Transcriptomics and functional genomics of plant defence induction by phloem-feeding insects

Abstract

The relationship between phloem-feeding insects (PFIs) and plants offers an intriguing example of a highly specialized biotic interaction. These insects have evolved to survive on a nutritionally imbalanced diet of phloem sap, and to minimize wound responses in their host plants. As a consequence, plant perception of and responses to PFIs differ from plant interactions with other insect-feeding guilds. Transcriptome-wide analyses of gene expression are currently being applied to characterize plant responses to PFIs in crop plants with race-specific innate resistance, as well as in compatible interactions with susceptible hosts. Recent studies indicate that PFIs induce transcriptional reprogramming in their host plants, and that plant responses to PFIs appear to be quantitatively and qualitatively different from responses to other insects or pathogens. Transcript profiling studies also suggest that PFIs induce cell wall modifications, reduce photosynthetic activity, manipulate source-sink relations, and modify secondary metabolism in their hosts, and many of these responses appear to occur within the phloem tissue. Plant responses to these insects appear to be regulated in part by the salicylate, jasmonate, and ethylene signalling pathways. As additional transcript profiling data become available, forward and reverse genetic approaches will be necessary to determine which changes in gene expression influence resistance or susceptibility to PFIs.

Apion miniatum Germ. Herbivory on the Mossy Sorrel, Rumex confertus Willd.: Induced Plant Volatiles and Weevil Orientation Responses

“…However, pathogen infection also can induce GLVs and terpenes [34]. VOCs can be involved in direct and indirect plant defenses against herbivores or pathogens [35,36]. VOCs were released from control plants only in small but detectable amounts.…”

Trichoderma gamsii affected herbivore feeding behaviour on Arabidopsis thaliana by modifying the leaf metabolome and phytohormones

“…For example, tryptophan plays a critical role in regulating plant responses to biotic and abiotic stresses (Radwanski and Last, 1995; Zhao and Last, 1996; Sangha et al ., 2011). Transcript profiling data generally show herbivory‐induced changes in the expression of genes related to the production of glutamine, glutamic acid, asparagine and aspartic acid (Thompson and Goggin, 2006; Caldana et al ., 2011; Appel and Cocroft, 2014; Zhou et al ., 2015), which are involved in nitrogen assimilation (Coruzzi and Last, 2000). Amino acids also play a role in signal transduction to induce defence gene expression.…”

Transcriptomics of induced defense responses to greenbug aphid feeding in near isogenic wheat lines

“…Following perception of piercing/sucking feeding patterns, plants activate early signal networks those trigger massive transcriptional reprogramming and downstream responses to defend against phloem-feeders [17]. The early signal transduction events induced by phloemfeeding insects are largely mediated by calcium flux, reactive oxygen species (ROS), phytohormones, volatiles organic compounds, and nonvolatile secondary metabolites that can serve as repellants, toxins, and even attract natural enemies [9,[18][19][20].…”