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Bragantia

Print version ISSN 0006-8705On-line version ISSN 1678-4499

Bragantia vol.31 no.unico Campinas  1972

http://dx.doi.org/10.1590/S0006-87051972000100006 

Microscopia electrônica de microrganismos do tipo micoplasma nos tecidos de milho afetado pelo enfezamento e nos órgãos da cigarrinha vectora portadora1

 

Electron microscopy of mycoplasma-like organisms in corn stunt — Infected plant tissues and in the organs of the leafhopper vector

 

 

E. W. Kitajima; A. S. Costa2

Engenheiros-agrônomos, Seção de Viroíogia Fitotêcnica, Instituto Agronômico

 

 


SINOPSE

Exames electrono-microscópicos de tecido foliar ou radicular de milho (Zea maysL.) afetado pelo enfezamento do milho, tanto a forma vermelha como a pálida, e de órgãos da cigarrinha vectora, Dalbulus maidisDe L. & W., portadora, demonstraram a ocorrência de corpúsculos pleomórficos, do tipo micoplasma, consistentemente associados a essa anomalia. Não se notou diferença na morfologia entre os microrganismos do tipo micoplasma associados às duas formas do enfezamento da planta nem tampouco entre estes e os presentes no inseto vector. Verificou-se também que na planta esses corpúsculos do tipo micoplasma ocorriam somente nos vasos crivados, e que no inseto eles se achavam presentes em diversos tipos de tecidos de diferentes órgãos — tubo digestivo, músculo, túbulos de Malphigi, epiderme, gânglio nervoso, glândula salivar, tecido adiposo. Nas células do inseto, os corpúsculos ocorriam dispersos no citoplasma ou em cavidades limitadas por membrana.


SUMMARY

Corn stunt in São Paulo State is usually of minor importance during normal summer crops but might induce significant losses if corn is planted late in the season. It is transmitted by leaf — hopper Dalbulus maidisDe L. & W. and two different forms of this disease have been recognized the chlorotic, similar to the Rio Grande type of the U.S., and the red, resembling the Mesa Central type of Mexico.
Electron microscopic examination of tissues from both affected plants or leafhopper reared on diseased plants, demonstrated the presence of pleomorphic, mycoplasma-like bodies, consistently associated with the corn stunt, which probably represent the causal agent the latter. No significant difference could be observed in the morphology of these mycoplasma-like bodies associated with the two disease types or with the insect vector. In the affected plants, these corpuscles were only found in the sieve tubes; in the insect body they were detected in several types of tissues of different organs — intestine, Malphigian tubules, muscle, nervous ganglion, salivary gland, fat body, epidermis. In the insect cells, the pleomorphic bodies occurred either scattered in the cytoplasm or in cytoplasmic cavities bounded by membrane.


 

 

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LITERATURA CITADA

1. ALSTATT, G. E. A new disease in the Rio Grande Valley. PL Dis. Reptr. 29:533-534, 1945.         [ Links ]

2. CHEN, T. A. & GRANADOS, R. R. Plant pathogenic mycoplasma-like organism: maintainance in vitroand transmission to Zea maysL. Science 167:1633-1636, 1970.         [ Links ]

3. COSTA, A. S.; KITAJIMA, E. W. & ARRUDA, S. Moléstias de vírus e de micoplasma do milho no Est. S. Paulo Reunião Anual Soe. Bras. Fitopat., 4, Piracicaba, 1971.         [ Links ]

4. DOI, Y.; TERANAKA, M., YORA, K. & ASUYAMA, H. Mycoplasma-or PLT-group-like microorganisms found in the phloem elements of plants infected with mulberry dwarf, potato witches' broom, aster yellows, or paulownia witches' broom. Ann. phytopath. Soc. Japan 33:259-266, 1967.         [ Links ]

5. ESAU, K. & CRONSHAW, J. Tubular and fibrillar components of mature and differentiating sieve elements. J. Cell Biol. 34:801-815, 1967.         [ Links ]

6. GRANADOS, R. R. Electron microscopy of plants and insect vectors infected with corn stunt disease agent. Contr. Boyce Thompson Inst. 24:173188, 1969.         [ Links ]

7. GRANADOS, R. R.; MARAMOROSCH, K. & SHIKATA, E. Mycoplasma suspected etiologic agent of corn stunt. Proc. natn. Acad. Sci. U.S.A. 60:841.844, 1968.         [ Links ]

8. KITAJIMA, E. W. & COSTA, A. S. Estruturas do tipo micoplasma no floema de tomateiro afetado pelo cálice gigante. Bragantia 27:XCVII-XCIX, 1968. Nota 23.         [ Links ]

9. ________ & ________ Micoplasma: possível agente etiológico de certas moléstias de plantas. Ciência e Cultura 22:351-363, 1970.         [ Links ]

10. ________ & ________ Corpúsculos do tipo micoplasma associados a diversas moléstias de planta, no grupo amarelo, no Est. S. Paulo. Ciência e Cultura 23:285-291, 1971.         [ Links ]

11. KUNKEL, L. L. Incubation period of corn stunt virus in the leafhop-per Baldulus maidis(DeL. and W.). Am. J. Bot. 33:830-831, 1946.         [ Links ]

12. LAFLECHE, D. & BOVÉ, J. M. Structures de type mycoplasme dans les feuilles d'orangers atteints de la maladie du greening. C. r. Acad. Sci. (Paris) 270 (série D) :1915-1917, 1970.         [ Links ]

13. MAILLET, P. L. Infection simultanée par des particules de type PLT (Ricketsiales) et de type PPLO (Mycoplasmatales) chez un insect vecteur de la phyllodie du trèfle, Euscelis lineolatusBrullé (Ho-moptera, Jassidae) J. Microscopie 9:827-832, 1970.         [ Links ]

14. ________, GOURRET, J. P. & GOURANTON, J. Biologie et cytopathologie des particles de type mycoplasme dans la plante et l'insect vecteur. Proc. 7th Int. Conf. Electron Microscopy 3:355-356, 1970.         [ Links ]

15. MARAMOROSCH, K.; SHIKATA, E. & GRANADOS, R. R. Structures resembling mycoplasma in diseased plants and in insect vectors. Trans. N. Y. Acad. Sci. (série II) 30:841-855, 1968.         [ Links ]

16. NASU, S.; JENSEN, D.D. & RICHARDSON, J. Electron microscopy of mycoplasma-like bodies associated with insect and plant hosts of peach western-X disease. Virology 41:583-595, 1970.         [ Links ]

 

 

Recebido para publicação em 20 de agosto de 1971.

 

 

1 Este trabalho recebeu auxílios financeiros da FAPESP (C. Agron. 69/879). CNPq (TC 12275) e do convênio CAPES/BID/BNDE.
2 Com bolsa de suplementação do CNPq.

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