Chloroplast DNA polymorphism in fertile and male-sterile cytoplasms of sorghum (Sorghum bicolor (L.) Moench)

Summary Restriction endonuclease patterns of chloroplast DNA (cpDNA) were consistently distinguishable between fertile and male-sterile cytoplasms of sorghum [Sorghum bicolor (L.) Moench], whereas no differences in restriction patterns of cpDNA among male-sterile (A₁) lines, including six isocytoplasmic strains, were revealed in this study. It is suggested that chloroplast DNA may contribute to the male sterility of A₁ lines used currently in hybrid sorghum production.This research was supported by a research grant from Kansas Grain Sorghum Commission, Kansas Board of Agriculture. Contribution 90-293-J from the Kansas Agricultural Experiment Station     

Restriction endonuclease analysis of mitochondrial DNA from sorghum with fertile and male-sterile cytoplasms

Summary Mitochondrial DNA from four paired (fertile and male-sterile) lines and six isocytoplasmic strains of sorghum (Sorghum bicolor (L.) Moench) were fragmented by endonucleases and their electrophoretic patterns were examined. Cytoplasmic male sterile lines differed from their male-fertile counterparts consistently. Among the isocytoplasmic strains, KS 36A (S. verticilli-florum cytoplasm), KS 38A (S. conspicum cytoplasm), and KS 39A (S. niloticum cytoplasm) showed minor differences from the other strains. Results suggest that restriction endonuclease patterns are useful in detecting differences in mitochondrial genomes.This study was supported by a research grant from Kansas Grain Sorghum Commission, Kansas Board of Agriculture. Contribution 89-28-J from the Kansas Agricultural Experiment Station.     

Phylogenetic analysis of Sorghum and related taxa using internal transcribed spacers of nuclear ribosomal DNA

The phylogenetic relationships of the genus Sorghum and related genera were studied by sequencing the nuclear ribosomal DNA (rDNA) internal transcribed spacer region (ITS). DNA was extracted from 15 Sorghum accessions, including one accession from each of the sections Chaetosorghum and Heterosorghum, four accessions from Parasorghum, two accessions from Stiposorghum, and seven representatives from three species of the section Sorghum (one accession from each of S. propinquum and S. halepense, and five races of S. bicolor). The maize (Zea mays) line, H95, and an accession from Cleistachne sorghoides were also included in the study. Variable nucleotides were used to construct a strict consensus phylogenetic tree. The analyses indicate that S. propinquum, S. halepense and S. bicolor subsp. arundinaceum race aethiopicum may be the closest wild relatives of cultivated sorghum; Sorghum nitidum may be the closest 2n=10 relative to S. bicolor, the sections Chaetosorghum and Heterosorghum appear closely related to each other and more closely related to the section Sorghum than Parasorghum; and the section Parasorghum is not monophyletic. The results also indicate that the genus Sorghum is a very ancient and diverse group.This research was partially supported by a Third Country Scholarship from Pioneer Hi-Bred International Incorporated Contribution 94-182-J from Kansas Agricultural Experiment Station     

Interactive effects of methyl jasmonate and salicylic acid on floret opening in spikelets of Sorghum

Floret opening of excised spikelets in Sorghum bicolor (L.) Moench and Sorghum Sudanesis (Piper) Stapf was significantly stimulated by immersing into 2 mM methyl jasmonate (MeJA) solution. In male sterile (MS) lines of Sorghum bicolor (L.) Moench, floret opening was more sensitive to MeJA than that in maintainer (MT) lines. Salicylic acid (SA) could abolish the effect of MeJA on the opening of spikelets. These data indicate that MeJA plays a role in floret opening in sorghum, and that SA interacts with MeJA in regulating of this process.     

