Host status of plants from the Cerrado Biome to Meloidogyne spp.

Hospedabilidade de plantas do Bioma Cerrado a Meloidogyne spp.

Abstract

Among the Brazilian biomes, Cerrado is the second in territorial extension and diversity of plants and animal species. The Cerrado's biodiversity has been studied in terms of its flora and fauna, lacking data from microorganisms representing the microfauna, such as root-knot nematodes. Meloidogyne spp. are sedentary endoparasitic nematodes of plants. Its presence in soil covered with native cerrado vegetation, under preservation, is a strong indication that its permanence occurs due to the parasitism of native plants. This work aimed to study the host suitability of cerrado plants to Meloidogyne spp. Thirty-five plant species from the Cerrado biome, including grasses and trees, were selected for inoculation with four Meloidogyne isolates, three of them previously collected in a native Cerrado area under preservation (Meloidogyne incognita, Meloidogyne javanica, and Meloidogyne morocciensis), and the fourth (Meloidogyne paranaensis) an exotic species in Cerrado. Five thousand eggs and second-stage juveniles (J2) of each nematode species were inoculated per plant. The experiments were conducted with 35 treatments (native plants) and 5 replicates, having been repeated in time. The variables assessed were gall index and egg mass index, eggs and J2 per gram of root and reproductive factor (RF), as well as the symptomatology caused by the nematodes on the roots. The following plant species were considered as hosts by presenting mean of the Reproduction Factor (RF)>1.0: Triplaris gardneriana for Meloidogyne javanica, Meloidogyne incognita, and Meloidogyne morocciensis; Andropogon bicornis for Meloidogyne javanica and Meloidogyne incognita and Copaifera langsdorffii for Meloidogyne incognita; The following plant species were classified as potential hosts by developing RF>1.0 in at least one of the replicates: Copaifera langsdorffii for Meloidogyne morocciensis; Esenbeckia leiocarpa for Meloidogyne javanica and Guibourtia hymenifolia for Meloidogyne incognita. The other plant species were classified as non-hosts considering the conditions of this study. The inoculated plants showed varied symptoms on the roots, such as galls associated with egg masses, egg masses without galls, swelling with egg masses, cracks with egg masses without galls, and swelling with egg masses.

Keywords:
Root-knot nematodes; Brazilian savanna; Native plants; Host plants