Toward a molecular evaluation of grain quality using glutenin subunits in Triticum carthlicum

The grain quality of tetraploid wheat, Triticum carthlicum was analyzed by examining seed storage glutenin (HMW) markers at Glu-A1, Glu-B1 and Glu-D1 loci by SDS-PAGE method, as well as confirmation by Zeleny and Farinograph tests. 15 populations were collected from Iran, some areas of the Middle East and the North of Africa with this assumption that this species has originated from the Middle East region. A high rate of electrophoretic polymorphism and a close relationship between molecular markers, protein content and quality were detected at the studied loci. Presence of 5+10 bands indicate high protein content and excellent quality, while the null band shows low protein and bakery quality. Populations were classified into four groups from excellent (4 Class) to low (1 Class) in the quality status. A total value of classes (TVC) for each country was calculated by adding up values of each country as a main index for quality comparisons. Iranian populations of T. carthlicum showed the highest value of quality (TVC= 9) between all populations. All of the Egyptian, Syrian and Iraqi accessions were classified in the second rank (TVC= 6) and the Turkish samples the lowest (TVC= 3). This study suggests that the glutenin (HMW) markers can still be used as a powerful and reliable tool for identification and prediction of important traits like grain quality

Characterisation of starch traits and genes in Australian rice germplasm

The physio-chemical properties of starch influence the nutritional value and the functional properties of starch containing foods. In this thesis, a population of 233 breeding lines of rice was analysed for variation in 17 rice starch synthesis genes, encoding seven classes of enzymes such as AGPases, GBSSs, SSs, Bes, DBEs, SPHOL and GPT1. This approach employed next-generation sequencing technology followed by a comprehensive association study of 110 functional SNP. SNP loci were analysed for associations with rice pasting and cooking quality. In total, The GBSSI and SSIIa had major influence on starch properties and the other genes had minor associations

The effect of exogenous glycine betaine on yield of soybean [Glycine max (L.) Merr.] in two contrasting cultivars Pershing and DPX under soil salinity stress

Salinity stress restricts growth of soybean plant [Glycine max (L.) Merr.]. Glycine betaine (GB) is among osmoprotectant compounds that are produced in tolerant plant species in response to environmental stresses. Soybean is sensitive to soil salinity and is classified as a low-ccumulator of glycine betaine. Therefore, this study was performed to evaluate the salinity tolerance of two contrasting soybean [Glycine max (L.) Merr.] cvs. Pershing and DPX at field saline soils (EC=11.1 dS/m-1). The exogenous glycine betaine (Exo-GB) treatments (0, 2.5, 5, 7.5 and 10 kg/ha) were applied in six foliar and near the flowering stages. During the growth period the amount of endogenous-glycine betaine (Endo-GB) was measured in ten foliar stages and in leaves of seeding stage. Results showed that the uptake of Na+ decreased in response to increment of Exo-GB levels, in which tolerant cv. DPX (24%) had a greater capacity to prevent Na+ uptake. Endo-GB had higher concentrations in younger leaves than in mature leaves. Exo-GB increased the number of lateral branches significantly (33%) and especially pods per plants (49%) in cv. DPX. There was no difference in seed number per pod between controls and all levels of Exo-GB treatments in two cultivars. All treatments of Exo-GB significantly increased weight of thousands grain (highest; 71% in 10 kg ha-1 GB) in salt tolerant cv. DPX. Application of Exo-GB on weight of thousands grain was cultivar-, dose-, and time-dependent. The grain yield of soybean was increased by foliar applications of Exo-GB. This was due to significant increase in number of lateral branches and pods and weight of thousands grain, without significant different between cultivars

