Mechanisms of resistance in the rice cultivar Manikpukha to the rice stem nematode Ditylenchus angustus

Abstract

The incompatible interaction between the rice cultivar Manikpukha and the rice stem nematode Ditylenchus angustus has been reported recently. This research focuses on the underlying mechanisms of resistance in Manikpukha. Invasion, post-infection development and reproduction of D. angustus were compared in compatible and incompatible interactions to identify the stage in which resistance occurs. The results indicate that resistance in Manikpukha is associated with reduced development and reproduction, implying that resistance acts post-invasion. We studied the possible involvement of three classical defence hormones, salicylic acid (SA), jasmonic acid (JA) and ethylene (ET), in response to infection in a compatible interaction using biosynthesis/signalling-deficient transgenic rice lines. All three hormones appear to have an influence on the basal defence of Nipponbare against the stem nematode. Although hormone application increases basal defences, expression studies and hormone analyses after nematode infection in Manikpukha did not show a clear involvement of the hormone defense pathways for SA, ET and JA. However, it seems that OsPAL1 plays a pivotal role in resistance, indicating that the phenylpropanoid pathway and its products might be key players in the incompatible interaction. Lignin measurement showed that, although basal levels are similar, Manikpukha had a significantly higher lignin content on nematode infection, whereas it was decreased in the susceptible cultivar. The results presented here show that SA, ET and JA are involved in basal defences, but the resistance of Manikpukha against D. angustus probably relies on products of the phenylpropanoid pathway.

Chorismate mutase and isochorismatase, two potential effectors of the migratory nematode Hirschmanniella oryzae, increase host susceptibility by manipulating secondary metabolite content of rice

“…The fact that the PAL genes, considered as the starting point of the phenylpropanoid pathway, are often up-and down-regulated in resistant and susceptible interactions, respectively, shows that phenylpropanoids are important defence molecules. This was shown in several plant-pathogen interaction experiments (Gao et al, 2008;Uehara et al, 2010;Feng et al, 2011;Khanam et al, 2018). In contrast to our observations, Djamei and colleagues (2011) reported an increase in phenylpropanoid biosynthesis products in plants infected with U. maydis, which indicates that chorismate is directed into the phenylpropanoid pathway.…”

Transcriptome analysis of roots from resistant and susceptible rice varieties infected with Hirschmanniella mucronata

“…Many genes involved in plant secondary metabolism, such as phenylpropanoid, lignin and flavonoids, were affected after nematode infection . The phenylpropanoid or lignin pathway and its products play important roles in the incompatible interaction and cultivar resistance against nematodes . Compared with R155, all 19 DEGs involved in phenylpropanoid (7 DEGs) or lignin (12 DEGs) metabolism were significantly up‐regulated in the uninfected roots of Jiabali (Table S4).…”

“…The expression of OsPAL1 (Os02g0627100) was up‐regulated 1.43‐fold compared with that of R155. In the rice‐resistant cultivar Manikpukha, OsPAL1 plays a pivotal role in resistance to the rice stem nematode Ditylenchus angustus , and the lignin content significantly increased after the nematode infection . That showed that rice resistance to the nematode partially relied on the metabolism of phenylpropanoid or the biosynthesis of lignin.…”

Transcriptomic Analysis of Resistant and Susceptible Responses in a New Model Root-Knot Nematode Infection System Using Solanum torvum and Meloidogyne arenaria

“…Indeed, silencing of the chalcone synthase gene increases lignin deposition in wheat (Eloy et al, 2017). Activation of the phenylpropanoid biosynthesis pathway may also be involved in the production of anti-PPN secondary metabolites (Khanam et al, 2018). For example, transcinnamaldehyde is a phenylpropanoid compound that is highly toxic to RKNs and pinewood nematodes (Oka, 2001;Kong et al, 2007).…”