Cereal host interactions with Russian wheat aphid: A review

Abstract

A lack of understanding the interaction between the Russian wheat aphid (RWA) and its host plant is a limitation in developing effective strategies for controlling the aphid. It is generally assumed that the interaction between aphid and plant is similar to that between plant and pathogen; that is, an elicitor from the insect is recognized by a protein from the host plant and a cascade of signal transduction events follows. However, evidence suggests that RWA feeding is eliciting both the SA-and JA/ethylene-dependent signaling pathways by mimicking aspects of both pathogen and herbivorous insect attacks. Results further suggest that phenotypic symptoms after RWA feeding are under regulation via two independent reactions, namely an immediate response (i.e., leaf rolling) and a downstream event (i.e., chlorosis). These defense responses enable a resistant host plant to defend itself and overcome the stress response, while their susceptible counterparts die. The processes involved in the onset of the defense response are discussed, and mechanisms enabling resistant plants to overcome the stress associated with the feeding process are presented as a working model for RWA-cereal host interaction. Knowledge of genes involved in wheat's defense responses against the RWA and an understanding of their functions may provide additional strategies for developing broad-spectrum resistance in plants.

Virus-induced gene silencing of WRKY53 and an inducible phenylalanine ammonia-lyase in wheat reduces aphid resistance

“…Lowered levels of ROS coupled with increased rates of aphid reproduction in silenced plants provide further evidence that the oxidative burst forms an integral component of antibiotic resistance. Whether the oxidative burst facilitates antibiosis only through defence signal transduction mediated by SA, or additionally through direct damage to the aphid through ingestion of free radicals (Botha et al. , 2005), still needs to be determined.…”

“…Whether the oxidative burst facilitates antibiosis only through defence signal transduction mediated by SA, or additionally through direct damage to the aphid through ingestion of free radicals (Botha et al, 2005), still needs to be determined.…”

Silencing of a unique integrated domain nucleotide-binding leucine-rich repeat gene in wheat abolishesDiuraphis noxiaresistance

“…The TDN+BSMV 5AL-B4 plants did not show any alteration in the prenymphipositional period of the aphids, but an increase in aphid fecundity compared to resistant controls was evident. Diuraphis noxia infestation on susceptible hosts causes the breakdown of chloroplast and cellular membranes, leading to longitudinal chlorotic streaking (Botha et al 2005). In resistant hosts, infestation leads to the development of small necrotic lesions similar to the localized cell death response observed in the HR (Botha et al 2006; van Ooijen et al 2008).…”

“…This included chlorosis visualized as chlorotic lesions and streaking, leaf rolling, and stunted growth. In contrast, the resistance response is likened to the classic gene-for-gene interaction mediated by an R -gene with hypersensitive-linked necrotic lesions observed at the site of aphid feeding (Botha et al 2005).…”

Plant resistance to aphid feeding: behavioral, physiological, genetic and molecular cues regulate aphid host selection and feeding

“…The minimal tissue damage resulting from the ‘stealth’ feeding of aphids and the prolonged duration of aphid feeding suggest that aphid saliva elicits plant defense responses that are very different from responses elicited by the saliva from insects with mandibulate mouthparts . Salivary proteins secreted by several aphid species contain signal peptide sequences, some of which promote or delay growth and colonization . These and related data provide evidence of the intimate involvement of aphid effectors in aphid host plant selection and suggest that effectors may be the initial factors determining plant resistance or susceptibility to aphid herbivory .…”