Heterodera schachtii Tyrosinase-like protein - a novel nematode effector modulating plant hormone homeostasis

Samer S. Habash,Radomira Vankova,Abdelnaser Elashry,Shahid Siddique,Zoran S. Radakovic,Cynthia Gleason,Florian M. W. Grundler,Petre Dobrev

doi:10.1038/s41598-017-07269-7

Abstract

The beet cyst nematode Heterodera schachtii causes major yield losses in sugar beet. Understanding the interaction between H. schachtii and its host plant is important for developing a sustainable management system. Nematode effectors play a crucial role in initializing and sustaining successful parasitism. In our study, we identified a gene (Hs-Tyr) encoding a tyrosinase functional domain (PF00264). We describe Hs-Tyr as a novel nematode effector. Hs-Tyr is localized in the nematode esophageal gland. Up-regulation of its expression coincided with the parasitic developmental stages of the nematode. Silencing Hs-Tyr by RNA interference made the treated nematodes less virulent. When RNAi-treated nematodes succeeded in infecting the plant, developing females and their associated syncytial nurse cells were significantly smaller than in control plants. Ectopically expressing the Hs-Tyr effector in Arabidopsis increased plant susceptibility to H. schachtii, but not to the root-knot nematode Meloidogyne incognita. Interestingly, Hs-Tyr in the plant promoted plant growth and changed the root architecture. Additionally, the expression of Hs-Tyr in Arabidopsis caused changes in the homeostasis of several plant hormones especially auxin and the ethylene precursor aminocyclopropane-carboxylic acid.

Highlights

Plant parasitic nematodes cause massive yield losses in many important crops and are considered as a major problem in crop production[1]
H. schachtii can dramatically decrease the yield of sugar beet
Recent advances in techniques such as RNAseq and generation sequencing facilitate the mining of plant parasitic nematode genes involved in parasitism[14, 15]

Summary

Introduction

Plant parasitic nematodes cause massive yield losses in many important crops and are considered as a major problem in crop production[1]. A recent study found that the H. schachtii effector 4F01 is mimicking plant annexin and, by doing so, alters the host defenses against nematodes[8]. In another example, effector 10A06 has been shown to interact with www.nature.com/scientificreports/. Basal defenses may be triggered by cell wall fragments produced during the nematode’s migration through the root or by unidentified PAMPs. H. schachtii venom-allergen like protein (VAP) acts as an apoplastic immune repressor which dampens the plant’s immune responses. In addition to effectors that seem to target plant defenses, nematodes are able to produce molecules with hormone activity. Nematodes secrete peptides that mimic the family of plant peptide hormones called CLEs, and this enables the nematodes to developmentally reprogram the root cells in order to initiate and maintain its feeding site[13]

Methods

Results

Conclusion