Engineering homoeologs provide a fine scale for quantitative traits in polyploid.

Numerous staple crops exhibit polyploidy and are difficult to genetically modify. However, recent advances in genome sequencing and editing have enabled polyploid genome engineering. The hexaploid black nightshade species Solanum nigrum has immense potential as a beneficial food supplement. We assembled its genome at the scaffold level. After functional annotations, we identified homoeologous gene sets, with similar sequence and expression profiles, based on comparative analyses of orthologous genes with close diploid relatives Solanum americanum and S. lycopersicum. Using CRISPR-Cas9-mediated mutagenesis, we generated various mutation combinations in homoeologous genes. Multiple mutants showed quantitative phenotypic changes based on the genotype, resulting in a broad-spectrum effect on the quantitative traits of hexaploid S. nigrum. Furthermore, we successfully improved the fruit productivity of Boranong, an orphan cultivar of S. nigrum suggesting that engineering homoeologous genes could be useful for agricultural improvement of polyploid crops.

Co-transient expression of PSA-Fc and PAP-Fc fusion protein in plant as prostate cancer vaccine candidates and immune responses in mice.

KEY MESSAGE: PAP-FcK and PSA-FcK prostate cancer antigenic proteins transiently co-expressed in plant induce their specific humoral immune responses in mice. Prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) have been considered as immunotherapeutic antigens for prostate cancer. The use of a single antigenic agent is unlikely to be effective in eliciting immunotherapeutic responses due to the heterogeneous and multifocal nature of prostate cancer. Thus, multiple antigens have been combined to enhance their anti-cancer effects. In the current study, PSA and PAP were fused to the crystallizable region (Fc region) of immunoglobulin G1 and tagged with KDEL, the endoplasmic reticulum (ER) retention signal motif, to generate PSA-FcK and PAP-FcK, respectively, and were transiently co-expressed in Nicotiana benthamiana. Western blot analysis confirmed the co-expression of PSA-FcK and PAP-FcK (PSA-FcK + PAP-FcK) with a 1:3 ratios in the co-infiltrated plants. PSA-FcK, PAP-FcK, and PSA-FcK + PAP-FcK proteins were successfully purified from N. benthamiana by protein A affinity chromatography. ELISA showed that anti-PAP and anti-PSA antibodies successfully detected PAP-FcK and PSA-FcK, respectively, and both detected PSA-FcK + PAP-FcK. Surface plasmon resonance (SPR) analysis confirmed the binding affinity of the plant-derived Fc fusion proteins to FcγRI/CD64. Furthermore, we also confirmed that mice injected with PSA-FcK + PAP-FcK produced both PSA- and PAP-specific IgGs, demonstrating their immunogenicity. This study suggested that the transient plant expression system can be applied to produce the dual-antigen Fc fusion protein (PSA-FcK + PAP-FcK) for prostate cancer immunotherapy.

Role of a ZF-HD Transcription Factor in miR157-Mediated Feed-Forward Regulatory Module That Determines Plant Architecture in Arabidopsis.

In plants, vegetative and reproductive development are associated with agronomically important traits that contribute to grain yield and biomass. Zinc finger homeodomain (ZF-HD) transcription factors (TFs) constitute a relatively small gene family that has been studied in several model plants, including Arabidopsis thaliana L. and Oryza sativa L. The ZF-HD family members play important roles in plant growth and development, but their contribution to the regulation of plant architecture remains largely unknown due to their functional redundancy. To understand the gene regulatory network controlled by ZF-HD TFs, we analyzed multiple loss-of-function mutants of ZF-HD TFs in Arabidopsis that exhibited morphological abnormalities in branching and flowering architecture. We found that ZF-HD TFs, especially HB34, negatively regulate the expression of miR157 and positively regulate SQUAMOSA PROMOTER BINDING-LIKE 10 (SPL10), a target of miR157. Genome-wide chromatin immunoprecipitation sequencing (ChIP-Seq) analysis revealed that miR157D and SPL10 are direct targets of HB34, creating a feed-forward loop that constitutes a robust miRNA regulatory module. Network motif analysis contains overrepresented coherent type IV feedforward motifs in the amiR zf-HD and hbq mutant background. This finding indicates that miRNA-mediated ZF-HD feedforward modules modify branching and inflorescence architecture in Arabidopsis. Taken together, these findings reveal a guiding role of ZF-HD TFs in the regulatory network module and demonstrate its role in plant architecture in Arabidopsis.

