Oral administration of Bifidobacterium longum WHH2270 ameliorates type 2 diabetes in rats.

Accumulating evidence suggests that specific probiotic strains exert hypoglycemic effects on type 2 diabetes mellitus (T2DM), and probiotic strains within Bifidobacterium exhibit potential beneficial effects on T2DM. In this study, α-glucosidase inhibitory activities of 14 Bifidobacterium strains were assessed in vitro. The hypoglycemic effects of Bifidobacterium longum WHH2270 with high α-glucosidase inhibitory activity (42.03%) were then investigated in a high-fat diet/streptozotocin-induced T2DM rat model. Oral administration of WHH2270 (4 × 109 CFU/kg/day) for 8 weeks significantly reversed the reduced body weight and ameliorated the levels of fasting blood glucose, serum triglyceride, serum total cholesterol, glucose tolerance, and insulin resistance in T2DM rats. Using 16S rRNA high-throughput sequencing of feces, WHH2270 was revealed to reshape the gut microbiome composition by increasing the abundances of Lactobacillus and Bifidobacterium and decreasing the abundances of UCG_005, Clostridium, and Faecalibacterium in T2DM rats. Besides, the fecal levels of short-chain fatty acids (SCFAs) including acetate, propionate, and butyrate were also elevated after WHH2270 administration. Moreover, the gene expressions of SCFA receptors FFAR2 and FFAR3 in the colon and pancreas of T2DM rats were restored by WHH2270 administration, accompanied by increased levels of serum acetate. In summary, these results provide evidence that WHH2270 has the potential to improve T2DM symptoms by alleviating hyperglycemia, which was associated with changes in the gut microbiome composition and SCFA production. PRACTICAL APPLICATION: Bifidobacterium longum WHH2270 with high α-glucosidase inhibitory activity may serve as a promising hypoglycemic agent for the treatment of T2DM.

Development and Application of Portable Reflectometric Spectroscopy Combined with Solid-Phase Extraction for Determination of Potassium in Flue-Cured Tobacco Leaves.

Potassium (K) plays important roles in the energy and substance conversion of tobacco metabolism and is also regarded as one of the important indicators of tobacco quality evaluation. However, the K quantitative analytical method shows poor performance in terms of being easy-to-use, cost-effective, and portable. Here, we developed a rapid and simple method for the determination of K content in flue-cured tobacco leaves, including water extraction with 100 °C heating, purification with solid-phase extraction (SPE), and analysis with portable reflectometric spectroscopy based on K test strips. The method development consisted of optimization of the extraction and test strip reaction conditions, screening of SPE sorbent materials, and evaluation of the matrix effect. Under the optimum conditions, good linearity was observed in 0.20-0.90 mg/mL with a correlation coefficient >0.999. The extraction recoveries were found to be in the range of 98.0-99.5% with a repeatability and reproducibility of 1.15-1.98% and 2.04-3.26%, respectively. The sample measured range was calculated to be 0.76-3.68% K. Excellent agreement was found in accuracy between the developed reflectometric spectroscopy method and the standard method. The developed method was applied to analyze the K content in different cultivars, and the content varied greatly among the samples with lowest and highest contents for Y28 and Guiyan 5 cultivars, respectively. This study can provide a reliable approach for K analysis, which may become available on-site in a quick on-farm test.

Author Correction: Evolutionary and expression analysis of CAMTA gene family in Nicotiana tabacum yielded insights into their origin, expansion and stress responses.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Molecular breeding approaches for production of disease-resilient commercially important tobacco.

