A Comparative Transcriptomic and Proteomic Analysis of Hexaploid Wheat’s Responses to Colonization by Bacillus velezensis and Gaeumannomyces graminis, Both Separately and Combined

Abstract

Tritrophic interactions involving a biocontrol agent, a pathogen, and a plant have been analyzed predominantly from the perspective of the biocontrol agent. To explore the adaptive strategies of wheat in response to beneficial, pathogenic, and combined microorganisms, we performed the first comprehensive transcriptomic, proteomic, and biochemical analysis in wheat roots after exposure to Bacillus velezensis CC09, Gaeumannomyces graminis var. tritici, and their combined colonization, respectively. The transcriptional or translational programming of wheat roots inoculated with beneficial B. velezensis showed mild alterations compared with that of pathogenic G. graminis var. tritici. However, the combination of B. velezensis and G. graminis var. tritici activated a larger transcriptional or translational program than for each single microorganism, although the gene expression pattern was similar to that of individual infection by G. graminis var. tritici, suggesting a prioritization of defense against G. graminis var. tritici infection. Surprisingly, pathogen-associated molecular pattern-triggered immunity and effector-triggered immunity made wheat pretreated with B. velezensis more sensitive to subsequent G. graminis var. tritici infection. Additionally, B. velezensis triggered a salicylic acid (SA)-dependent mode of induced systemic resistance that resembles pathogen-induced systemic acquired resistance. Wheat plants mainly depend on SA-mediated resistance, and not that mediated by jasmonic acid (JA), against the necrotrophic pathogen G. graminis var. tritici. Moreover, SA–JA interactions resulted in antagonistic effects regardless of the type of microorganisms in wheat. Further enhancement of SA-dependent defense responses such as lignification to the combined infection was shown to reduce the level of induced JA-dependent defense against subsequent infection with G. graminis var. tritici. Altogether, our results demonstrate how the hexaploid monocot wheat responds to beneficial or pathogenic microorganisms and prolongs the onset of take-all disease through modulation of cell reprogramming and signaling events.

Take-All Disease: New Insights into an Important Wheat Root Pathogen

“…A gene encoding an enzyme involved in the synthesis of abscisic acid (ABA) was found to be upregulated during G. tritici infection, suggesting that the fungus uses ABA to manipulate the host defence response [73]. The study was later extended by a transcriptomic, proteomic, and biochemical analysis of the plant response to take-all infection in the presence and absence of B. velezensis, revealing that during G. tritici infection wheat plants show a strong salicylic acid (SA)-mediated resistance response, which was stronger than the jasmonic acid (JA) accumulation response [74]. These results contradict the role of JA in plant defence observed during pathogen infections of leaves, confirming previous observations that defence signalling in roots cannot be extrapolated from research on leaves [75].…”

Transcriptomic and Proteomic Studies to Investigate the Basal Stem Rot Disease in Oil Palm Seedlings

“…Unique, 14-3-3 proteins are phosphate-binding proteins carbohydrate metabolism, cellular processes, protein metabolism, and sugar metabolism. These main metabolic processes were also identified in soybean root diseases, Chinese cabbage, and wheat (Bai et al, 2019;Kang et al, 2019;Lan et al, 2019). Carbohydrate metabolism, cellular processes, energy and protein metabolisms, signalling, and stress response were higher in asymptomatic seedlings.…”

GapB Is Involved in Biofilm Formation Dependent on LrgAB but Not the SinI/R System in Bacillus cereus 0-9

“…Bacillus cereus 0-9 is a highly adaptable bacterium that is widely distributed in soil, water, plants, and wheat rhizospheres (Kang et al, 2019). Our previous study showed that the wild-type B. cereus 0-9 isolates can form pellicles on air-liquid interfaces and architecturally complex colonies on solid surfaces (Zhang et al, 2020a).…”