Gene expression profiling and shared promoter motif for cell wall-modifying proteins expressed in soybean cyst nematode-infected roots.

Mark L Tucker,Ronghui Yang,Charles A Murphy

doi:10.1104/pp.110.170357

Mark L Tucker, Ronghui Yang + Show 1 more

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https://doi.org/10.1104/pp.110.170357

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Journal: Plant physiology	Publication Date: Mar 23, 2011
Citations: 12	License type: CC BY 4.0

Affiliation: Beltsville Agricultural Research Center

Abstract

We hypothesized that soybean cyst nematode (SCN; Heterodera glycines) co-opts part or all of one or more innate developmental process in soybean (Glycine max) to establish its feeding structure, syncytium, in soybean roots. The syncytium is formed within the vascular bundle by partial degradation of cell walls and membranes between adjacent parenchyma cells. A mature syncytium incorporates as many as 200 cells into one large multinucleated cell. Gene expression patterns for several cell wall-modifying proteins were compared in multiple tissues undergoing major shifts in cell wall integrity. These included SCN-colonized roots, root tips where vascular differentiation occurs, flooded roots (aerenchyma), adventitious rooting in hypocotyls, and leaf abscission zones. A search in the 5' upstream promoters of these genes identified a motif (SCNbox1: WGCATGTG) common to several genes that were up-regulated in several different tissues. The polygalacturonase 11 promoters (GmPG11a/b) include the SCNbox1 motif. The expression pattern for GmPG11a was examined further in transgenic soybean containing a PG11a promoter fused to a β-glucuronidase (GUS) reporter gene. GUS expression was highest in cells undergoing radial expansion in the stele and/or cell wall dissolution. GUS staining was not observed in cortical cells where a lateral root tip or a growing nematode emerged through the root cortex.

Highlights

We hypothesized that soybean cyst nematode (SCN; Heterodera glycines) co-opts part or all of one or more innate developmental process in soybean (Glycine max) to establish its feeding structure, syncytium, in soybean roots
We hypothesized that SCN-secreted proteins must co-opt one or more innate developmental processes in soybean to complete the necessary structural changes required for formation of the feeding structure
Cell separation associated with aerenchyma development in soybean roots might have gene expression patterns similar to those associated with formation of the SCN syncytium, and the two processes may share regulatory signals

Summary

Introduction

We hypothesized that soybean cyst nematode (SCN; Heterodera glycines) co-opts part or all of one or more innate developmental process in soybean (Glycine max) to establish its feeding structure, syncytium, in soybean roots. Gene expression patterns for several cell wall-modifying proteins were compared in multiple tissues undergoing major shifts in cell wall integrity These included SCN-colonized roots, root tips where vascular differentiation occurs, flooded roots (aerenchyma), adventitious rooting in hypocotyls, and leaf abscission zones. Soybean cyst nematode (SCN; Heterodera glycines) forms a large multinucleated feeding cell (syncytium) within the vascular cylinder of the soybean (Glycine max) root by inducing the degradation of cell walls and membranes between adjoining cells (Goverse et al, 2000). Since formation of the syncytium requires cell wall degradation between cells, one of the processes evoked by the nematode must include a coordinated expression of proteins that disassemble the cell wall. Several of the same genes were expressed in root tips where vascular development occurs and in leaf abscission where extensive cell wall degradation leads to separation of the petiole from the stem (Tucker et al, 2007)

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