Tobacco is one of the most widely cultivated nonfood cash crops, a source of income, model organism for plant molecular research, a natural pesticide and of pharmaceutical importance. First domesticated in South Americas, the modern-day tobacco (Nicotiana tabacum) is now cultivated in more than 125 countries to generate revenues worth billions of dollars each year. However, the production of this crop is highly threatened by the global presence of devastating infectious agents, which cause huge fiscal loss. These threats have been battled through breeding for acquiring disease resilience in tobacco plants, first, via conventional and now with the use of modern molecular breeding approaches. For efficacy and precision, the characterization of the genetic components underlying disease resistance is the key tool in tobacco for resistance breeding programs. The past few decades have witnessed significant progress in resilience breeding through advanced molecular techniques. The current review discusses history of tobacco breeding since its time of origin till date, highlighting the most widely used techniques and recent advances in molecular research and strategies for resistance breeding. In addition, we narrate the budding possibilities for the future. This review will provide a comprehensive and valuable information for the tobacco growers and researchers to deal with the destructive infectious diseases.

Systematic study of the stress-responsive Rboh gene family in Nicotiana tabacum: Genome-wide identification, evolution and role in disease resistance.

Plant respiratory burst oxidase homolog (Rboh) gene family encodes the key enzymatic subunits of reactive oxygen species (ROS) production pathways, and play crucial role in plant signaling, development and stress responses. In present work, twenty genes were identified in Nicotiana tabacum Rboh family (NtabRboh) and classified into four phylogenetic groups (I-IV). Fourteen NtabRboh genes were positioned on ten chromosomes (i.e., Ch1, 2, 4, 7-11, 14 and 21), and six scaffolds. Synteny and evolutionary analysis showed that most of the NtabRboh genes have evolved from the genomes of the ancestor species (N. tomentosiformis and N. sylvestris), which afterwards expanded through duplication events. The promoter regions of the NtabRboh genes contained numerous cis-acting regulatory elements for hormones, plant growth, and different biotic and abiotic factors. The NtabRbohF gene transcript comprised target sites for wounding and stress responsive microRNAs: nta-miR166a-d, g and h. The transcript abundance of NtabRboh genes in different tissues reflected their important for plant growth and organ development in tobacco. RT-qPCR-assays demonstrated that the expression of NtabRboh genes are regulated by viral and bacterial pathogens, drought, cold and cadmium stress. The expression levels NtabRbohA, B and C were significantly up-regulated in "black shank and tobacco mosaic virus-inoculated susceptible and transgenic tobacco cultivars, showing that these genes play important roles in disease resistance.

Ubiquitin Extension Protein UEP1 Modulates Cell Death and Resistance to Various Pathogens in Tobacco.

Ubiquitin (Ub) extension proteins (UEPs) are fusion proteins of a Ub at the N terminus to a ribosomal protein. They are the main source of Ub and the only source of extension ribosomal protein. Although important roles of the Ub-26S proteasome system in various biological processes have been well established, direct evidence for the role of UEP genes in plant defense is rarely reported. In this study, we cloned a Ub-S27a-type UEP gene (NbUEP1) from Nicotiana benthamiana and demonstrated its function in cell death and disease resistance. Virus-induced gene silencing of NbUEP1 led to intensive cell death, culminating in whole-seedling withering. Transient RNA interference (RNAi) of NbUEP1 caused strong cell death in infiltrated areas, while stable NbUEP1-RNAi tobacco plants constitutively formed necrotic lesions in leaves. NbUEP1-RNAi plants exhibited increased resistance to the oomycete Pythium aphanidermatum and viruses Tobacco mosaic virus and Cucumber mosaic virus while displaying decreased resistance to the nematode Meloidogyne incognita compared with non-RNAi control plants. Transcription profiling analysis indicated that jasmonate and ethylene pathways, lipid metabolism, copper amine oxidase-mediated active species generation, glycine-rich proteins, vacuolar processing enzyme- and RD21-mediated cell death and defense regulation, and autophagy might be associated with NbUEP1-mediated cell death and resistance. Our results provided evidence for the important roles of plant UEPs in modulating plant cell death and disease resistance.

Emission level of seven mainstream smoke toxicants from cigarette with variable tobacco leaf constituents.

