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Endophytic bacteria from legume roots and nodules play important roles in regulating plant growth and health. Therefore, the aim is to focus on the community structure and network of pea root endophytes throughout the plant life cycle. We collected five edible pea cultivars to study the endophytic bacterial community during the whole developmental period using Illumina sequencing of 16S rRNA gene. The structure and complexity of root endophytes was significantly affected by the development period and different root endophytes were recruited by peas at different developmental stages. Pea cultivars gave no significant influence on the patterns of root endophytic bacterial community during plant growth. Here, the complexity of root-endophytic bacterial community was the highest at seedling stage and became more and more simple after that. Rhizobium was a dominant root bacteria during the whole developmental stage. The amount of Rhizobium began to accumulate in pea seedling roots, and reached the highest at flowering stage and decreased at the mature stage. The relative abundance of Pseudomonas increased overtime throughout the pea entire life cycle, whereas the amount of Bacteroides decreased overtime. The pea root and nodule endophytes were dominated by Rhizobium, Pseudomonas and Bacteroides. These findings provide an endophyte-based characterization of the reference stock bacteria detail for the establishment of root endophytic bacteria throughout the plant life cycle. Specially, a proper synthetic microbial community to improve pea yields.

Common vetch (CV), a leguminous crop cultivated for green manure and fodder rich in protein and starch, is widespread over much area of the northern hemisphere. Its seeds can be used as a protein source to human consumption. CV protein isolates (CVPI) and major protein fractions (CV albumin protein, CVAP; CV globulin protein, CVGP; CV glutelin protein, CVGTP) from 4 samples were investigated the properties to facilitate full use of protein resources. Protein comprises 27.70 %-32.14 % of the dry CV seed weight, which is mainly composed by CVAP (26.79 %-56.12 %) and CVGP (22.78 %-52.42 %). CVPI, CVAP and CVGP mainly presented 7S and 11S components. CVGTP mainly contained the 11S component. They showed difference in thermal properties and surface hydrophobicity. Circular dichroism data showed that α-helix was their major secondary structure. CVPI and major protein fractions exhibited a U-shape protein solubility. CVPI and CVAP had advantages in emulsifying and foaming properties. This study provided novel insights on unexploited sources of CV proteins with interesting characteristics in terms of potential uses as protein-based foods.

Background and aims Endophytic bacteria from legume roots and nodules play important roles in regulating plant growth and health. However, little is known about how the endophytic bacteria community changes and how it interacts with each other throughout the plant life cycle. Methods We collected twenty pea cultivars to study the composition and structure of endophytic bacterial community during the whole developmental period using Illumina sequencing of 16S rRNA gene. Results Here we show that the development period significantly affected the structure of root endophytic bacterial community and peas recruit different root microbes during different developmental stages. The complexity of microbial community first increased and then decreased with the growth of pea. Rhizobium began to accumulate in pea seedling roots, and the content peaked at flowering stage and remained at high levels during the mature stage. In the flowering and mature stage, the relative abundance of Pseudomonas increased. Conclusions These findings can deepen the overall understanding of the community structure and interaction network of endophytic bacteria from pea root and nodules, and provide a detail for the establishment of root endophytic bacteria throughout the plant life cycle.

Pea (Pisum sativum L.), a diploid (2n = 2x = 14) annual cool-season legume crop adapted to a wide range of climates and altitudes, plays a very important role for sustainable agriculture as rotation and cash crops for food, vegetable, fodder, manure, etc. The genome size of a pea is estimated at 4.45 Gb comprising large amount of repetitive sequences with high complexity, so that the complete reference genome sequence of pea has not been published yet, which hindered the development of genome-assisted breeding in pea. This chapter discussed the challenges, priorities, and prospects of pea as climate-smart (CS) crop, in food, nutrition, energy, and environment security, effects on global warming and climate change to the industry and breeding of pea. For details, studies on CS agronomic traits of peas like flowering time, root characters, nutrient-use efficiency, water use efficiency, carbon and nitrogen sequestration, greenhouse gas emission, genome plasticity, as well as specific traits for vegetable purposes, were reviewed; CS stress tolerance/resistance traits studies of peas, like cold tolerance, drought tolerance, salinity tolerance, disease resistance, insect resistance were also reviewed. Pea-hosted biological nitrogen fixation (BNF) and soil resources, rhizobium for nodulation, characterization for rhizobium, interaction between pea and its anchored rhizobium, interaction between rhizobium and soil, optimized operation for rhizobium fertilization were illustrated. Utilizations of primary gene pool, secondary gene pool, tertiary gene pool, artificially induced/incorporated traits/genes in CS pea genetic development were reviewed. Of CS pea studies, classical mapping efforts, classical breeding achievements (yield, quality, stress resistance, etc.), limitations of traditional breeding and rationale for molecular breeding, genetic diversity analysis of Pisum genus using various means, such as association mapping studies between important traits and markers, molecular mapping of CS genes and QTLs, marker-assisted breeding for CS traits, genomic-aided breeding for CS traits, were all reviewed. Social, political, and regulatory issues concerning CS peas, for concerns and compliances, patent and IPR issues, disclosure of sources of GRs, access and benefit sharing, famers’ rights, traditional knowledge, treaties and conventions, participatory breeding, in China and elsewhere were discussed. Peas, especially green pea production dramatically expanded and became increasingly important from the beginning of this century. Achievements on pea studies will lead to genomics, phenomics, and genome editing exploration to assist CS pea breeding purpose in the future.