In vitro propagation of Matthiola incana (Brassicaceae) - an ornamental plant

Tissue culture techniques are applied for micropropagation and production of pathogen-free plants. Successful in vitro propagation requires an understanding of specific requirements and precise manipulation of various factors. Direct plant production from cultured explants is important to minimize somaclonal variation in regenerated plants. In this study, an efficient protocol for micropropagation of Matthiola incana using shoot tips is presented. Seeds from mother plants were germinated on MS medium without growth regulators. Shoot tips from in vitro germinated seedlings were subcultured on solid MS medium supplemented with kinetin (KIN)(0, 0.5, 1 and 2 mg/L) and naphthalene acetic acid (NAA)(0, 0.5, 1 and 2 mg/L). Four-week-old in vitro plants, obtained from microcuttings, showed successful shooting and rooting. MS medium supplemented with 2 mg/L KIN without NAA resulted in the best shoot length (1.166 cm) and largest number of node (4.64). When the shoot tips were inoculated in the medium containing 2 mg/L NAA without KIN and medium containing the combination of 1 mg/L NAA + 2 mg/L KIN, the best result was observed for root number (1.85) and root length (5.2 cm). Moreover, fresh weight, dry weight and chlorophyll content of plants were calculated

Advances in detection of stress tolerance in plants through metabolomics approaches

Heat and drought stresses are presently the principal risk on world's food quantity, limiting yield. Both of these two stresses affect plants metabolism, physiological and morphological processes, which ultimately reduces the productivity. The plant cell develops different stress induced self-defence mechanisms to reduce the effect of stresses. These defence mechanisms are developed by modifying gene expression pattern, which results in qualitative and quantitative deviations in proteins synthesis, leading to the modulation of certain metabolic and defensive pathways. New metabolic profiling technologies offer a great opportunity for biologist to understand defence mechanism of plants under stress conditions. Metabolomics technologies presently enabled the using of different multi-variate analyses, generated from various hyphenated and chromatographic discovery systems, such as gas or liquid chromatography together with mass spectrometry, or nuclear magnetic resonance (NMR) based methods. Investigation and mining of metabolomics data can be done through a blend of different statistical methods, such as independent component analysis and analysis of variance. Metabolomics in combination with gene expression, protein interaction and other different regulatory pathways can be useful to diverse organisms with trivial alterations. In recent time, this technology has been used to investigate drought tolerance in plant crops to find particular stress related patterns in metabolic expression. These studies identified the vital roles of primary and secondary metabolites associated with abiotic stress tolerance

The infection processes of Sclerotinia sclerotiorum in basal stem tissue of a susceptible genotype of Helianthus annuus L.

Sunflower, Helianthus annuus L., is a major oil seed crop widely cultivated throughout the globe. White mold, caused by necrotrophic pathogen Sclerotinia sclerotiorum (Lib.) de Bary, is a common and widespread pathogen of sunflower. The infection process of S, sclerotiorum was studied in the stem base of infected host tissues by light microscopy and Hemi-thin sectioning techniques. Host-pathogen interactions were examined at the plant surface and cellular level of a susceptible genotype (C146), 12,24 and 48 h of post inoculation. The results showed that the appressoria were formed and the hyphal strands branched upon contact of pathogen with the host surface. Moreover a direct penetration of fungal hyphae was observed through the cuticle within 12h of inoculation. Microscopic observation of inoculated tissues after 24 hours revealed that fungal hyphae have developed both inter- and intra-cellular layer. Moreover, the fungal hyphae growth was incremental among and inside the host cells. The host cells were completely colonized by fungal mycelium 48 hour after inoculation, leading to a tissue collapse. The hyphae invaded the dead host tissues and emerged from the host tissue after extensive colonization. The present study has detailed the infection processes and pathogen development both at plant surface and inside the host tissues. The results of this study will be useful for engineering of disease-resistant genotypes and development of markers for screening pathogen resistance individuals

Discovery of polymorphisms in starch-related genes in rice germplasm by amplification of pooled DNA and deeply parallel sequencing

