Gene expression changes in diapause or quiescent potato cyst nematode, Globodera pallida, eggs after hydration or exposure to tomato root diffusate.

Juan Emilio Palomares-Rius,Vivian C Blok,Jenny A Morris,Peter J.A Cock,Pete Hedley,John T Jones

doi:10.7717/peerj.1654

Juan Emilio Palomares-Rius, Vivian C Blok + Show 4 more

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https://doi.org/10.7717/peerj.1654

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Journal: PeerJ	Publication Date: Feb 4, 2016
Citations: 27	License type: CC BY 4.0

Affiliation: James Hutton Institute, University of St Andrews

Abstract

Plant-parasitic nematodes (PPN) need to be adapted to survive in the absence of a suitable host or in hostile environmental conditions. Various forms of developmental arrest including hatching inhibition and dauer stages are used by PPN in order to survive these conditions and spread to other areas. Potato cyst nematodes (PCN) (Globodera pallida and G. rostochiensis) are frequently in an anhydrobiotic state, with unhatched nematode persisting for extended periods of time inside the cyst in the absence of the host. This paper shows fundamental changes in the response of quiescent and diapaused eggs of G. pallida to hydration and following exposure to tomato root diffusate (RD) using microarray gene expression analysis encompassing a broad set of genes. For the quiescent eggs, 547 genes showed differential expression following hydration vs. hydratation and RD (H-RD) treatment whereas 708 genes showed differential regulation for the diapaused eggs following these treatments. The comparison between hydrated quiescent and diapaused eggs showed marked differences, with 2,380 genes that were differentially regulated compared with 987 genes following H-RD. Hydrated quiescent and diapaused eggs were markedly different indicating differences in adaptation for long-term survival. Transport activity is highly up-regulated following H-RD and few genes were coincident between both kinds of eggs. With the quiescent eggs, the majority of genes were related to ion transport (mainly sodium), while the diapaused eggs showed a major diversity of transporters (amino acid transport, ion transport, acetylcholine or other molecules).

Highlights

Plant-parasitic nematodes cause damage to crops throughout the world, with costs due to nematode damage calculated as being in excess of US$80 billion each year (Nicol et al, 2011)
For potato cyst nematodes (PCN), diapause is broken after exposure to a period of cold and is followed by quiescence, which is broken by exposure to root exudates from a suitable host plant
Genes regulated during the hatching process in quiescent and diapaused eggs and between hydrated and hydrated-root diffusate (RD) soaked eggs

Summary

Introduction

Plant-parasitic nematodes cause damage to crops throughout the world, with costs due to nematode damage calculated as being in excess of US$80 billion each year (Nicol et al, 2011). In the case of PCN, cysts with viable eggs can persist for up to 20 years or more in the absence of a suitable host (Lane & Trudgill, 1999). Nematodes that enter this dormant state are frequently desiccated in order to allow them to survive environmental extremes such as freezing. For PCN, diapause is broken after exposure to a period of cold (winter) and is followed by quiescence, which is broken by exposure to root exudates from a suitable host plant. This allows the nematode to ensure that they do not resume their life cycle until winter has passed and a suitable host is growing nearby

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