Novel crosstalk between ethylene‐ and jasmonic acid‐pathway responses to a piercing–sucking insect in rice

Abstract

Summary Ethylene (ET) and jasmonic acid (JA) play important roles in plant defenses against biotic stresses. Crosstalk between JA and ET has been well studied in mediating pathogen resistance, but its roles in piercing–sucking insect resistance are unclear. The brown planthopper (BPH; Nilaparvata lugens) is the most notorious piercing–sucking insect specific to rice (Oryza sativa) that severely affects yield. A genetic analysis revealed that OsEBF1 and OsEIL1, which are in the ET signaling pathway, positively and negatively regulated BPH resistance, respectively. Molecular and biochemical analyses revealed direct interactions between OsEBF1 and OsEIL1. OsEBF1, an E3 ligase, mediated the degradation of OsEIL1 through the ubiquitination pathway, indicating the negative regulation of the ET‐signaling pathway in response to BPH infestation. An RNA sequencing analysis revealed that a JA biosynthetic pathway‐related gene, OsLOX9, was downregulated significantly in the oseil1 mutant. Biochemical analyses, including yeast one‐hybrid, dual luciferase, and electrophoretic mobility shift assay, confirmed the direct regulation of OsLOX9 by OsEIL1. This study revealed the synergistic and negative regulation of JA and ET pathways in response to piercing–sucking insect attack. The synergistic mechanism was realized by transcriptional regulation of OsEIL1 on OsLOX9. OsEIL1‐OsLOX9 is a novel crosstalk site in these two phytohormone signaling pathways.

Suppression of a leucine‐rich repeat receptor‐like kinase enhances host plant resistance to a specialist herbivore

“…Both active MPKs and TFs regulate the signaling networks by activating or suppressing one or more components in different signaling pathways mediated by (among others) JA, SA, ET and reactive oxygen species (ROS) (Bakshi & Oelmuller, 2014;Hu et al, 2015;Li, Liu, et al, 2019). JA signaling is considered to be the core signaling pathway for triggering plant resistance to herbivores (Ruan et al, 2019;Wang, Wu, Wang, & Xie, 2019), whereas the ETand SA-mediated signaling pathways are multi-faceted players in plant-herbivore interactions (Li, Han, Feng, Yuan, & Huang, 2019;Lu et al, 2014;Ma, Yang, Shi, & Miao, 2020;Zust & Agrawal, 2016). ROS is implicated in plant defense against piercing-sucking herbivores (Hu, Meng Ye, Peng Kuai, and Lingfei Hu contributed equally to this work.…”

“…BPH is a phloem feeder which causes substantial yield losses and is among the most damaging rice pests on earth (Heong, Cheng, & Escalada, 2016). Although rice plants can activate a variety of defense signaling molecules, including MPKs, WRKYs, JA, SA, ET and H 2 O 2 , and then produce defense responses when infested by BPH (Hu et al, 2016;Li, Liu, et al, 2019;Lu et al, 2014;Ma et al, 2020;Zhou et al, 2009Zhou et al, , 2019, BPH can also circumvent and suppress host plant resistance in several ways (Ji et al, 2017;Ye et al, 2017). BPH can, for instance, secrete salivary endo-β-1,4-glucanase to overcome plant cell wall defense in rice without inducing defense-related signal molecules (Ji et al, 2017), and can inhibit H 2 O 2 production in rice via reducing cellular Ca 2+ levels by secreting salivary calcium-binding proteins (Ye et al, 2017).…”

Studies on Inducer Mediated Resistance Responses against Biological Fitness of Brevicoryne brassicae (Homoptera: Aphididae) on Brassica napus

“…But they are costly enough to restrict their field application practically (Dhandhukia and Thakkar 2007). Also, they may antagonize plant defense against the specialist pest due to issues in defensive signaling crosstalk (Schmiesing et al 2016;Li et al 2019;Irigoyen et al 2020;Ma et al 2020). As B. brassicae is also a specialist pest (Nouri-Ganbalani et al 2018), thus some alternative bio-activators such as SA and CA suitable against such pest, are needed to explore.…”

Current understanding of the genomic, genetic, and molecular control of insect resistance in rice

“…The exogenous application of ABA suppressed β-1,3glucanase while inducing callose synthase activity, promoting callose deposition and thereby preventing BPH feeding (Liu et al 2017). A recent study revealed that OsEIL1-OsLOX9 undergo crosstalk to negatively regulate JA and ET signaling pathways, thereby affecting plant responses to sucking insect attack (Ma et al 2019).…”