A sucrose ferulate cycle linchpin for ferulyolation of arabinoxylans in plant commelinids.

A transformation in plant cell wall evolution marked the emergence of grasses, grains and related species that now cover much of the globe. Their tough, less digestible cell walls arose from a new pattern of cross-linking between arabinoxylan polymers with distinctive ferulic acid residues. Despite extensive study, the biochemical mechanism of ferulic acid incorporation into cell walls remains unknown.

Independent evolution of transposase and TIRs facilitated by recombination between transposons from divergent clades in maize.

Nearly all eukaryotes carry DNA transposons of the Robertson's () superfamily, a widespread source of genome instability and genetic variation. Despite their pervasive impact on host genomes, much remains unknown about the evolution of these transposons. Transposase recognition of terminal inverted repeats (TIRs) is thought to drive and constrain coevolution of transposase genes and TIRs.

Maize domestication phenotypes reveal strigolactone networks coordinating grain size evolution with kernel-bearing cupule architecture.

The maize (Zea mays) ear represents one of the most striking domestication phenotypes in any crop species, with the cob conferring an exceptional yield advantage over the ancestral form of teosinte. Remodeling of the grain-bearing surface required profound developmental changes. However, the underlying mechanisms remain unclear and can only be partly attributed to the known domestication gene Teosinte glume architecture 1 (Tga1).

The sugar transporter ZmSUGCAR1 of the nitrate transporter 1/peptide transporter family is critical for maize grain filling.

Maternal-to-filial nutrition transfer is central to grain development and yield. nitrate transporter 1/peptide transporter (NRT1-PTR)-type transporters typically transport nitrate, peptides, and ions. Here, we report the identification of a maize (Zea mays) NRT1-PTR-type transporter that transports sucrose and glucose.

A Core Metabolome Response of Maize Leaves Subjected to Long-Duration Abiotic Stresses.

Abiotic stresses reduce crop growth and yield in part by disrupting metabolic homeostasis and triggering responses that change the metabolome. Experiments designed to understand the mechanisms underlying these metabolomic responses have usually not used agriculturally relevant stress regimes. We therefore subjected maize plants to drought, salt, or heat stresses that mimic field conditions and analyzed leaf responses at metabolome and transcriptome levels.

The Moderately (D)efficient Enzyme: Catalysis-Related Damage and Its Repair.

Enzymes have life spans. Analysis of life spans, i.e.

The SUMO ligase MMS21 profoundly influences maize development through its impact on genome activity and stability.

The post-translational addition of SUMO plays essential roles in numerous eukaryotic processes including cell division, transcription, chromatin organization, DNA repair, and stress defense through its selective conjugation to numerous targets. One prominent plant SUMO ligase is METHYL METHANESULFONATE-SENSITIVE (MMS)-21/HIGH-PLOIDY (HPY)-2/NON-SMC-ELEMENT (NSE)-2, which has been connected genetically to development and endoreduplication. Here, we describe the potential functions of MMS21 through a collection of UniformMu and CRISPR/Cas9 mutants in maize (Zea mays) that display either seed lethality or substantially compromised pollen germination and seed/vegetative development.

The Mutation of Arabidopsis Highlights How the Thiamin Economy Impacts the Methylerythritol 4-Phosphate Pathway.

The thiamin-requiring mutants of Arabidopsis have a storied history as a foundational model for biochemical genetics in plants and have illuminated the central role of thiamin in metabolism. Recent integrative genetic and biochemical analyses of thiamin biosynthesis and utilization imply that leaf metabolism normally operates close to thiamin-limiting conditions. Thus, the mechanisms that allocate thiamin-diphosphate (ThDP) cofactor among the diverse thiamin-dependent enzymes localized in plastids, mitochondria, peroxisomes, and the cytosol comprise an intricate thiamin economy.

Chromosome-level genome assembly of a regenerable maize inbred line A188.

Background: The maize inbred line A188 is an attractive model for elucidation of gene function and improvement due to its high embryogenic capacity and many contrasting traits to the first maize reference genome, B73, and other elite lines. The lack of a genome assembly of A188 limits its use as a model for functional studies.

Results: Here, we present a chromosome-level genome assembly of A188 using long reads and optical maps.

Structural variation affecting DNA backbone interactions underlies adaptation of B3 DNA binding domains to constraints imposed by protein architecture.

Functional and architectural diversification of transcription factor families has played a central role in the independent evolution of complex development in plants and animals. Here, we investigate the role of architectural constraints on evolution of B3 DNA binding domains that regulate plant embryogenesis. B3 domains of ABI3, FUS3, LEC2 and VAL1 proteins recognize the same cis-element.

The number of catalytic cycles in an enzyme's lifetime and why it matters to metabolic engineering.

Metabolic engineering uses enzymes as parts to build biosystems for specified tasks. Although a part's working life and failure modes are key engineering performance indicators, this is not yet so in metabolic engineering because it is not known how long enzymes remain functional in vivo or whether cumulative deterioration (wear-out), sudden random failure, or other causes drive replacement. Consequently, enzymes cannot be engineered to extend life and cut the high energy costs of replacement.

Emb15 encodes a plastid ribosomal assembly factor essential for embryogenesis in maize.