[Introduction] Seven smoke constituents, including hydrogen cyanide (HCN), ammonia (NH3), phenol, benzo[α]pyrene (B[a]P), carbon monoxide (CO)¸ crotonaldehyde, and 4-(methylnitrosamino)-1- (3-pyridyl)-1-butanone (NNK), are proposed be the most relevant constituents for smoking-related diseases. [Methods] Different combinations of leaf stalk positions, varieties and locations were used to create variable chemistry of cigarette filler and smoke. Experimental cigarettes were measured for emission level of seven smoke toxicants and content of seventy-three filler components. [Results] The ranges of coefficient of variation (CV) for seven smoke toxicants were 15.43%-43.15%. The emission pattern of NNK and crotonaldehyde were different from that of other five smoke toxicants. Most of the seven smoke toxicants were influenced in following order: stalk position > location > variety. The leaf constitutes closely correlated with seven smoke toxicants were analyzed. [Conclusions] The results showed that seven toxicants were significantly influenced by leaf position and location, and closely correlated with leaf components, such as potassium, malate and alkaloid contents. The results provide useful and comprehensive information on the affecting factors and correlating leaf constituents for the variations of seven smoke toxicants.

Genome-wide identification, evolution and expression analysis of cyclic nucleotide-gated channels in tobacco (Nicotiana tabacum L.).

Tobacco (Nicotiana tabacum) serve as the top leading commercial, non-food, and model crop worldwide. Cyclic nucleotide-gated channels (CNGCs) are ligand-gated, calcium-permeable, divalent, cation-selective channels, involved in important biological functions. Here, we systematically characterized thirty-five CNGC genes in the genome of Nicotiana tabacum, and classified into four phylogenetic groups. Evolutionary analysis showed that NtabCNGC family of N. tabacum originated from the parental genome of N. sylvestris and N. tomentosiformis, and further expanded via tandem and segmental duplication events. Tissue-specific expression analysis showed that twenty-three NtabCNGC genes are involved in the development of various tobacco tissues. Subsequent RT-qPCR analyses indicated that these genes are sensitive towards external abiotic and biotic stresses. Notable performances were exhibited by group-I and IV CNGC genes against black shank, Cucumber mosaic virus, Potato virus Y, cold, drought, and cadmium stresses. Our analyses also suggested that NtabCNGCs can be regulated by phosphorylation and miRNAs, and multiple light, temperature, and pathogen-responsive cis-acting regulatory elements present in promotors. These results will be useful for elaborating the biological roles of NtabCNGCs in tobacco growth and development.

Identification and expression analysis of EDR1-like genes in tobacco (Nicotiana tabacum) in response to Golovinomyces orontii.

ENHANCED DISEASE RESISTANCE1 (EDR1) encodes a Raf-like mitogen-activated protein kinase, and it acts as a negative regulator of disease resistance and ethylene-induced senescence. Mutations in the EDR1 gene can enhance resistance to powdery mildew both in monocotyledonous and dicotyledonous plants. However, little is known about EDR1-like gene members from a genome-wide perspective in plants. In this study, the tobacco (Nicotiana tabacum)EDR1-like gene family was first systematically analyzed. We identified 19 EDR1-like genes in tobacco, and compared them to those from Arabidopsis, tomato and rice. Phylogenetic analyses divided the EDR1-like gene family into six clades, among them monocot and dicot plants were respectively divided into two sub-clades. NtEDR1-1A and NtEDR1-1B were classified into clade I in which the other members have been reported to negatively regulate plant resistance to powdery mildew. The expression patterns of tobacco EDR1-like genes were analyzed after plants were challenged by Golovinomyces orontii, and showed that several other EDR1-like genes were induced after infection, as well as NtEDR1-1A and NtEDR1-1B. Expression analysis showed that NtEDR1-13 and NtEDR1-16 had exclusively abundant expression patterns in roots and leaves, respectively, and the remaining NtEDR1-like members were actively expressed in most of the tissue/organ samples investigated. Our findings will contribute to further study of the physiological functions of EDR1-like genes in tobacco.

Evolutionary and expression analysis of CAMTA gene family in Nicotiana tabacum yielded insights into their origin, expansion and stress responses.

