Regulation of maize growth and immunity by ZmSKI3-mediated RNA decay and post-transcriptional gene silencing.

Disease resistance is often associated with compromised plant growth and yield due to defense-growth tradeoffs. However, key components and mechanisms underlying the defense-growth tradeoffs are rarely explored in maize. In this study, we find that ZmSKI3, a putative subunit of the SUPERKILLER (SKI) complex that mediates the 3'-5' degradation of RNA, regulates both plant development and disease resistance in maize.

Spatial accumulation of lignin monomers and cellulose underlying stalk strength in maize.

Lodging largely affects yield, quality and mechanical harvesting of maize. Stalk strength is one of the major factors that affect maize lodging. Although plant cell wall components including lignin and cellulose were known to be associated with stalk strength and lodging resistance, spatial accumulation of specific lignin monomers and cellulose in different tissues and their association with stalk strength in maize was not clearly understood.

Copine proteins are required for brassinosteroid signaling in maize and Arabidopsis.

Copine proteins are highly conserved and ubiquitously found in eukaryotes, and their indispensable roles in different species were proposed. However, their exact function remains unclear. The phytohormone brassinosteroids (BRs) play vital roles in plant growth, development and environmental responses.

A genome-wide association study identifies genes associated with cuticular wax metabolism in maize.

The plant cuticle is essential in plant defense against biotic and abiotic stresses. To systematically elucidate the genetic architecture of maize (Zea mays L.) cuticular wax metabolism, 2 cuticular wax-related traits, the chlorophyll extraction rate (CER) and water loss rate (WLR) of 389 maize inbred lines, were investigated and a genome-wide association study (GWAS) was performed using 1.

Tissue-preferential recruitment of electron transfer chains for cytochrome P450-catalyzed phenolic biosynthesis.

Cytochrome P450 system consists of P450 monooxygenase and redox pattern(s). While the importance of monooxygenases in plant metabolism is well documented, the metabolic roles of the related redox components have been largely overlooked. Here, we show that distinct electron transfer chains are recruited in phenylpropanoid-monolignol P450 systems to support the synthesis and distribution of different classes of phenolics in different plant tissues.

Quantitative disease resistance: Multifaceted players in plant defense.

In contrast to large-effect qualitative disease resistance, quantitative disease resistance (QDR) exhibits partial and generally durable resistance and has been extensively utilized in crop breeding. The molecular mechanisms underlying QDR remain largely unknown but considerable progress has been made in this area in recent years. In this review, we summarize the genes that have been associated with plant QDR and their biological functions.

, a bHLH Transcriptional Regulator from , Improves Grain Yield, Shade and Osmotic Stress Tolerances in Common Wheat.

Common wheat, , is the most widely grown staple crop worldwide. To catch up with the increasing global population and cope with the changing climate, it is valuable to breed wheat cultivars that are tolerant to abiotic or shade stresses for density farming. LONG HYPOCOTYL IN FAR-RED 1 (AtHFR1), a photomorphogenesis-promoting factor, is involved in multiple light-related signaling pathways and inhibits seedling etiolation and shade avoidance.

Evolutionary characterization of miR396s in Poaceae exemplified by their genetic effects in wheat and maize.

MiR396s play important roles in regulating plant growth and stress response, and great potential for crop yield promotion was anticipated. For more comprehensive and precise understanding of miR396s in Poaceae, we analyzed the phylogenetic linkage, gene expression, and chromosomal distribution of miR396s in this study. Although the mature miR396s' sequences were mostly conserved, differential expression patterns and chromosomal distribution were found among Poaceae species including the major cereal crops rice, wheat, and maize.

Barley GRIK1-SnRK1 kinases subvert a viral virulence protein to upregulate antiviral RNAi and inhibit infection.

Viruses often usurp host machineries for their amplification, but it remains unclear if hosts may subvert virus proteins to regulate viral proliferation. Here, we show that the 17K protein, an important virulence factor conserved in barley yellow dwarf viruses (BYDVs) and related poleroviruses, is phosphorylated by host GRIK1-SnRK1 kinases, with the phosphorylated 17K (P17K) capable of enhancing the abundance of virus-derived small interfering RNAs (vsiRNAs) and thus antiviral RNAi. Furthermore, P17K interacts with barley small RNA-degrading nuclease 1 (HvSDN1) and impedes HvSDN1-catalyzed vsiRNA degradation.

Commonly and Specifically Activated Defense Responses in Maize Disease Lesion Mimic Mutants Revealed by Integrated Transcriptomics and Metabolomics Analysis.

Disease lesion mimic (/) mutants display disease-like spontaneous lesions in the absence of pathogen infection, implying the constitutive activation of defense responses. However, the genetic and biochemical bases underlying the activated defense responses in those mutants remain largely unknown. Here, we performed integrated transcriptomics and metabolomics analysis on three typical maize mutants , , and with large, medium, and small lesion size, respectively, thereby dissecting the activated defense responses at the transcriptional and metabolomic level.

A high-quality genome assembly highlights rye genomic characteristics and agronomically important genes.

Rye is a valuable food and forage crop, an important genetic resource for wheat and triticale improvement and an indispensable material for efficient comparative genomic studies in grasses. Here, we sequenced the genome of Weining rye, an elite Chinese rye variety. The assembled contigs (7.

Cytochrome Is an Obligate Electron Shuttle Protein for Syringyl Lignin Biosynthesis in Arabidopsis.