Narrow lpa1 Metaxylems Enhance Drought Tolerance and Optimize Water Use for Grain Filling in Dwarf Rice.

Rice cultivation needs extensive amounts of water. Moreover, increased frequency of droughts and water scarcity has become a global concern for rice cultivation. Hence, optimization of water use is crucial for sustainable agriculture. Here, we characterized Loose Plant Architecture 1 (LPA1) in vasculature development, water transport, drought resistance, and grain yield. We performed genetic combination of lpa1 with semi-dwarf mutant to offer the optimum rice architecture for more efficient water use. LPA1 expressed in pre-vascular cells of leaf primordia regulates genes associated with carbohydrate metabolism and cell enlargement. Thus, it plays a role in metaxylem enlargement of the aerial organs. Narrow metaxylem of lpa1 exhibit leaves curling on sunny day and convey drought tolerance but reduce grain yield in mature plants. However, the genetic combination of lpa1 with semi-dwarf mutant (dep1-ko or d2) offer optimal water supply and drought resistance without impacting grain-filling rates. Our results show that water use, and transports can be genetically controlled by optimizing metaxylem vessel size and plant height, which may be utilized for enhancing drought tolerance and offers the potential solution to face the more frequent harsh climate condition in the future.

Current Advancements in the Molecular Mechanism of Plasma Treatment for Seed Germination and Plant Growth.

Low-temperature atmospheric pressure plasma has been used in various fields such as plasma medicine, agriculture, food safety and storage, and food manufacturing. In the field of plasma agriculture, plasma treatment improves seed germination, plant growth, and resistance to abiotic and biotic stresses, allows pesticide removal, and enhances biomass and yield. Currently, the complex molecular mechanisms of plasma treatment in plasma agriculture are fully unexplored, especially those related to seed germination and plant growth. Therefore, in this review, we have summarized the current progress in the application of the plasma treatment technique in plants, including plasma treatment methods, physical and chemical effects, and the molecular mechanism underlying the effects of low-temperature plasma treatment. Additionally, we have discussed the interactions between plasma and seed germination that occur through seed coat modification, reactive species, seed sterilization, heat, and UV radiation in correlation with molecular phenomena, including transcriptional and epigenetic regulation. This review aims to present the mechanisms underlying the effects of plasma treatment and to discuss the potential applications of plasma as a powerful tool, priming agent, elicitor or inducer, and disinfectant in the future.

The comparisons of expression pattern reveal molecular regulation of fruit metabolites in S. nigrum and S. lycopersicum.

Solanum nigrum, known as black nightshade, is a medicinal plant that contains many beneficial metabolites in its fruit. The molecular mechanisms underlying the synthesis of these metabolites remain uninvestigated due to limited genetic information. Here, we identified 47,470 unigenes of S. nigrum from three different tissues by de novo transcriptome assembly, and 78.4% of these genes were functionally annotated. Moreover, gene ontology (GO) analysis using 18,860 differentially expressed genes (DEGs) revealed tissue-specific gene expression regulation. We compared gene expression patterns between S. nigrum and tomato (S. lycopersicum) in three tissue types. The expression patterns of carotenoid biosynthetic genes were different between the two species. Comparison of the expression patterns of flavonoid biosynthetic genes showed that 9 out of 14 enzyme-coding genes were highly upregulated in the fruit of S. nigrum. Using CRISPR-Cas9-mediated gene editing, we knocked out the R2R3-MYB transcription factor SnAN2 gene, an ortholog of S. lycopersicum ANTHOCYANIN 2. The mutants showed yellow/green fruits, suggesting that SnAN2 plays a major role in anthocyanin synthesis in S. nigrum. This study revealed the connection between gene expression regulation and corresponding phenotypic differences through comparative analysis between two closely related species and provided genetic resources for S. nigrum.

