Impact of New Natural Biostimulants on Increasing Synthesis in Plant Cells of Small Regulatory si/miRNA With High Anti-Nematodic Activity

Abstract

Plant endoparasitic cyst nematode Heterodera schachtii Schmidt, gallic nematode Meloidogyne incognita and stem nematode Ditylenchus destructor damage various agricultural crops. The application of ecologically safe natural biostimulants with bioprotective properties is a newer approach for increasing plant resistance to parasitic nematodes. The molecular-genetic analysis of biostimulants action on plant genome is necessary for creation of new effective bioregulators for plant protection against phytopathogenic organisms. In our field and greenhouse experiments, we investigated the influence of new natural biostimulants Avercom and its derivatives on plant protection against nematodes Meloidogyne incognita and Ditylenchus destructor. Considerable increase of resistance to nematodes and productivity of cucumber and potato were observed for plants treated by biostimulant Avercom and its derivatives. Impact of biostimulants Radostim-super and Avercom on increase of resistance of sugar beet and cucumber sprouts to nematodes Heterodera schachtii and Meloidogyne incognita was studied in the laboratory conditions. Comparative analysis of morpho-physiological signs of control and experimental plants showed that plants treated by Radostim-super and Avercom were more viable and resistant to these nematodes as compared to control sprouts. In the molecular-genetic experiments, we studied the impact of these biostimulants on inducing synthesis of small regulatory si/miRNA, which plays key role in plant immune protection. Using method Dot-blot hybridization we studied degree of homology between si/miRNA with mRNA populations, isolated from plants untreated and treated with new natural biostimulants. We found considerable difference in the degree of homology (6-28%) between populations of mRNA and si/miRNA from nematode-infected plants that were either untreated or treated with biostimulants. We have also investigated silencing of translation of mRNA activity of si/miRNA in the wheat embryo cell-free system of protein synthesis. In these experiments, we found high inhibitory activity (38-65%) of si/miRNA from plants treated by biostimulants as compared to low inhibitory activity (15-20%) of si/miRNA from untreated plants. Obtained differences in the degree of homology between populations of mRNA and si/miRNA from untreated and treated with biostimulants plants, which were infected by nematode, and also the high inhibitory activity of si/miRNA from plants treated by biostimulants confirm that these biostimulants induce synthesis of anti-nematodic si/miRNA in plants, resulting in considerable increase of their resistance to these phytopathogens.Keywords: Heterodera schachtii, Meloidogyne іncognita, Ditylenchus destructor, natural biostimulants, anti-nematodic si/miRNA, the degree of homology between mRNA and si/miRNA, silencing activity of si/miRNA in the wheat embryo cell-free system of protein synthesis, plant resistance to nematodes www.ccsenet.org/ijb

Control of mosaic disease using microbial biostimulants: insights from mathematical modelling

“…Experimental evidence suggests that streptomycete-derived MBs stimulate growth and viability of crops, as has been recently demonstrated during in vitro, in vivo and greenhouse experiments on wheat [52,53,64], cucumbers [56], rapeseed [59], and Chinese cabbage [57]. Thus, we replace a constant growth rate of uninfected plants by a growing saturated function of the amount of applied MBs…”

“…with r (0) = r 0 and r (∞) = r 0 /s. Molecular genetic analyses show that MBs trigger a significant increase in the within-plant synthesis of si/miRNA homologous with plant genes associated with proteins that are important for a successful infection, as well as with viral genes, whose expression is needed for viral replication in plants [19,53,55,56,58,59]. To model this effect, we take the rate of disease transmission from infected vectors to plants in the form of a decreasing function of the amount of applied MBs as follows,…”

“…In terms of protection against parasites, extensive experimental studies have comprehensively demonstrated that these MBs trigger within-plant production of RNAi products complementary with mRNA (messenger RNA) of plant parasitic nematodes, and upon consumption by nematodes, these products trigger their death by silencing essential nematode housekeeping genes. More specifically, nematicidal effects of these MBs on root-knot nematode M. incognita have been shown in vitro [54], and specific RNAi-mediated bioprotective effects of MBs have been demonstrated in wheat against the cereal cyst nematode H. avenae [52,53], in rapeseed [55,56], Brassica rapa subs. pekinensis (Chinese cabbage) [57], and sugar beet [58] against the cyst nematode H. schachtii, and in cucumber and sugar beet against both of these nematodes [59].…”

RNAi-Based Biocontrol of Wheat Nematodes Using Natural Poly-Component Biostimulants

“…Biostimulants developed on the basis of metabolites of these streptomycetes have also shown nematicidal effects on root-knot nematode M. incognita in vitro (Biliavska et al, 2015a), as well as bioprotective RNAi-mediated effects against cyst nematode H. schachtii in rape (Tsygankova et al, 2013, 2014a), Brassica rapa subs. pekinensis (Chinese cabbage) (Biliavska et al, 2016c), and sugar beet (Tsygankova et al, 2012b), as well as on both of these nematodes in sugar beet and cucumber (Tsygankova et al, 2014b). It should be noted that we are using the term “biostimulant” loosely to describe poly-component substances without discriminating them by the mode of their action, such as biopesticides, plant growth regulators etc., hence avoiding the need to abide by one of the more restrictive definitions Calvo et al, 2014; Brown and Saa, 2015; du Jardin, 2015; Nardi et al, 2016.…”

Screening of Five and Six-Membered Nitrogen-Containing Heterocyclic Compounds as New Effective Stimulants of Linum Usitatissimum L. Organogenesis in Vitro

“…At the Institute of Bioorganic Chemistry and Petrochemistry of NAS of Ukraine together with the National Enterprise Interdepartmental Science and Technology Center "Agrobiotech" of NAS and MES of Ukraine the several new ecologically safe plant growth regulators of synthetic origin: Ivin and natural origin: Emistim, Poteitin, Zeastimulin, Charkor, Biolan, Biogen, Radostim, Radostim-super, Regoplant and Stimpo that accelerate plant growth, increase yield crop of vegetables, grains, legumes and fruit crops, as well increase plant immune protection against pathogenic and parasitic organisms were created [27][28][29][30][31]. Our previous studies have shown the possibility of using of new synthetic and natural compounds in the isolated tissue cultures of agricultural and medicinal plants to induce morphogenetic processes and increase the synthesis of secondary metabolites [32][33][34].…”