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Abstract Omega-3 fatty acids (ω3 FAs) are essential components of cell membranes that also serve as precursors of numerous regulatory molecules. α-Linolenic acid (ALA), one of the most important ω3 FAs in plants, is synthesized in both the plastid and extraplastidial compartments. FA desaturase 3 (FAD3) is an extraplastidial enzyme that converts linoleic acid (LA) to ALA. Phylogenetic analysis suggested that FAD3 proteins are distinct from FAD7 and FAD8 desaturases, which convert LA to ALA in plastids. Structural analysis of FAD3 proteins indicated a positive relationship between enzymatic activity and transmembrane pore length and width. An inverse relationship between temperature and ALA biosynthesis was also evident, with ALA accumulation decreasing with increasing temperature. These findings suggest that certain FAD3 enzymes are more effective at converting LA to ALA than others. This information could potentially be used to engineer crop plants with higher levels of ALA. 

Alternative polyadenylation (APA) is an important contributor to the regulation of gene expression in plants. One subunit of the complex that cleaves and polyadenylates mRNAs in the nucleus, CPSF30 (for the 30 kD subunit of the mammalian Cleavage and Polyadenylation Specificity Factor), has been implicated in a wide-ranging network of regulatory events. CPSF30 plays roles in root development, flowering time, and response to biotic and abiotic stresses. CPSF30 also is a conduit that links cellular signaling and RNA modification with alternative RNA processing events and transcriptional dynamics. While much is known about CPSF30 and its roles in plants, questions remain regarding the connections between CPSF30-mediated APA and the downstream events that lead to specific phenotypic outcomes. To address these, we conducted a detailed analysis of poly(A) site usage in the CPSF30 mutant. Our results corroborate earlier reports that link CPSF30 with a distinctive cis element (AAUAAA) that is present 10-30 nts upstream of some, but not all, plant pre-mRNAs. Interestingly, our results reveal a distinctive shift in poly(A) site in mutants deficient in CPSF30, resulting in cleavage and polyadenylation at the location of motifs similar to AAUAAA. Importantly, CPSF30-associated APA had at best a small impact on mRNA functionality. These results necessitate the formulation of new hypotheses for mechanisms by which CPSF30-mediated APA influences physiological processes. 

Abstract Previous reports indicate variable soybean quality parameters exported from different geographic regions. This review compares soybean and soybean co‐products grown under diverse environmental conditions. While numerous studies have been conducted on whole soybean and soybean meal (SBM) composition by origin, similar analysis of soybean oil is lacking. This review has two objectives: 1) summarize soybean and SBM quality by origin using a meta‐analysis approach, and 2) analyze collected crude degummed soybean oil samples that originate from the US, Brazil and Argentina for key quality attributes. Soybeans from Brazil have higher levels of protein (P < 0.05) than US soybeans, but US soybeans have lower heat damage (P < 0.05) and total damage (P < 0.05) than soybeans from Brazil. US and Brazil SBM have higher crude protein (CP) (P < 0.05) than SBM from Argentina. At equal CP content, US SBM had less fiber (P < 0.0001), more sucrose (P < 0.0001) and lysine (P < 0.0001) and better protein quality than South American SBMs. Methionine, threonine, and cysteine levels were similar in soybean protein from US and Argentina and higher than that in soybean protein from Brazil. Crude degummed soybean oil from Brazil had more (P < 0.05) free fatty acids, neutral oil loss, phosphorus, calcium and magnesium than crude degummed soybean oil from the US or Argentina. Our analysis suggests that environmental conditions under which soybeans are grown, stored, and handled can have a large impact on chemical composition and nutrient quality of soybean meal and soybean oil. 

