Isolation and identification of induced systemic resistance determinants from Bacillus simplex Sneb545 against Heterodera glycines

Abstract

Heterodera glycines is one of the most destructive pathogens of soybean. Soybean seeds coated with Bacillus simplex Sneb545 have shown resistance to H. glycines as a result of induced systemic resistance (ISR) in the plants. In this study, we aimed to identify the resistance-inducing determinants from this B. simplex strain. Combining the ISR bioassay, six ISR-active compounds were isolated from a culture of B. simplex Sneb545 using organic solvent gradient extraction, silica gel column chromatography, Sephadex LH-20 column chromatography, and semi-preparative high-performance liquid chromatography (HPLC), and all systems were based on activity tracking. The compounds were determined as cyclic(Pro-Tyr), cyclic(Val-Pro), cyclic(Leu-Pro), uracil, phenylalanine, and tryptophan using 1 H nMR and 13 C NMR. In plants from seeds coated with Bacillus simplex Sneb545, these six ISRactive compounds delayed the development of H. glycines in soybean roots. Moreover, cyclic(Pro-Tyr), cyclic(Val-Pro), and tryptophan reduced the number of nematodes in soybean roots. The expression levels of defense-related genes with cyclic(Val-Pro), tryptophan and uracil treatment soybean analysed using Quantitative real-time PCR (qRT-PCR). The results indicate cyclic(Val-Pro), tryptophan and uracil induced the expression of defense-related genes involved in the SA-and JA-pathways to against H. glycines. Our research results provide new agents for the control of H. glycines. Soybean is an important economic crop, which is widely used in oil and food production. The United States of America, Brazil, and Argentina are the top three producers of soybean, producing approximately 123.7, 117.0, and 55.0 million metric tons annually, respectively, China is ranked fourth globally, with a production of 15.9 million metric tons per year (https ://soyst ats.com/inter natio nal-world-soybe an-produ ction , 2019). Heterodera glycines (soybean cyst nematode, SCN) is one of the most destructive pathogens of soybean 1. This nematode is a considerable threat to soybean production and is responsible for annual losses of up to USD 1.5 billion globally 2. Chemical nematicides are widely used to control parasitic nematode disease in soybean 3. However, their application not only causes widespread environmental pollution but also threatens human health. In addition, drug tolerance of nematodes has been enhanced by the long-term use of chemical nematicides 4,5. It is necessary, therefore, to seek safe, effective, and environmentally friendly products to defend soybean plants against SCN 6. The life cycle of SCN consists of four juvenile stages (J1-J4). The embryo in the egg develops into the first stage (J1) of juvenile and then molts in the egg to form the infested second-stage juveniles (J2). The J2 penetrates the root of the host plant, once J2 reach the vascular cylinder, they will establish a feeding site at the root, and then begins to develop into the third (J3) and fourth (J4) juvenile stages in the root system. Finally, matures to an adult female or male an...

In Vitro Evaluation and Genome Mining of Bacillus subtilis Strain RS10 Reveals Its Biocontrol and Plant Growth-Promoting Potential

“…Similarly, B. velezensis strain FZB42 produces bacilysin, bacillaene, and diffcidin which suppress fire blight disease in plants [8]. Recently, it was reported that B. subtilis SL18r and B. simplex Sneb545 elicit induce systemic resistance in plants against Botrytis cinerea and Heterodera glycines, respectively [9,10]. Furthermore, volatile organic compounds such as acetoin and 2,3-butanediol have also been reported to trigger systemic resistance in plants [11].…”

Acorenone C: A New Spiro-Sesquiterpene from a Mangrove-Associated Fungus, Pseudofusicoccum sp. J003

“…Ten known compounds, uracil (2) ( Xing et al, 2020 ), cyclo-(L-Pro-L-Tyr) (3) ( Jayatilake et al, 1996 ), bis-(2-ethylhexyl) terephthalate (4) ( Firdovsi et al, 2007 ), 4-hydroxybenzaldehyde (5) ( Shataer et al, 2020 ), 2-phenylethanol (6) ( Guerrini et al, 2011 ), 4-hydroxyphenethyl-alcohol (7) ( Wei et al, 2013 ), estigmast-4-en-6β-ol-3-ona (8) ( Correia et al, 2003 ), ergosterol (9) ( Zhang et al, 2002 ), ergosterol peroxide (10) ( Hybelbauerová et al, 2008 ), and cerevisterol (11) ( Kang et al, 2017 ) were also isolated from Pseudofusicoccum sp. J003.…”

Survey of plant growth promoting and antagonistic traits in winter wheat grain endophytic bacteria

“…atrofaciens (McCulloch). Endophytic microorganisms of grain are considered as one of the most important resistance-inducing determinants of the plant resistance to the phytopathogen [23]. Considering this, grains of Podolyanka wheat variety were chosen for the search of endophytic bacteria with PGPT and antagonistic activity against phytopathogenic bacteria.…”