An Arabidopsis ATPase gene involved in nematode‐induced syncytium development and abiotic stress responses

Muhammad Amjad Ali,Moritz Ammelburg,Krzysztof Wieczorek,Abdelnaser Elashry,Stephan Plattner,Zoran Radakovic,Florian M.W Grundler,Holger Bohlmann,Shahid Siddique

doi:10.1111/tpj.12170

Abstract

The beet cyst nematode Heterodera schachtii induces syncytia in the roots of Arabidopsis thaliana, which are its only nutrient source. One gene, At1g64110, that is strongly up-regulated in syncytia as shown by RT-PCR, quantitative RT-PCR, in situ RT-PCR and promoter::GUS lines, encodes an AAA+-type ATPase. Expression of two related genes in syncytia, At4g28000 and At5g52882, was not detected or not different from control root segments. Using amiRNA lines and T-DNA mutants, we show that At1g64110 is important for syncytium and nematode development. At1g64110 was also inducible by wounding, jasmonic acid, salicylic acid, heat and cold, as well as drought, sodium chloride, abscisic acid and mannitol, indicating involvement of this gene in abiotic stress responses. We confirmed this using two T-DNA mutants that were more sensitive to abscisic acid and sodium chloride during seed germination and root growth. These mutants also developed significantly smaller roots in response to abscisic acid and sodium chloride. An in silico analysis showed that ATPase At1g64110 (and also At4g28000 and At5g52882) belong to the ‘meiotic clade’ of AAA proteins that includes proteins such as Vps4, katanin, spastin and MSP1.

Highlights

Nematodes are a large group of animals that include freeliving and parasitic species of animals, humans and plants
The At1g64110/DAA1 gene belongs to a small sub-family of three very similar genes in A. thaliana and Arabidopsis lyrata, designated ORTHO000440 by PLAZA within the gene family HOM000025
The two other genes in this sub-family are At4g28000, which is expressed at very low levels in roots and syncytia (Szakasits et al, 2009), and At5g52882, which is not represented on the Affymetrix Arabidopsis GeneChip (Table S1)

Summary

Introduction

Nematodes are a large group of animals that include freeliving and parasitic species of animals, humans and plants. Among the economically important pathogens are two main groups with a sedentary lifestyle They induce a feeding site within the plant root that consists of several giant cells in case of root-knot nematodes (genus Meloidogyne) or a syncytium in case of cyst nematodes (genera Heterodera and Globodera). These feeding sites are the sole source of nutrients throughout the whole life of these sedentary nematodes (Gheysen and Mitchum, 2011). Female cyst nematodes never leave their feeding site and continue to feed after fertilization. They produce several hundred eggs that remain within their enlarged bodies, which subsequently harden to form cysts, which protect the eggs until infective J2 larvae hatch again under favourable conditions (Sobczak and Golinowski, 2011)

Results

Discussion

Conclusion