Nematicidal potential of Streptomyces antibioticus strain M7 against Meloidogyne incognita

Abstract

Meloidogyne spp. are microscopic, obligatory endoparasites with worldwide distribution which cause severe damage to agricultural crops. The present study revealed the nematicidal activity of Streptomyces antibioticus strain M7 against Meloidogyne incognita. The culture supernatant of the isolate caused 100% J2 mortality after 24 h and inhibited egg hatching (only 3%). In addition, the nematicidal activity of actinomycins V, X2 and D purified from strain M7 was also checked. In vitro studies displayed 97.0–99.0% juvenile mortality and 28.0–44.0% egg hatching after 168 h at 240 µg/ml of actinomycin, with LD50 (lethal dose) values of 28–120 µg/ml. In vivo study further validated the nematicidal activity of strain M7, where nematode infested tomato plants treated with culture supernatant/cells/solvent extract showed reduction in root galls and egg masses per plant by 50.0–62.06% and 53.48–76.74%, respectively, and significantly enhanced the shoot length (54.67–76.39%), root length (36.45–64.88%), shoot fresh weight (111–171.77%), root fresh weight (120–163.33%), shoot dry weight (54.45–145.45%), and root dry weight (100–133.3%) over the nematode infested plants treated with water. Furthermore, tomato plants treated with cells/culture supernatant/extract of strain M7 without nematode infestation also showed significant increase in various plant growth parameters. Thus, the outcome of the study revealed the potential of S. antibioticus strain M7 and actinomycins produced from it to be developed as safe nematicidal agents to control the root knot nematodes, and to increase the crop yield.

Insights into the Role of Streptomyces hydrogenans as the Plant Growth Promoter, Photosynthetic Pigment Enhancer and Biocontrol Agent against Meloidogyne incognita in Solanum lycopersicum Seedlings

“…Our study also revealed inclined levels of photosynthetic pigments in S. hydrogenans treated S. lycoperscum seedlings infested with M. incognita . Our findings are supported from the previous studies conducted by Sharma, et al [ 18 ] in tomato plants. They observed that plants treated with S. antibioticus strain M7 showed an enhancement in the levels of pigments due to triggered photosynthetic activities of plants.…”

“…This decline in plant pigments is mainly because of the inhibition of crucial enzymes required in the Violoxanthin pathway, this in turn impairs the stability of the photosynthetic apparatus [ 59 ]. Likewise, Sharma, et al [ 18 ] reported lowered or disrupted photosynthetic pigments in tomato plants subjected to nematode infections. Reduction in the plant pigments are attributed to the formation of galls over root surfaces, leading to disrupted water transportation and chlorophyll a and b levels [ 60 ].…”

“…Generally, root exudates constitute various essential nutrients [ 16 ], which gets affected by the infestation of RKNs into the host plants [ 17 ]. The visible symptoms of RKNs infected plants include growth impairment, chlorosis and reduction in the level of photosynthetic pigments [ 18 ]. Infestation of these nematodes inside the plant tissue causes the oxidative burst that results in the production and generation of reactive oxygen species (ROS), like hydrogen peroxide (H 2 O 2 ), superoxide anions, malondialdehyde (MDA), hydroxyl radicals, etc.…”

Volatiles from the fungus Fusarium oxysporum affect interactions of Brassica rapa plants with root herbivores

“…Nematodes are indeed endowed with high sensitivity to volatiles for their navigation in soil (Rasmann et al 2012a;Rengarajan & Hallem 2016). Previous studies have shown that volatiles from soil or root-associated microorganisms can affect nematode development and behaviour (Wuyts et al 2006;Turlings et al 2012;Cheng et al 2017;Sharma et al 2019;Wolfgang et al 2019). For example, volatiles emitted by some F. oxysporum strains negatively affect egg hatching of the root-knot nematode Meloidogyne incognita (Terra et al 2018).…”

Odours from friends and foes: ecological consequences of volatiles from soil-borne fungion plant growth and defence against herbivoress

“…Previous studies have shown that volatiles from roots or soil microorganisms can affect nematode development and behaviour (Wuyts et al, 2006;Turlings et al, 2012;Cheng et al, 2017;Sharma et al, 2019;Wolfgang et al, 2019). For example, volatiles emitted by some F. oxysporum strains negatively affect egg hatching of the root-knot nematode Meloidogyne incognita (Terra et al, 2018).…”