Larkinella humicola sp. nov., a gamma radiation-resistant bacterium isolated from soil.

A Gram-negative, short rod-shaped, and pink-pigmented bacterial strain, designated MA1T, was isolated from a soil sample from Gijang-gun, Busan in Republic of Korea. The 16S rRNA gene sequence analysis showed that strain MA1T belonged to the genus Larkinella and was closely related to "Larkinella punicea" (97.5% similarity), Larkinella rosea 15J16-1T3AT (96.5%), and Larkinella knui 15J6-3T6T (96.2%). Polar lipid profile of strain MA1T contained phosphatidylethanolamine, two unidentified aminolipids, and three unidentified lipids. Menaquinone-7 was the only quinone and the main fatty acids were C16:1 ω5c (36.7%), iso-C15:0 (30.0%), iso-C17:0 3-OH (7.7%), and summed feature 3 (C16:1 ω6c and/or C16:1 ω7c and/or iso-C15:0 2-OH) (7.3%). The genomic DNA G + C content was 52.3 mol% based on the whole-genome analysis. Strain MA1T exhibited a relatively low level of ANI and in silico DDH values with "Larkinella punicea" (91.9 and 47.1%, respectively), Larkinella rosea (79.7 and 23.3%), and Larkinella knui (81.9 and 25.7%). Based on its phenotypic properties and phylogenetic distinctiveness, strain MA1T should be classified in the genus Larkinella as a representative of a novel species, for which the name Larkinella humicola sp. nov. is proposed. The type strain is MA1T (= KCTC 72629T = NBRC 114191T).

Hymenobacter telluris sp. nov., isolated from soil in South Korea.

Two novel bacterial strains, designated as BT186T and BT505, were isolated from a soil sample collected in South Korea and characterized. Both strains were Gram-stain-negative, rod-shaped, aerobic, circular, convex, and had red-colored colonies. The level of 16S rRNA gene sequence similarity between the strains BT186T and BT505 was 100%, indicating that they represent an identical species. 16S rRNA sequence analysis indicated that strains BT186T and BT505 belong to a distinct lineage within the genus Hymenobacter (family Hymenobacteraceae, order Cytophagales, class Cytophagia, phylum Bacteroidetes, Kingdom Bacteria). Both strains were closely related to Hymenobacter norwichensis DSM 15439T (98.3% 16S rRNA gene similarity), Hymenobacter aquaticus JCM 31653T (96.8%), and Hymenobacter perfusus LMG26000T (96.5%). Strain BT186T was found to have the MK-7 as the major respiratory quinone. The major polar lipid of strain BT186T was identified to be phosphatidylethanolamine (PE). The major cellular fatty acid profiles of strain BT186T were C16:1 ω5c (24.3%), iso-C15:0 (20.3%) and summed feature 3 (C16:1 ω6c/C16:1 ω7c) (19.9%). Characterization based on polyphasic analysis indicated that strains BT186T and BT505 represent novel species of the genus Hymenobacter and the name Hymenobacter telluris sp. nov. is proposed. The type strain of Hymenobacter telluris is BT186T (= KCTC 72338T = NBRC 114968T).

Effect of an Endoplasmic Reticulum Retention Signal Tagged to Human Anti-Rabies mAb SO57 on Its Expression in Arabidopsis and Plant Growth.