Angiosperms have evolved the metabolic capacity to synthesize -hydroxyphenyl, guaiacyl (G), and syringyl (S) lignin subunits in their cell walls to better adapt to the harsh terrestrial environment. The structural characteristics of lignin subunits are essentially determined by three cytochrome P450-catalzyed reactions. NADPH-dependent cytochrome P450 oxidoreductase (CPR) is commonly regarded as the electron carrier for P450-catalyzed reactions during monolignol biosynthesis.

The scaffold proteins of lignin biosynthetic cytochrome P450 enzymes.

Lignin is a complex and irregular biopolymer of crosslinked phenylpropanoid units in plant secondary cell walls. Its biosynthesis requires three endoplasmic reticulum (ER)-resident cytochrome P450 monooxygenases, C4H, C3'H and F5H, to establish the structural characteristics of its monomeric precursors. These P450 enzymes were reported to associate with each other or potentially with other soluble monolignol biosynthetic enzymes to form an enzyme complex or a metabolon.

Calcium Pumps and Interacting BON1 Protein Modulate Calcium Signature, Stomatal Closure, and Plant Immunity.

Calcium signaling is essential for environmental responses including immune responses. Here, we provide evidence that the evolutionarily conserved protein BONZAI1 (BON1) functions together with autoinhibited calcium ATPase10 (ACA10) and ACA8 to regulate calcium signals in Arabidopsis. BON1 is a plasma membrane localized protein that negatively regulates the expression of immune receptor genes and positively regulates stomatal closure.

Sumoylation E3 Ligase SIZ1 Modulates Plant Immunity Partly through the Immune Receptor Gene SNC1 in Arabidopsis.

The small ubiqutin-like modifier E3 ligase SIZ1 regulates multiple processes in Arabidopsis, including salicylic-acid-dependent immune responses. However, the targets of SIZ1 in plant immunity are not known. Here, we provide evidence that the plant immune receptor nucleotide-binding leucine-rich repeat gene SNC1 partially mediates the regulation of plant immunity by SIZ1.

The MYB107 Transcription Factor Positively Regulates Suberin Biosynthesis.

Suberin, a lipophilic polymer deposited in the outer integument of the Arabidopsis (Arabidopsis thaliana) seed coat, represents an essential sealing component controlling water and solute movement and protecting seed from pathogenic infection. Although many genes responsible for suberin synthesis are identified, the regulatory components controlling its biosynthesis have not been definitively determined. Here, we show that the Arabidopsis MYB107 transcription factor acts as a positive regulator controlling suberin biosynthetic gene expression in the seed coat.

Opposing Effects on Two Phases of Defense Responses from Concerted Actions of HEAT SHOCK COGNATE70 and BONZAI1 in Arabidopsis.

The plant immune system consists of multiple layers of responses targeting various phases of pathogen infection. Here, we provide evidence showing that two responses, one controlling stomatal closure and the other mediated by intracellular receptor proteins, can be regulated by the same proteins but in an antagonistic manner. The HEAT SHOCK COGNATE70 (HSC70), while previously known as a negative regulator of stomatal closure, is a positive regulator of immune responses mediated by the immune receptor protein SUPPRESSOR OF NPR1-1, CONSTITUTIVE1 (SNC1) as well as basal defense responses.

Down-regulation of Kelch domain-containing F-box protein in Arabidopsis enhances the production of (poly)phenols and tolerance to ultraviolet radiation.

Phenylpropanoid biosynthesis in plants engenders myriad phenolics with diverse biological functions. Phenylalanine ammonia-lyase (PAL) is the first committed enzyme in the pathway, directing primary metabolic flux into a phenylpropanoid branch. Previously, we demonstrated that the Arabidopsis (Arabidopsis thaliana) Kelch domain-containing F-box proteins, AtKFB01, AtKFB20, and AtKFB50, function as the negative regulators controlling phenylpropanoid biosynthesis via mediating PAL's ubiquitination and subsequent degradation.

Tailoring lignin biosynthesis for efficient and sustainable biofuel production.

Increased global interest in a bio-based economy has reinvigorated the research on the cell wall structure and composition in plants. In particular, the study of plant lignification has become a central focus, with respect to its intractability and negative impact on the utilization of the cell wall biomass for producing biofuels and bio-based chemicals. Striking progress has been achieved in the last few years both on our fundamental understanding of lignin biosynthesis, deposition and assembly, and on the interplay of lignin synthesis with the plant growth and development.

Arabidopsis ABCG14 protein controls the acropetal translocation of root-synthesized cytokinins.

Cytokinins are a major group of phytohormones regulating plant growth, development and stress responses. However, in contrast to the well-defined polar transport of auxins, the molecular basis of cytokinin transport is poorly understood. Here we show that an ATP-binding cassette transporter in Arabidopsis, AtABCG14, is essential for the acropetal (root to shoot) translocation of the root-synthesized cytokinins.

Arabidopsis Kelch repeat F-box proteins regulate phenylpropanoid biosynthesis via controlling the turnover of phenylalanine ammonia-lyase.

Phenylalanine ammonia-lyase (PAL) catalyzes the first rate-limiting step in the phenylpropanoid pathway, which controls carbon flux to a variety of bioactive small-molecule aromatic compounds, and to lignin, the structural component of the cell wall. PAL is regulated at both the transcriptional and translational levels. Our knowledge about the transcriptional regulation of PAL is relatively comprehensive, but our knowledge of the molecular basis of the posttranslational regulation of PAL remains limited.

Complex regulation of an R gene SNC1 revealed by auto-immune mutants.

Plants have evolved resistance (R) proteins to detect pathogen effectors and trigger plant defense responses in the so named effector-triggered immunity (ETI). R proteins are under negative regulation in plants as upregulated activation of R protein is detrimental to plant growth. Autoimmune mutants have been instrumental in understanding the fine tuning of plant defense responses.