Endophytic Bacillus bacteria with RNase activity in the resistance of potato plants to viruses

Viral diseases annually cause significant crop losses and significantly reduce the quality of products, including potatoes, some of the most important crops. Currently, viruses cannot be controlled with chemical pesticides, since known antiviral compounds are teratogenic and hazardous to people’s health. Biocontrol agents based on endophytic microorganisms may be an alternative to them. Many strains of Bacillus produce ribonucleases (RNases). Our laboratory possesses a collection of bacteria that produce various metabolites and have RNase activity. The results showed that the inoculation of potato with B. subtilis 26D and B. thuringiensis increased the grain yield by 32–43 %. In addition, the treatment of potato plants with Bacillus spp. significantly reduced the infection of potato plants with virus M. The prevalence of the disease in potato plants was significantly reduced from 60 % in the control to 18 % (B. subtillis 26D) and 25–33 % (B. thuringiensis) in the inoculated plants. Similarly, the infection index decreased from 14 in the control to 1 in the inoculated plants. The further study of molecular mechanisms related to bacterial induction of plant defense reactions in response to viral infections will lead to a better understanding of stress resistance problems. The endophytic microorganisms studied in this report may become the basis for the creation of biological agents for plant protection

Comparing very low birth weight versus very low gestation cohort methods for outcome analysis of high risk preterm infants

© 2017 The Author(s). Background: Compared to very low gestational age (<32 weeks, VLGA) cohorts, very low birth weight (<1500 g; VLBW) cohorts are more prone to selection bias toward small-for-gestational age (SGA) infants, which may impact upon the validity of data for benchmarking purposes. Method: Data from all VLGA or VLBW infants admitted in the 3 Networks between 2008 and 2011 were used. Two-thirds of each network cohort was randomly selected to develop prediction models for mortality and composite adverse outcome (CAO: mortality or cerebral injuries, chronic lung disease, severe retinopathy or necrotizing enterocolitis) and the remaining for internal validation. Areas under the ROC curves (AUC) of the models were compared. Results: VLBW cohort (24,335 infants) had twice more SGA infants (20.4% vs. 9.3%) than the VLGA cohort (29,180 infants) and had a higher rate of CAO (36.5% vs. 32.6%). The two models had equal prediction power for mortality and CAO (AUC 0.83), and similarly for all other cross-cohort validations (AUC 0.81-0.85). Neither model performed well for the extremes of birth weight for gestation (<1500 g and ≥32 weeks, AUC 0.50-0.65; ≥1500 g and <32 weeks, AUC 0.60-0.62). Conclusion: There was no difference in prediction power for adverse outcome between cohorting VLGA or VLBW despite substantial bias in SGA population. Either cohorting practises are suitable for international benchmarking

Influence of the genus

The authors studied the effect of treatment with bacteria Bacillus subtilis Cohn (strains 26D) and B. thuringiensis Berliner (strain B-6066) on the hydrogen peroxide (H2O2) content, the activity of hydrolytic enzymes and their protein inhibitors in potato plants (Solanum tuberosum L.) in connection with development of resistance to the late blight pathogen - oomycete Phytophthora infestans Mont. de Bary. Studies were carried out on potato plants of the susceptible Early Rose potato cultivar that were treated with a suspension of B. subtilis and B. thuringiensis bacteria (108 cells/ml) and infected with P. infestans (107 spores/ml). A decrease in the degree of leaf damage by oomycete was revealed under the influence of the genus Bacillus bacteria, depending on the strain. The increase in potato resistance to P. infestans infection was mediated by the stimulating effect of the B. subtilis 26D and the B. thuringiensis B-6066 bacteria on the concentration of H2O2, the modulating effect on the activity of hydrolytic enzymes and the enhancement of the transcriptional activity of protease and amylase inhibitor genes in plant tissues. Differences in the degree of activation of the transcriptional activity of hydrolase inhibitor genes by the B. subtilis 26D and the B. thuringiensis B-6066 bacteria were revealed, which suggests differential ways of forming the potato resistance to P. infestans under their influence