Transgenic Arabidopsis thaliana expressing an anti-rabies monoclonal antibody (mAb), SO57, was obtained using Agrobacterium-mediated floral dip transformation. The endoplasmic reticulum (ER) retention signal Lys-Asp-Glu-Leu (KDEL) was tagged to the C-terminus of the anti-rabies mAb heavy chain to localize the mAb to the ER and enhance its accumulation. When the inaccurately folded proteins accumulated in the ER exceed its storage capacity, it results in stress that can affect plant development and growth. We generated T1 transformants and obtained homozygous T3 seeds from transgenic Arabidopsis to investigate the effect of KDEL on plant growth. The germination rate did not significantly differ between plants expressing mAb SO57 without KDEL (SO plant) and mAb SO57 with KDEL (SOK plant). The primary roots of SOK agar media grown plants were slightly shorter than those of SO plants. Transcriptomic analysis showed that expression of all 11 ER stress-related genes were not significantly changed in SOK plants relative to SO plants. SOK plants showed approximately three-fold higher mAb expression levels than those of SO plants. Consequently, the purified mAb amount per unit of SOK plant biomass was approximately three times higher than that of SO plants. A neutralization assay revealed that both plants exhibited efficient rapid fluorescent focus inhibition test values against the rabies virus relative to commercially available human rabies immunoglobulins. KDEL did not upregulate ER stress-related genes; therefore, the enhanced production of the mAb did not affect plant growth. Thus, KDEL fusion is recommended for enhancing mAb production in plant systems.

Noviherbaspirillum galbum sp. nov., a bacterium isolated from soil.

A Gram-stain-negative, aerobic, non-motile and yellow-colored bacterium, strain 17J57-3 T, was isolated from soil collected in Pyeongchang city, Korea. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain 17J57-3 T formed a distinct lineage within the family Oxalobacteraceae (order Burkholderiales, class Betaproteobacteria). Strain 17J57-3 T was the most closely related to Noviherbaspirillum humi U15T (96.4% 16S rRNA gene sequence similarity) and Noviherbaspirillum massiliense JC206T (96.2%). The draft genome size of strain 17J57-3 T was 6,117,206 bp. Optimal growth occurred at 30 °C, pH 7.0 without NaCl. The predominant cellular fatty acids were summed feature 3 (C16:1 ω6c/C16:1 ω7c) and C16:0. The major respiratory quinone was Q-8. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Biochemical, chemotaxonomic and phylogenetic analyses indicated that strain 17J57-3 T represents a novel bacterial species within the genus Noviherbaspirillum, for which the name Noviherbaspirillum galbum is proposed. The type strain of Noviherbaspirillum galbum is 17J57-3 T (= KCTC 62213 T = NBRC 114384 T).

Fertility of Pedicellate Spikelets in Sorghum Is Controlled by a Jasmonic Acid Regulatory Module.

As in other cereal crops, the panicles of sorghum (Sorghum bicolor (L.) Moench) comprise two types of floral spikelets (grass flowers). Only sessile spikelets (SSs) are capable of producing viable grains, whereas pedicellate spikelets (PSs) cease development after initiation and eventually abort. Consequently, grain number per panicle (GNP) is lower than the total number of flowers produced per panicle. The mechanism underlying this differential fertility is not well understood. To investigate this issue, we isolated a series of ethyl methane sulfonate (EMS)-induced multiseeded (msd) mutants that result in full spikelet fertility, effectively doubling GNP. Previously, we showed that MSD1 is a TCP (Teosinte branched/Cycloidea/PCF) transcription factor that regulates jasmonic acid (JA) biosynthesis, and ultimately floral sex organ development. Here, we show that MSD2 encodes a lipoxygenase (LOX) that catalyzes the first committed step of JA biosynthesis. Further, we demonstrate that MSD1 binds to the promoters of MSD2 and other JA pathway genes. Together, these results show that a JA-induced module regulates sorghum panicle development and spikelet fertility. The findings advance our understanding of inflorescence development and could lead to new strategies for increasing GNP and grain yield in sorghum and other cereal crops.

Identification of Differentially Up-regulated Genes in Apple with White Rot Disease.

