Phospholipid metabolism in cotyledons of wild and cultivated peas

The amount of phospholipids in the membrane fractions of the endoplasmic reticulum (ER) and plasma membrane of cotyledons of Pisum sativum and P. elatius was followed during germination. Incorporation of [¹⁴C-methyl]choline into the ER and the plasma membrane was followed as well as [U-¹⁴C]glycerol into the ER. The pool size of endogenous choline was determined and found to be much greater in the wild pea and to increase early in germination. In both species membranes are synthesized in large quantities early in germination and both turnover and synthesis of the backbone and the phosphatidyl tail occur throughout 48 hr of germination. In P. sativum incorporation peaks earlier than in P. elatius and degradation also begins earlier than in P. elatius. This is consistent with the general behaviour of the two species.     

First report of non-mycorrhizal plant mutants (Myc) obtained in pea (Pisum sativum L.) and fababean (Vicia faba L.)

Genetic resistance to vesicular-arbuscular (VA) mycorrhiza formation has been obtained in spontaneous or chemically induced mutants of two mycorrhiza-forming species (Pisum sativum L. and Vicia faba L.). The eight mutants, termed myc⁻, are characterized by aborted infections limited to one or two host cells. Expression of the myc⁻ character is associated with that of the nod⁻ character in both legumes, and is likewise under recessive genetic control. Preliminary analysis of the genetic behaviour of the myc⁻ mutants in diallel crosses has shown that at least three genes are involved in VA mycorrhiza infection.     

豌豆茎基腐病病原菌分离鉴定及其对杀菌剂的敏感性测定

豌豆(Pisum sativum)是我国重要的豆类经济作物, 病害对豌豆生产造成重大经济损失。通过形态学观察、分子鉴定以及致病性测定, 最终确定引起豌豆茎基腐病的3种病原菌分别为尖孢镰刀菌(Fusarium oxysporum)、芸苔链格孢菌(Alternaria brassicae)和格氏镰刀菌(F. grosmichelii), 优势菌株为尖孢镰刀菌, 分离率为53.6%。室内毒力测定结果表明, 5种供试杀菌剂对3种病原菌的菌丝生长均有抑制作用, 其中咯菌腈和戊唑醇的抑菌效果最好。研究结果为豌豆茎基腐病的防治提供了科学依据。     

基于ITS和matK基因对牡丹组序列分析及其亲缘关系的研究

以芍药属牡丹组全部9个野生种、5个紫斑牡丹栽培品种及3个中原牡丹品种为试材,进行核糖体内转录间隔区（ITS）和叶绿体成熟酶K （matK）基因片段测序分析,探讨ITS和matK序列为牡丹组所有野生种种间关系提供分子证据。从GeneBank中选取了1个牡丹及3个外类群芍药、川赤芍和草芍药的ITS及matK序列。对试验样品进行DNA提取、PCR扩增并双向测序得到44条序列,人工校正后将所得44条序列进行比对;计算碱基组成频率、变异位点、简约信息位点数、转换/颠换比率、种内及种间遗传距离,以邻接法进行系统发育分析。结果表明,牡丹组所有个体ITS序列长度在750~800 bp,含有86个多态位点,74个简约信息位点,转换/颠换比率（R）为1.2;而matK序列含有20个简约信息位点,转换/颠换比率（R）为1.7。ITS序列分析将牡丹组野生种分为两大枝,稷山牡丹、紫斑牡丹、卵叶牡丹和杨山牡丹聚为一枝,狭叶牡丹、滇牡丹、黄牡丹和大花黄牡丹聚为另一枝,这两枝分别与革质花盘亚组和肉质花盘亚组相对应,而四川牡丹位于革质花盘亚组最底端,支持前人研究将四川牡丹归为革质花盘亚组。matK序列分析的牡丹组野生种间遗传距离结果不理想,未能清晰的表明野生种之间的亲缘关系。由此说明,ITS序列更适合牡丹组野生种间亲缘关系的研究分析。     

Genetic diversity and structure of the zombi pea (<Emphasis Type="Italic">Vigna vexillata</Emphasis> (L.) A. Rich) gene pool based on SSR marker analysis

