Biomedical subjects

Tsanko Gechev

Publications and source records attributed to Tsanko Gechev.

2 recordsLinked to original sources

PubMed2026

Bacillus subtilis isolated from medicinal plants rhizosphere effectively controls Cercospora leaf spot and improves plant growth in mung bean (Vigna radiata).

BACKGROUND: Mung bean is an important leguminous crop, which is reported to face devastating yield losses of up to 70% due to Cercospora leaf spot (CLS) disease. Traditional methods, such as the application of agrochemicals and fungicides, have been used to control CLS, but their intensive use has toxic effects on edible crops. METHODS: To find out a sustainable alternative, this study characterizes a strain, Bacillus subtilis Medicinal_04, isolated from Cannabis sativa rhizosphere and explores its role as an eco-friendly biofungicide and biostimulant. The species level identification of the isolate was confirmed by Average Nucleotide Identity (ANIb) and a digital DNA-DNA hybridization (dDDH). The antagonistic efficacy of B. subtilis Medicinal_04 against Cercospora canescens was evaluated in vitro as well as in planta assays. RESULTS: ANIb of 97.80% and a dDDH score of 85.90% against the reference B. subtilis str. 168. confirmed this isolate as B. subtilis. The in-vitro results showed that B. subtilis robustly inhibited C. canescens growth by 81.5%, strongly correlated with positive chitinolytic activity and a diverse genomic array of secondary metabolite biosynthetic gene clusters. The in planta results demonstrated that B. subtilis seed priming reduced disease incidence by 80 and 71.4%, while foliar application resulted in reductions of 90 and 85.7% for NM-51 and NM-20-21 varieties, respectively. Furthermore, fungicide application successfully reduced disease, however it caused noticeable phytotoxic reductions in root-shoot architecture and chlorophyll content. In contrast, biological interventions completely bypassed these trade-offs as B. subtilis application displayed improved root-shoot length, pod number, and chlorophyll content, while simultaneously enhancing antioxidative enzyme activities (SOD, POD, and CAT) and PR-1 gene expression. CONCLUSION: These findings demonstrate that B. subtilis Medicinal_04 has the potential to serve as a multifunctional biocontrol agent and is capable of securing high-level disease suppression and optimizing plant productivity, offering a valuable toolkit for climate-smart, sustainable agriculture.

Bacillus subtilis↗

PubMed2025

Genomics control of biostimulant-induced stress tolerance and crop yield enhancement.

Biostimulants are changing modern agriculture, as they have the potential to secure healthy and sustainable food production while preserving the environment. They have two main biological effects: growth promotion and stress protection. Both effects can lead to enhancement of the yield and improvement of the marketable grade of the produce in crops, without compromising crop quality. Their use increased exponentially in the past decade, as they are highly efficient, ecologically friendly (non-toxic, biodegradable), and applicable to all major crops. While exponential data on the physiological mechanisms of stress protection is accumulating in recent years, the information as to how biostimulants act at the molecular level is still rather limited. Here we review the growing evidence of the biostimulants role in stress protection and yield enhancement of crops, as well as the recent transcriptomic and metabolomic data, which indicate biostimulants' molecular mode of action. In particular, we outline the role of genes encoding signaling components, plant hormones (abscisic acid, brassinosteroids, and ethylene), genes encoding transcription factors from ERF, WRKY, NAC, and MYB families, and genes related to growth, photosynthesis, and stress response. Finally, we describe strategies to study the genetic and genomics control of biostimulants mode of action, with foci on stress tolerance and yield enhancement. In Arabidopsis, established systems for biostimulants-induced protection against drought and oxidative stress will allow both forward and reverse genetics approaches to identify key genes from the biostimulants network. Mutations in such genes compromise the stress-protective effect of biostimulants. In major crops such as pepper and tomato, large Genome Wide Association Studies (GWAS) panels can be utilized to study crops responses to biostimulants in terms of drought tolerance, fruit qualities, and yield in order to pinpoint genes controlling biostimulants-induced stress protection and yield enhancement. The combination of these approaches allows identification and verification of important genes involved in the pathways of biostimulant-induced stress protection and yield enhancement, as well as deciphering parts of the intricate biostimulant-signaling network.

Crops, Agricultural↗