CRISPR/Cas9 editing of two adenine phosphoribosyl transferase coding genes reveals the functional specialization of adenine salvage proteins in common bean.

Adenine metabolism is important for common bean (Phaseolus vulgaris L.) productivity since this legume uses ureides derived from the oxidation of purine nucleotides as its primary nitrogen storage molecules. Purine nucleotides are produced from de novo synthesis or through salvage pathways.

Transcriptomic and metabolomic analysis reveals that symbiotic nitrogen fixation enhances drought resistance in common bean.

Common bean (Phaseolus vulgaris L.), one of the most important legume crops, uses atmospheric nitrogen through symbiosis with soil rhizobia, reducing the need for nitrogen fertilization. However, this legume is particularly sensitive to drought conditions, prevalent in arid regions where this crop is cultured.

Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein and hairy roots: a perfect match for gene functional analysis and crop improvement.

Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas) gene editing has become a powerful tool in genome manipulation for crop improvement. Advances in omics technologies, including genomics, transcriptomics, and metabolomics, allow the identification of causal genes that can be used to improve crops. However, the functional validation of these genetic components remains a challenge due to the lack of efficient protocols for crop engineering.

Differential Regulation of Drought Responses in Two Genotypes.

Drought is probably the most harmful stress affecting common bean crops. Domestication, worldwide spread and local farming practices has entailed the development of a wide variety of common bean genotypes with different degrees of resistance to water stress. In this work, physiological and molecular responses to water stress have been compared in two common bean accessions, PHA-0683 and PMB-0220, previously identified as highly and moderately resistant to water stress, respectively.

Transcriptomic Response to Water Deficit Reveals a Crucial Role of Phosphate Acquisition in a Drought-Tolerant Common Bean Landrace.

Drought is one of the most critical factors limiting legume crop productivity. Understanding the molecular mechanisms of drought tolerance in the common bean is required to improve the yields of this important crop under adverse conditions. In this work, RNA-seq analysis was performed to compare the transcriptome profiles of drought-stressed and well-irrigated plants of a previously characterized drought-tolerant common bean landrace.

Sustaining Programs: Lessons Learned from Former Federal Grantees.

Introduction: A common concern of federal funders and grant recipients is how to sustain program activities once their federal funding period ends. Federal funding can be intended to develop or seed a program but not necessarily to continue its activities indefinitely. Understanding the importance of programmatic sustainability, the Office of Population Affairs (OPA) conducted research in 2015 on the elements that contribute to sustainability.

Molecular and biochemical analysis of XDH from Phaseolus vulgaris suggest that uric acid protects the enzyme against the inhibitory effects of nitric oxide in nodules.

Xanthine dehydrogenase (XDH) is essential for the assimilation of symbiotically fixed nitrogen in ureidic legumes. Uric acid, produced in the reaction catalyzed by XDH, is the precursor of the ureides, allantoin and allantoate, which are the main N-transporting molecules in these plants. XDH and uric acid have been reported to be involved in the response to stress, both in plants and animals.

Functional specialization of one copy of glutamine phosphoribosyl pyrophosphate amidotransferase in ureide production from symbiotically fixed nitrogen in Phaseolus vulgaris.

Purines are essential molecules formed in a highly regulated pathway in all organisms. In tropical legumes, the nitrogen fixed in the nodules is used to generate ureides through the oxidation of de novo synthesized purines. Glutamine phosphoribosyl pyrophosphate amidotransferase (PRAT) catalyses the first committed step of de novo purine synthesis.

Comparison of inhibition of N2 fixation and ureide accumulation under water deficit in four common bean genotypes of contrasting drought tolerance.

Background And Aims: Drought is the principal constraint on world production of legume crops. There is considerable variability among genotypes in sensitivity of nitrogen fixation to drought, which has been related to accumulation of ureides in soybean. The aim of this study was to search for genotypic differences in drought sensitivity and ureide accumulation in common bean (Phaseolus vulgaris) germplasm that may be useful in the improvement of tolerance to water deficit in common bean.

Molecular and functional characterization of allantoate amidohydrolase from Phaseolus vulgaris.

Allantoate degradation is an essential step for recycling purine-ring nitrogen in all plants, but especially in tropical legumes where the ureides allantoate and allantoin are the main compounds used to store and transport the nitrogen fixed in nodules. Two enzymes, allantoate amidohydrolase (AAH) and allantoate amidinohydrolase (allantoicase), could catalyze allantoate breakdown, although only AAH-coding sequences have been found in plant genomes, whereas allantoicase-related sequences are restricted to animals and some microorganisms. A cDNA for AAH was cloned from Phaseolus vulgaris leaves.

Molecular characterization of PVAS3: an asparagine synthetase gene from common bean prevailing in developing organs.

In common bean, asparagine synthetase (AS; EC 6.3.5.

Local inhibition of nitrogen fixation and nodule metabolism in drought-stressed soybean.

Drought stress is a major factor limiting symbiotic nitrogen fixation (NF) in soybean crop production. However, the regulatory mechanisms involved in this inhibition are still controversial. Soybean plants were symbiotically grown in a split-root system (SRS), which allowed for half of the root system to be irrigated at field capacity while the other half remained water deprived.

Developmental effects on ureide levels are mediated by tissue-specific regulation of allantoinase in Phaseolus vulgaris L.

