Category Technology

A group from National Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Shandong, China has reported on Bacillus amyloliquefaciens QSB-6 strain isolated from apple orchard soils and its effect on apple tree roots and disease.
https://www.frontiersin.org/articles/10.3389/fmicb.2021.746799/full

Authors compared effects of 4 types of soils on apple tree roots.

• untreated soil from a 31-year-old orchard (CK1)
• the same soil fumigated with methyl bromide (CK2)
• the same soil treated with the manure carrier only (T1)
• the same soil treated with Bacillus amyloliquefaciens strain QSB-6 manure treatment (T2)

Interestingly, the CK2, T2, and T1 treatments significantly promoted the growth of apple tree roots, and the relative treatment effects were ranked from high to low: CK2 > T2 > T1 > CK1.

The number of rhizobacteria increased significantly after T2 treatment by 9.64 times higher in T2 than in CK1, and soil fungal numbers were reduced significantly by 85.58% (in CK2) and 81.74% (in T2) compared with CK1.
Extracellular metabolites from strain QSB-6 showed a strong inhibitory effect on Fusarium hyphal growth and spore germination as shown below.

(A) Fusarium proliferatum, (B) Fusarium solani, (C) Fusarium verticillioides, (D) Fusarium oxysporum

In summary, B. amyloliquefaciens QSB-6 has a good inhibitory effect on Fusarium in the soil and can significantly promote apple tree root growth. It has great potential as a biological control agent against apple disease.

A group from Technical University of Denmark, Kongens Lyngby, Denmark, etc. has reported that Bacillus velezensis recruited Pseudomonas stutzeri for plant through metabolic cross-feeding
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8483172/

Generally, Bacillus spp. and Pseudomonas spp. are the most extensively studied beneficial microorganisms in the rhizosphere. Plant beneficial Bacillus, including B. velezensis SQR9 are known for plant growth promotion, disease suppression, and enhanced salt stress tolerance. Root colonization and plant growth-promoting properties require efficient biofilm formation (including exopolysaccharide EPS and TasA protein fibers) on the roots.

To explore the effects of B. velezensis SQR9 on rhizosphere microbiota, two-weeks-old cucumber seedlings were inoculated with strain SQR9 and the rhizosphere soil samples were collected after sixteen days. It was found that members of the genera Pseudomonas, Vogesella, Pseudoxanthomonas, Chryseobacterium, Pseudoduganella, Lysobacter, Klebsiella, and Cellvibrio were increased after SQR9 application. Remarkably, 38% of increased rhizobacteria mapped to the Pseudomonas genus, suggesting that B. velezensis SQR9 may recruit and then synergistically interact with Pseudomonas spp.

The rhizobacteria consortium had a stronger promoting effect in paddy soil, as the dual-species (Bacillus and Pseudomonas) consortium significantly increased the shoot height, shoot dry weight, and chlorophyll content of plants in comparison to plant inoculated with one species. In the case of salt treated paddy soil, Pseudomonas stutzeri XL272 protects the plant against salt stress at the most comparing with non-inoculated control plants. The protective effect of the rhizobacteria consortium was higher than that of P. stutzeri XL272 alone in comparison to control plants. These results support the suggestion that the PGPR can induce the assemblage of the indigenous beneficial microbiome, leading to the promotion of plant health and resistance to salt stress.

A big question is how B. velezensis SQR9 recruited Pseudomonas spp. etc.? Authors suggested that the metabolic cross-feeding such as branched-chain amino acids would be a key to understand the mechanism through analysis transcriptional alterations of bacillus and pseudomonas.
The image is like this; B. velezensis SQR9 is attracted by root exudates and colonizes the rhizosphere. After establishing biofilm on plant roots, it secretes metabolites that increase the abundance of indigenous plant beneficial genera (such as Pseudomonas spp.). Forming tightly associated biofilm, they share extracellular matrix and essential metabolites that increase their fitness in the rhizosphere, and help plant growth and increase resistant to salt stress.

A group from Faculté de Pharmacie, Université Paul, Sabatier, Toulouse, France, etc has reported that Helix pomatia lectin (HPA) is not only a good tool as cancer marker, but could also be used for therapeutic applications.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8431231/

Morniga G lectin and HPA lectin are know to have binding specificity to Tn-antigen. Authors demonstrated in the past that Morniga G can interact with Tn antigen present on Jurkat human leukemia, inducing tumor cell death but not death of Tn-negative healthy peripheral blood lymphocytes. However, very little information was known about the putative functional role of HPA-binding glycoproteins on tumor cells.

In this paper, authors have demonstrated for the first time that HPA induces cell death in human Jurkat T-cell leukemia and mouse EL4 T-cell lymphoma. In the mouse, HPA is clearly more toxic than Morniga G for EL4 cells. In addition, HPA appears to be non-toxic for healthy lymphocytes, suggesting that HPA could be used for therapeutic applications.

