A Plant Nutrient- and Microbial Protein-Based Resistance Inducer Elicits Wheat Cultivar-Dependent Resistance Against Zymoseptoria tritici

Abstract

The induction of plant defense mechanisms by resistance inducers is an attractive and innovative alternative to reduce the use of fungicides on wheat against Zymoseptoria tritici, the responsible agent of Septoria tritici blotch (STB). Under controlled conditions, we investigated the resistance induction in three wheat cultivars with different susceptible levels to STB as a response to a treatment with a sulfur, manganese sulfate, and protein-based resistance inducer (NECTAR Céréales). While no direct antigermination effect of the product was observed in planta, more than 50% reduction of both symptoms and sporulation were recorded on the three tested cultivars. However, an impact of the wheat genotype on resistance induction was highlighted, which affects host penetration, cell colonization, and the production of cell-wall degrading enzymes by the fungus. Moreover, in the most susceptible cultivar Alixan, the product upregulated POX2, PAL, PR1, and GLUC gene expression in both noninoculated and inoculated plants and CHIT2 in noninoculated plants only. In contrast, defense responses induced in Altigo, the most resistant cultivar, seem to be more specifically mediated by the phenylpropanoid pathway in noninoculated as well as inoculated plants, since PAL and CHS were most specifically upregulated in this cultivar. In Premio, the moderate resistant cultivar, NECTAR Céréales elicits mainly the octadecanoid pathway, via LOX and AOS induction in noninoculated plants. We concluded that this complex resistance-inducing product protects wheat against Z. tritici by stimulating the cultivar-dependent plant defense mechanisms.

The Algal Polysaccharide Ulvan Induces Resistance in Wheat Against Zymoseptoria tritici Without Major Alteration of Leaf Metabolome

“…Accordingly, no significant upregulation of flavonoids or coumarins was observed in our metabolomic analysis. The activation of PAL and CHS genes has been involved with the basal resistance of wheat ( Adhikari et al, 2007 ; Ors et al, 2018 ) and after induction by the application of inducers, but mainly in resistant genotypes ( Ors et al, 2019 ). Similarly, no induction of PAL was observed after treatment with the Dalgin Active ® , inducer in susceptible plants ( Somai-Jemmali et al, 2020 ), suggesting that the activation of the phenylpropanoid pathway in bread wheat may be a cultivar- and/or elicitor-dependent response.…”

Tramesan Elicits Durum Wheat Defense against the Septoria Disease Complex

“…This effect occurs within 48 hours after Tramesan is applied, albeit not all the markers tested react linearly: the mitogen-activated protein MPK3 and the LysM receptor kinase CERK1 display high basal levels [31,32] even if induced by Tramesan and fungal infection. In contrast, PAL, MCA2, and RBOH are evidently controlled by additional inputs other than stress (ABA (-TAS14) and auxin (-PIN2)) [33,34]. The set of genes putatively regulated by SA, such as PR1 and PR9, or by JA, such as PR4 [35,36], showed a straight correlation with the hormone levels.…”

Endophytes Bacillus amyloliquefaciens AW3 (CGMCC1.16683) improves the growth of Populus davidiana × Populus bolleana (PdPap) and induces its resistance to wilt disease by Fusarium oxysporum Fox68 (CFCC86068)

“…Another PAL enzyme initiates the phenylpropanoid pathway, resulting in the biosynthesis of phytoalexins or phenolic compounds. Some studies have shown that activation of the phenylpropanoid pathway protects plants from pathogen infection (Ors et al, 2019). However, increased activities of the four enzymes observed in AW3-treated PdPap plants significantly reduced the disease index and promoted PdPap growth.…”