接种AMF对煤矿废弃物上高丹草的生长和叶绿素荧光的影响

为改善采矿废弃物上植被生长状况,提高植物成活率,该研究采用盆栽试验法,以高丹草为材料,选用摩西球囊霉(Glomus mosseae,G.m)和地表球囊霉(G.versiforme,G.v)两种AM真菌,分别研究单接种和混合接种对粉煤灰(S1)、煤矸石(S2)和粉煤灰与煤矸石混合物(S3)三种煤矿废弃物基质上高丹草(Sorghum bicolor×S.sudanense)生长及叶绿素荧光的影响,并以正常沙土(S4)作为对照。结果表明:(1)4种基质上,3种接种处理均获得较高侵染率,在基质S1、S3和S4上均为接种摩西球囊霉对高丹草根系侵染率最高,分别为49.04%、57.40%、43.34%,在基质S2上,混合接种处理对高丹草根系侵染效果最好,达49.33%。(2)3种煤矿废弃物基质上高丹草根长、干重、叶绿素含量、F_v/F_o、q P和Yield显著降低。接种AM真菌显著提高了高丹草的生长和光合效率。与其他处理相比,在基质S1、S3和S4上,接种摩西球囊霉显著增加了根长、干重、叶绿素含量、F_v/F_o、q P和Yield,在基质S2上,接种地表球囊霉显著增加了根长、干重,接种地表球囊霉和摩西球囊霉+地表球囊霉(G.mv)处理间叶绿素荧光参数均无显著差异。这表明在煤矿废弃物基质的复合逆境中高丹草生长和光合作用显著受到抑制,AM真菌可通过提高高丹草叶绿素含量,改善叶片叶绿素荧光和光合作用,促进植物生长,来缓解该复合逆境对高丹草造成的伤害,增强其对煤矿废弃物不良环境的抗逆性,提高煤矿区植被恢复效果。接种摩西球囊霉对粉煤灰以及粉煤灰和煤矸石混合基质上高丹草的促进作用最佳,而接种地表球囊霉更适于煤矸石基质上高丹草的生长。     

Effects of species of VA-mycorrhizal fungi on growth and mineral uptake of sorghum at different temperatures

Sorghum [Sorghum bicolor (L.) Moench] plants were grown in growth chambers at 20, 25 and 30°C in a low P Typic Argiudoll (3.65 µg P g^–1 soil, pH 8.3) inoculated with Glomus fasciculatum, Glomus intraradices, and Glomus macrocarpum to determine effects of vesicular-arbuscular mycorrhizal fungi (VAMF) species on plant growth and mineral nutrient uptake. Sorghum root colonization by VAMF and plant responses to Glomus species were temperature dependent. G. macrocarpum colonized sorghum roots best and enhanced plant growth and mineral uptake considerably more than the other VAMF species, especially at 30°C. G. fasciculatum enhanced shoot growth at 20 and 25°C, and mineral uptake only at 20°C. G. intraradices depressed shoot growth and mineral uptake at 30°C. G. macrocarpum enhanced shoot P, K, and Zn at all temperatures, and Fe at 25 and 30°C above that which could be accounted for by increased biomass. Sorghum plant growth responses to colonization by VAMF species may need to be evaluated at different temperatures to optimize beneficial effects.     

Studies on the expression of NDH-H,a subunit of the NAD(P)H-plastoquinone-oxidoreductase of higher-plant chloroplasts

