Cell Wall Modifications in Giant Cells Induced by the Plant Parasitic Nematode Meloidogyne incognita in Wild-Type (Col-0) and the fra2 Arabidopsis thaliana Katanin Mutant

Abstract

Meloidogyne incognita is a root knot nematode (RKN) species which is among the most notoriously unmanageable crop pests with a wide host range. It inhabits plants and induces unique feeding site structures within host roots, known as giant cells (GCs). The cell walls of the GCs undergo the process of both thickening and loosening to allow expansion and finally support nutrient uptake by the nematode. In this study, a comparative in situ analysis of cell wall polysaccharides in the GCs of wild-type Col-0 and the microtubule-defective fra2 katanin mutant, both infected with M. incognita has been carried out. The fra2 mutant had an increased infection rate. Moreover, fra2 roots exhibited a differential pectin and hemicellulose distribution when compared to Col-0 probably mirroring the fra2 root developmental defects. Features of fra2 GC walls include the presence of high-esterified pectic homogalacturonan and pectic arabinan, possibly to compensate for the reduced levels of callose, which was omnipresent in GCs of Col-0. Katanin severing of microtubules seems important in plant defense against M. incognita, with the nematode, however, to be nonchalant about this “katanin deficiency” and eventually induce the necessary GC cell wall modifications to establish a feeding site.

Τhe Nematicidal Potential of Bioactive Streptomyces Strains Isolated from Greek Rhizosphere Soils Tested on Arabidopsis Plants of Varying Susceptibility to Meloidogyne spp.

“…Roots of fra2 katanin mutants exhibited more of both nematodes’ females ( M. incognita and M. javanica ; Figure 3 ) per mg of their dry root weight compared to Col-0, indicating that root invasion success was higher in fra2 mutants (this study; [ 20 ]). Treatments performed with spore suspensions of S. monomycini ATHUBA 220 could successfully reduce the M. incognita burden in both Col-0 and fra2 ( Figure 3 A), while ATHUBA 438 was effective and restrained nematode population only in fra2 mutants.…”

“…The impact of the two-best performing actinomyces in paralysis experiments were further used in pot bioassays. In particular, we studied the effect of S. monomycini ATHUBA 220 and S. colombiensis ATHUBA 438 spore suspension application, prior to M. incognita and M. javanica infestation in wild type Arabidopsis thaliana L. plants (ecotype Columbia; Col-0) and fragile fiber 2 (fra2) katanin mutant (fra2 is already proven susceptible to M. incognita [20]). Streptomyces spore suspensions were added in soil where Arabidopsis plants were established 15 days before the artificial inoculation with the nematodes, to impede root penetration by M. javanica and M. incognita via parasitism or secondary metabolites' production.…”

“…The antimicrobial-effective Streptomyces strains were further tested for their nematicidal activity against M. incognita and M. javanica. In specific (1) both culture supernatants and solvent extracts were tested for the paralysis caused at second-stage juveniles (J2) and (2) spore suspensions of nematode-effective Streptomyces strains were further evaluated for the parasites' biological cycle arrest in Arabidopsis host plants, of already proven susceptibility to M. incognita [20]. Additional assessment of shoot dry weight was made to lay light on the potential plant growth-promoting effect of every application performed.…”

Hemicelluloses and associated compounds determine gall functional traits

“…The morphogenesis of plant organs and of gall morphotypes involves refined cell dynamics (Baskin 2005; Crowell et al 2010; Isaias et al 2013), which may reflect alterations in cell wall components (Carneiro et al 2014; Magalhães et al 2014; Suzuki et al 2015; Teixeira et al 2018; Meidani et al 2019; Ferreira et al 2020). The development of gall morphotypes demands alterations in the physical properties of the primary cell walls, and consequently in the dynamics of cell expansion (Suzuki et al 2015; Bedetti et al 2017; Teixeira et al 2018).…”

Plant Cell and Organism Development

“…In another article, Meidani et al [14] characterise the modifications in the call wall composition in the so-called giant cells (GC) that are induced by Meloidogyne incognita. This root-knot nematode is an obligatory plant parasite and is one of the most notoriously unmanageable crop pests with a wide host range.…”