Calmodulin-binding transcription activators (CAMTAs) represent the novel gene family of transcriptional regulators, which play important biological functions. Though, the first ever plant CAMTA gene was evidenced in Nicotiana tabacum in 2002. But, the systematic identification, origin and function of this gene family has not been performed due to the lack of reference genome information until now. Here, we identified 29 CAMTA genes in four Nicotiana species, including thirteen NtabCAMTAs, six NsylCAMTAs, and five NtomCAMTAs and NbenCAMTAs. These CAMTA families were classified into five phylogenetic groups (I-V), among which, the group-IV CAMTAs probably emerged the earliest. The NtabCAMTA family genes have diverse structures, and are randomly localized on five chromosomes and scaffolds. N. tabacum acquired 11 copies of homolog CAMATA genes from the parental genomes of N. tomentosiformis and N. sylvestris, followed by expansion through polyploidization and duplication. The NtabCAMTA genes were differentially expressed in different plant parts, and showed sensitivity towards different abiotic and biotic stresses. Co-expression network analysis revealed that some NtabCAMTA subunits interact with each other, and co-expressed. The current study is the first report presenting a comprehensive overview of Nicotiana CAMTA families, and opens a new avenue for the improvement of the cultivated tobacco.

Complete Genome Sequence of Lactobacillus reuteri WHH1689, Isolated from Traditional Chinese Highland Barley Wine.

Here, we report the complete genome sequence of Lactobacillus reuteri WHH1689, which was isolated from traditional Chinese highland barley wine in the Tibetan Plateau of China. The genome consists of a circular chromosome (2.04 Mb).

Potential probiotic characterization of Lactobacillus reuteri from traditional Chinese highland barley wine and application for room-temperature-storage drinkable yogurt.

The aim of this study was to select probiotic strains that could be used in drinkable yogurt to yield viable cells following storage at room temperature (RT). The uniquely high altitude conditions in Tibet and the alcoholic environment of certain products, such as the highland barley wine homemade in Tibet, may induce unusual characteristics of microbial strains. A total of 27 lactic acid bacteria were isolated from homemade highland barley wines. One strain, Lactobacillus reuteri WHH1689, demonstrated no ability for lactose utilization, exhibited a high survival rate during storage at RT in drinkable yogurts, and produced very weak post-acidification. This strain showed great resistance to conditions simulating the gastrointestinal tract, including strong adherence to HT-29 cells and inhibitory activity against Escherichia coli, Shigella flexneri, Salmonella paratyphi ß, and Staphylococcus aureus. A dextran sulfate sodium (DSS)-induced mouse model was used to evaluate the in vivo influence of Lb. reuteri WHH1689 on the intestinal flora and showed that strain WHH1689 increased viable counts of bifidobacteria in feces of mice. The probiotic strain selected in this study-with its high survival at RT and lack of serious post-acidification problems-may provide significant improvements for dairy industry products by extending the storage time of dairy products with living cells.

Comprehensive genomic analysis of the CNGC gene family in Brassica oleracea: novel insights into synteny, structures, and transcript profiles.