Zombi pea (Vigna vexillata (L.) A. Rich) is an underutilized legume species and a useful gene source for resistance to biotic and abiotic stresses, although there is little understanding on its genetic diversity and structure. In this study, 422 (408 wild and 14 cultivated) accessions of zombi pea from diverse origins (201 from Africa, 126 from America, 85 from Australia, 5 from Asia and 5 from unknown origin) were analyzed with 20 simple sequence repeat (SSR) markers to determine its genetic diversity and genetic structure. The SSR markers detected 273 alleles in total with a mean of 13.6 alleles per locus. Polymorphism information content values of the markers varied from 0.58 to 0.90 with an average of 0.76. Overall gene diversity was 0.715. Gene diversity and average allelic richness was highest in Africa (0.749 and 8.08, respectively) and lowest in America (0.435 and 4.10, respectively). Nei’s genetic distance analysis revealed that the highest distance was between wild Australia and cultivated Africa (0.559), followed by wild West Africa and wild Australia (0.415). STRUCTURE, neighbor-joining (NJ), and principal coordinate analyses consistently showed that these zombi pea accessions were clustered into three major groups, viz. America, Africa and Asia, and Australia. NJ tree also suggested that American and Australian accessions are originated from East African zombi peas, and that the cultivated accessions from Africa and Asia were genetically distinct, while those from America were clustered with some cultivated accessions from Africa. These results suggest that Africa is the center of origin and diversity of zombi pea, and that domestication of this pea took place more than once in different regions.     

Purification of pea nodule symbiosomes using an aqueous polymer two-phase system

Symbiosomes were obtained from mature pea (Pisum sativum cv. Argona) root nodules infected with a Rhizobium leguminosarum strain (biov. viciae 3841) and purified using an aqueous polymer two-phase system (APS). The APS consists of a mixture of polymers, usually dextran T500 and poly(ethylene glycol) 3350, prepared as aqueous solutions on a weight per weight basis, where each fraction distributes according to their surface characteristics. Results of ATPase activity, cytochrome c oxidase activity, glucan synthase II activity, NAD(P)H-cytochrome c reductase activity, NO₃⁻-sensitive ATPase activity, transport of [¹⁴C]malate vs. [¹⁴C]glutamate and MAC 57 antigen analysis showed that the APS method provided intact symbiosomes with low bacteroid, plasma membrane, endoplasmic reticulum and/or mitochondria contamination. No complicated equipment is needed and the method was simple and fast, compared with other purification techniques.     

Modification of the basic subunits of pea legumin on storage

Basic subunits of legumin of Pisum sativum undergo a modification on storage of dry seeds which increases their apparent MW on SDS-polyacrylamide gel electrophoresis and decreases their pI values.     

Origins of the African Yam bean (Sphenostylis stenocarpa,leguminosae): evidence from morphology,isozymes, chloroplast DNA,and linguistics

Cladistic and phenetic analyses of morphological, chloroplast DNA, and isozyme variation were used to examine relationships among multiple accessions of Sphenostylis sten ocarpa, representing wild and cultivated populations from throughout the range of the species. In morphometric and isozyme analyses, greater variability was detected among wild than among cultivated populations, and no differentiation was found between races cultivated for tubers and those cultivated for seeds. cpDNA data, however, revealed five groups of plastomes within S. stenocarpa: one in accessions cultivated for tubers, one in accessions cultivated for seeds, and three among wild accessions. Linguistic evidence and observations on the uses of the species in its two main areas of cultivation suggest independent origins of tuber- and seed- cultivated races. The data support two alternative explanations for the distribution of extant cultivated accessions ofS. stenocarpa. The first hypothesis is that the species was domesticated independently in western and central Africa, but that domestication events involved selection from a single restricted gene pool. The second hypothesis is that a single domestication event occurred in one of the two areas, but that human dispersal to the second area occurred prior to dispersal within either area.     

卵孢侧耳野生菌株人工栽培及营养成分分析

采自西藏日喀则地区的两份野生蘑菇标本及其分离菌株,通过形态学及基于ITS序列的分子系统发育分析鉴定为卵孢侧耳Pleurotus placentodes。该物种在2016年首次报道于中国。人工驯化栽培试验表明卵孢侧耳可以在人工条件下出菇,生长周期80-95d;初步的营养成分分析表明,卵孢侧耳蛋白质、粗多糖、氨基酸含量比香菇、糙皮侧耳（平菇）、金针菇、柱状田头菇（茶树菇）等都高,尤其含有较高的组氨酸和丰富的矿物质,如铁、钙、锌等。卵孢侧耳可作为新的食用菌进行开发利用。     