The plastid genomes of higher plants contain eleven reading frames (ndhA-K) that are homologous to genes encoding subunits of the mitochondrial NADH-ubiquinone-oxidoreductase (complex I). The carboxyterminal end of the NDH-H subunit from rice (Oryza sativa L.) was expressed as a fusion protein in Escherichia coli and antibodies against the fusion protein were generated in rabbits. The antibody was used to study the expression of NDH-H, and the following results were obtained: (i) NDH-H is expressed in mono- and dicotyledonous plants, (ii) NDH-H is localized on the stroma lamellae of the thylakoid membrane and (iii) NDH-H is expressed in etioplasts. Together with the finding that two other ndh genes (ndhI and ndhK) are expressed in plastids, these results point to the existence of an NAD(P)H-plastoquinone-oxidoreductase on the thylakoid membrane. The possible function of the enzyme in plastids is discussed and it is suggested that it works in balancing the ATP/ADP and the NADPH/NADP ratios during changing external (i.e. light) or internal (i.e. ATP and NADPH demands of biosynthetic pathways of the plastid) conditions.Abbreviations PVDF polyvinylidene difluoride - SDS sodium dodecyl sulfate We thank Professor M. Sugiura for the rice plastid DNA clone bank, Oliver Buchholz for Sorghum plastid membranes, Pioneer Hi-Bred Inc. for maize and Sorghum seeds and the Deutsche Forschungsgemeinschaft for financial support (SFB189).     

Synthesis of ribulose 1,5-bisphosphate carboxylase by isolatedSorghum mesophyll chloroplasts

Chloroplasts isolated fromSorghum vulgare are active in light-dependent, organelle protein synthesis. Intact chloroplasts can use light as an energy source; photosynthetically inactive chloroplasts require the addition of ATP for this protein synthesis. Preincubation of chloroplasts in light at 25°C for 1 h depleted the endogenous templates completely; such preincubated chloroplasts translated exogenously added heterologous templates efficiently. When total cellular RNA fromChlorella protothecoides, a C₃ plant, was used as template for translation in a cell-free light-dependent system of isolated mesophyll chloroplasts fromSorghum vulgare, a C₄ type plant, polypeptides of 55 kDa (large subunit) and 15 kDa (small subunit) were detectable in the fluorographic profile of the newly synthesized proteins; these polypeptides were absent in the products obtained with endogenous RNA. Evidence for the fidelity of the system was obtained by immunological analysis of ribulose 1, 5-bisphosphate carboxylase obtained by the translation ofChlorella cellular RNAs.     

Molecular genetic analysis of the soriz genome (<Emphasis Type="Italic">Sorghum oryzoidum</Emphasis>)

A molecular genetic analysis of soriz genotypes (Sorghum oryzoidum), its parental form Sorghum bicolor (L.) Moench (grain sorghum), possible parents (Sorghum sudanense (Piper.) Stapf. (Sudan grass) and Oryza sativa L. (Rice planting), as well as its closest relatives, has been carried out with the use of microsatellite loci of sorghum and rice. Based on the obtained data, the genetic distances were calculated and the examined species were clustered. It was shown that soriz did not carry rice DNA fragments, but its genome contained DNA fragments, which belonged to Sudan grass. This confirms that the origin of soriz is associated with representatives of Sorghum sudanense.     

高粱属植物的地理分布

为探讨高粱属(Sorghum Moench)的系统发育关系,通过野外调查及查阅标本和文献资料,对高粱属植物的地理分布进行了整理和研究。高粱属植物约有29种,分布于全世界热带到温带地区,其中澳大利亚22种,亚洲15种,非洲9种,欧洲3种,地中海2种,美洲6种。中国有5种,分布在东北、西南到华南各省(区)。高粱属有5亚属,仅高粱亚属(subgen.Sorghum)延伸至新世界,其他亚属均分布在旧世界,高粱亚属覆盖非洲并扩散到全世界热带到温带地区;拟高粱亚属(subgen.Parasorghum)分布在非洲、亚洲、澳大利亚;有柄高粱亚属(subgen.Stiposorghum)主要分布在澳大利亚,个别种分布到亚洲;多毛高粱亚属(subgen.Chaetosorghum)分布在澳大利亚;异高粱亚属(subgen.Heterosorghum)分布在澳大利亚和亚洲。这表明澳大利亚东北部是高粱属的现代分布中心和多样化中心,非洲东北部和热带亚洲是否是高粱属的起源地尚需确证。     