High-throughput sequencing of pooled DNA was applied to polymorphism discovery in candidate genes involved in starch synthesis. This approach employed semi- to long-range PCR (LR-PCR) followed by next-generation sequencing technology. A total of 17 rice starch synthesis genes encoding seven classes of enzymes, including ADP-glucose pyrophosphorylase (AGPase), granule starch synthase (GBSS), soluble starch synthase (SS), starch branching enzyme (BE), starch debranching enzyme (DBE) and starch phosphorylase (SPHOL) and phosphate translocator (GPT1) from 233 genotypes were PCR amplified using semi- to long-range PCR. The amplification products were equimolarly pooled and sequenced using massively parallel sequencing technology (MPS). By detecting single nucleotide polymorphism (SNP) ⁄ Indels in both coding and noncoding areas of the genes, we identified genetic differences and characterized the SNP ⁄ Indel variation and distribution patterns among individual starch candidate genes. Approximately, 60.9 million reads were generated, of which 54.8 million (90%) mapped to the reference sequences. The average coverage rate ranged from 12 708 to 38 300 times for SSIIa and SSIIIb, respectively. SNPs and single ⁄ multiple-base Indels were analysed in a total assembled length of 116 403 bp. In total, 501 SNPs and 113 Indels were detected across the 17 starch-related loci. The ratio of synonymous to nonsynonymous SNPs (Ka ⁄ Ks) test indicated GBSSI and isoamylase 1 (ISA1) as the least diversified (most purified) and conservative genes as the studied populations have been through cycles of selection. This report demonstrates a useful strategy for screening germplasm by MPS to discover variants in a specific target group of genes

Breaking the tight genetic linkage between the a1 and sh2 genes led to the development of anthocyanin-rich purple-pericarp super-sweetcorn

Abstract The existence of purple-pericarp super-sweetcorn based on the supersweet mutation, shrunken2 (sh2), has not been previously reported, due to its extremely tight genetic linkage to a non-functional anthocyanin biosynthesis gene, anthocyaninless1 (a1). Generally, pericarp-pigmented starchy purple corn contains significantly higher anthocyanin. The development of purple-pericarp super-sweetcorn is dependent on breaking the a1–sh2 tight genetic linkage, which occurs at a very low frequency of < 1 in 1000 meiotic crossovers. Here, to develop purple-pericarp super-sweetcorn, an initial cross between a male purple-pericarp maize, ‘Costa Rica’ (A1Sh2.A1Sh2) and a female white shrunken2 super-sweetcorn, ‘Tims-white’ (a1sh2.a1sh2), was conducted. Subsequent self-pollination based on purple-pericarp-shrunken kernels identified a small frequency (0.08%) of initial heterozygous F3 segregants (A1a1.sh2sh2) producing a fully sh2 cob with a purple-pericarp phenotype, enabled by breaking the close genetic linkage between the a1 and sh2 genes. Resulting rounds of self-pollination generated a F6 homozygous purple-pericarp super-sweetcorn (A1A1.sh2sh2) line, ‘Tim1’. Genome sequencing revealed a recombination break between the a1 and yz1 genes of the a1–yz1-x1–sh2  multigenic interval. The novel purple-pericarp super-sweetcorn produced a similar concentration of anthocyanin and sugar as in its purple-pericarp maize and white super-sweetcorn parents, respectively, potentially adding a broader range of health benefits than currently exists with standard yellow/white sweetcorn

Loss of plastid ndh genes in an autotrophic desert plant

Plant plastid genomes are highly conserved with most flowering plants having the same complement of essential plastid genes. Here, we report the loss of five of the eleven NADH dehydrogenase subunit genes (ndh) in the plastid of a desert plant jojoba (Simmondsia chinensis). The plastid genome of jojoba was 156,496 bp with one large single copy region (LSC), a very small single copy region (SSC) and two expanded inverted repeats (IRA + IRB). The NADH dehydrogenase (NDH) complex is comprised of several protein subunits, encoded by the ndh genes of the plastome and the nucleus. The ndh genes are critical to the proper functioning of the photosynthetic electron transport chain and protection of plants from oxidative stress. Most plants are known to contain all eleven ndh genes. Plants with missing or defective ndh genes are often heterotrophs either due to their complete or holo- or myco- parasitic nature. Plants with a defective NDH complex, caused by the deletion/pseudogenisation of some or all the ndh genes, survive in milder climates suggesting the likely extinction of plant lineages lacking these genes under harsh climates. Interestingly, some autotrophic plants do exist without ndh gene/s and can cope with high or low light. This implies that these plants are protected from oxidative stress by mechanisms excluding ndh genes. Jojoba has evolved mechanisms to cope with a non-functioning NDH complex and survives in extreme desert conditions with abundant sunlight and limited water