黄麻种质资源遗传多样性的SRAP分析

为明确黄麻(Corchorus L.)种质资源的遗传多样性,采用SRAP分子标记方法,对来自13个国家的两个黄麻栽培种及野生种共96份黄麻种质资源进行了分析。研究结果如下:(1)供试黄麻种质资源之间的遗传距离在0.0169至0.9667之间,变幅较大,其中近缘野生种与其他种质的遗传距离最大,基本在0.8以上;圆果栽培黄麻与其他种质的遗传距离最小,平均<0.5。(2)当在聚类图上遗传距离为0.53处划切割线L₁时,96份黄麻种质资源被分为两个大类群(Ⅰ、Ⅱ)、一个小类群(Ⅲ)和5个独立个类。(3)当在遗传距离为0.33处作切割线L₂时,各大类群被分为不同的亚类群,并表现出按地域聚类的趋势。(4)供试黄麻种质资源基于SRAP分子标记的聚类与形态学上的表现并不完全一致。     

Simple sequence repeat diversity in diploid and tetraploid Coffea species.

Thirty-four fluorescently labeled microsatellite markers were used to assess genetic diversity in a set of 30 Coffea accessions from the CENICAFE germplasm bank in Colombia. The plant material included one sample per accession of seven East African accessions representing five diploid species and 23 wild and cultivated tetraploid accessions of Coffea arabica from Africa, Indonesia, and South America. More allelic diversity was detected among the five diploid species than among the 23 tetraploid genotypes. The diploid species averaged 3.6 alleles/locus and had an average polymorphism information content (PIC) value of 0.6, whereas the wild tetraploids averaged 2.5 alleles/locus and had an average PIC value of 0.3 and the cultivated tetraploids (C. arabica cultivars) averaged 1.9 alleles/locus and had an average PIC value of 0.22. Fifty-five percent of the alleles found in the wild tetraploids were not shared with cultivated C. arabica genotypes, supporting the idea that the wild tetraploid ancestors from Ethiopia could be used productively as a source of novel genetic variation to expand the gene pool of elite C. arabica germplasm.     

Genetic relationships among subspecies of Vigna unguiculata (L.) Walp. based on allozyme variation

 The cowpea [Vigna unguiculata (L.) Walp.] is a morphologically and genetically variable species composed of wild perennial, wild annual, and cultivated forms that are mainly used for edible seeds and pods. In this study, genetic variation in 199 germplasm accessions of wild and cultivated cowpea was evaluated using an allozyme analysis. The results from this survey showed that wild cowpea exhibits genetic variation perfectly fitted with the existing morphological classification. The cowpea gene-pool is characterized by its unusually large size. It encompasses taxa (ranked as subspecies) that could be considered as different species considering the high genetic distances observed between accessions belonging to different taxa. These subspecies can be classified into three groups characterized by their breeding systems: perennial outcrossers, perennial out-inbreds, and inbred annuals. Allozyme data confirm this grouping. Perennial outcrossers look primitive and are more remote from each other and from perennial out-inbreds. Within this large gene-pool, mainly made of perennial taxa, cultivated cowpeas (ssp. unguiculata var. unguiculata) form a genetically coherent group and are closely related to annual cowpeas (ssp. unguiculata var. spontanea) which may include the most likely progenitor of cultivated cowpeas. Received: 15 June 1998 / Accepted: 29 September 1998     

Natural interploidy hybridization among the key taxa involved in the origin of horticultural chrysanthemums

Understanding hybridization and introgression between natural plant populations can give important insights into the origins of cultivated species. Recent studies suggest differences in ploidy might not create such strong reproductive barriers as once thought, and thus studies into cultivated origins should examine all co-occurring taxa, including those with contrasting ploidy levels. Here, we characterized hybridization between Chrysanthemum indicum L., Chrysanthemum vestitum (Hemsley) Ling and Chrysanthemum vestitum var. latifolium (Zhou & Chen), the most important wild species involved in the origins of cultivated chrysanthemums. We analyzed the population structure of 317 Chrysanthemum accessions based on 13 microsatellite markers and sequenced chloroplast trnL-trnF for a subset of 103 Chrysanthemum accessions. We identified three distinct genetic clusters, corresponding to the three taxa. We detected 20 hybrids between species of different ploidy levels, of which 19 were between C. indicum (4x) and C. vestitum (6x) and one was between C. indicum and C. vestitum var. latifolium (6x). Fourteen hybrids between C. indicum and C. vestitum were from one of the five study sites. Chrysanthemum vestitum and C. vestitum var. latifolium share only one chloroplast haplotype. The substantially different number of hybrids between hybridizing species was likely due to different levels of reproductive isolation coupled with environmental selection against hybrids. In addition, human activities could play a role in the different patterns of hybridization among populations.     