Benefit and cost analysis and phosphorus efficiency of VA mycorrhizal fungi colonizations with sorghum (Sorghum bicolor) genotypes grown at varied phosphorus levels

Sorghum [Sorghum bicolor (L.) Moench] was grown in a greenhouse in a low P (3.6 mg kg^-1) soil (Typic Argiudolls) inoculated with the vesicular-arbuscular mycorrhizal fungi (VMAF) Glomus fasciculatum and P added at 0, 12.5, 25.0, and 37.5 mg kg^-1 soil to determine the effects of VAMF-root associations on plant growth, benefit and cost analysis, and P efficiency (dry matter produced/unit P absorbed). Root colonization with VAMF and shoot growth enhancements decreased with increased soil P applications. Mycorrhizal plants were less P efficient than nonmycorrhizal plants. Shoot dry matter differences between mycorrhizal and nonmycorrhizal plants were considered the benefit derived by plants from VAMF-root associations. Shoot dry matter differences between mycorrhizal and nonmycorrhizal plants with similar P concentrations were considered the costs paid by plants for VAMF-root associations. Values of benefit and cost analysis for VAMF-root associations were highest when soil P was lowest and decreased with increasing P applications. Genotypic differences for calculated costs were pronounced, but not benefits. Benefit and cost analysis.may be helpful to evaluate host plant genotypes and VAMF species to optimize efficiencies of VAMF symbiosis in different soil environments.     

Sequence Comparison of Plant Ornithine Decarboxylases Reveals High Homology and Lack of Introns

We have designed and constructed four oligonucleotides corresponding to the most conserved regions of ornithine decarboxylases (ODC; EC 4.1.1.17) of plant origin. These oligonucleotides were used for the amplification of homologous fragments from several plants (Zea mays, Capsicum annuum, Sorghum bicolor, Phaseolus vulgaris, Carica papaya and Daucus carota). The amplified fragments were cloned and sequenced, revealing high homology to other ODCs. Peptide sequences coded by these fragments were compared by Clustal analyses. These analyses identified the location of the conserved sequences corresponding to the binding sites of substrate and cofactor. Data demonstrated that the plant ODCs fragments lacked intron sequences and were extremely homologous (over 80 %), constituting a compact group separated from other eukaryotic ODCs. This revised version was published online in July 2006 with corrections to the Cover Date.     

Chromosome endoreduplication as a factor of salt adaptation in Sorghum bicolor

Summary. Nuclear DNA amounts were measured by Feulgen cytophotometry in Sorghum bicolor cv. 610 plants early exposed to 150 mM NaCl, a treatment known to induce an increased tolerance to salinity in plants carrying this genotype. In salt-treated plants, the percentages of 8C, 16C, and 32C nuclei in roots in the primary state of growth were 21.9%, 13.3%, and 4.3%, respectively. By contrast, in nonsalinized plants, only 3.5% of the nuclei had an 8C content and no higher DNA contents were observed. The salt treatment induced chromosome endoreduplication during the differentiation of cells in the root cortex, where 41.2% of the cells displayed a DNA content higher than 4C (versus 1.3% in control plants). No enhancement of endopolyploidy was observed in cells of the root vascular cylinder or the leaves of the salt-treated plants. In another S. bicolor genotype (DK 34-Alabama), noncompetent for salt adaptation, the same NaCl treatment did not induce chromosome endoreduplication in root cortex cells. Endopolyploidy may be considered as a part of the adaptive response of S. bicolor competent genotypes to salinity. Correspondence and reprints: Dipartimento di Biologia Cellulare e Ambientale, Università di Perugia, Via A. Pascoli, 06123 Perugia, Italy.     

