldwide, the genetic basis of its pathogenicity and potential host association is poorly understood. The production of high-quality reference genome assemblies of Cff strains associated with different hosts sheds light on the genetic basis of its pathogenic variability and host association. Moreover, the study of recent outbreaks of bacterial wilt and microevolution of the pathogen in Australia requires access to high-quality, reference genomes that are sufficiently closely related to the population being studied within Australia. We provide the first genome assemblies of Cff strains associated with mungbean and soybean, which revealed high variability in their plasmid composition. The analysis of Cff genomes revealed an extensive suite of carbohydrate-active enzymes potentially associated with pathogenicity, including four carbohydrate esterases, 50 glycoside hydrolases, 23 glycosyl transferases, and a polysaccharide lyase. We also identified 11 serine peptidases, three of which were located within a linear plasmid, pCff119. These high-quality assemblies and annotations will provide a foundation for population genomics studies of Cff in Australia and for answering fundamental questions regarding pathogenicity factors and adaptation of Cff to various hosts worldwide, and, at a broader scale, contribute to unravelling genomic features of Gram-positive, xylem-inhabiting bacterial pathogens

Genera of phytopathogenic fungi: GOPHY 3

This paper represents the third contribution in the Genera of Phytopathogenic Fungi (GOPHY) series. The series provides morphological descriptions, information about the pathology, distribution, hosts and disease symptoms for the treated genera, as well as primary and secondary DNA barcodes for the currently accepted species included in these. This third paper in the GOPHY series treats 21 genera of phytopathogenic fungi and their relatives including: Allophoma, Alternaria, Brunneosphaerella, Elsinoe, Exserohilum, Neosetophoma, Neostagonospora, Nothophoma, Parastagonospora, Phaeosphaeriopsis, Pleiocarpon, Pyrenophora, Ramichloridium, Seifertia, Seiridium, Septoriella, Setophoma, Stagonosporopsis, Stemphylium, Tubakia and Zasmidium. This study includes three new genera, 42 new species, 23 new combinations, four new names, and three typifications of older names