Fuji, a major apple cultivar in Korea, is susceptible to white rot. Apple white rot disease appears on the stem and fruit; the development of which deteriorates fruit quality, resulting in decreases in farmers' income. Thus, it is necessary to characterize molecular markers related to apple white rot resistance. In this study, we screened for differentially expressed genes between uninfected apple fruits and those infected with Botryosphaeria dothidea, the fungal pathogen that causes white rot. Antimicrobial tests suggest that a gene expression involved in the synthesis of the substance inhibiting the growth of B. dothidea in apples was induced by pathogen infection. We identified seven transcripts induced by the infection. The seven transcripts were homologous to genes encoding a flavonoid glucosyltransferase, a metallothionein-like protein, a senescence-induced protein, a chitinase, a wound-induced protein, and proteins of unknown function. These genes have functions related to responses to environmental stresses, including pathogen infections. Our results can be useful for the development of molecular markers for early detection of the disease or for use in breeding white rotresistant cultivars.

Endoplasmic reticulum retention motif fused to recombinant anti-cancer monoclonal antibody (mAb) CO17-1A affects mAb expression and plant stress response.

The endoplasmic reticulum (ER) is the main site of protein synthesis, folding, and secretion to other organelles. The capacity of the ER to process proteins is limited, and excessive accumulation of unfolded and misfolded proteins can induce ER stress, which is associated with plant diseases. Here, a transgenic Arabidopsis system was established to express anti-cancer monoclonal antibodies (mAbs) that recognize the tumor-associated antigen GA733-2. Monoclonal antibody (mAb) CO17-1A recognize a tumor-associated epitope expressed on the colorectal cancer cell surface. The ER retention Lys-Asp-Glu-Leu (KDEL) motif sequence was added to the C-terminus of the heavy chain to retain anti-colorectal cancer mAbs in the ER, consequently boosting mAb production. Agrobacterium-mediated floral dip transformation was used to generate T1 transformants, and homozygous T4 seeds obtained from transgenic Arabidopsis plants expressing anti-colorectal cancer mAbs were used to confirm the physiological effects of KDEL tagging. Germination rates were not significantly different between both plants expressing mAb CO without KDEL mAb CO (CO plant) and mAb CO with KDEL mAb COK (COK plant). However, COK plants primary root lengths were shorter than those of CO plants and non-transgenic Arabidopsis plants in in vitro media. Most ER stress-related genes, with the exception of bZIP28 and IRE1a, were upregulated in COK plants compared to CO plants. Western blot and SDS-PAGE analyses showed that COK plants exhibited up to five times higher expression and mAb amounts than plants. Enhanced expression in mAb COK plants was confirmed by immunohistochemical analyses. mAb COK was distributed across most of the area of leaf tissues, whereas mAb CO was mainly distributed in extracellular areas. Surface plasmon resonance analyses revealed that mAb CO and mAb COK possessed equivalent or slightly better binding activities to antigen EpCAM compared to a commercially available parental antibody. N-glycosylation analysis showed that mAb CO had plant specific residues whereas mAb COK mainly showed an oligo-mannose N-glycan structure without the plant specific glycan residues. In this study, the reduction of plant growth and biomass induced by ER retention signal peptide might be only in in vitro conditions, and thus should be carefully considered for the initial screening for transgenic lines on culture media. Taken together, nevertheless the fusion of ER retention signal peptide is an effective approach for enhancing the yields of recombinant proteins in vivo.

Functional conservation of Arabidopsis LNG1 in tobacco relating to leaf shape change by increasing longitudinal cell elongation by overexpression.

