Meloidogyne javanica fatty acid- and retinol-binding protein (Mj-FAR-1) regulates expression of lipid-, cell wall-, stress- and phenylpropanoid-related genes during nematode infection of tomato

Abstract

BackgroundThe secreted Meloidogyne javanica fatty acid- and retinol-binding (FAR) protein Mj-FAR-1 is involved in nematode development and reproduction in host tomato roots. To gain further insight into the role of Mj-FAR-1 in regulating disease development, local transcriptional changes were monitored in tomato hairy root lines with constitutive mj-far-1 expression compared with control roots without inoculation, and 2, 5 and 15 days after inoculation (DAI), using mRNA sequencing analysis.ResultsGene-expression profiling revealed a total of 3970 differentially expressed genes (DEGs) between the two lines. Among the DEGs, 1093, 1039, 1959, and 1328 genes were up- or downregulated 2-fold with false discovery rate < 0.001 in noninoculated roots, and roots 2, 5, and 15 DAI compared with control roots, respectively. Four main groups of genes that might be associated with Mj-FAR-1-mediated susceptibility were identified: 1) genes involved in biotic stress responses such as pathogen-defense mechanisms and hormone metabolism; 2) genes involved in phenylalanine and phenylpropanoid metabolism; 3) genes associated with cell wall synthesis, modification or degradation; and 4) genes associated with lipid metabolism. All of these genes were overrepresented among the DEGs. Studying the distances between the treatments, samples from noninoculated roots and roots at 2 DAI clustered predominantly according to the temporal dynamics related to nematode infection. However, at the later time points (5 and 15 DAI), samples clustered predominantly according to mj-far-1 overexpression, indicating that at these time points Mj-FAR-1 is more important in defining a common transcriptome.ConclusionsThe presence of four groups of DEGs demonstrates a network of molecular events is mediated by Mj-FAR-1 that leads to highly complex manipulation of plant defense responses against nematode invasion. The results shed light on the in vivo role of secreted FAR proteins in parasitism, and add to the mounting evidence that secreted FAR proteins play a major role in nematode parasitism.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1426-3) contains supplementary material, which is available to authorized users.

The Pratylenchus penetrans Transcriptome as a Source for the Development of Alternative Control Strategies: Mining for Putative Genes Involved in Parasitism and Evaluation of in planta RNAi

“…In animal-parasitic nematodes FAR proteins have been projected to facilitate nematode infection by scavenging and transporting fatty acids, required for developmental processes and cellular differentiation of the nematode, or playing a role in interfering with intracellular and intercellular lipid signaling related to host defenses [ 46 , 48 ]. In plant-parasitic nematodes they have been pointed out as a mediator of a complex manipulation of plant defenses responses against the invasion process of cyst and root-knot nematode species [ 47 , 49 ]. It will be interesting to validate whether FAR-1 will have similar functions on root lesion nematode species.…”

Plant-parasitic nematodes: towards understanding molecular players in stress responses

“…At the plant cell surface, two major oxidant enzyme families govern the oxidative burst responses, corresponding to the plasma membrane-localized nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs, which are also called respiratory burst oxidases, or Rbohs) and/or the cell-wall-localized (or apoplastic) peroxidases (Lambeth, 2004; Mittler et al , 2011; Siddique et al , 2014). In addition, other oxidative enzymes are also implicated in the production of reactive species, such as xanthine oxidases, oxalate oxidases and amine oxidases (Wojtaszek, 1997; Hewezi et al , 2010; Moschou and Roubelakis-Angelakis, 2014; Iberkleid et al , 2015). Together, these enzymes contribute to the generation of reactive species, with distinct roles in MTI- and ETI-signalling responses (Daudi et al , 2012; Considine et al , 2015).…”

Developing a method for real-time visualization of cellulase activity

“…To test our newly developed visualization technique in a physiologically relevant scenario, we chose to visualize interactions with Root Knot Nematode (RKN). RKN is a widespread root pathogen that penetrates the root by secreting Plant Cell Wall Degrading Enzymes (PCWDE) including cellulase [52][53][54] , causing substantial damage to crops around the world 22,[55][56][57][58] . We applied RKN to the center of the dyed CMC film and incubated for 2h at either 37°C (ideal temperature for the hydrolysis reaction) or 27°C (ideal temperature for RKN).…”

“…Spatial resolution can be crucial in the context of plant interactions with microorganisms, and highly relevant for studying plant-pathogen interactions. For example, though some soil borne pathogens are known to enter the root in specific locations [22][23][24] , the structural basis for this preference has received little attention. Additionally, synthetic systems were proven efficient in depicting the structural preference in leaves 25,26 .…”