It is believed that common vetch (Vicia sativa L.) contains a relatively high quantity of starch. In this study, the starch content of 36 common vetch accessions was monitored, within the range of 20.56–47.53% on a whole seed basis. The amylose content ranged from 17.75 to 38.68% on a dry starch basis. Among them, 8 common vetch accessions were selected for physicochemical and functional analysis, by comparing with 2 smooth pea cultivars and 2 chickpea cultivars. The isolated starches differed significantly in granule morphology, thermal parameters and pasting properties. The shapes of common vetch starch granules were kidney, spherical or oval varied with size from 7.77 to 23.16 μm. The crystalline structures of all starches were C-type. The relative crystallinity of common vetch starches ranged from 22.70 to 34.32% and gelatinization temperature ranged from 63.10 to 66.80 °C. A wider variation of breakdown (BD) (197-910 cp) was observed in common vetch starches than smooth pea and chickpea starches. And the setback (SB) (1314-2221 cP) was lower than that of the pea cultivar P2 and two chickpea cultivars. These could lead common vetch starches to a broad application prospect.

To study hybrid speciation in wheatgrass Douglasdeweya wangii and to investigate the evolutionary pattern of nuclear ribosomal DNA (nrDNA) internal transcribed spacer sequences (ITSs) in allotetraploids, DNA sequence variation of ITSs and chloroplast trnL-F sequences from D. wangii and its putative donors were analyzed. The ITSs revealed that D. wangii had an StP genome composition. Most accessions of D. wangii had one parental ITS copy in their genome, one accession had two parental ITSs. The trnL-F sequences revealed an especially close relationship of Pseudoroegneria to all D. wangii individuals included, and the two accessions of Pseudoroegneria tauri (PI401324 and PI401331) were maternal candidates of the studied D. wangii individuals. Both of ITS and trnL-F trees suggested multiple origins and recurrent hybridization of D. wangii. Thus, the results suggested that: (1) the St and P genome in allotetraploid D. wangii were donated by Pseudoroegneria and Agropyron, respectively;(2) Pseudoroegneria was the maternal donor of D. wangii, and P. tauri 26 (accession PI401324) and P. tauri 27 (accession PI401331) were most likely the potential candidates of maternal donors; (3) D. wangii individuals studied here showed multiple origins and experienced recurrent hybridization; and (4) bidirectional interlocus concerted evolution of ITSs had occurred in most D. wangii accessions, while in one accession concerted evolution among homeologous loci did not occur.

Seed-mediated gene flow can considerably affect population genetic structure of strictly self-pollinating species, but little is known on the extent and nature of such gene flow among pastoral plant populations. Molecular fingerprints provide a powerful tool to address the relevant issues. Genetic structure of 22 populations of two self-pollinating pasture species, Elymus nutans and E. burchan-buddae, collected from various altitudes of the Qinghai–Tibetan Plateau was studied using fluorescence-based amplified fragment length polymorphism technique. Analysis of molecular variance revealed 42.97% and 37.63% among-population variation for the two Elymus species, respectively, indicating that the majority of the total variation presented within populations. This result contradicts the common genetic variation pattern for a selfing plant species: lower genetic variation within populations. Further analysis suggested higher level of gene flow among populations within the same region than among different regions across the sampled area for the two Elymus species. STRUCTURE analyses of the Elymus populations indicated an evident admixture genetic structure, particularly among neighboring populations from the same region, supporting the hypothesis of considerable seed dispersal among populations. The excess within-region gene flow of E. nutans and E. burchan-buddae might be caused by grazing animals that promote seed dispersal when moved around the pastoral lands during foraging. The among-population gene flow promulgated by grazing animals may promote the maintenance of genetic diversity in the pasture species, particularly in small and fragmented populations within a given region.