Genetic differentiation of wild relatives of rice as assessed by RFLP analysis

To study genetic diversity and relationships of wild relatives of rice, 58 accessions of Oryza rufipogon, Oryza nivara, Oryza sativa f. spontanea and the cultivated Oryza sativa, representing a wide range of their distribution, were analyzed using the restriction fragment length polymorphism (RFLP) technique. All 30-used RFLP probes detected polymorphisms among the Oryza accessions, with an average of 3.8 polymorphic fragments per probe. Considerable genetic diversity was scored among the Oryza accessions with a similarity coefficient ranging from 0.28 to 0.93; but the cluster analysis of the accessions did not show an apparent grouping based on the species classification, instead they were scattered randomly in different groups. Noticeably, the Oryza accessions from the same geographic region, or near-by geographic regions, tended to be clustered in the same groups. The indica rice varieties showed relatively high genetic diversity and were scattered in different groups of their wild relatives, but the japonica varieties showed a relatively low variation and formed an independent group. It is concluded from the molecular analytical result that: (1) the four Oryza taxa have a remarkably close relationship and their independent species status need to be carefully reviewed; (2) geographic isolation has played a significant role in the differentiation of the Oryza accessions; therefore, a wide geographic range needs to be covered in collecting wild rice germplasm for ex situ conservation; and (3) the conventional conclusion of indica rice being directly domesticated from its ancestral wild species, and japonica rice being derived from indica, gains support from our data.     

Effects of sodium tungstate on the ultrastructure and growth of pea (Pisum sativum) and cotton (Gossypium hirsutum) seedlings

Pea (Pisum sativum L. cv. Onmard) and cotton (Gossypium hirsutum L. cv. Campo) seedlings were treated with two concentrations (200 and 500 mg/l) of sodium tungstate (Na₂WO₄) and the developmental effects were investigated. Tungstate retarded seedling growth rate and stopped root elongation in both species. Seedling growth recovered when tungstate was removed, but primary roots continued to be stunted, while lateral root initiation and growth were stimulated. Tungstate induced premature vacuolation in cells of the root apical meristem, with vacuoles having an unusual semi-circular or cap-like shape around the nucleus. In control roots, the nuclei were spherical with prominent nucleoli bearing several randomly distributed fibrillar centres. In the tungstate-treated cells nuclei contained spherical nucleoli with a big nucleolar vacuole. Occasionally, cytoplasmic components, such as mitochondria, were entrapped in the nucleoplasm of interphasic cells of the treated roots. In these roots, most cell plates were fused to only one lateral parental wall suggesting a non-uniform centrifugal extension. The vesicles in these cell plates were dark and fused to each other at a much lower rate than in the dividing cells of the untreated seedlings. Phragmoplast and cortical microtubules were abundant in the untreated cells, but scarcely detected in the treated ones. All these observations are consistent with the view that tungstate causes considerable toxic effects to pea and cotton seedlings.     

Alterations of lipid composition in Friend leukemia cell tumors in mice treated with tumor necrosis factor-α

The monocarboxylate (pyruvate) transporter from pea (Pisum sativum) mitochondria was identified by means of a specific monoclonal antibody. The antibody blocked pyruvate-dependent oxaloacetate metabolism without interfering with the metabolism of malate, -ketoglutarate, or glycine. The antibody also blocked the pyruvate/pyruvate exchange reaction of the partially purified transporter reconstituted into phospholipid membranes. Using the specific monoclonal antibody, the transporter was identified on Western blots as a minor 19 kDa protein.     

Evidence for conspecificity of Piper methysticum forst. f. and Piper wichmannii C. DC

Morphological, chemical, cytological and genetic evidence demonstrating the absence of taxonomic distinction between Piper methysticum and Piper wichmannii are reviewed. Piper methysticum is not a separate species, but rather a group of sterile cultivars selected from somatic mutants of P. wichmannii. As P. methysticum was described first (1786), it has priority and P. wichmannii (1910) is superfluous. A new subspecific classification is suggested that makes a distinction between the sterile cultivars (P. methysticum var. methysticum) and the wild populations (P. methysticum var. Wichmannii).     

