The identification of C. globosum HKH_AMG from the susceptible cultivar Taichung 29 highlights the untapped potential of seed-associated fungal microbiota for the sustainable management of STB.
Abstract
Septoria tritici blotch (STB), caused by
Zymoseptoria tritici
, is among the most damaging wheat diseases worldwide and requires sustainable alternatives to intensive fungicide use. While resistant cultivars are often considered promising sources of beneficial microbiota for biocontrol discovery, the potential of endophytes associated with susceptible cultivars remains poorly explored. Contrary to expectations, a seed-associated isolate of
Chaetomium globosum
(HKH_AMG), recovered from the STB-susceptible wheat cultivar Taichung 29, provided the strongest disease suppression among 45 representative fungal endophytes selected for greenhouse screening from wheat, rice, and pistachio tissues. Pretreatment with HKH_AMG significantly reduced lesion development, pycnidial coverage, and pathogen biomass in the susceptible wheat cultivar Tirgan. Disease suppression was associated with reduced stomatal penetration, early hydrogen peroxide accumulation, and enhanced levels of defence-related phenolic compounds, including salicylic and gallic acids. Collectively, our findings demonstrate that disease-susceptible wheat cultivars should not be overlooked as potential sources of highly effective biocontrol endophytes. The identification of
C. globosum
HKH_AMG from the susceptible cultivar Taichung 29 highlights the untapped potential of seed-associated fungal microbiota for the sustainable management of STB.
India contributes 26% of global banana production, yet cultivation is severely threatened by Fusarium wilt (Fusarium oxysporum f. sp. cubense, Foc), necessitating sustainable, eco-friendly management strategies. This study evaluated the biocontrol potential of endophytic bacteria isolated from Foc-resistant and -susceptible banana cultivars. Isolates from the pseudostem, corm, and root of the resistant cultivar showed significantly greater inhibitory activity than those from the susceptible cultivar, underscoring the role of host genotype in shaping functionally competent endophytic communities. Among all isolates, Bacillus sp. from the corm of cv. Rose (AB) showed the highest mycelial inhibition of Foc (70.37–76.54%) in vitro. GC-MS-based metabolite profiling revealed a chemically diverse array of secondary metabolites, fatty acid esters, steroids, terpenoids, siloxanes, and nitrogenous compounds. Corm-associated endophytes exhibited membrane-disruptive and cytotoxic activity, while root-associated endophytes contributed protective, defense-modulatory effects. Halomonas sp. RoRo2 and B. subtilis RoC1 showed the highest inhibition in both agar-well and in planta assays, with unsaturated fatty acids and organic acid derivatives implicated as key antifungal effectors acting through multiple biochemical pathways. These findings identify metabolically versatile endophytes as promising candidates for developing efficient, environmentally compatible bioinoculants as sustainable alternatives to chemical control of Fusarium wilt in banana.
D. P. Mohite, Kavino Mathiyazhagan, Nakkeeran Sevugapperumal et al.· Pathogens· 0 citations
Fusarium wilt of banana threatens banana production world-wide. Although beneficial rhizomicrobiomes are linked to disease resistance, whether resistant cultivars systemically recruit disease-suppressive rhizomicrobiomes after pathogen challenge remains unclear. Using a split-root system combined with rhizomicrobiome transfer, we tested whether systemically recruited rhizomicrobiomes from different cultivars after pathogen challenge could alter disease development in a susceptible cultivar. Rhizosphere soil suspension from the pathogen-challenged highly resistant cultivar GCTCV119 was the only donor treatment that significantly reduced the disease index in the susceptible recipient cultivar Guijiao No. 1. This effect was associated with pathogen-induced enrichment of absolute bacterial abundance and absolute Bacillus abundance in the rhizosphere of GCTCV119, whereas such enrichment was not observed in the other donor cultivars. A syncom of seven Bacillus strains from the GCTCV119 rhizosphere most effectively reduced (by 90.20%) the disease index by the induction of plant resistance. Soil incubation showed that pathogen-induced D-sorbitol accumulation in GCTCV119 significantly increased total bacterial abundance and Bacillus abundance, and reduced the disease index. This study highlights pathogen-triggered rhizomicrobiome reshaping, higher absolute bacterial abundance, and the suppressive role of Bacillus as key features linked to disease resistance in banana, providing insights into microbiome-mediated disease suppression.