A method for direct soil extraction and PCR amplification of endomycorrhizal fungal DNA

 DNA from endomycorrhizal fungi was extracted directly from a weathered soil (alfisol) mixed with sand. Mycorrhizae were established in a greenhouse culture of Glomus clarum with Sudan grass (Sorghum vulgare var. sudanense) host plants. The extraction procedure included enzymatic digestion of cell walls, sodium dodecyl sulfate lysis of cells, polyvinylpolypyrrolidone absorption of organic compounds, and ethanol precipitation of the DNA. DNA in the extracts was amplified by the polymerase chain reaction using primers from the nuclear 17S rRNA sequence that were general to fungi or were specific to endomycorrhizae. Accepted: 17 July 1996     

Relative quantification of chrysanthemum yellows (16Sr I) phytoplasma in its plant and insect host using real-time polymerase chain reaction

A real-time polymerase chain reaction (PCR) method for the quantification of chrysanthemum yellows (CY) phytoplasma DNA in its plant (Chrysanthemum carinatum) and insect (Macrosteles quadripunctulatus) host is described. The quantity of CY DNA was measured in each run relative to the amount of host DNA in the sample. Primers and a TaqMan probe for the specific PCR amplification of phytoplasma DNA were designed on a cloned CY-specific ribosomal fragment. Primers and TaqMan probes were also designed on sequences of the internal transcribed spacer region of the insect’s ITS1 rDNA and of the plant’s 18S rDNA for amplification from C. carinatum and M. quadripunculatus, respectively. Absolute quantification of CY DNA was achieved by comparison with a dilution series of the plasmid containing a CY 16S rDNA target sequence. Absolute quantification of plant and insect DNAs was achieved by comparison with a dilution series of the corresponding DNAs. Quantification of CY DNA in relation to host DNA was finally expressed as genome units (GU) of phytoplasma DNA per nanogram of host (plant or insect) DNA. Relative quantification avoided influences due to different yields during the DNA extraction procedure. The quantity of CY DNA was about 10,000–20,000 GU/ng of plant DNA and about 30,000–50,000 GU/ng of insect DNA. The method described could be used to phytoplasma multiplication and movement in different plant and insect hosts.     

Molecular cloning and sequence analysis of a cDNA encoding a cysteine proteinase inhibitor fromSorghum bicolor seedlings

A 711-bp cDNA encoding a cysteine proteinase inhibitor (cystatin) was isolated from a cDNA library prepared from 7–10 cmSorghum bicolor seedlings. The nearly full-length cDNA clone encodes 130 amino acid residues, which include the Gln-Val-Val-Ala-Gly motif, conserved among most of the known cystatins as a probable binding site for cysteine proteinases. The amino acid sequence of sorghum cystatin deduced from the cDNA clone shows significantly homology to those of other plant cystatins. The sorghum cystatin expressed inE. coli showed a strong papain-inhibitory activity.     

Recycling spent larval food of Corcyra cephalonica Stainton for preparing spawn and sporophore of Pleurotus sajor-caju (Fr.) Singer

Large scale production of the rice moth, Corcyra cephalonica Stainton in pearl millet grain medium leads to a huge accumulation of spent larval medium in commercial insectaries. We attempted bioconversion of spent larval medium of C. cephalonica (CLM) for cultivation of the mushroom Pleurotus sajor-caju (Fr.) Singer, to increase the usage of these residues. Maximum efficiency limits of CLM for spawn run, sporophore cropping and as bed substrate were assessed with varying combinations of sorghum and rice straw. Sorghum grains and rice straw were the best substrates for spawn run and sporophore yield respectively. Having been crushed, macerated, heated and sterilized, CLM could also become a suitable substrate along with sorghum or rice straw. Sorghum and CLM at 16.7% + 83.3% and 33.3% + 66.7% combinations were very effective in supporting mycelial growth and quicker colonization of fungus, and mother spawn yield. The spawn that was obtained from these combinations yielded higher sporophore as well. The fungus did not rapidly colonize on other combinations (50% + 50%, 66.7% + 33.3% and 83.3% + 16.7%), and was completely unable to grow on CLM 100%. Combination of rice straw and CLM at 75% + 25% and 50% + 50% as bed substrate contributed higher sporophore yield. Analysis of the substrates indicated variation in their chemical and mineral composition, but they were good sources of N, P and Ca. The prospects of exploring CLM for the mushroom cultivation are discussed.     