Summary • To estimate the phylogenetic relationship of polyploid Elymus in Triticeae, nuclear ribosomal internal transcribed spacer (ITS) and chloroplast trnL-F sequences of 45 Elymus accessions containing various genomes were analysed with those of five Pseudoroegneria (St), two Hordeum (H), three Agropyron (P) and two Australopyrum (W) accessions. • The ITS sequences revealed a close phylogenetic relationship between the polyploid Elymus and species from the other genera. The ITS and trnL-F trees indicated considerable differentiation of the StY genome species. • The trnL-F sequences revealed an especially close relationship of Pseudoroegneria to all Elymus species included. Both the ITS and trnL-F trees suggested multiple origins and recurrent hybridization of Elymus species. • The results suggested that: the St, H, P, and W genomes in polyploid Elymus were donated by Pseudoroegneria, Hordeum, Agropyron and Australopyrum, respectively, and the St and Y genomes may have originated from the same ancestor; Pseudoroegneria was the maternal donor of the polyploid Elymus; and some Elymus species showed multiple origin and experienced recurrent hybridization.

Elymus L. is the largest genus in Triticeae, containing about 150 species with four recognized genome donors (St, H, P, and W). Traditionally, the genome compound of this genus is identified based on cytological data. Recently, molecular phylogenetic analysis was used to investigate its genomic combination. Here we describe a restriction fragment length polymorphism (RFLP) assay based on digesting alcohol dehydrogenase (Adh) amplicons with two restriction enzyme combinations, EcoRI-HindIII and EcoRI-PstI, which easily can be used to distinguish Elymus and its closely related genera genomes. The method includes only four steps: (1) amplifying nuclear Adh genes with universal primers; (2) purifying and cloning PCR products; (3) digesting plasmids with restriction enzymes that identify a given genome; (4) running the digested products on an agarose gel and identify the sample based on the restriction profiles. Results showed that: (1) PCR products ranged from 1,200 to 2,000 bp; (2) Adh2 gene was amplified from all the tested genomes; Adh1 gene was amplified from almost all of the tested genomes except the W genome; Adh3 gene was amplified only from the St genome; (3) the EcoRI-HindIII combination was effective to distinguish different Adh gene types (Adh1, Adh2, and Adh3); (4) the Adh2-EcoRI-PstI fragments could be used to distinguish Elymus and its closely related genera genomes. Therefore, This RFLP assay provides an inexpensive and simple means of identifying Elymus genomes.

In this study, we rapidly identified Bacillus thuringiensis 4.0718 strain that harbored the known cryl and cry2 type genes by a PCR strategy. Three pairs of universal oligonucleotide primers were designed to detect all known cry1, cry2 and cry3 type gene sequences. Then the DNA of the positive strain 4.0718 was probed with a set of specific primers. One feature of this screening method was that each gene was expected to produce a PCR product having a precise molecular weight. PCR products having different sizes probably represented the gene was a potentially novel gene. Differentiations among these genes was determined on the basis of the electrophoresis patterns of PCR products. Finally, five cry1 type genes (cry1 Aa, cry1 Ab, cry1 Ac, cry1 Cb, a novel cry4.5 type genes) and one cry2 Ac type gene had been detected from Bacillus thuringiensis 4.0718 strain.

Barley Yellow Dwarf Virus (BYDV) is a pathogen caused serious yield losses in cereals, which may become even more important due to its intrinsic adaptation and global warming. As a perennial species in Triticeae, Elymus shandongensis contains genes resistant to BYDV. The 27 molecular markers linked to BYDV resistance genes developed from Triticeae species were characterized. The 25 loci were polymorphic, and 2 loci were monomorphic in this study. The number of alleles ranged from 1 to 6. The effective number of alleles (Ne) of each primer ranged from 1 to 1.932 (mean= 1.624). The Shannon's information index (I) of each primer ranged from 0 to 0.662 (mean= 0.499), and the unbiased genetic diversity (He) ranged from 0 to 0.481 (mean= 0.353). The population from the Lingshan island (PL) showed a lower level of genetic variation (P =80.25%, I =0.477, and He =0.338), whereas the population from the surrounding areas of the Laoshan reservoir (PS†) had a higher level of genetic diversity (P =90.12%, I =0.520, and He =0.368). Four private alleles were found in PL and 1 private allele was found in PS†. The results indicated the 27 markers could be used in future genetic study of E. shandongensis that might be useful in a context of wheat breeding, germplasms conservation, finding useful resistant genotype to BYDV and adaptive evolution at resistance loci to virus in natural populations.