BACKGROUND: The cyclic nucleotide-gated ion channel (CNGC) family affects the uptake of cations, growth, pathogen defence, and thermotolerance in plants. However, the systematic identification, origin and function of this gene family has not been performed in Brassica oleracea, an important vegetable crop and genomic model organism. RESULTS: In present study, we identified 26 CNGC genes in B. oleracea genome, which are non-randomly localized on eight chromosomes, and classified into four major (I-IV) and two sub-groups (i.e., IV-a and IV-b). The BoCNGC family is asymmetrically fractioned into the following three sub-genomes: least fractionated (14 genes), most fractionated-I (10), and most fractionated-II (2). The syntenic map of BoCNGC genes exhibited strong relationships with the model Arabidopsis thaliana and B. rapa CNGC genes and provided markers for defining the regions of conserved synteny among the three genomes. Both whole-genome triplication along with segmental and tandem duplications contributed to the expansion of this gene family. We predicted the characteristics of BoCNGCs regarding exon-intron organisations, motif compositions and post-translational modifications, which diversified their structures and functions. Using orthologous Arabidopsis CNGCs as a reference, we found that most CNGCs were associated with various protein-protein interaction networks involving CNGCs and other signalling and stress related proteins. We revealed that five microRNAs (i.e., bol-miR5021, bol-miR838d, bol-miR414b, bol-miR4234, and bol-miR_new2) have target sites in nine BoCNGC genes. The BoCNGC genes were differentially expressed in seven B. oleracea tissues including leaf, stem, callus, silique, bud, root and flower. The transcript abundance levels quantified by qRT-PCR assays revealed that BoCNGC genes from phylogenetic Groups I and IV were particularly sensitive to cold stress and infections with bacterial pathogen Xanthomonas campestris pv. campestris, suggesting their importance in abiotic and biotic stress responses. CONCLUSION: Our comprehensive genome-wide analysis represents a rich data resource for studying new plant gene families. Our data may also be useful for breeding new B. oleracea cultivars with improved productivity, quality, and stress resistance.

Anaerobic and sequential aerobic production of high-titer ethanol and single cell protein from NaOH-pretreated corn stover by a genome shuffling-modified Saccharomyces cerevisiae strain.

In this study, a Saccharomyces cerevisiae recombinant strain 14 was constructed through genome shuffling method by transferring the whole genomic DNA of Candida intermedia strain 23 into a thermo-tolerant S. cerevisiae strain. The recombinant strain 14 combined the good natures of both parent strains that efficiently produced ethanol from glucose and single cell protein from xylose with 54.6% crude protein and all essential amino acids except cysteine at 35°C. Importantly, the recombinant strain 14 produced 64.07g/L ethanol from 25%(w/v) NaOH-pretreated and washed corn stover with the ethanol yield of 0.26g/g total stover by fed-batch simultaneous saccharification and fermentation and produced 66.50g/L dry cell mass subsequently from the residual hydrolysate and ethanol. Therefore, this study represents a feasible method to comprehensively utilize hexose and pentose in lignocellulosic materials.

Sequencing and characterization of leaf transcriptomes of six diploid Nicotiana species.

BACKGROUND: Nicotiana belongs to the Solanaceae family that includes important crops such as tomato, potato, eggplant, and pepper. Nicotiana species are of worldwide economic importance and are important model plants for scientific research. Here we present the comparative analysis of the transcriptomes of six wild diploid Nicotiana species. Wild relatives provide an excellent study system for the analysis of the genetic basis for various traits, especially disease resistance. RESULTS: Whole transcriptome sequencing (RNA-seq) was performed for leaves of six diploid Nicotiana species, i.e. Nicotiana glauca, Nicotiana noctiflora, Nicotiana cordifolia, Nicotiana knightiana, Nicotiana setchellii and Nicotiana tomentosiformis. For each species, 9.0-22.3 Gb high-quality clean data were generated, and 67,073-182,046 transcripts were assembled with lengths greater than 100 bp. Over 90 % of the ORFs in each species had significant similarity with proteins in the NCBI non-redundant protein sequence (NR) database. A total of 2491 homologs were identified and used to construct a phylogenetic tree from the respective transcriptomes in Nicotiana. Bioinformatic analysis identified resistance gene analogs, major transcription factor families, and alkaloid transporter genes linked to plant defense. CONCLUSIONS: This is the first report on the leaf transcriptomes of six wild Nicotiana species by Illumina paired-end sequencing and de novo assembly without a reference genome. These sequence resources hopefully will provide an opportunity for identifying genes involved in plant defense and several important quality traits in wild Nicotiana and will accelerate functional genomic studies and genetic improvement efforts of Nicotiana or other important Solanaceae crops in the future.

Exogenous auxin regulates multi-metabolic network and embryo development, controlling seed secondary dormancy and germination in Nicotiana tabacum L.

