Bacillus species as tools for biocontrol of plant diseases: A meta-analysis of twenty-two years of research, 2000-2021.

The traditional way of dealing with plant diseases has been the use of chemical products, but these harm the environment and are incompatible with the global effort for sustainable development. The use of Bacillus and related species in the biological control of plant diseases is a trend in green agriculture. Many studies report the positive effect of these bacteria, but a synthesis is still necessary. So, the objective of this work is to perform a meta-analysis of Bacillus biocontrol potential and identify factors that drive its efficacy. Data were compiled from articles published in journals listed in two of the main scientific databases between 2000 and 2021. Among 6159 articles retrieved, 399 research papers met the inclusion criteria for a systematic review. Overall, Bacilli biocontrol agents reduced disease by 60% compared to control groups. Furthermore, experimental tests with higher concentrations show a strong protective effect, unlike low and single concentration essays. Biocontrol efficacy also increased when used as a protective inoculation rather than therapeutic inoculation. Inoculation directly in the fruit has a greater effect than soil drenching. The size of the effect of Bacillus-based commercial products is lower than the newly tested strains. The findings presented in this study confirm the power of Bacillus-based bioinoculants and provide valuable guidance for practitioners, researchers, and policymakers seeking effective and sustainable solutions in plant disease management.

Plant bZIP Proteins: Potential use in Agriculture - A Review.

With global climate changes and the increased demand for food due to expected world population growth, genetic improvement programs have aimed at producing crops with increased yield and tolerance to environmental stresses, such as drought, salinity, and pathogens. On the other hand, genetic improvement programs via biotechnology require candidate genes that confer traits of interest to be incorporated into improved crops. In this regard, genes encoding transcription factors (TFs) can be promising since they are proteins that transcriptionally regulate the expression of target genes related to the most diverse roles in the plant, including defense against stresses. Among TFs, bZIP (basic leucine zipper) proteins regulate many developmental and physiological processes in the plant, such as seed formation, fruit ripening, nutrient assimilation, and defense response to abiotic and biotic stresses. In this review, we aim to highlight the main advances in the potential use of bZIP TFs in the genetic improvement of crops. We address this potential mainly regarding crop tolerance to stresses and other agricultural traits, such as increased yield and fruit features.

Halophytes and other molecular strategies for the generation of salt-tolerant crops.

The current increase in salinity can intensify the disparity between potential and actual crop yields, thus affecting economies and food security. One of the mitigating alternatives is plant breeding via biotechnology, where advances achieved so far are significant. Considering certain aspects when developing studies related to plant breeding can determine the success and accuracy of experimental design. Besides this strategy, halophytes with intrinsic and efficient abilities against salinity can be used as models for improving the response of crops to salinity stress. As crops are mostly glycophytes, it is crucial to point out the molecular differences between these two groups of plants, which may be the key to guiding and optimizing the transformation of glycophytes with halophytic tolerance genes. Therefore, this can broaden perspectives in the trajectory of research towards the cultivation, commercialization, and consumption of salt-tolerant crops on a large scale.

A new Piper nigrum cysteine proteinase inhibitor, PnCPI, with antifungal activity: molecular cloning, recombinant expression, functional analyses and molecular modeling.

MAIN CONCLUSION: A new Piper nigrum cysteine proteinase inhibitor, PnCPI, belonging to group I of phytocystatins, with inhibitory activity against papain and growth of Fusarium solani f. sp. piperis, was isolated and characterized. Previous studies (de Souza et al. 2011) have identified a partial cDNA sequence of putative cysteine proteinase inhibitor differentially expressed in roots of black pepper (P. nigrum L.) infected by F. solani f. sp. piperis. Here, we aimed to isolate the full-length cDNA and genomic sequences of the P. nigrum cysteine proteinase inhibitor gene, named PnCPI. Sequence analyses showed that the PnCPI gene encodes a deduced protein of 108 amino acid residues with a predicted molecular mass of 12.3 kDa and isoelectric point of 6.51. Besides the LARFAV-like sequence, common to all phytocystatins, PnCPI contains three conserved motifs of the superfamily cystatin: a glycine residue at the N-terminal region, the QxVxG reactive site more centrally positioned, and one tryptophan in the C-terminal region. PnCPI, belonging to group I of phytocystatins, showed high identity with cystatins isolated from several plant species. Sequence analyses also revealed no putative signal peptide at the N-terminal of PnCPI, as well as no introns within the genomic sequence corresponding to the PnCPI coding region. Molecular modeling showed the ability of PnCPI to interact with papain, while its inhibitory activity against this protease was confirmed after heterologous expression in Escherichia coli. The effects of heat treatments on the inhibitory activity of recombinant PnCPI, rPnCPI, were evaluated. In addition, rPnCPI exhibited in vitro activity against F. solani f. sp. piperis, revealing a new cystatin with the potential antifungal application. The identification of PnCPI as a functional cystatin able to inhibit the in vitro growth of F. solani f. sp. piperis indicates other factors contributing to in vivo susceptibility of black pepper to root rot disease.