The LONGIFOLIA1 (LNG1) gene of Arabidopsis regulates leaf shape by polar cell elongation independent of ROTUNDAFOLIA3 (ROT3). To expand our knowledge on the function of this gens in plant systems, Arabidopsis LNG1 (AtLNG1) was introduced both sense and antisense orientation under the control of 35S CaMV promoter into tobacco plants that lack AtLNG1 homolog. Resulting transgenic tobacco plants were analyzed by their phenotype, anatomy and transcript levels. AtLNG1-overexpressing tobacco lines showed increase in the leaf petiole and leaf blade compared with wild type tobacco line. The overexpressors also showed elongated palisade cells as well as epidermal cells in the leaf length direction, but no increase in cell number. Ectopic expression of AtLNG1 in tobacco plants also increased the expression of cell wall modification-related genes, such as NT_XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE9 (NT_XTH9), NT_XTH15 and NT_XTH33, indicating that these genes appear to be target of AtLNG1. As results of molecular and cellular examination, AtLNG1 seemed to have a conserved functional role in shaping leaf morphology in both Arabidopsis and tobacco.

Functionally redundant LNG3 and LNG4 genes regulate turgor-driven polar cell elongation through activation of XTH17 and XTH24.

KEY MESSAGE: In this work, we genetically characterized the function of Arabidopsis thaliana, LONGIFOLIA (LNG1), LNG2, LNG3, LNG4, their contribution to regulate vegetative architecture in plant. We used molecular and biophysical approaches to elucidate a gene function that regulates vegetative architecture, as revealed by the leaf phenotype and later effects on flowering patterns in Arabidopsis loss-of-function mutants. As a result, LNG genes play an important role in polar cell elongation by turgor pressure controlling the activation of XTH17 and XTH24. Plant vegetative architecture is related to important traits that later influence the floral architecture involved in seed production. Leaf morphology is the primary key trait to compose plant vegetative architecture. However, molecular mechanism on leaf shape determination is not fully understood even in the model plant A. thaliana. We previously showed that LONGIFOLIA (LNG1) and LONGIFOLIA2 (LNG2) genes regulate leaf morphology by promoting longitudinal cell elongation in Arabidopsis. In this study, we further characterized two homologs of LNG1, LNG3, and LNG4, using genetic, biophysical, and molecular approaches. Single loss-of-function mutants, lng3 and lng4, do not show any phenotypic difference, but mutants of lng quadruple (lngq), and lng1/2/3 and lng1/2/4 triples, display reduced leaf length, compared to wild type. Using the paradermal analysis, we conclude that the reduced leaf size of lngq is due to decreased cell elongation in the direction of longitudinal leaf growth, and not decreased cell proliferation. This data indicate that LNG1/2/3/4 are functionally redundant, and are involved in polar cell elongation in Arabidopsis leaf. Using a biophysical approach, we show that the LNGs contribute to maintain high turgor pressure, thus regulating turgor pressure-dependent polar cell elongation. In addition, gene expression analysis showed that LNGs positively regulate the expression of the cell wall modifying enzyme encoded by a multi-gene family, xyloglucan endotransglucosylase/hydrolase (XTH). Taking all of these together, we propose that LNG related genes play an important role in polar cell elongation by changing turgor pressure and controlling the activation of XTH17 and XTH24.

MSD1 regulates pedicellate spikelet fertility in sorghum through the jasmonic acid pathway.

Grain number per panicle (GNP) is a major determinant of grain yield in cereals. However, the mechanisms that regulate GNP remain unclear. To address this issue, we isolate a series of sorghum [Sorghum bicolor (L.) Moench] multiseeded (msd) mutants that can double GNP by increasing panicle size and altering floral development so that all spikelets are fertile and set grain. Through bulk segregant analysis by next-generation sequencing, we identify MSD1 as a TCP (Teosinte branched/Cycloidea/PCF) transcription factor. Whole-genome expression profiling reveals that jasmonic acid (JA) biosynthetic enzymes are transiently activated in pedicellate spikelets. Young msd1 panicles have 50% less JA than wild-type (WT) panicles, and application of exogenous JA can rescue the msd1 phenotype. Our results reveal a new mechanism for increasing GNP, with the potential to boost grain yield, and provide insight into the regulation of plant inflorescence architecture and development.

