Biological control of Pythium, Rhizoctonia and Sclerotinia in lettuce: association of the plant protective activity of the bacterium Paenibacillus alvei K165 with the induction of systemic resistance

Abstract

The soilborne fungi Sclerotinia sclerotiorum, Rhizoctonia solani and the oomycete Pythium ultimum are among the most destructive pathogens for lettuce production. The application of the biocontrol agent Paenibacillus alvei K165 to the transplant soil plug of lettuce resulted in reduced S. sclerotiorum, R. solani and P. ultimum foliar symptoms and incidence compared to untreated controls, despite the suppressive effect of the pathogens on the rhizosphere population of K165. In vitro, K165 inhibited the growth of S. sclerotiorum and R. solani but not P. ultimum. Furthermore, the expression of the pathogenesis‐related (PR) gene PR1, a marker gene of salicylic acid (SA)‐dependent plant defence, and of the Lipoxygenase (LOX) and Ethylene response factor 1 (ERF1) genes, markers of ethylene/jasmonate (ET/JA)‐dependent plant defence was recorded. K165‐treated plants challenged with P. ultimum showed up‐regulation of PR1, whereas challenge with R. solani resulted in up‐regulation of LOX and ERF1, and challenge with S. sclerotiorum resulted in up‐regulation of PR1, LOX and ERF1. This suggests that K165 triggers the SA‐ and the ET/JA‐mediated induced systemic resistance against P. ultimum and R. solani, respectively, while the simultaneous activation of the SA and ET/JA signalling pathways is proposed for S. sclerotiorum.

Expression of candidate genes related to white mold resistance in common beans

“…The ERF1 (Ethylene response factor 1) gene encodes a transcription factor that acts by increasing cellular ethylene production, causing senescence and, consequently, cell death, preventing disease progression to other tissues. The importance of ethylene in white mold resistance has been identified in several species such as lettuce, Brassica napus, and Arabidopsis (Fatouros et al 2017;Perchepied et al 2010;Zhao et al 2009). In the present study, no significant differences in the expression of this gene between times and genotypes were noted.…”

Microbial Consortia for Effective Biocontrol of Root and Foliar Diseases in Tomato

“…T. harzianum strain T22 is one of the best characterized and commercialized Trichoderma strains. It effectively antagonizes soil pathogens (Wilson et al, 2008;Percival et al, 2011;Roberti et al, 2015;Fatouros et al, 2018) and can trigger ISR against diverse above-and belowground attackers (Tucci et al, 2011;Vitti et al, 2016;Coppola et al, 2017Coppola et al, , 2019Debode et al, 2018;Pocurull et al, 2020;Alınç et al, 2021). Besides promoting plant growth, T. harzianum ESALQ1306 has been shown to highly reduce Sclerotinia sclerotiorum disease severity through parasitism and to induce ISR against spider mites (Geraldine et al, 2013;De Oliveira et al, 2018;Barroso et al, 2019;Canassa et al, 2020).…”

Towards Biological Control of Aspergillus carbonarius and Botrytis cinerea in Grapevine Berries and Transcriptomic Changes of Genes Encoding Pathogenesis-Related (PR) Proteins

“…FP12 and Arthrobacter sp. FP15 [ 15 , 17 , 18 , 19 ], we investigated their capacity to protect grape berries against A. carbonarius and B. cinerea , along with their plant defense triggering activity.…”

“…Previous studies have shown that strain K165 can protect plants from various soil-inhabiting pathogens such as Verticillium dahliae , Fusarium oxysporum f.sp. melonis , and Pythium ultimum , reducing disease severity by 50% compared with controls [ 13 , 14 , 15 ]. The plant protective activity of K165 lies mostly in its plant recognition by the FLS2 receptor and the subsequent induction of systemic resistance [ 16 ].…”