Mechanisms of plant–insect interaction

The study of plant–insect interactions continues to be an exciting and fast-moving field that builds upon the more extensive literature available in plant–microbe interactions and offers new and significant insights into both the unique molecular determinants of plant–insect interactions and the wider ecological context. This special issue of the Journal of Experimental Botany brings together a collection of reviews and original research papers that reflect the breadth and quality of work undertaken in contemporary research into plant–insect interactions. The review by Mark Mescher and Consuelo De Moraes (2015) gives a historical perspective of the often-controversial field of plant sensory perception and how this relates to the capacity of plants to recognize and respond to the presence of both beneficial and detrimental insects. These authors provide an overview of the acute sensory capacity of plants, revealing the emerging story of mechano-and chemoreception. The exquisite capacity of plants to recognize subtle differences in mechanical stimuli is highlighted, with the suggestion that this is crucial in distinguishing mechanical stimuli caused by insects from those caused by other external factors such as wind and rain. These capabilities are supplemented with a highly evolved capacity for chemoreception that not only allows plants to respond to direct insect attack but also provides a mechanism for recognizing chemical elicitors associated with processes such as egg laying, allowing anticipatory upregulation of defensive traits prior to larval hatching. Combined with a discussion of the capacity for detection and response to insect-induced volatile emissions from neighbouring plants, this review highlights the sophistication and complexity of plant sensory responses to an ever-changing external environment. A parallel and complementary theme is explored in the review by Simon Zebelo and Massimo Maffei (2015), which focuses on the early signalling events following insect infestation in plants. Highlights include recent findings regarding the role of electrical signalling in plant–insect interactions and the integration of early and late signalling events that are mediated via hormonal signals among other things. Joe Louis and Jyoti Shah (2015) continue the theme of signalling in plant defence with their review on the role of PAD4 in aphid resistance. This protein exhibits key functions in both basal and effector-triggered immunity against microbial pathogens and is also an integral component of salicylic acid (SA) signalling and response. However, as Louis and Shah argue, it has distinct molecular activities in response to aphid infestation that differ from its role in defence against microbes. …