Sedentary Plant-Parasitic Nematodes Alter Auxin Homeostasis via Multiple Strategies

Abstract

Sedentary endoparasites such as cyst and root-knot nematodes infect many important food crops and are major agro-economical pests worldwide. These plant-parasitic nematodes exploit endogenous molecular and physiological pathways in the roots of their host to establish unique feeding structures. These structures function as highly active transfer cells and metabolic sinks and are essential for the parasites’ growth and reproduction. Plant hormones like indole-3-acetic acid (IAA) are a fundamental component in the formation of these feeding complexes. However, their underlying molecular and biochemical mechanisms are still elusive despite recent advances in the field. This review presents a comprehensive overview of known functions of various auxins in plant-parasitic nematode infection sites, based on a systematic analysis of current literature. We evaluate multiple aspects involved in auxin homeostasis in plants, including anabolism, catabolism, transport, and signalling. From these analyses, a picture emerges that plant-parasitic nematodes have evolved multiple strategies to manipulate auxin homeostasis to establish a successful parasitic relationship with their host. Additionally, there appears to be a potential role for auxins other than IAA in plant-parasitic nematode infections that might be of interest to be further elucidated.

Comparative Transcriptome Analysis Reveals the Specific Activation of Defense Pathways Against Globodera pallida in Gpa2 Resistant Potato Roots

“…We found downregulation of IAA14 at 6 dpi; this gene is particularly important for lateral root formation and is induced during feeding site establishment (Fukaki et al, 2002;Grunewald et al, 2008). Similarly, gene expression of the SAUR family is often detected in nematode feeding sites, and the majority of SAUR genes is downregulated during nematode infection (Oosterbeek et al, 2021). SAURs can modulate IAA transport and, thereby, affect the cell expansion and division process (Ren and Gray, 2015).…”

“…The activation of Gpa2 leads to the arrest of cyst nematode feeding site development. Auxin is known to be crucial for plant root formation and nematode feeding site development and consists of three major classes: IAA, GRETCHEN HAGEN 3 (GH3), and small auxin up RNA (SAUR) (Oosterbeek et al, 2021). We found downregulation of IAA14 at 6 dpi; this gene is particularly important for lateral root formation and is induced during feeding site establishment (Fukaki et al, 2002;Grunewald et al, 2008).…”

Understanding Molecular Plant–Nematode Interactions to Develop Alternative Approaches for Nematode Control

“…Phytohormones have significant roles in plant-nematode interactions since sedentary PPNs can alter auxin homeostasis via multiple strategies. Recent functional analyses indicated that PPNs have developed multiple approaches to manipulate indole-3-acetic acid (IAA) homeostasis to set an effective parasitic relation with their susceptible plants [119]. In contrast, the role of other hormones, such as salicylic acid, could also be exploited to boost plant resistance against PPNs [7,33].…”

Dissecting Gpa2-mediated immune signaling pathways involved in resistance to the potato cyst nematode Globodera pallida

“…We found downregulation of IAA14 at 6 dpi, this gene is particular important for lateral root formation and is induced during feeding sites establishment (Fukaki et al, 2002;Grunewald et al, 2008). Similarly, gene expression of the SAUR family is often detected in nematode feeding sites and the majority of SAUR genes is downregulated during nematode infection (Oosterbeek et al, 2021). SAURs can modulate IAA transport and thereby affect the cell expansion and division process (Ren and Gray, 2015).…”

“…The activation of Gpa2 leads to the arrest of cyst nematode feeding site development. Auxin is known to be crucial for plant root formation as well as nematode feeding site development and consists of three major classes: IAA, GRETCHEN HAGEN 3 (GH3), and small auxin up RNA (SAUR) (Oosterbeek et al, 2021). We found downregulation of IAA14 at 6 dpi, this gene is particular important for lateral root formation and is induced during feeding sites establishment (Fukaki et al, 2002;Grunewald et al, 2008).…”