Patterns of genetic diversity in the Andean gene pool of common bean reveal a candidate domestication gene

Most studies on the genetic diversity of common bean (Phaseolus vulgaris L.) have focussed on accessions from the Mesoamerican gene pool compared to the Andean gene pool. A deeper knowledge of the genetic structure of Argentinian germplasm would enable researchers to determine how the Andean domestication event affected patterns of genetic diversity in domesticated beans and to identify candidates for genes targeted by selection during the evolution of the cultivated common bean. A collection of 116 wild and domesticated accessions representing the diversity of the Andean bean in Argentina was genotyped by means of 114 simple sequence repeat (SSR) markers. Forty-seven Mesoamerican bean accessions and 16 Andean bean accessions representing the diversity of Andean landraces and wild accessions were also included. Using the Bayesian algorithm implemented in the software STRUCTURE we identified five major groups that correspond to Mesoamerican and Argentinian wild accessions and landraces and a group that corresponds to accessions from different Andean and Mesoamerican countries. The neighbour-joining algorithm and principal coordinate clustering analysis confirmed the genetic relationships among accessions observed with the STRUCTURE analysis. Argentinian accessions showed a substantial genetic variation with a considerable number of unique haplotypes and private alleles, suggesting that they may have played an important role in the evolution of the species. The results of statistical analyses aimed at identifying genomic regions with consistent patterns of variation were significant for 35 loci (~20 % of the SSRs used in the Argentinian accessions). One of these loci mapped in or near the genomic region of the glutamate decarboxylase gene. Our data characterize the population structure of the Argentinian germplasm. This information on its diversity will be very valuable for use in introgressing Argentinian genes into commercial varieties because the majority of present-day common bean varieties are of Andean origin.     

Evolutionary relationships among Ascochyta species infecting wild and cultivated hosts in the legume tribes Cicereae and Vicieae

Evolutionary relationships were inferred among a worldwide sample of Ascochyta fungi from wild and cultivated legume hosts based on phylogenetic analyses of DNA sequences from the ribosomal internal transcribed spacer regions (ITS), as well as portions of three protein-coding genes: glyceraldehyde-3-phosphate-dehydrogenase (G3PD), translation elongation factor 1-alpha (EF) and chitin synthase 1 (CHS). All legume-associated Ascochyta species had nearly identical ITS sequences and clustered with other Ascochyta, Phoma and Didymella species from legume and nonlegume hosts. Ascochyta pinodes (teleomorph: Mycosphaerella pinodes [Berk. & Blox.] Vestergen) clustered with Didymella species and not with well characterized Mycosphaerella species from other hosts and we propose that the name Didymella pinodes (Berk. & Blox.) Petrak (anamorph: Ascochyta pinodes L.K. Jones) be used to describe this fungus. Analysis of G3PD revealed two major clades among legume-associated Ascochyta fungi with members of both clades infecting pea ("Ascochyta complex"). Analysis of the combined CHS, EF and G3PD datasets revealed that isolates from cultivated pea (P. sativum), lentil (Lens culinaris), faba bean (Vicia faba) and chickpea (Cicer arietinum) from diverse geographic locations each had identical or similar sequences at all loci. Isolates from these hosts clustered in well supported clades specific for each host, suggesting a co-evolutionary history between pathogen and cultivated host. A. pisi, A. lentis, A. fabae and A. rabiei represent phylogenetic species infecting pea, lentil, faba bean and chickpea, respectively. Ascochyta spp. from wild relatives of pea and chickpea clustered with isolates from related cultivated hosts. Isolates sampled from big-flower vetch (Vicia grandiflora) were polyphyletic suggesting that either this host is colonized by phylogenetically distinct lineages of Ascochyta or that the hosts are polyphyletic and infected by distinct evolutionary lineages of the pathogen. Phylogenetic species identified among legume-associated Ascochyta spp. were fully concordant with previously described morphological and biological species.     

Polyphyly and species delimitation of Picea brachytyla (Pinaceae) based on population genetic data

Accurate species delimitation is fundamental to biodiversity conservation. The endangered spruce Picea brachytyla (Franch.) E. Pritz. was suggested to be polyphyletic based on a limited number of samples in previous studies. To evaluate polyphyly of P. brachytyla, we sampled 139 individuals from 16 populations across most of its distributional range, plus representatives of two related species, Picea likiangensis (Franch.) E. Pritz. and Picea wilsonii Mast. We sequenced 13 nuclear loci and three chloroplast and two mitochondrial loci for the following species delimitation. Phylogenetic analyses of nuclear loci grouped all individuals of P. brachytyla from Sichuan and Chongqing into one distinct lineage and those from Yunnan and Tibet (southern distribution) nested within the P. likiangensis species complex. Structure analyses confirmed this result. Networks of chloroplast DNA haplotypes similarly showed that P. brachytyla from the southern distribution nested within the P. likiangensis species complex, whereas haplotypes for the northern distribution comprised a separate and well-supported lineage. These results suggest that P. brachytyla from the southern distribution is a part of the P. likiangensis species complex and should be removed from P. brachytyla. Our study highlights the utility of population genetic evidence in delimitating endangered species and understanding the conservation status of such species.