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Mung bean [Vigna radiata (L.) Wilczek] is an important cash pulse crop extensively cultivated in the arid region of Pakistan, which encounters intimidating charcoal rot disease caused by Macrophomina phaseolina (Tassi) Goid. The current research was conducted to check the potential of Zn (1.25, 2.44 and 5 mg kg −1) and FYM [farmyard manure (1% and 2%)] in mono-, bi-and trilateral interaction in managing disease and improving yield. Suppression of plant immunity by M. phaseolina was indicated by the change in activities of antioxidant enzymes (CAT and SOD) and cell wall strengthening enzymes (POX and PAL) that revealed inability of the protein receptor to identify the pathogen elicitor. FYM improved soil physicochemical properties and beneficial microbes activity, which released antimicrobial protein-and plant defense-stimulating protein and in response to ROS (reactive oxygen species) signaling molecules plant susceptibility was reduced. However, Zn as a co-factor chastened the ROS in stressed cells by upregulation of antioxidant enzymes in favor of the plant. The complex interaction of FYM and Zn potentially hijacked the further multiplication of pathogen. Finally, soil amendment improved biological attributes and grain yield to profitable farming in terms of harvest index percentage and benefit-cost ratio.

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Sclerotium rolfsii is a soil-borne plant pathogen that causes root diseases in hundreds of plant species. It also causes collar rot disease in chickpea (Cicer arietinum L.). The present pot study was carried out to investigate the effect of soil amendment with dry biomass of a weed Chenopodium album L. and two antagonistic fungi, namely Trichoderma harzianum and T. viride, on growth and yield of chickpea variety Noor 2009 in soil infected with S. rolfsii. The pathogen-contaminated soil was amended either with 1, 2, or 3% C. album dry biomass, T. harzianum, and T. viride alone, or combinations of either of the two Trichoderma species and plant dry biomass. The lowest shoot and root dry biomass and grain yield of chickpea were recorded in S. rolfsii inoculation alone without any soil amendment (positive control). Plant growth and yield were significantly and gradually increased over positive control with an increase in C. album dry biomass application in the soil. Likewise, soil application of either of the two Trichoderma species significantly enhanced plant growth and yield over positive control under biotic stress of S. rolfsii. Combined application of either T. harzianum or T. viride with 3% dry biomass of C. album also proved highly effective in alleviating biotic stress of S. rolfsii on growth and yield of chickpea.

Background Sclerotium rolfsii is a soil-borne fungal pathogen causing diseases in more than 500 plant species. It causes southern blight disease in chili. Chemical fungicides are used to control this disease, which also pollute the environment. The present study was designed to assess the potential of two species of plant-growth-promoting rhizobacteria (PGPR) viz. Bacillus megaterium and Pseudomonas fluorescence, and an allelopathic weed, Anagallis arvensis L., for the control of southern blight disease of chili. Results Initially, three PGPR strains, viz. B. megaterium OSR3, B. megaterium ZMR6, and P. fluorescence PF-097, were selected for their in vitro antagonistic assessment against S. rolfsii by dual culture technique on potato dextrose agar medium. OSR3 showed the highest antagonistic potential (68%), followed by PF-097 (54%) and ZMR6 (33%). In a pot experiment, the two best strains of PGPR, namely OSR3 and PF-097, and dried biomass of A. arvensis (DBA) in different concentrations (1, 2 and 3%) were used to manage southern blight disease of chili. In positive control treatment (S. rolfsii only), plant survival was low (73%) than the negative control (100%). OSR3, PF-097, OSR3 + 2% DBA, and PF-097 + 2% DBA significantly enhanced plant survival over positive control. The highest increase in chili growth over positive control was recorded due to OSR3, followed by PF-097 inoculations. Contents of carotenoid and chlorophyll were significantly decreased due to the fungal pathogen and improved due to PGPR strains. Application of the two PGPR strains and different concentrations of A. arvensis distinctly increased the catalase (CAT), peroxidase (POX), and polyphenol peroxidase (PPO) activities over positive control. Conclusions The present study concluded that PGPR strains B. megaterium OSR3 and P. fluorescence PF-097 can control southern blight disease effectively and increase growth and yield of chili.

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Sclerotium rolfsii is a soil-borne fungal plant pathogen that causes diseases in more than 500 plant species. Chemical fungicides used to control this disease cause environmental pollution, therefore, plant derived compounds can be used as alternative to synthetic fungicides to reduce environmental pollution. Chenopodium album is a weed of family Chenopodiaceae that is used as food and also has medicinal importance. In the present study, antifungal activity of methanolic root extract of C. album was evaluated against S. rolfsii using six concentrations viz. 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 g 100 mL-1 amended in malt extract as growth medium. All the root extract concentrations significantly reduced fungal biomass by 15-58% over control. Gas chromatography-mass spectrometry (GC-MS) analysis of the methanolic root extract of C. album was performed. Six compounds were identified in methanolic root extract through GC-MS analysis. The most abundant compound was 1,2-benzenedicarboxylic acid, mono(2-ethylhexyl) ester (58.56%) followed by 9-octadecenoic acid (Z)-, methyl ester (12.75%) and 9-octadecenoic acid (Z)-, methyl ester (10.27%), which might be responsible for antifungal activity of methanolic root extract of C. album.

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