Investigating the Diuraphis noxia - Triticum aestivum interaction using transcriptomics

Aphids often overcome host plant resistance by developing virulence. However, the underlying mechanisms and the precise modifications involved remain poorly understood. Additionally, the molecular response of resistant host plants during compatible (virulent aphid) and incompatible (avirulent aphid) interactions is another area requiring further investigation.

Here, Diuraphis noxia (Russian wheat aphid) biotypes of varying virulence were transferred from susceptible Triticum aestivum to a near-isogenic line containing the Dn7 resistance gene. Transcriptomes of the D. noxia biotypes and the resistant host were sequenced before and after the host shift.

Transcriptomic analysis indicated that the D. noxia biotypes had unique responses which were involved in detoxification (e.g. L-xylulose reductase), membrane transport (e.g. Tert-1) and epigenetic regulation. In addition, many transposable elements were rapidly differentially regulated between biotypes and because of the host shift. In the host plant, all biotypes induced jasmonic acid signalling and terpenoid biosynthesis. However, the mono- and diterpenoid pathways were only upregulated following feeding by the biotypes avirulent to Dn7 and not SAMv2.

Rapid differential expression of transposons suggests a mechanism of adaptation for clonally reproducing aphids. Furthermore, SAMv2 may possess mechanisms to modulate the defence response of Dn7 -containing T. aestivum .