Gramene 2018: unifying comparative genomics and pathway resources for plant research.

Gramene (http://www.gramene.org) is a knowledgebase for comparative functional analysis in major crops and model plant species. The current release, #54, includes over 1.7 million genes from 44 reference genomes, most of which were organized into 62,367 gene families through orthologous and paralogous gene classification, whole-genome alignments, and synteny. Additional gene annotations include ontology-based protein structure and function; genetic, epigenetic, and phenotypic diversity; and pathway associations. Gramene's Plant Reactome provides a knowledgebase of cellular-level plant pathway networks. Specifically, it uses curated rice reference pathways to derive pathway projections for an additional 66 species based on gene orthology, and facilitates display of gene expression, gene-gene interactions, and user-defined omics data in the context of these pathways. As a community portal, Gramene integrates best-of-class software and infrastructure components including the Ensembl genome browser, Reactome pathway browser, and Expression Atlas widgets, and undergoes periodic data and software upgrades. Via powerful, intuitive search interfaces, users can easily query across various portals and interactively analyze search results by clicking on diverse features such as genomic context, highly augmented gene trees, gene expression anatomograms, associated pathways, and external informatics resources. All data in Gramene are accessible through both visual and programmatic interfaces.

Signaling from maize organ primordia via FASCIATED EAR3 regulates stem cell proliferation and yield traits.

Shoot apical meristems are stem cell niches that balance proliferation with the incorporation of daughter cells into organ primordia. This balance is maintained by CLAVATA-WUSCHEL feedback signaling between the stem cells at the tip of the meristem and the underlying organizing center. Signals that provide feedback from organ primordia to control the stem cell niche in plants have also been hypothesized, but their identities are unknown. Here we report FASCIATED EAR3 (FEA3), a leucine-rich-repeat receptor that functions in stem cell control and responds to a CLAVATA3/ESR-related (CLE) peptide expressed in organ primordia. We modeled our results to propose a regulatory system that transmits signals from differentiating cells in organ primordia back to the stem cell niche and that appears to function broadly in the plant kingdom. Furthermore, we demonstrate an application of this new signaling feedback, by showing that weak alleles of fea3 enhance hybrid maize yield traits.

Sugar and acid content of Citrus prediction modeling using FT-IR fingerprinting in combination with multivariate statistical analysis.

A high-throughput screening system for Citrus lines were established with higher sugar and acid contents using Fourier transform infrared (FT-IR) spectroscopy in combination with multivariate analysis. FT-IR spectra confirmed typical spectral differences between the frequency regions of 950-1100 cm(-1), 1300-1500 cm(-1), and 1500-1700 cm(-1). Principal component analysis (PCA) and subsequent partial least square-discriminant analysis (PLS-DA) were able to discriminate five Citrus lines into three separate clusters corresponding to their taxonomic relationships. The quantitative predictive modeling of sugar and acid contents from Citrus fruits was established using partial least square regression algorithms from FT-IR spectra. The regression coefficients (R(2)) between predicted values and estimated sugar and acid content values were 0.99. These results demonstrate that by using FT-IR spectra and applying quantitative prediction modeling to Citrus sugar and acid contents, excellent Citrus lines can be early detected with greater accuracy.

Gramene Database: Navigating Plant Comparative Genomics Resources.

Gramene (http://www.gramene.org) is an online, open source, curated resource for plant comparative genomics and pathway analysis designed to support researchers working in plant genomics, breeding, evolutionary biology, system biology, and metabolic engineering. It exploits phylogenetic relationships to enrich the annotation of genomic data and provides tools to perform powerful comparative analyses across a wide spectrum of plant species. It consists of an integrated portal for querying, visualizing and analyzing data for 44 plant reference genomes, genetic variation data sets for 12 species, expression data for 16 species, curated rice pathways and orthology-based pathway projections for 66 plant species including various crops. Here we briefly describe the functions and uses of the Gramene database.