A Cassava CPRF-2-like bZIP Transcription Factor Showed Increased Transcript Levels during Light Treatment.

BACKGROUND: bZIP proteins participate in the regulation of gene expression, playing crucial roles in various biological processes in plants, including response to environmental changes. Luminosity is an environmental factor of extreme importance for plant metabolism, acting as a regulator of its growth and development. Despite advances in the identification of bZIP proteins in several plant species, studies on these transcription factors in cassava are lacking. Cassava (Manihot esculenta Crantz) is one of the most important food crops in tropical and subtropical regions, mainly in developing countries, where its storage root is a major source of calories for low-income people. OBJECTIVES: Our main aim was the isolation of a cDNA sequence encoding a bZIP protein from cassava (MebZIP) as well as the in silico characterization of its nucleotide and deduced amino acid sequences. In addition, we evaluated the expression pattern of the MebZIP gene in response to light, and its possible relationship with regulation of the chalcone synthase (MeCHS) gene. METHODS: RT-PCR and 3' and 5' RACE assays were used to isolate the full-length cDNA sequence of MebZIP. Bioinformatics tools were used to characterize the nucleotide and amino acid sequences of MebZIP. Semiquantitative RT-PCR assays were used to evaluate the expression levels of MebZIP and MeCHS genes. RESULTS: We isolated the full-length cDNA sequence of MebZIP with a 1320-bp ORF encoding a deduced protein with a predicted molecular weight and isoelectric point of 47 kDa and 5.85, respectively. Comparative analyses with GenBank sequences showed high identity of MebZIP with bZIP CPRF-2 of Hevea brasiliensis (XP_021650934) and Petroselinum crispum (Q99090.2). Besides the basic region and leucine zipper domains, MebZIP contains putative conserved domains (D1- D4), found in parsley CPRF-2 and bZIP proteins closely related to this protein. Since CPRF proteins are known for their function in regulation of the CHS gene by light, we evaluated the expression levels of the MebZIP gene and the possible target gene to be regulated by MebZIP (the MeCHS gene) in cassava under light conditions. Semi-quantitative RT-PCR assays revealed that MebZIP transcription increased in response to white light, with maximum expression levels at 6 h of light exposure. On the other hand, the expression levels of the MeCHS gene were statistically constant in all samples, indicating that they were not influenced by the experimental conditions used here. CONCLUSION: The putative MebZIP protein identified in this work contains the conserved domains (bZIP, D1-D4) that indicate its functionality, thus allowing it to be considered a new member of the bZIP transcription factor CPRF-2 family. The expression levels of the MebZIP gene increased during white light exposure, indicating a potential function in light-response in cassava.

Molecular cloning and characterization of a cassava translationally controlled tumor protein gene potentially related to salt stress response.

Cassava (Manihot esculenta Crantz) is one of the most important tropical crops showing tolerance to abiotic stress and adaptations to a wide range of environmental conditions. Here, we aimed to isolate and characterize the full-length cDNA and genomic sequences of a cassava translationally controlled tumor protein gene (MeTCTP), and evaluate its potential role in response to salt stress. The MeTCTP full-length cDNA sequence encodes for a deduced protein with 168 amino acid residues, with theoretical isoelectric point and molecular weight of 4.53 and 19 kDa, respectively, containing two putative signatures of TCTP family and one site for myristoylation. The MeTCTP genomic sequence includes four introns and five exons within a 1,643 bp coding region, and a 264 bp partial promoter sequence containing several putative cis-acting regulatory elements, among them, two putative GT-1 motifs, which may be related to response to sodium chloride (NaCl) and pathogen infection. Semi-quantitative RT-PCR assays showed that MeTCTP transcripts were higher in roots than leaves, and were significantly increased in detached leaves treated with NaCl. Furthermore, the recombinant MeTCTP conferred a protective function against salt stress in bacterial cells. We report for the first time the molecular cloning and characterization of a cassava TCTP with potential role in salt-stress response. Since salinity is one the most important abiotic factors affecting the production of crops worldwide, the MeTCTP gene could be a candidate gene for generation of salt tolerant crops.