Eukaryotic elongation factors (eEFs) are protein factors that mediate the extension of peptide chain, among which eukaryotic elongation factor 1 alpha (eEF1A) is one of the most abundant protein synthesis factors. Previously we showed that the P3 protein of Soybean mosaic virus (SMV), one of the most destructive and successful viral pathogens of soybean, targets a component of the soybean translation elongation complex to facilitate its pathogenesis. Here, we conducted a systematic analyses of the soybeaneEF(GmeEF) gene family in soybean and examinedits role in virus resistance. In this study, GmeEF family members were identified and characterized based on sequence analysis. The 42 members, which were unevenly distributed across the 15 chromosomes, were renamed according to their chromosomal locations. The GmeEF members were further divided into 12 subgroups based on conserved motif, gene structure, and phylogenetic analyses. Analysis of the promoter regions showed conspicuous presence of myelocytomatosis (MYC) and ethylene-responsive (ERE) cis-acting elements, which are typically involved in drought and phytohormone response, respectively, and thereby in plant stress response signaling. Transcriptome data showed that the expression of 15GmeEFgene family members changed significantly in response to SMV infection. To further examine EF1A function in pathogen response, three different Arabidopsis mutants carrying T-DNA insertions in orthologous genes were analyzed for their response to Turnip crinkle virus (TCV) and Cucumber mosaic virus (CMV). Results showed that there was no difference in viral response between the mutants and the wild type plants. This study provides a systematic analysis of theGmeEFgene family through analysis of expression patterns and predicted protein features. Our results lay a foundation for understanding the role ofeEFgene in soybean anti-viral response. 

Abstract Systemic acquired resistance (SAR), a type of long-distance immunity in plants, provides long-lasting resistance to a broad spectrum of pathogens. SAR is thought to involve the rapid generation and systemic transport of a mobile signal that prepares systemic parts of the plant to better resist future infections. Exploration of the molecular mechanisms underlying SAR have identified multiple mobile regulators of SAR in the last few decades. Examination of the relationship among several of these seemingly unrelated molecules depicts a forked pathway comprising at least two branches of equal importance to SAR. One branch is regulated by the plant hormone salicylic acid (SA), and the other culminates (based on current knowledge) with the phosphorylated sugar derivative, glycerol-3-phosphate (G3P). This review summarizes the activities that contribute to pathogen-responsive generation of SA and G3P and the components that regulate their systemic transport during SAR. 

Chloroplasts are key players in plant immune signaling, contributing to not only de novo synthesis of defensive phytohormones but also the generation of reactive oxygen and nitrogen species following activation of pattern recognition receptors or resistance (R) proteins. The local hypersensitive response (HR) elicited by R proteins is underpinned by chloroplast-generated reactive oxygen species. HR-induced lipid peroxidation generates important chloroplast-derived signaling lipids essential to the establishment of systemic immunity. As a consequence of this pivotal role in immunity, pathogens deploy effector complements that directly or indirectly target chloroplasts to attenuate chloroplast immunity (CI). Our review summarizes the current knowledge of CI signaling and highlights common pathogen chloroplast targets and virulence strategies. We address emerging insights into chloroplast retrograde signaling in immune responses and gaps in our knowledge, including the importance of understanding chloroplast heterogeneity and chloroplast involvement in intraorganellular interactions in host immunity. 

The plant cuticle is often considered a passive barrier from the environment. We show that the cuticle regulates active transport of the defense hormone salicylic acid (SA). SA, an important regulator of systemic acquired resistance (SAR), is preferentially transported from pathogen-infected to uninfected parts via the apoplast. Apoplastic accumulation of SA, which precedes its accumulation in the cytosol, is driven by the pH gradient and deprotonation of SA. In cuticle-defective mutants, increased transpiration and reduced water potential preferentially routes SA to cuticle wax rather than to the apoplast. This results in defective long-distance transport of SA, which in turn impairs distal accumulation of the SAR-inducer pipecolic acid. High humidity reduces transpiration to restore systemic SA transport and, thereby, SAR in cuticle-defective mutants. Together, our results demonstrate that long-distance mobility of SA is essential for SAR and that partitioning of SA between the symplast and cuticle is regulated by transpiration.