Early stages of infection of maize (Zea mays) and Pennisetum setosum roots by the parasitic plant Striga hermonthica

• Published in: European journal of plant pathology Vol. 103; no. 9; pp. 815 - 827
• Main Authors: Mayer, M.J. (Institute of Food Research, Norwich (United Kingdom). Norwich Lab.), Steel, J, Child, D.V, Hargreaves, J.A, Bailey, J.A
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01-12-1997; Springer Nature B.V
• Subjects: Biological and medical sciences; CELL WALLS; Corn; Fundamental and applied biological sciences. Psychology; HOST PARASITE RELATIONS; Immunization; INFECCION; INFECTION; Parasites; PARASITIC PLANTS; Parasitic plants. Weeds; PARED CELULAR; PAROI CELLULAIRE; PENNISETUM; Phytopathology. Animal pests. Plant and forest protection; Plant tissues; PLANTAS PARASITAS; PLANTE PARASITE; RACINE; RAICES; RELACIONES HUESPED PARASITO; RELATION HOTE PARASITE; ROOTS; STRIGA HERMONTHICA; ZEA MAYS; Host parasite relation; Monocotyledones; Zea mays; Root; Pathogenesis; Tropical crop; Cereal crop; Gramineae; Dicotyledones; Angiospermae; Scrophulariaceae; Spermatophyta; Fodder crop; Parasitic plant
• ISSN: 0929-1873; 1573-8469
• DOI: 10.1023/A:1008648512446

Infection of young roots of maize (Zea mays L.) by the parasitic plant Striga hermonthica (Del.) Benth. was examined. Attachment to and penetration of roots occurred within 1-2 days after inoculation. Subsequent growth through the cortex to the host stele and proliferation of parasite xylem tissue was commonly completed by 3-4 days after inoculation. Histochemical staining showed that young maize roots do not contain major wall-thickening components. However, an increase in cell wall fluorescence and endodermal cell wall thickness was often seen at the site of infection and in the surrounding maize root tissue at 3 days after inoculation. This host response was variable and did not prevent rapid and successful penetration by the parasite. In contrast, uninfected roots of Pennisetum setosum (Sw.) L. Rich., a species resistant to S. hermonthica, had substantial thickening of the inner endodermal cell walls and exhibited further cell wall thickening at the stele upon infection. Examination of infections on both hosts demonstrated the presence of autofluorescent material at the host-parasite interface. This material was thicker and more extensive at the P. setosum-S. hermonthica interface than at the maize-S. hermonthica interface, and contained polyphenols and lignin. Examination of the host-parasite xylem connections in maize revealed substantial invasion of the host stele by both parenchyma and tracheary elements. In a few cases of P. setosum infection, parasite cells entered the stele; however, this did not lead to successful establishment of the parasite.[PUBLICATION ABSTRACT]