BACKGROUND: Auxin was recognized as a secondary dormancy phytohormone, controlling seed dormancy and germination. However, the exogenous auxin-controlled seed dormancy and germination remain unclear in physiological process and gene network. RESULTS: Tobacco seeds soaked in 1000 mg/l auxin solution showed markedly decreased germination compared with that in low concentration of auxin solutions and ddH2O. Using an electron microscope, observations were made on the seeds which did not unfold properly in comparison to those submerged in ddH2O. The radicle traits measured by WinRHIZO, were found to be also weaker than the other treatment groups. Quantified by ELISA, there was no significant difference found in ß-1,3glucanase activity and abscisic acid (ABA) content between the seeds imbibed in gradient concentration of auxin solution and those soaked in ddH2O. However, gibberellic acid (GA) and auxin contents were significantly higher at the time of exogenous auxin imbibition and were gradually reduced at germination. RNA sequencing (RNA-seq), revealed that the transcriptome of auxin-responsive dormancy seeds were more similar to that of the imbibed seeds when compared with primary dormancy seeds by principal component analysis. The results of gene differential expression analysis revealed that auxin-controlled seed secondary dormancy was associated with flavonol biosynthetic process, gibberellin metabolic process, adenylyl-sulfate reductase activity, thioredoxin activity, glutamate synthase (NADH) activity and chromatin regulation. In addition, auxin-responsive germination responded to ABA, auxin, jasmonic acid (JA) and salicylic acid (SA) mediated signaling pathway (red, far red and blue light), glutathione and methionine (Met) metabolism. CONCLUSIONS: In this study, exogenous auxin-mediated seed secondary dormancy is an environmental model that prevents seed germination in an unfavorable condition. Seeds of which could not imbibe normally, and radicles of which also could not develop normally and emerge. To complete the germination, seeds of which would stimulate more GA synthesis to antagonize the stimulation of exogenous auxin. Exogenous auxin regulates multi-metabolic networks controlling seed secondary dormancy and germination, of which the most important thing was that we found the auxin-responsive seed secondary dormancy refers to epigenetic regulation and germination to enhance Met pathway. Therefore, this study uncovers a previously unrecognized transcriptional regulatory networks and physiological development process of seed dormancy and germination with superfluous auxin signal activate.

Identification and characterization of miRNAome in tobacco (Nicotiana tabacum) by deep sequencing combined with microarray.

Tobacco is one of the most important economic and agricultural crops worldwide. miRNAs have been increasingly acknowledged for their important roles in different biological processes of tobacco. However, few miRNAs have been identified so far in tobacco impeding the development of new tobacco strains with better properties. In this study, high-throughput sequencing technology was employed to identify novel tobacco miRNAs. A total of 84 potential miRNAs were obtained in tobacco, including 33 conserved and 51 novel miRNAs. Tissue-specific and topping-related miRNAs were identified. A tobacco miRNA microarray was also constructed to investigate miRNA expression patterns in different tissues, and their expression patterns were further validated by qRT-PCR and Northern Blot. Finally, the potential targets of these miRNAs were predicted based on a sequence homology search. Thus, in the current study, we have performed the comprehensive analysis of tobacco miRNAs, including their identification, expression pattern and target prediction. Our study opens a new avenue for further elucidation for their roles underlying the regulation of diversity of physiological processes.

DNA methylation polymorphism in flue-cured tobacco and candidate markers for tobacco mosaic virus resistance.

DNA methylation plays an important role in the epigenetic regulation of gene expression during plant growth, development, and polyploidization. However, there is still no distinct evidence in tobacco regarding the distribution of the methylation pattern and whether it contributes to qualitative characteristics. We studied the levels and patterns of methylation polymorphism at CCGG sites in 48 accessions of allotetraploid flue-cured tobacco, Nicotiana tabacum, using a methylation-sensitive amplified polymorphism (MSAP) technique. The results showed that methylation existed at a high level among tobacco accessions, among which 49.3% sites were methylated and 69.9% allelic sites were polymorphic. A cluster analysis revealed distinct patterns of geography-specific groups. In addition, three polymorphic sites significantly related to tobacco mosaic virus (TMV) resistance were explored. This suggests that tobacco breeders should pay more attention to epigenetic traits.

