Phytohormones Related to Host Plant Manipulation by a Gall-Inducing Leafhopper

Abstract

The maize orange leafhopper Cicadulina bipunctata (Hemiptera: Cicadellidae) induces galls characterized by growth stunting and severe swelling of leaf veins on various plants of Poaceae. Previous studies revealed that galls are induced not on feeding site but on distant, newly extended leaves during the feeding, and strongly suggested that some chemicals injected by the leafhopper affect at the leaf primordia. To approach the mechanism underlying gall induction by C. bipunctata, we examined physiological response of plants to feeding by the leafhopper. We performed high-throughput and comprehensive plant hormone analyses using LC-ESI-MS/MS. Galled maize leaves contained higher contents of abscisic acid (ABA) and trans-Zeatin (tZ) and lower contents of gibberellins (GA1 and GA4) than ungalled maize leaves. Leafhopper treatment significantly increased ABA and tZ contents and decreased GA1 and GA4 contents in extending leaves. After the removal of leafhoppers, contents of tZ and gibberellins in extending leaves soon became similar to the control values. ABA content was gradually decreased after the removal of leafhoppers. Such hormonal changes were not observed in leafhopper treatment on leaves of resistant maize variety. Water contents of galled leaves were significantly lower than control leaves, suggesting water stress of galled leaves and possible reason of the increase in ABA content. These results imply that ABA, tZ, and gibberellins are related to gall induction by the leafhopper on susceptible variety of maize.

Phytohormones in red seaweeds: a technical review of methods for analysis and a consideration of genomic data

“…Tokuda et al 2013). A sufficient pretreatment procedure permits analysis with small amounts of plant tissue or thallus (~20-100 mg dry weight) (Mikami et al 2016).…”

“…Recent advances in techniques to analyze phytohormones using liquid chromatography-mass spectrometry (LC-MS) allow simultaneous analysis of multiple hormones for a comprehensive view of phytohormone dynamics (for example, Tokuda et al 2013, Schäfer et al 2016. Despite these advances, no comprehensive analysis of phytohormones has yet been carried out in red seaweeds.…”

Unraveling the tripartite interactions among the woolly poplar aphid, its host tree, and their environment: a lead to improve the management of a major tree plantation pest?

“…Höglund et al (2015) demonstrated that willow resistance to a gall midge was rather due to a lack of induced susceptibility than to an induced HR. Likewise, in some plant-gall-inducer systems, resistance is related to a failure in the manipulation of plant hormones concentrations (Matsukura et al 2012;Tokuda et al 2013).…”

“…Likewise, a detailed monitoring of early events during the onset of compatible and incompatible interactions could be performed. In particular, monitoring the accumulation of phytohormones involved in stress signaling, like jasmonic acid, ethylene and salicylic acid, and phytohormones potentially involved in the manipulation of host tissue and metabolism, like auxins and cytokinins, would allow pointing out the key processes involved in either the success or failure of plant manipulation as in other plant-gall-inducer systems (e.g., Tokuda et al 2013). …”

Occurrence of Cicadulina bipunctata (Hemiptera: Cicadellidae) in southwestern Shikoku, Japan and comparisons of gall-inducing ability between Kyushu and Shikoku populations

“…Galls are induced only on leaves which are newly expanding during leafhopper feeding, but not on leaves already developed or those which expand after the removal of leafhoppers (Ofori and Francki 1983;Ohata 1993;Matsukura et al 2009b). The degree of gall induction depends on the density and duration of feeding by C. bipunctata (Matsukura et al 2009a;Matsukura and Matsumura 2010;Tokuda et al 2013).…”