DNA polymorphisms in grain sorghum (Sorghum bicolor (L.) Moench)

Molecular markers [random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP)] were used to determine the frequency of DNA polymorphism in grain sorghum (Sorghum bicolor (L.) Moench). Twenty-nine oligonucleotide primers were employed for RAPDs, generating a total of 262 DNA fragments, of which 145 were polymorphic in at least one pairwise comparison between 36 genotypes. Individual primers differed significantly in their ability to detect genetic polymorphism in the species. The overall frequency of polymorphisms was low with a mean frequency of 0.117 polymorphisms per RAPD band being obtained from all pairwise comparisons between genotypes, with maximum and minimum values of 0.212 and 0.039, respectively. Results from phenetic analysis of bandsharing data were consistent with current sub-specific groupings of the species, with clusters of Durra, Zerazera, Caud-Nig, Caud-Kaura and Caffrorum being discernible. The results also indicated that individuals of a similar taxonomic grouping but different geographic origin may be genetically less identical than previously considered. Similar frequencies of polymorphism to that obtained with RAPDs were obtained with RFLPs. Results from these experiments indicated that a high level of genetic uniformity exists within S. bicolor.     

Mineral allocation to reproduction in Sorhum bicolor and Sorghum halepense in relation to parental nutrient supply

Summary This experiment investigated the effect of parental nutrient shortage on the allocation of five nutrients to seeds and rhizomes in Sorghum halepense, a perennial, noxious weed, and to seeds in Sorghum bicolor, an annual, cultivated species. Plants from both species were grown from seeds and supplied with fertilizer at three concentrations. The allocation of biomass and nutrients (N, P, K, Ca and Mg) to reproductive and vegetative parts was determined. Relative biomass allocation to reproduction (either sexual or vegetative) remained constant in S. halepense in spite of large differences in total plant weight. In S. bicolor, however, biomass allocation to sexual reproductive structures decreased significantly with decreasing nutrient supply. Individual seed weight was not modified by parental nutrient supply in S. halepense, but it increased with decreasing nutrient availability in S. bicolor. Important differences in mineral allocation to seeds were found between the two species. While S. bicolor seeds were largely buffered from the differences in parental nutrient status, concentration of nutrients in S. halepense seeds decreased significantly with decreasing supply for all the nutrients analyzed except Ca. However, mineral nutrient concentration in S. halepense rhizomes remained remarkably constant despite differences in the external supply, evincing the priority given to vegetative reproduction at the expense of sexual reproduction. Overall, the pattern of nutrient allocation in S. bicolor seeds under different nutrient supply resembled the pattern observed in S. halepense rhizomes, but it had little resemblance to the pattern of nutrient allocation in S. halepense seeds. The results are discussed in terms of differences and similarities in the reproductive strategy of these two species.     

Cloning and characterization of a DNA repair gene inHaemophilus influenzae

Using a high-efficiency DNA cloning vector pJ1–8, a DNA repair geneuvr1 has been self-cloned in bacteriumHaemophilus influenzae. Chimeric plasmid pKuvrl, carrying wild type allele ofuvr1 gene and flanking DNA sequences, specifically complements auvr1 gene mutation in the bacterial chromosome. Auvr1_} mutation could be transferred from chromosome byin vivo recombination to pKuvr1 and isolated and designated as plasmid pKuvrl₋. Plasmid pKuvrl carries a 11.3 kb chromosomal DNA insert which was scanned for the presence of any other DNA repair genes by a novel method of directed mutagenesis. Preliminary analysis of the 3 new mutants isolated by this method supports the notion that the insert contains more than one gene concerned with ultraviolet radiation-sensitivity.