Isolation and evaluation of bacterial endophytes against Sclerospora graminicola (Sacc.) Schroet, the causal of pearl millet downy mildew

Abstract

Background Pearl millet remains prone to many diseases; among them downy mildew caused by Sclerospora graminicola (Sacc.) Schroet is economically more important. The use of endophytic bacteria for management of downy mildew of pearl millet as eco-friendly approach is increasing attention as sustainable alternative to pesticides. The objective of the present study was to isolate endophytic bacteria from roots of pearl millet cultivars and assess for biocontrol activity against Sclerospora graminicola. Results Thirty pearl millet root bacterial endophytes (PMRBEs) were isolated and screened in vitro for biocontrol activities such as: siderophore production, hydrogen cyanide (HCN) production and 1-amino cyclopropane-1-carboxylate (ACC) deaminase activity. Sixteen isolates possessed siderophore production potential, 3 isolates were found to be HCN producers, and 30% of the bacterial endophytes showed a good growth on ACC supplemented plates. On the basis of biocontrol activities, promising endophyte PMRBE6 was selected for seed treatment as well as a foliar spray to manage downy mildew of pearl millet in screen house experiment. The isolate PMRBE6 was found to be effective in managing downy mildew disease. Grain yield, test weight, plant height and average number of productive tillers were found to be maximum on inoculation of seeds of different pearl millet cultivars with PMRBE6, and the results were statistically significant as compared to control. Conclusions On the basis of biochemical characterization and partial 16S rRNA sequencing, the isolate PMRBE6 was identified as Bacillus subtilis strain PD4 (Accession no. MN400209). Pearl millet root bacterial endophyte (PMRBE6) exhibiting biocontrol activities could be exploited in friendly, sustainable organic agriculture.

Dynamics, phylogeny and phyto-stimulating potential of chitinase synthesizing bacterial root endosymbiosiome of North Western Himalayan Brassica rapa L.

“…(1), Delftia, (1) and Enterobacter (1). The large biochemical diversity concerning indole production, H 2 S, catalase, cellulase, oxidase production, etc., observed in the isolated chitinase producing endosymbiotic microflora is in tone with the previous investigations 11 , Which reported the existence of thirty bacterial endophytes in pearl millet with varying degree of biochemical and morphological attributes. It could be attributed to studying bacteria's endosymbiotic niche colonization lifestyle 1 .…”

“…There has been a close association of microbes with the plants for a variety of reasons, such as growth elevation, improved yield, and disease control; such associations continue to happen for centuries and are driven by the dependence of the microbes for their survival on the host plants 10 . These endophytes have defined niches in the plants and modulate the growth of the host by discharging nutrients, the defense system inductions, and the second synthesis of metabolites 11 , 12 . They communicate information to the plant host through interactions and biological reactions that result in phytohormone production, such as indole acetic acid (IAA), gibberellins or) 13 , organic compounds 14 allelopathy, as well as systemic acquired resistance against the diseases 15 .…”

Antagonistic and growth-promoting potential of multifarious bacterial endophytes against Fusarium wilt of chickpea

“…HC 5 (resistant) and JG 62 (susceptible) grown in Fusarium wilt infected plot at Pulses Section, Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar, India (Latitude: 29°14′92'' N, Longitude: 75°72′17'' E and Altitude: 215 m AMSL). The standard protocol for isolation of endophytic bacteria given by Sangwan et al (2021) was followed. Roots were washed with running tap water and surface sterilized sequentially in 75% (v/v) ethanol for 2 min, 2.6% (w/v) sodium hypochlorite solution for 5 min and 75% (v/v) ethanol for 1 min followed by thorough five to six times washing with sterile distilled water.…”