Abscisic acid interacts antagonistically with classical defense pathways in rice–migratory nematode interaction

Abstract

SummaryStudies involving plant-nematode interactions provide an opportunity to unravel plant defense signaling in root tissues. In this study, we have characterized the roles of salicylate (SA), jasmonate (JA), ethylene (ET) and abscisic acid (ABA) in plant defense against the migratory nematode Hirschmanniella oryzae in the monocot model plant rice (Oryza sativa).Experiments with exogenous hormone applications, biosynthesis inhibition and mutant/ transgenic lines were executed to test the effect on H. oryzae parasitism in rice roots.Our results demonstrate that an intact ET, JA and SA biosynthesis pathway is a prerequisite for defense against H. oryzae. By contrast, exogenous ABA treatment drastically compromised the rice defense towards this nematode. Gene expression analyses using quantitative reverse transcription polymerase chain reaction (qRT-PCR) demonstrate that the disease-inducing effect of ABA is likely to be the result of an antagonistic interaction between this hormone and the SA/JA/ET-dependent basal defense system.Collectively, in rice defense against H. oryzae, at least three pathways, namely SA, JA and ET, are important, while ABA plays a negative role in defense. Our results suggest that the balance of ABA and SA/JA/ET signaling is an important determinant for the outcome of the rice-H. oryzae interaction.

The HERBIVORE ELICITOR-REGULATED1 Gene Enhances Abscisic Acid Levels and Defenses against Herbivores in Nicotiana attenuata Plants

“…In addition, Spodoptera littoralis and Spodoptera exigua larvae grew better on Arabidopsis ABA2-1-deficient mutants and ABA-deficient tomato plants, respectively (Thaler and Bostock, 2004;Bodenhausen and Reymond, 2007). The application of exogenous ABA and the balance of ABA and SA/JA/ethylene affected rice's defenses against Hirschmanniella oryzae (Nahar et al, 2012). Such findings are consistent with a significant role of ABA in regulating plant-herbivore interactions; however, the mechanisms of ABA's role, known as the typical drought-related hormone, in defense against herbivores remain to be understood in detail.…”

Cooperative Regulatory Functions of miR858 and MYB83 during Cyst Nematode Parasitism

“…7A). While the function of jasmonic acid and abscisic acid signaling in directing plant response to cyst nematodes is not fully understood (Kammerhofer et al, 2015), it has been recently demonstrated that these pathways regulate defense responses and basal immunity against sedentary and migratory nematodes (Nahar et al, 2011(Nahar et al, , 2012Ozalvo et al, 2014).…”

Molecular Cloning and Characterization of Two Genes Encoding Tryptophan Decarboxylase from Aegilops variabilis with Resistance to the Cereal Cyst Nematode (Heterodera avenae) and Root-Knot Nematode (Meloidogyne naasi)

“…The JA pathway is a key player in systemic induced defense against RKN in tomato (Cooper et al 2005), and SA actions downstream in initiating Mi-1-mediated resistance to both aphids and nematodes (Branch et al 2004;Li et al 2006). However, the ABA pathway antagonizes the SA/JAdependent core defense system, leading to enhanced susceptibility to root-parasitic nematodes (Hirschmanniella oryzae) (Nahar et al 2011(Nahar et al , 2012. The importance of the JA pathway to nematode resistance has also been reported in rice (Frey et al 1997).…”

“…A total of 5 μg RNA was treated with DNase-I and used for first-strand cDNA synthesis using Maloney murine leukemia virus reverse transcriptase (TaKaRa, Dalian, China) according to the manufacturer's protocol and primed by Oligo18 (Nahar et al 2012). RNA quality was measured by separation in 1.0 % agarose gels, staining with ethidium bromide and observing under UV.…”