Recent molecular advances on downstream plant responses to abiotic stress.

Abiotic stresses such as extremes of temperature and pH, high salinity and drought, comprise some of the major factors causing extensive losses to crop production worldwide. Understanding how plants respond and adapt at cellular and molecular levels to continuous environmental changes is a pre-requisite for the generation of resistant or tolerant plants to abiotic stresses. In this review we aimed to present the recent advances on mechanisms of downstream plant responses to abiotic stresses and the use of stress-related genes in the development of genetically engineered crops.

Evidence for a novel biological role for the multifunctional ß-1,3-glucan binding protein in shrimp.

ß-1,3-Glucan binding proteins (ßGBPs) are soluble pattern recognition proteins/receptors that bind to ß-1,3-glucans from fungi cell walls. In crustaceans, ßGBPs are abundant plasmatic proteins produced by the hepatopancreas, and have been proved to play multiple biological functions. Here, we purified and characterized novel members of the ßGBP family from the hemolymph of two Brazilian shrimps, Farfantepenaeus paulensis (FpßGBP) and Litopenaeus schmitti (LsßGBP). As observed for other crustacean species, FpßGBP and LsßGBP are monomeric proteins (∼100kDa) able to enhance the activation of the prophenoloxidase system, a potent antimicrobial defense conserved in arthropods. More interestingly, we provided here evidence for a novel biological activity for shrimp ßGBPs: the agglutination of fungal cells. Finally, we investigated the modulation of the ßGBP gene in F. paulensis shrimps experimentally infected with a cognate fungal pathogen, Fusarium solani. From our expression data, ßGBP gene is constitutively expressed in hepatopancreas and not modulated upon a non-lethal fungal infection. Herein, we have improved our knowledge about the ßGBP family by the characterization of a novel biological role for this multifunctional protein in shrimp.

Molecular cloning and characterization of a novel RING zinc-finger protein gene up-regulated under in vitro salt stress in cassava.

Cassava (Manihot esculenta Crantz) is one of the world's most important food crops. It is cultivated mainly in developing countries of tropics, since its root is a major source of calories for low-income people due to its high productivity and resistance to many abiotic and biotic factors. A previous study has identified a partial cDNA sequence coding for a putative RING zinc finger in cassava storage root. The RING zinc finger protein is a specialized type of zinc finger protein found in many organisms. Here, we isolated the full-length cDNA sequence coding for M. esculenta RZF (MeRZF) protein by a combination of 5' and 3' RACE assays. BLAST analysis showed that its deduced amino acid sequence has a high level of similarity to plant proteins of RZF family. MeRZF protein contains a signature sequence motif for a RING zinc finger at its C-terminal region. In addition, this protein showed a histidine residue at the fifth coordination site, likely belonging to the RING-H2 subgroup, as confirmed by our phylogenetic analysis. There is also a transmembrane domain in its N-terminal region. Finally, semi-quantitative RT-PCR assays showed that MeRZF expression is increased in detached leaves treated with sodium chloride. Here, we report the first evidence of a RING zinc finger gene of cassava showing potential role in response to salt stress.

Pt2L4 protein, a homologue to Hev b 5 from rubber tree, may not be responsible for the cross-reactions to cassava show by people allergic to latex.

Pt2L4 is a protein from cassava homologue to Hevb5, a principal allergen from latex. Here we aimed to elucidate immunological relationships between these proteins. Our results revealed that epitopes found in Hev b 5 are not entirely conserved in Pt2L4 which is not recognized by IgE from patients allergic to Hev b 5.

A cDNA sequence coding for a glutamic acid-rich protein is differentially expressed in cassava storage roots.

We report the isolation and characterization of a cDNA sequence (Mec1) coding for a glutamic acid-rich protein (Pt2L4) from cassava storage roots. Comparative sequence analysis showed a high identity of Pt2L4 with cassava protein C54, which is expressed in vascular tissues of storage roots. Northern blot analysis showed that the Mec1 transcript expression pattern might be related to the maturation of the storage parenchyma cells.