A group from Gansu Agricultural University, Lanzhou, China, etc. has reported on the effects of different vegetable rotations on the tomato’s rhizobacteria.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8459948/

The vegetable rotations, cabbage/tomato (B), kidney bean/tomato (D), and celery/tomato (Q), were compared with the continuous tomato cropping (CK) as a control from view points of changes in tomato’s rhizobacteria and effects on tomato plants growth.

The light and photosynthetic parameters of the leaves (intercellular CO² concentration, transpiration rate, stomatal conductance, net photosynthetic rate) were higher in the celery/tomato rotation that the continuous tomato cropping. As for the changes in tomato’s rhizobacteria, Actinomycetaies decreased, and Actinobacteria, Anaerolineaceae, Hyphomicrobium increased in the celery/tomato rotation significantly compared with the continuous tomato cropping.

A group from Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA, etc. has reported that FIB-4 would be a good independent predictor of COVID-19 mortality.
https://aasldpubs.onlinelibrary.wiley.com/doi/10.1002/hep4.1650

A total of 202 participants were selected from the two cohorts (n = 87 from the MassCPR cohort and n = 115 from the BWH cohort).
FIB-4 is defined by the following formula:
FIB-4=(Age(year)xAST(U/L)/(PLT(100/uL)x√ALT(U/L))

In logistic regression analysis, higher FIB-4 was associated with mortality and an unadjusted OR = 1.75 (95% CI, 1.37, 2.23; P < 0.001), and after adjusting for sex, BMI, ethnicity, hypertension, diabetes, remdesivir use, and liver diseases, FIB-4 remained to be associated with mortality (adjusted OR = 1.79; 95% CI, 1.36, 2.35; P < 0.001) In conclusion, it was shown that FIB-4 at admission would be a good independent index in predicting COVID-19 death, with an AUC of 0.79.

A group from Department of Molecular Genetics, University of Groningen, Groningen, Netherlands, etc. has reported that Bacillus cabrialesii BH5 Protects Tomato Plants Against Botrytis cinerea.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8441496/

To date, more and more reports show that applying plant growth-promoting rhizobacteria (PGPR) into agriculture as biological control agents is a successful strategy for plant disease control. PGPR can influence plant growth by either facilitating resource acquisition or modulating plant hormone levels. Moreover, PGPR can decrease the various pathogenic effects, either by evoking immunity of plants or by producing antimicrobial compounds.

It was shown that Bacillus cabrialesii BH5 isolated from the rhizosphere soil of a healthy tomato plant shows potent biocontrol activity against fungal pathogens via producing an antifungal compound named fengycin H (see below).

(The antifungal activity of volatile organic compounds (fengycin H) produced by BH5, strong inhibition against botrytis cinerea)

It was also found that B. cabrialesii BH5 is able to promote tomato plant resistance to B. cinerea by activating the jasmonic acid (JA) signaling pathway, which is own mechanism to deal with pathogens and to coordinate the appropriate defense responses. Actually, the expression of the JA signaling pathway-related gene SlLoxD in fengycin H or BH5 treatment was always significantly higher than that in control from 48 to 96 h.

The effect of BH5 on the growth of tomato seedlings was monitored by measuring the shoot/root length, shoot/root fresh weight, and dry weight. B. cabrialesii BH5 showed a significantly increase of fresh and dry weight both of the shoot and root.

A group from Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna Austria, etc. has reported CLEC4G and CD209c lectins could block SARS-CoV-2 infections.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8420505/

Of 168 annotated carbohydrate recognition domains (CRDs) of mouse C‐type lectins, Galectins and Siglecs, 143 lectin‐CRDs as IgG2a‐Fc fusion proteins were expressed with human HEK293F cells. The resulting dimeric lectin‐Fc fusion proteins will be the first comprehensive library of mammalian CRDs. Through this study, the dimeric lectin-Fc fusion proteins were used as lectins.

The detected N‐glycan species from SARS-CoV-2 Spike ranged from poorly processed oligo‐mannose structures to highly processed multi‐antennary complex N‐glycans in a site‐dependent manner. The two glycosylation sites N331 and N343 located in the RBD carried more extended glycans, including sialylated and di‐fucosylated structures, when expressed as an independent construct as opposed to the full‐length Spike protein. It has to be noted that the N‐glycosylation of the RBD within full‐length trimeric Spike is different from N‐glycosylation of the RBD expressed as minimal ACE2 binding domain. This highlights the importance of using a full‐length trimeric Spike protein for its functional studies. This also suggests slight changes in glycosylation might explain differences in antiviral immunity and possibly severity of the disease.

Anyway, it was demonstrated that two lectins, CLEC4G and CD209c, were identified to strongly bind to Spike. CLEC4G and CD209c binding to Spike was visualized in real time and at single‐molecule resolution using atomic force microscopy, and the 3D modelling showed that both lectins can bind to a glycan within the RBD‐ACE2 interface and thus interferes with Spike binding to cell surfaces. Finally, it was shown that CLEC4G and CD209c significantly reduced SARS‐CoV‐2 infection.

The Viral RNA was measured with qRT–PCR 15 h after infection of SARS‐CoV‐2. Data are presented as fold changes of viral loads over mock (only SARS‐CoV‐2 was added).