The Glycine max Conserved Oligomeric Golgi (COG) Complex Functions During a Defense Response to Heterodera glycines.

Bisho Ram Lawaju,Gary W. Lawrence,Kathy S. Lawrence,Prakash Niraula,Vincent P. Klink

doi:10.3389/fpls.2020.564495

Bisho Ram Lawaju, Gary W. Lawrence + Show 3 more

Open Access

https://doi.org/10.3389/fpls.2020.564495

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Abstract

The conserved oligomeric Golgi (COG) complex, functioning in retrograde trafficking, is a universal structure present among eukaryotes that maintains the correct Golgi structure and function. The COG complex is composed of eight subunits coalescing into two sub-complexes. COGs1–4 compose Sub-complex A. COGs5–8 compose Sub-complex B. The observation that COG interacts with the syntaxins, suppressors of the erd2-deletion 5 (Sed5p), is noteworthy because Sed5p also interacts with Sec17p [alpha soluble NSF attachment protein (α-SNAP)]. The α-SNAP gene is located within the major Heterodera glycines [soybean cyst nematode (SCN)] resistance locus (rhg1) and functions in resistance. The study presented here provides a functional analysis of the Glycine max COG complex. The analysis has identified two paralogs of each COG gene. Functional transgenic studies demonstrate at least one paralog of each COG gene family functions in G. max during H. glycines resistance. Furthermore, treatment of G. max with the bacterial effector harpin, known to function in effector triggered immunity (ETI), leads to the induced transcription of at least one member of each COG gene family that has a role in H. glycines resistance. In some instances, altered COG gene expression changes the relative transcript abundance of syntaxin 31. These results indicate that the G. max COG complex functions through processes involving ETI leading to H. glycines resistance.

Highlights

Heterodera glycines [soybean cyst nematode (SCN)] is the most economically important pathogen of Glycine max
The principal findings are that the G. max conserved oligomeric Golgi (COG) complex families each has two members, one component of each gene family functions in defense, the expression of some of the family members are inducible by the bacterial effector harpin and some appear to influence the expression of syntaxin 31
Transgenic functional analyses, a harpin elicitor study, and the effect that COG component overexpression/RNA interference (RNAi) have on syntaxin 31 expression have been performed (Table 2)

Summary

Introduction

Heterodera glycines [soybean cyst nematode (SCN)] is the most economically important pathogen of Glycine max (soybean). The J2s slice through root cells including epidermal, cortex, and endodermal cells with a mouth apparatus known as a stylet that is both rigid and tubular It takes approximately 24 h for the J2 to reach its site of parasitism (Endo, 1965; Endo, 1991). Another function of the H. glycines stylet is to deliver effectors into a G. max pericycle or neighboring cell that it will parasitize. During this process, occurring over a period of days, the cell walls of the H. glycinesparasitized root cells dissolve. The syncytium is where the localized defense response occurs, a process involving components of effector triggered immunity (ETI) and pathogen-activated molecular pattern (PAMP)-triggered immunity (PTI) (Ross, 1958; Endo, 1965, 1991; Jones and Dangl, 2006; Matsye et al, 2011, 2012; Pant et al, 2014; McNeece et al, 2017, 2019) (Figure 1)

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