The ureides allantoin and allantoate are key molecules in the transport and storage of nitrogen in ureide legumes. In shoots and leaves from Phaseolus vulgaris plants using symbiotically fixed nitrogen as the sole nitrogen source, ureide levels were roughly equivalent to those of nitrate-supported plants during the whole vegetative stage, but they exhibited a sudden increase at the onset of flowering. This rise in the level of ureides, mainly in the form of allantoate, was accompanied by increases in allantoinase gene expression and enzyme activity, consistent with developmental regulation of ureide levels mainly through the tissue-specific induction of allantoate synthesis catalysed by allantoinase.

Constraints to virus infection in Nicotiana benthamiana plants transformed with a potyvirus amplicon.

Background: Plant genomes have been transformed with full-length cDNA copies of viral genomes, giving rise to what has been called 'amplicon' systems, trying to combine the genetic stability of transgenic plants with the elevated replication rate of plant viruses. However, amplicons' performance has been very variable regardless of the virus on which they are based. This has boosted further interest in understanding the underlying mechanisms that cause this behavior differences, and in developing strategies to control amplicon expression.

Molecular analysis of ureide accumulation under drought stress in Phaseolus vulgaris L.

Under water deficit, ureidic legumes accumulate ureides in plant tissues, and this accumulation has been correlated with the inhibition of nitrogen fixation. In this work we used a molecular approach to characterize ureide accumulation under drought stress in Phaseolus vulgaris. Accumulation of ureides, mainly allantoate, was found in roots, shoots and leaves, but only a limited transient increase was observed in nodules from drought-stressed plants.

An antibody derivative expressed from viral vectors passively immunizes pigs against transmissible gastroenteritis virus infection when supplied orally in crude plant extracts.

To investigate the potential of antibody derivatives to provide passive protection against enteric infections when supplied orally in crude plant extracts, we have expressed a small immune protein (SIP) in plants using two different plant virus vectors based on potato virus X (PVX) and cowpea mosaic virus (CPMV). The epsilonSIP molecule consisted of a single-chain antibody (scFv) specific for the porcine coronavirus transmissible gastroenteritis virus (TGEV) linked to the epsilon-CH4 domain from human immunoglobulin E (IgE). In some constructs, the sequence encoding the epsilonSIP molecule was flanked by the leader peptide from the original murine antibody at its N-terminus and an endoplasmic reticulum retention signal (HDEL) at its C-terminus to allow the expressed protein to be directed to, and retained within, the endoplasmic reticulum.

Salicylic acid-mediated and RNA-silencing defense mechanisms cooperate in the restriction of systemic spread of plum pox virus in tobacco.

Plum pox virus (PPV) is able to replicate in inoculated leaves of Nicotiana tabacum, but is defective in systemic movement in this host. However, PPV produces a systemic infection in transgenic tobacco expressing the silencing suppressor P1/HC-Pro from tobacco etch virus (TEV). In this work we show that PPV is able to move to upper non-inoculated leaves of tobacco plants expressing bacterial salicylate hydroxylase (NahG) that degrades salicylic acid (SA).

Use of virus vectors for the expression in plants of active full-length and single chain anti-coronavirus antibodies.

To extend the potential of antibodies and their derivatives to provide passive protection against enteric infections when supplied orally in crude plant extracts, we have expressed both a small immune protein (SIP) and a full-length antibody in plants using two different plant virus vectors based on potato virus X (PVX) and cowpea mosaic virus (CPMV). The alphaSIP molecule consisted of a single chain antibody (scFv) specific for the porcine coronavirus, transmissible gastroenteritis virus (TGEV) linked to the alpha-CH3 domain from human IgA. To express the full-length IgA, the individual light and heavy chains from the TGEV-specific mAb 6A.

Multiple resistance traits control Plum pox virus infection in Arabidopsis thaliana.

Twelve Arabidopsis accessions were challenged with Plum pox potyvirus (PPV) isolates representative of the four PPV strains. Each accession supported local and systemic infection by at least some of the PPV isolates, but high variability was observed in the behavior of the five PPV isolates or the 12 Arabidopsis accessions. Resistance to local infection or long-distance movement occurred in about 40% of all the accession-isolate combinations analyzed.

Identification of a plum pox virus CI-interacting protein from chloroplast that has a negative effect in virus infection.

The cylindrical inclusion (CI) protein of potyviruses is involved in virus replication and cell-to-cell movement. These two processes should rely on multiple plant-virus interactions; however, little is known about the host factors that are involved in, or that may interfere with, CI functions. By using a yeast two-hybrid system, the CI protein from Plum pox virus (PPV) was found to interact with the photosystem I PSI-K protein, the product of the gene psaK, of Nicotiana benthamiana.

Identification of secret agent as the O-GlcNAc transferase that participates in Plum pox virus infection.

Serine and threonine of many nuclear and cytoplasmic proteins are posttranslationally modified with O-linked N-acetylglucosamine (O-GlcNAc). This modification is made by O-linked N-acetylglucosamine transferases (OGTs). Genetic and biochemical data have demonstrated the existence of two OGTs of Arabidopsis thaliana, SECRET AGENT (SEC) and SPINDLY (SPY), with at least partly overlapping functions, but there is little information on their target proteins.

Natural variability in the Arabidopsis response to infection with Erwinia carotovora subsp. carotovora.

The natural variation in the response of Arabidopsis thaliana (L.) Heynh. to Erwinia carotovora subsp.

Antibiotic activities of peptides, hydrogen peroxide and peroxynitrite in plant defence.

Genes encoding plant antibiotic peptides show expression patterns that are consistent with a defence role. Transgenic over-expression of defence peptide genes is potentially useful to engineer resistance of plants to relevant pathogens. Pathogen mutants that are sensitive to plant peptides in vitro have been obtained and a decrease of their virulence in planta has been observed, which is consistent with their hypothetical defence role.