INFLUENCE OF THE TEMPERATURE ON THE ATTACHMENT AND DEVELOPMENT OF PASTEURIA PENETRANS ON MELOIDOGYNE INCOGNITA

2009 ◽  
Vol 1 (2) ◽  
pp. 37-43
Author(s):  
Harry Samaliev
2009 ◽  
Vol 35 (1) ◽  
pp. 15-19
Author(s):  
Fernando da Silva Rocha ◽  
Vicente Paulo Campos ◽  
Renata da Silva Canuto ◽  
Ricardo Magela de Souza

Neste trabalho, objetivou-se estudar o efeito do período de armazenamento no teor de lipídios de juvenis do segundo estádio (J2) de M. incognita com endósporos de P. penetrans na infectividade e reprodução em tomateiro. Suspensões de M. incognita contendo ou não endósporos de P. penetrans aderidos à cutícula foram armazenadas por 0, 3, 6, 9 e 12 dias, a 28ºC. Após cada período de estocagem, determinou-se a concentração de lipídios neutros corporais por meio da análise de imagem dos J2 coloridos com o corante "Oil Red O". Em seguida, 1.000 J2 foram inoculados em mudas de tomateiros. Após 28 dias, avaliou-se o número de fêmeas parasitadas, número de endósporos/fêmea, número de galhas, massas de ovos e de ovos/g de raiz. O teor de lipídio dos J2 reduziu-se com o aumento do período de estocagem. Porém, maiores perdas ocorreram nos J2 sem endósporos de P. penetrans. A proporção entre as perdas dos J2 com e sem P. penetrans foi pequena e decrescente com o período de estocagem. Entretanto, a desproporção foi grande entre 3 e 6 dias de armazenamento dos J2 com e sem P. penetrans com relação aos parâmetros reprodução e número de galhas, indicando consumo de fontes alternativas ao lipí dio neutro de energia p elo J2 parasitado. Mas o período de armazenamento sempre reduziu a reprodução e número de galhas formadas em tomateiros por J2 com e sem P. penetrans. A perda dessas fontes de energia, ao que tudo indica, leva muitos J2 a morrer antes de chegar ao estádio adulto, pois o número de fêmeas parasitadas reduz-se com o armazenamento, além de propiciar menor produção de endósporos por fêmea. O J2 parasitado por P. penetrans necessita encontrar rapidamente a raiz e não permanecer no solo por mais de 6 dias antes de parasitar a planta.


Nematology ◽  
2012 ◽  
Vol 14 (7) ◽  
pp. 799-804 ◽  
Author(s):  
Uma Rao ◽  
Tim H. Mauchline ◽  
Keith G. Davies

The molecular interactions between hosts and parasites is an active area of research, and the parasitism of root-knot nematodes, obligate parasites of plants, by the hyper-parasitic bacterium Pasteuria penetrans offers a model by which to investigate aspects of innate immunity. Using a pouch system we were able to demonstrate by PCR, infection of Meloidogyne incognita 4 days prior to any microscopic observations of parasitism. The pouch system, although not strictly axenic, offered a relatively clean, flexible approach with a greatly reduced number of contaminating microbial species than in any soil-based system, whereby the early stages of nematode infection could be manipulated and controlled.


2008 ◽  
Vol 45 (1) ◽  
pp. 54-56 ◽  
Author(s):  
E. Tzortzakakis

AbstractSpore attachment of three Pasteuria penetrans isolates was assessed on juveniles of Meloidogyne incognita and Meloidogyne javanica populations from Greece. The nematode populations differed in their ability to reproduce on tomatoes with the Mi gene, conferring resistance to rootknot nematodes. The numbers of attached spores did not discriminate virulent from avirulent populations within each species. The differences in attachment rates probably reflect the specificity of Pasteuria penetrans to different Meloidogyne populations of the same species, within a country or even the same area.


1991 ◽  
Vol 100 (3) ◽  
pp. 613-622
Author(s):  
A. Persidis ◽  
J.G. Lay ◽  
T. Manousis ◽  
A.H. Bishop ◽  
D.J. Ellar

Pasteuria penetrans spores were fragmented by glass bead vortexing, producing exosporial membranes and spore fragments, which consisted of fibre bundles. Both exosporia and spore fragments are capable of host-specific attachment to the cuticle of Meloidogyne incognita, a root-knot nematode host. Putative M. incognita receptors appear to be soluble in beta-mercaptoethanol (BME) but not SDS, and are also sensitive to tryptic digestion and deglycosylation by endoglycosidase F. Polyclonal antibodies against intact spores and spore fragments of antispore antibodies produced 100% inhibition. The antibodies, however, did not show preferential staining of particular spore structures in thin section immunolabelling studies. Exposure of Pasteuria penetrans spores to HCl or urea-SDS-dithiothreitol renders them incapable of attachment to their host juveniles and extensively disrupts fibres that surround the spore core. Protein extracts from spore fragments or from exosporial membranes are identical, and urea-BME extracts from either structure, but not SDS extracts, can inhibit the attachment of spores to juveniles by 60–80%. An inhibitory BME extract from spore fragments was analysed by anion-exchange chromatography and adsorption onto host cuticle followed by immunoblotting. It appeared to contain six potential spore adhesins of approximate Mr 24–29, 38–47, 59, 89, 126, and 190 (x10(3)). Lectin affinity blotting with wheat germ agglutinin and concanavalin A showed that all of these proteins bear terminal N-acetylglucosamine residues and the 38–47 kDa band also bears terminal Glc/Man residues.(ABSTRACT TRUNCATED AT 250 WORDS)


Nematology ◽  
2007 ◽  
Vol 9 (6) ◽  
pp. 845-851 ◽  
Author(s):  
Maria Célia Cordeiro ◽  
Regina Carneiro ◽  
Pedro Cirotto ◽  
Luiz de Mesquita ◽  
Maria Ritta Almeida ◽  
...  

AbstractAn obligate parasite bacterium of the root-knot nematode, Pasteuria penetrans strain P10, isolated from Meloidogyne incognita females on banana roots in Imperatriz Maranhão State, Brazil, was evaluated in glasshouse conditions, using two doses of a dry root bionematicide (107 endospores (5.0 g/seedling) and 106 endospores (0.5 g/seedling)) on seedlings of cv. Mundo Novo coffee. The soil in which coffee seedlings were raised was inoculated previously with these two doses of P. penetrans and after 2 months the plants were transferred to soils of different textures: clay-sandy soil (38% clay, 2% silt and 60% sand) and sandy soil (17% clay, 0% silt and 83% sand). When the coffee plants were 30 cm high, they were inoculated with 20 000 eggs/plant of M. incognita race 1. The coffee plants were examined 8, 16 and 24 months after nematode plant infestation. The effectiveness of the biological control was determined by the reduction of nematode reproduction factor, which ranged from 62 to 67% in clay-sandy soil and 80 to 85% in sandy soil. The mechanism of suppression caused by the bacterium was evaluated by the percentage of infected second-stage juveniles (J2), number of endospores attached/J2 and number of infected females. The high levels of suppression were related to time, increasing from 8 to 24 months, and to the percentage of sand in the soil.


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