Wenlong Zhang, Shengtao Xu, Hongwei Yu et al.· New Phytologist· 0 citations
Fusarium oxysporum is a persistent soil-borne pathogen that causes severe vascular wilt in tomato and remains difficult to manage under intensive greenhouse production. This study evaluated the individual and combined performance of three microbial antagonists, Papiliotrema terrestris PT22AV, Bacillus amyloliquefaciens BO7, and Trichoderma harzianum T22, against the aggressive isolate FO23 under controlled greenhouse conditions. Tomato seedlings of the susceptible cultivar San Marzano Nano were grown in pathogen-infested substrate and treated with microbial agents individually or as a consortium. Plant response was assessed through symptom expression, chlorosis, plant height, leaf area, vigor, and overall disease suppression. Among the single agents, PT22AV showed the strongest performance, combining visible disease suppression with a clear biostimulant effect. BO7 also reduced pathogen damage and improved plant development, whereas T22 provided only modest protection under the tested conditions. The microbial consortium composed of PT22AV, BO7, and T22 produced the best overall plant response, with improved vigor, greener foliage, and reduced symptom severity compared with the pathogen-only treatment. The observed differences among microbial treatments indicate that biological control performance depends not only on pathogen suppression but also on the capacity of the antagonist to improve plant physiological status. The integration of complementary microorganisms within a consortium may therefore represent a promising strategy for sustainable greenhouse tomato production under high disease pressure.
Elion Ismailaj, Aris Huqi, Skënder Varaku et al.· International Science Journa...· 0 citations
Clubroot is a soil-borne disease caused by the obligate biotrophic pathogen Plasmodiophora brassicae, severely affecting cruciferous crops worldwide, especially Brassica napus. However, cultivar-dependent features associated with contrasting clubroot phenotypes under natural field conditions remain poorly understood. To investigate these multi-omics features at the late disease stage, an integrated transcriptomic, untargeted metabolomic, and root endophytic microbiome analysis was performed using resistant and susceptible B. napus cultivars collected from a naturally infested field. Comparative analysis revealed significant multi-omics differences between the two cultivars. Among the enriched pathways, phenylpropanoid biosynthesis was identified as a major resistance-associated feature, supported by the upregulation of multiple structural genes involved in lignin and phenolic compound biosynthesis, including PAL, 4CL, CCR, POD, CAD, and F5H, together with the increased accumulation of phenylpropanoid-related metabolites such as Caffeic acid, Coniferyl aldehyde, and Sinapyl alcohol. In addition, resistant roots showed elevated levels of glucosinolate-derived metabolites, particularly isothiocyanate-related compounds. Hormone signaling-related genes, especially those associated with jasmonate and auxin pathways, also displayed differential expression patterns between resistant and susceptible cultivars and were further supported by RT-qPCR validation. Microbiome analysis further revealed differences in root endophytic bacterial community composition between the two cultivars, with several bacterial genera showing positive correlations with metabolites enriched in resistant roots. Overall, these findings reveal cultivar-dependent multi-omics differences accompanying contrasting clubroot phenotypes under natural field infection conditions and provide a basis for future studies of clubroot resistance in B. napus.
Chuan-Feng Xiong, Qian Liu, Xiaomin Sun et al.· Plant Disease· 0 citations
The root parasitic weed Phelipanche aegyptiaca poses a serious threat to tomato production in arid regions of Northwest China, yet effective and environmentally friendly control measures remain limited. In this study, an endophytic bacterial strain G24 with strong inhibitory activity against P. aegyptiaca seed germination was isolated from healthy tomato tissues. In vitro germination assays showed that both the fermentation broth and cell-free supernatant of G24 completely inhibited seed germination even at 1000-fold dilution, indicating that the active metabolites are extracellularly produced or released. Pot experiments further demonstrated that G24 inoculation significantly reduced the number, fresh weight, and dry weight of parasitic broomrape nodules on tomato roots, with reductions of 69.4%, 89.0%, and 88.6%, respectively, compared with the control. Moreover, G24 significantly increased tomato stem diameter, indicating its intrinsic plant growth-promoting capacity. Although both sterile NB medium and G24 suspension increased whole-plant fresh weight, no statistically significant difference was observed between the two treatments (p > 0.05). The reduced leaf chlorophyll concentration per unit fresh weight in G24-treated tomatoes was a typical growth dilution effect and did not suppress overall plant performance, and no phytotoxicity was detected. Based on morphological, physiological–biochemical, and multilocus phylogenetic analyses (16S rDNA, gyrB, and rpoB), strain G24 was identified as Lelliottia nimipressuralis. As a native endophyte of tomato, L. nimipressuralis G24 exhibits excellent host compatibility, biocontrol efficacy, and growth-promoting activity, with no adverse effects on tomato development. This study expands the application potential of the genus Lelliottia in parasitic weed management and provides a novel microbial resource for the integrated and sustainable control of P. aegyptiaca.