Ribosome assembly factors guide the complex process by which ribosomal proteins and the ribosomal RNAs form a functional ribosome. However, the assembly of plant plastid ribosomes is poorly understood. In the present study, we discovered a maize (Zea mays) plastid ribosome assembly factor based on our characterization of the embryo defective 15 (emb15) mutant.

: A Sequence-Indexed Resource of Transposon-Induced Maize Mutations for Functional Genomics Studies.

Sequence-indexed insertional libraries in maize () are fundamental resources for functional genetics studies. Here, we constructed a () insertional library in the B73 inbred background designated A total of 1,152 -tagged F-families were sequenced using the -seq approach. We detected 225,936 genomic insertion sites and 41,086 high quality germinal insertions covering 16,392 of the annotated maize genes (37% of the B73v4 genome).

Transposable elements employ distinct integration strategies with respect to transcriptional landscapes in eukaryotic genomes.

Transposable elements (TEs) are ubiquitous DNA segments capable of moving from one site to another within host genomes. The extant distributions of TEs in eukaryotic genomes have been shaped by both bona fide TE integration preferences in eukaryotic genomes and by selection following integration. Here, we compare TE target site distribution in host genomes using multiple de novo transposon insertion datasets in both plants and animals and compare them in the context of genome-wide transcriptional landscapes.

Construction and applications of a B vitamin genetic resource for investigation of vitamin-dependent metabolism in maize.

The B vitamins provide essential co-factors for central metabolism in all organisms. In plants, B vitamins have surprising emerging roles in development, stress tolerance and pathogen resistance. Hence, there is a paramount interest in understanding the regulation of vitamin biosynthesis as well as the consequences of vitamin deficiency in crop species.

Rethinking the PDH Bypass and GABA Shunt as Thiamin-Deficiency Workarounds.

The PDH bypass and the GABA shunt serve to maintain mainline metabolic fluxes during episodes of organellar thiamin diphosphate deficiency.

Maize is a bacterial TamB homologue required for chloroplast envelope biogenesis.

Chloroplasts are of prokaryotic origin with a double-membrane envelope separating plastid metabolism from the cytosol. Envelope membrane proteins integrate chloroplasts with the cell, but envelope biogenesis mechanisms remain elusive. We show that maize () is critical for envelope biogenesis.

Effects of long-term exposure to elevated temperature on Zea mays endosperm development during grain fill.

Cereal yields decrease when grain fill proceeds under conditions of prolonged, moderately elevated temperatures. Endosperm-endogenous processes alter both rate and duration of dry weight gain, but underlying mechanisms remain unclear. Heat effects could be mediated by either abnormal, premature cessation of storage compound deposition or accelerated implementation of normal development.

The maize W22 genome provides a foundation for functional genomics and transposon biology.

The maize W22 inbred has served as a platform for maize genetics since the mid twentieth century. To streamline maize genome analyses, we have sequenced and de novo assembled a W22 reference genome using short-read sequencing technologies. We show that significant structural heterogeneity exists in comparison to the B73 reference genome at multiple scales, from transposon composition and copy number variation to single-nucleotide polymorphisms.

Autonomous and non-autonomous functions of the maize Shohai1 gene, encoding a RWP-RK putative transcription factor, in regulation of embryo and endosperm development.

In plants, establishment of the basic body plan during embryogenesis involves complex processes of axis formation, cell fate specification and organ differentiation. While molecular mechanisms of embryogenesis have been well studied in the eudicot Arabidopsis, only a small number of genes regulating embryogenesis has been identified in grass species. Here, we show that a RKD-type RWP-RK transcription factor encoded by Shohai1 (Shai1) is indispensable for embryo and endosperm development in maize.

Identification of a metabolic disposal route for the oncometabolite -(2-succino)cysteine in .

Cellular thiols such as cysteine spontaneously and readily react with the respiratory intermediate fumarate, resulting in the formation of stable -(2-succino)-adducts. Fumarate-mediated succination of thiols increases in certain tumors and in response to glucotoxicity associated with diabetes. Therefore, -(2-succino)-adducts such as -(2-succino)cysteine (2SC) are considered oncometabolites and biomarkers for human disease.

Corrigendum: Divisions of labor in the thiamin biosynthetic pathway among organs of maize.

[This corrects the article on p. 370 in vol. 5, PMID: 25136345.

A plastidial pantoate transporter with a potential role in pantothenate synthesis.

The pantothenate (vitamin B) synthesis pathway in plants is not fully defined because the subcellular site of its ketopantoate → pantoate reduction step is unclear. However, the pathway is known to be split between cytosol, mitochondria, and potentially plastids, and inferred to involve mitochondrial or plastidial transport of ketopantoate or pantoate. No proteins that mediate these transport steps have been identified.

Mutations Recovered in Transposon-Active Lines of S Male-Sterile Maize.

Mitochondria execute key pathways of central metabolism and serve as cellular sensing and signaling entities, functions that depend upon interactions between mitochondrial and nuclear genetic systems. This is exemplified in cytoplasmic male sterility type S (CMS-S) of , where novel mitochondrial open reading frames are associated with a pollen collapse phenotype, but nuclear (restorer) mutations rescue pollen function. To better understand these genetic interactions, we screened (), (), and () transposon-active CMS-S stocks to recover new restorer mutants.