Additive Effect of the Composition of Endophytic Bacteria <i>Bacillus subtilis</i> on Systemic Resistance of Wheat against Greenbug Aphid <i>Schizaphis graminum</i> Due to Lipopeptides

The use of biocontrol agents based on endophytic bacteria against phloem-feeding insects is limited by a lack of knowledge and understanding of the mechanism of action of the endophyte community that makes up the plant microbiome. In this work, the mechanisms of the additive action of endophytic strains B. subtilis 26D and B. subtilis 11VM on the resistance of bread spring wheat against greenbug aphid Schizaphis graminum, was studied. It was shown that B. subtilis 26D secreted lipopeptide surfactin and phytohormones cytokinins, and B. subtilis 11VM produced iturin and auxins into the cultivation medium. Both strains and their lipopeptide-rich fractions showed direct aphicidal activity against greenbug aphid. For the first time, it was shown that B. subtilis 26D and B. subtilis 11VM in the same manner, as well as their lipopeptide-rich fractions, activated the expression of salicylate- and ethylene-dependent PR genes, and influenced plant redox metabolism, which led to an increase in plant endurance against aphids. The composition of endophytic strains B. subtilis 26D + B. subtilis 11VM had an additive effect on plant resistance to aphids due to an increase in the number of endophytic bacterial cells, and, as well as due to the synergistic effect of their mixture of lipopeptides − surfactin + iturin, both on the aphid mortality and on the expression of PR1 and PR3 genes. All these factors can be the reason for the observed increase in the growth of plants affected by aphids under the influence of B. subtilis 26D and B. subtilis 11VM, individually and in composition. The study demonstrates the possibility of creating in the future an artificial composition to enhance plant microbiome with endophytic bacteria, which combines growth-promoting and plant immunity stimulating properties against phloem-feeding insects. This direction is one of the most promising approaches to green pesticide discovery in the future

COOPERATIVE APPLICATION OF ENDOPHYTIC STRAINS OF BEAUVERIA BASSIANA UFA-2 AND BACILLUS SUBTILIS 26Д FOR COMPREHENSIVE DEFENSE OF POTATO

Endophytic habitation of Beauveria bassiana Ufa-2 and Bacillus subtilis 24D was demonstrated. Presence of these strains decreased the level of late blight symptoms and Colorado potato beetle eating of plants.Работа выполнена при поддержке гранта двухлетних прикладных научных исследований, направленных на создание продукции и технологий, по приоритетному направлению «Науки о жизни» в рамках мероприятия 1.2 Программы Министерства образования и науки РФ № 14.604.21.0016

By Modulating the Hormonal Balance and Ribonuclease Activity of Tomato Plants Bacillus subtilis Induces Defense Response against Potato Virus X and Potato Virus Y

Endophytic plant-growth-promoting microorganisms can protect plants against pathogens, but they have rarely been investigated as potential biocontrol agents and triggers of induced systemic resistance (ISR), regulated by phytohormones, against viruses. We studied the role of endophytic strains Bacillus subtilis 26D and B. subtilis Ttl2, which secrete ribonucleases and phytohormones, in the induction of tomato plant resistance against potato virus X and potato virus Y in a greenhouse condition. The endophytes reduced the accumulation of viruses in plants, increased the activity of plant ribonucleases and recovered the fruit yield of infected tomato plants. Both the 26D and Ttl2 strains induced ISR by activating the transcription of genes related to salicylate- and jasmonate-dependent responses. The 26D and Ttl2 strains increased the content of cytokinins and decreased the level of indolacetic acid in plants infected with PVX or PVY. PVY led to an increase of the abscisic acid (ABA) content in tomato plants, and PVX had the opposite effect. Both strains reduced the ABA content in plants infected with PVY and induced ABA accumulation in plants infected with PVX, which led to an increase in the resistance of plants. This is the first report of the protection of tomato plants against viral diseases by foliar application of endophytes