Natural occurrence of perithecia of Gibberella coronicola on wheat plants with crown rot in Australia

2001 ◽  
Vol 30 (4) ◽  
pp. 353 ◽  
Author(s):  
B. A. Summerell ◽  
L. W. Burgess ◽  
D. Backhouse ◽  
S. Bullock ◽  
L. J. Swan
2008 ◽  
Vol 98 (2) ◽  
pp. 250-255 ◽  
Author(s):  
Alison R. Bentley ◽  
John F. Leslie ◽  
Edward C. Y. Liew ◽  
Lester W. Burgess ◽  
Brett A. Summerell

Crown rot, caused by the fungus Fusarium pseudograminearum (teleomorph Gibberella coronicola) is a major disease of wheat in the Australian grain belt. However, there is little information available on the population structure of this pathogen. We measured genetic diversity as assessed with amplified fragment length polymorphism (AFLP) analysis within and between populations of F. pseudograminearum from northeastern, south central, and southwestern regions of the Australian grain belt. Amongst the 217 isolates, 176 haplotypes were identified and grouped into two main clusters. One cluster contained isolates from populations in northeastern Australia, and the other cluster contained isolates from populations in south central and southwestern Australia. The southern populations were distinguished from the northeastern populations by higher levels of population differentiation (Gst) between them and genetic identity amongst the regional populations. We hypothesize that the F. pseudograminearum populations from northeastern and southern Australia are independent, which could result from different founding events or from geographic isolation and the accumulation of genetic differences due to genetic drift and/or selection.


Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 328-328 ◽  
Author(s):  
A. Vitale ◽  
G. Polizzi

Leaf spots, stem lesions, crown rot, and root rot, caused by heterothallic fungus Cylindrocladium pauciramosum C.L. Schoch & Crous,, on young plants in a nursery represent an important problem in many representative ornamental plant-growing areas of Italy since the disease was first reported in 1993 (2). Symptoms observed during surveys in Italy from 1993 to 2005 were attributed solely to the asexual stage, and the teleomorph (Calonectria pauciramosa C.L. Schoch & Crous) was never found. In October 2005, orange-to-red brown fungal fruiting bodies pertaining to the genus Calonectria were observed in belowground regions and at the soil line on collar and stem tissues of seedlings of the mastic tree (Pistacia lentiscus L., Anacardiaceae) affected by damping off in two nurseries of eastern Sicily. The sexual structures were solitary or in groups, orange-to-red brown, subglobose to ovoid. On the basis of 50 microscopic observations of leaf tissues, they ranged from 180 to 280 μm in diameter and from 270 to 400 μm high. In the presence of adequate moisture, ascospores were discharged from mature perithecia in visible, viscous, and white droplets. Asci containing eight ascospores were clavate and tapering to a long thin stalk. Fusoid ascospores were hyaline and guttulate with rounded ends, slightly curved, 1-septate, not or slightly constricted at the septum, and measured 33 to 39 μm long and 6 to 8 μm wide. However, measurements show that perithecia, asci, and ascospores also fall within the range described by Schoch et al. (3). Single ascospore cultures did not produce perithecia. On the basis of these descriptions and the ability of single-ascospore cultures to mate with two Italian (DISTEF-G87 and DISTEF-G128) and two South African (STE-U 971 and STE-U 1670) selected tester strains of Cylindrocladium pauciramosum (2), the perithecia were identified as C. pauciramosa. To our knowledge, this is the first natural occurrence of the perfect stage of Cylindrocladium pauciramosum in Italy. The presence of the teleomorph is very important because it represents a second means of spread after conidia. Furthermore, the occurrence of the teleomorph also could lead to a 1:1 mating type ratio. In this case, lower percentages of hermaphrodites should be expected (1,4). References: (1) G. Polizzi et al. J. Plant Pathol. 80:262, 1998. (2) G. Polizzi and P. W. Crous. Eur. J. Plant Pathol. 105:413, 1999. (3) C. L. Schoch et al. Mycologia 91:286, 1999. (4) C. L. Schoch et al. Plant Dis. 85:941, 2001.


Author(s):  
A. Baronnet ◽  
M. Amouric

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.


2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Adriana Muniz De Almeida Albuquerque

The water purification procedure aims to obtain a product appropriate for human consumption, minimizing the presence of contaminants and toxic substances present in the water. Among these contaminants, some radionuclides of natural origin, such as uranium, thorium and their descendants, have been identified. Studies have shown that the stages of purification are quite effective in removing the radionuclides contained in water. The removal is due to co-precipitation of the radionuclides with the suspended materials and the precipitated material is accumulated and characterized as a Technologically Concentrated Natural Occurrence Radioactive Material (TENORM) by the United States Environmental Protection Agency (USEPA). This residue can present significant levels of radioactivity and, when discarded in the environment without any treatment, can generate a problem of environmental impact and a risk to the health of the population. In this way, some gamma emitters of the series of U, Th and the K-40 were determined in the residues generated at the Potable Water Treatment Plants – PWTPs in six municipalities of Pernambuco. The results obtain corroborate the classification of the residues generated in the PWTPs as concentrators of the radioactive components contained in the water supplied to the system and reinforce the need for the release to the environment, which is the usual way of disposal of this waste, to be carried out only after considering the radiological protection standards established.


2013 ◽  
Vol 62 (1) ◽  
pp. 14-18 ◽  
Author(s):  
Lei Cui ◽  
Khalid Abbas ◽  
Yongyao Yu ◽  
Weimin Wang ◽  
Li Zhou ◽  
...  

1994 ◽  
Vol 60 (2) ◽  
pp. 167-174
Author(s):  
Masami YOSHIKAWA ◽  
Norihisa HASHIMOTO ◽  
Tatsuo YOKOYAMA

2019 ◽  
Vol 23 (9) ◽  
pp. 1045-1075 ◽  
Author(s):  
Saigal ◽  
Sumbulunnisan Shareef ◽  
Habibur Rahman ◽  
Md. Musawwer Khan

Aminocoumarins are one of the important core structural systems, present in several biologically and medicinally active compounds. Owing to its natural occurrence, potential pharmacological applications and remarkable versatility as a privileged precursor, several proficient synthetic protocols have been reported in the literature over the past years. The presence of an amino group and enamine carbon enhances its chemical reactivity and thus such functionality is repeatedly used for the construction of various fused and simple heterocycles. This review highlights the preparation of different aminocoumarins and their applications for the construction of a variety of five, six and eight membered fused heterocycles.


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