RNAi-mediated Resistance against Plant Parasitic Nematodes of Wheat Plants Obtained in Vitro Using Bioregulators of Microbiological Origin

Abstract

Background: Plant parasitic nematodes are dangerous pests that damage various agricultural crops and decrease their productivity. Objective: The resistance of new lines of wheat (Triticum aestivum L.) plants obtained under in vitro conditions on MS media containing microbial bioregulators to plant parasitic nematodes was studied under in vitro and greenhouse conditions. Methods: Here we conducted physiological and molecular-genetic studies of resistance of wheat plants to nematodes. Results: In vitro experiments showed that wheat plants grown on MS media with microbial bioregulators had 20-37 % of infestation with cereal cyst nematode Heterodera avenae, significantly lower when compared with 73 % of infestation of the control plants grown without bioregulators. Bioregulators increased morphometric parameters of the wheat plants obtained under in vitro conditions on MS media and further grown under greenhouse conditions on the natural invasive background: stem height increased 13.6-37.5 %, flag leaf length 18.0-19.3 %, ear length 6.8-24.6 %, and ear weight 27.0- 54.5 %, when compared with control wheat plants. The difference in the degree of hybridizated molecules mRNA and si/miRNA from control and experimental wheat plants increased: 15-39 % in plants grown under in vitro conditions on the invasive background created by H. avenae and 33-56 % in seeds of plants grown under greenhouse conditions on the natural invasive background. The silencing activity of si/miRNA from wheat plants grown on MS media with bioregulators increased: 20-51 % in plants grown under in vitro conditions on the invasive background created by H. avenae or 38-64 % in plants grown under greenhouse conditions on the natural invasive background. Conclusion: Our studies confirm the RNAi-mediated resistance to plant nematodes of wheat plants obtained on media with microbial bioregulators and grown under in vitro and greenhouse conditions.

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,…”

“…These MBs contain a wide range of antibacterial and plant stimulating compounds, as well as amino acids, lipids and plant hormones, which together significantly contribute towards disease resistance and improvement of plant growth and development [50,51]. This positive effect of biostimulants on plant growth has been demonstrated through improved callogenesis and organogenesis in wheat [52,53]. 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.…”

“…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

“…Products of different streptomycetes have recently been shown provide effective nematicidal action (Ruanpanun et al, 2010; Rashad et al, 2015; Kaur et al, 2016). Recent work has shown that metabolites produced by some of the streptomycetes have a significant positive effect on plant performance through improved growth and development, and they also yield protection against nematode through stimulating production in plant cells of appropriate si/miRNA (Jailani and Mukherjee, 2017; Tsygankova et al, 2019). More specifically, metabolites and cell culture supernatant of soil streptomycetes S. avermitilis (Biliavska et al, 2012; Iutynska, 2012), S. netropsis (Biliavska et al, 2016a), and S. violaceus (Biliavska et al, 2016b) have been shown to possess strong antagonistic activity against various phytopathogenic micromycetes and bacteria (Iutynska et al, 2017).…”