Generation and characterization of two novel low phytate mutations in soybean (Glycine max L. Merr.).

Phytic acid (PA, myo-inositol 1, 2, 3, 4, 5, 6 hexakisphosphate) is important to the nutritional quality of soybean meal. Organic phosphorus (P) in PA is indigestible in humans and non-ruminant animals, which affects nutrition and causes P pollution of ground water from animal wastes. Two novel soybean [(Glycine max L. (Merr.)] low phytic acid (lpa) mutations were isolated and characterized. Gm-lpa-TW-1 had a phytic acid P (PA-P) reduction of 66.6% and a sixfold increase in inorganic P (Pi), and Gm-lpa-ZC-2 had a PA-P reduction of 46.3% and a 1.4-fold increase in Pi, compared with their respective non-mutant progenitor lines. The reduction of PA-P and increase of Pi in Gm-lpa-TW-1 were molar equivalent; the decrease of PA-P in Gm-lpa-ZC-2, however, was accompanied by the increase of both Pi and lower inositol phosphates. In both mutant lines, the total P content remained similar to their wild type parents. The two lpa mutations were both inherited in a single recessive gene model but were non-allelic. Sequence data and progeny analysis indicate that Gm-lpa-TW-1 lpa mutation resulted from a 2 bp deletion in the soybean D: -myo-inositol 3-phosphate synthase (MIPS1 EC 5.5.1.4) gene 1 (MIPS1). The lpa mutation in Gm-lpa-ZC-2 was mapped on LG B2, closely linked with microsatellite loci Satt416 and Satt168, at genetic distances of approximately 4.63 and approximately 9.25 cM, respectively. Thus this mutation probably represents a novel soybean lpa locus. The seed emergence rate of Gm-lpa-ZC-2 was similar to its progenitor line and was not affected by seed source and its lpa mutation. However, Gm-lpa-TW-1 had a significantly reduced field emergence when seeds were produced in a subtropic environment. Field tests of the mutants and their progenies further demonstrated that the lpa mutation in Gm-lpa-ZC-2 does not negatively affect plant yield traits. These results will advance understanding of the genetic, biochemical and molecular control of PA synthesis in soybean. The novel lpa mutation in Gm-lpa-ZC-2, together with linked simple sequence repeat (SSR) markers, will be of value for breeding productive lpa soybeans, with meal high in digestible Pi eventually to improve animal nutrition and lessen environmental pollution.

Generation and characterization of low phytic acid germplasm in rice (Oryza sativa L.).

Phytic acid (PA, myo-inositol 1,2,3,4,5,6-hexakisphosphate), or its salt form, phytate, is commonly regarded as the major anti-nutritional component in cereal and legume grains. Breeding of low phytic acid (lpa) crops has recently been considered as a potential way to increase nutritional quality of crop products. In this study, eight independent lpa rice mutant lines from both indica and japonica subspecies were developed through physical and chemical mutagenesis. Among them, five are non-lethal while the other three are homozygous lethal. None of the lethal lines could produce homozygous lpa plants through seed germination and growth under field conditions, but two of them could be rescued through in vitro culture of mature embryos. The non-lethal lpa mutants had lower PA content ranging from 34 to 64% that of their corresponding parent and four of them had an unchanged total P level. All the lpa mutations were inherited in a single recessive gene model and at least four lpa mutations were identified mutually non-allelic, while the other two remain to be verified. One mutation was mapped on chromosome 2 between microsatellite locus RM3542 and RM482, falling in the same region as the previously mapped lpa1-1 locus did; another lpa mutation was mapped on chromosome 3, tightly linked to RM3199 with a genetic distance of 1.198 cM. The latter mutation was very likely to have happened to the LOC_Os03g52760, a homolog of the maize myo-inositol kinase (EC 2.7.1.64) gene. The present work greatly expands the number of loci that could influence the biosynthesis of PA in rice, making rice an excellent model system for research in this area.