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Avirulence genes and mating types in the populations of Leptosphaeria maculans collected from infected oilseed rape plants in Poland in autumn 2010

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Kaczmarek J., Brachaczek A., Shu D., Irzykowski W., Jedryczka M.
Progress in Plant Protection
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2013
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tom 53
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nr 3
The fungi Leptosphaeria maculans and L. biglobosa cause stem canker – one of the most damaging diseases of oilseed rape in Poland and worldwide. The aim of this study was to characterize the composition of avirulence genes and mating types present in current populations of L. maculans in Poland. The study was done in autumn 2010. The isolates of L. maculans (254) were obtained from infected winter rapeseed leaves collected at six locations. DNA (deoxyribonucleic acid) of each isolate was extracted using a CTAB (cetyltrimethyl ammonium bromide) method. The taxonomic identity of isolates was checked by RAPD (random amplification of polymorphic DNA) using OPJ-10 primer and compared with specific banding patterns characteristic for the representatives of L. maculans and L. biglobosa. Isolates of L. maculans were studied to identify a mating type and avirulence alleles AvrLm1 and AvrLm6. Mating types MAT1.1 and MAT1.2 were found in similar frequencies at all sites, what suggests that both types are well adapted to environment. The AvrLm1 avirulence allele was observed only in isolates obtained at one collection site. For the first time in Poland the avrLm6 virulence allele has been found.
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Trunk ornament on the palaeoscolecid worms Cricocosmia and Tabelliscolex from the Early Cambrian Chengjiang deposits of China

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Han J., Liu J., Zhang Z., Zhang X., Shu D.
Acta Palaeontologica Polonica
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2007
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tom 52
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nr 2
Cricocosmia jinningensis, one of the most abundant palaeoscolecid worms from the Lower Cambrian Chengjiang deposits of south China, was originally described as bearing double longitudinal rows of lateral conical sclerites on the trunk. New observation reveals that the ventral trunk bears an additional set of ventral sclerites while the lateral sclerites display a tubercle−bearing (inner surface) and net−like (outer surface) microstructure similar to that of Tabelliscolex hexagonus. These findings mean that: (1) Cricocosmia shows a dorso−ventral and antero−posterior differentiation in trunk ornament; (2) as seen from the microstructure, Cricocosmia is close to Tabelliscolex hexagonus, supporting the idea that lobopodians and arthropods, both of which show an upper capping layer in the outer sclerites, are more closely related than the palaeoscolecidans; and (3) the similarities among the scalids, pharyngeal teeth and the trunk spines of palaeoscolecidans are superficial. Tabelliscolex maanshanensis sp. nov., characterized by an inner concentric circlet of laminae in each tubercle of the lateral trunk plate, is proposed herein. Element mapping reveal that four known pathways of preservation can be found co−occurring in a single specimen of Cricocosmia or Tabelliscolex, which sheds new light on the preservation of the Chengjiang fossils.
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Soft-tissue preservation in the Lower Cambrian linguloid brachiopod from South China

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Zhang Z., Han J., Zhang X., Liu J., Shu D.
Acta Palaeontologica Polonica
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2004
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tom 49
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nr 2
The organization of the lophophore and the digestive system are recognized as two of the diagnostic characters in the definition of higher brachiopod taxa, and hence play a major role in their phylogenetic analysis, their structure, however, is very rarely fossilized. Here we describe and interpret specimens of the brachiopod Lingulellotreta malongensis, from the Lower Cambrian Chengjiang Lagerstätte (South China), one of the earliest known taxa of the Lingulellotretidae, in which lophophores and intact, U−shaped digestive tracts are extraordinarily well−preserved. The lophophore, with clearly preserved tentacles, corresponds to an early spirolophe developmental stage. The digestive tract consists of a mouth, esophagus, distended stomach, intestine and an anterior anus, and differs from that of the Chengjiang obolid Lingulella chengjiangensis by the presence of the dilated stomach and by the absence of a looped intestine as in Lingula. In addition, the relative sizes of the mantle and visceral cavities of Lingulellotreta malongensis also are described. These fossils demonstrate that by the Atdabanian brachiopods had already possessed advanced features, and suggest that a lophophore and a U−shaped intestine with an anterior anus are brachiopod plesiomorphies.
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A large xenusiid lobopod with complex appendages from the Lower Cambrian Chengjiang Lagerstatte

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Liu J., Shu D., Han J., Zhang Z., Zhang X.
Acta Palaeontologica Polonica
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2006
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tom 51
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nr 2
A large lobopod, Jianshanopodia decora gen. et sp. nov., with body length (excluding appendages) about 220 mm from the Lower Cambrian Haikou section, near Kunming, Yunnan, southwest China, shows a mixture of characters, including features of the lobopod Xenusion Pompeckj, 1927, e.g., a large cylindrical body with annulations, stout and strong lobopod appendages each bearing bases of serial tubercles, and of Aysheaia Walcott, 1911, i.e., a pair of large frontal appendages. This suggests that the new genus might be a connecting link between Xenusion and Aysheaia. Besides, Jianshanopodia shares some features with the Early Cambrian stem group arthropod Pambdelurion Budd, 1997, and Kerygmachela Budd, 1993, e.g., the pairs of mid−gut diverticula, the possible presence of tail fan, the mouth cone, the frontal pharyngeal structures and the pharynax are surrounded by the bases of the large frontal appendages. However, compared with a series of segmentally arranged, imbricating, paddle−shaped, movable lateral flaps of both Pambdelurion and Kerygmachela, Jianshanopodia possesses distinct complex appendages with tree−like or lamellate branches. The discovery of this rare transitional form not only throws new light on the early diversification of lobopods, and may also have significance with respect to the origin of arthropods.
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The lobopod Onychodictyon from the Lower Cambrian Chengjiang Lagerstatte revisited

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Liu J., Shu D., Han J., Zhang Z., Zhang X.
Acta Palaeontologica Polonica
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2008
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tom 53
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nr 2
Onychodictyon ferox, from the Lower Cambrian Chengjiang Lagerstätte, is a worm−like armored lobopod with 10 pairs of dorsal plates and a pair of probable sensory appendages (“antennae”). Newly discovered complete specimens show that Onychodictyon is represented by two species: O. ferox with a “head” bearing a pair of dorsal “antennae” and a trunk with 11 pairs of limbs, whereas O. gracilis has a blunt anterior end without any appendages and a trunk with 12 pairs of limbs. Because of the close resemblance of the “antennae” of O. ferox and those of the lobopod Miraluolishania, they are considered to be homologous structures. The “antennae” of Cambrian lobopodians are proposed to be homologous with the arthropod antennulae.
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