Histopathological characterization of Coffea arabica cultivar IPR 106 resistance to Meloidogyne paranaensis

Abstract

Meloidogyne species are widely distributed in coffee growing areas in Brazil, where M. paranaensis is responsible to significant losses to the crop. One of the main management strategies is the use of resistant cultivars, such as Apoatã rootstock and cultivars IPR 100 and IPR 106. However, the parasitic relationship between coffee and M. paranaensis in cultivars carrying resistance genes has been poorly understood. The objective of this paper was to characterize the resistance response of Coffea arabica cv. IPR 106 to M. paranaensis. For this, penetration and histopathological studies were carried out using root tissues parasitized by the nematode. 'IPR 106' and 'Mundo Novo' (susceptible cultivar) seedlings were inoculated with 4,000 eggs of M. paranaensis and, 15 days after inoculation (DAI), roots were stained with fuchsine to verify the penetration rates of the nematode. Histopathological studies were conducted at 15, 30, 45 and 60 DAI and nematode reproduction was calculated at 120 DAI. 'IPR 106' did not avoid completely nematode penetration at 15 DAI, although the number of nematodes was 50 % lower than in Mundo Novo, disregarding the hypothesis of a pre-infectional mechanism of resistance that could prevent nematode penetration completely. However, giant cells and collapsed nematodes were observed in 'IPR 106' at 30 DAI, suggesting that the resistance mechanism to M. paranaensis in 'IPR 106' involves a post-infectional response and could be mediated by a hypersensitive reaction.

IPR 106: new Arabica coffee cultivar, resistant to some Meloidogyne paranaensis and M. incognita nematode populations of Paraná

“…The resistance to both nematodes observed in this study confirmed previous findings of the simultaneous resistance of this cultivar against the nematodes M. incognita and M. paranaensis (Ito et al 2008). Another histopathological study reported that the resistance of IPR 106 is apparently due to hypersensitive-like response and was detected at 30 days after inoculation with population 98.1 of M. paranaensis, when abnormal giant host cells were observed and malformed nematode females (Shigueoka et al 2019). IPR 106 has not yet been tested for all known M. exigua and M. incognita races.…”