Somatic Hybrid Lines Research Articles

Efficacy of water and methanol potato peel extracts from a somatic hybrid line in sunflower oil stability

Efficacy of water and methanol potato peel extracts from a somatic hybrid line in sunflower oil stability

Asymmetric Somatic Hybridization Affects Synonymous Codon Usage Bias in Wheat.

Asymmetric somatic hybridization is an efficient strategy for crop breeding by introducing exogenous chromatin fragments, which leads to whole genomic shock and local chromosomal shock that induces genome-wide genetic variation including indel (insertion and deletion) and nucleotide substitution. Nucleotide substitution causes synonymous codon usage bias (SCUB), an indicator of genomic mutation and natural selection. However, how asymmetric somatic hybridization affects SCUB has not been addressed. Here, we explored this issue by comparing expressed sequence tags of a common wheat cultivar and its asymmetric somatic hybrid line. Asymmetric somatic hybridization affected SCUB and promoted the bias to A- and T-ending synonymous codon (SCs). SCUB frequencies in chromosomes introgressed with exogenous fragments were comparable to those in chromosomes without exogenous fragments, showing that exogenous fragments had no local chromosomal effect. Asymmetric somatic hybridization affected SCUB frequencies in indel-flanking sequences more strongly than in non-flanking sequences, and this stronger effect was present in both chromosomes with and without exogenous fragments. DNA methylation-driven SCUB shift was more pronounced than other SC pairs. SCUB shift was similar among seven groups of allelic chromosomes as well as three sub-genomes. Our work demonstrates that the SCUB shift induced by asymmetric somatic hybridization is attributed to the whole genomic shock, and DNA methylation is a putative force of SCUB shift during asymmetric somatic hybridization. Asymmetric somatic hybridization provides an available method for deepening the nature of SCUB shift and genetic variation induced by genomic shock.

Nutritional analysis and molecular characterization of hybrid mushrooms developed through intergeneric protoplast fusion between Pleurotus sajor-caju and Calocybe indica with the purpose to achieve improved strains.

Two edible mushrooms Calocybe indica and Pleurotus sajor-caju were chosen as parent strains in this study to approach the concept of hybridization through theprotoplast fusion technique. Protoplast fusion in presence of polyethylene glycol (PEG) was conducted between the parent strains and by further double selection screening method, six somatic hybrid lines were developed. Those fruit bodies of the hybrid lines showed phenotypic resemblance with Pleurotus sajor-caju when grown on paddy straw under favorable conditions. The hybridity of the newly developed somatic hybrid strains was established by barrage reaction, morphological traits, fruitbody parameter and, inter single sequence repeat (ISSR) profiling. One-way analysis of variance (ANOVA) was used for the analysis of phenotypic data of hybrid lines and parents. Five ISSR primers were used to generate 51 amplified DNA fragments ranged between 250 and 3000bp in size in six hybrids and two parents with 90.19% polymorphism. Some of the hybrids contain some non-parental bands whichindicate that recombination might happen in thehybrid genome hence confirming the hybridity of newly developed strains. The dendrogram was created using theAverage Linkage (Between Groups) method based on ISSR profiling and genetic distance between parent-hybrids and hybrid-hybrid was analyzed by Jaccard's proximity matrix. A definite improvement in nutritional properties and biological activity was observed in the study. Due to ease in their cultivation, it can play a significant role in the rural economic development.

Assessment of physiological age and antioxidant status of new somatic hybrid potato seeds during extended cold storage

Yield components of potato are largely affected by the physiology age of the tuber seeds at planting. The current study focuses on monitoring seed tuber aging in two CN1 and CN2 somatic hybrid lines and Spunta (Sp) variety during 270 days of storage at 4 °C. Aging rate was monitored based on sprouting, emergence and tissue oxidation rates. Investigation of sprouting parameters such as physiological age index (PAI) considering physiological and chronological age and the incubation period (IP) indicated lower physiological age in hybrids than in Sp during the storage. Moreover, these analyses showed that off-seasonal growing conditions increased the aging, more clearly, in Sp tubers than in hybrid ones. However, dormancy periods (endodormancy and after storage dormancy) were equivalent in the different tuber lots. PAI and IP data when combined with those from emergence parameters (duration until emergence and stem number) seem more efficient for the characterization of the different potato lines. However, emergence indicators, when considered separately, were not able to distinguish clearly between seasonal and off-seasonal tubers. Data suggest that hybrid seeds exhibited high performances since they produced higher stem number per plant than Sp. The high aging rate in Sp tubers seems to be associated with the few developed stems. Biochemical analyses supported in part morphophysiological differences between hybrids and Sp seeds although these indicators seem more sensitive to aging. Indeed data showed that the dormancy break, and then, the development were associated with some level of tissue oxidation. Antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and carotenoids seem more enhanced after the release of dormancy. However, induction of these activities started earlier in off-seasonal tubers than in seasonal ones, this was consistent with their advanced aging level revealed by PAI and IP data. Activation of these antioxidants appears to respond effectively to the increase of ROS suggesting a better control of postharvest development and tissue deterioration especially in CN2 off-seasonal tubers. This study suggests that CN2 followed by CN1 exhibited the best performance compared to Sp variety.

The non-random patterns of genetic variation induced by asymmetric somatic hybridization in wheat

BackgroundAsymmetric somatic hybridization is an efficient crop breeding approach by introducing several exogenous chromatin fragments, which leads to genomic shock and therefore induces genome-wide genetic variation. However, the fundamental question concerning the genetic variation such as whether it occurs randomly and suffers from selection pressure remains unknown.ResultsHere, we explored this issue by comparing expressed sequence tags of a common wheat cultivar and its asymmetric somatic hybrid line. Both nucleotide substitutions and indels (insertions and deletions) had lower frequencies in coding sequences than in un-translated regions. The frequencies of nucleotide substitutions and indels were both comparable between chromosomes with and without introgressed fragments. Nucleotide substitutions distributed unevenly and were preferential to indel-flanking sequences, and the frequency of nucleotide substitutions at 5′-flanking sequences of indels was obviously higher in chromosomes with introgressed fragments than in those without exogenous fragment. Nucleotide substitutions and indels both had various frequencies among seven groups of allelic chromosomes, and the frequencies of nucleotide substitutions were strongly negatively correlative to those of indels. Among three sets of genomes, the frequencies of nucleotide substitutions and indels were both heterogeneous, and the frequencies of nucleotide substitutions exhibited drastically positive correlation to those of indels.ConclusionsOur work demonstrates that the genetic variation induced by asymmetric somatic hybridization is attributed to both whole genomic shock and local chromosomal shock, which is a predetermined and non-random genetic event being closely associated with selection pressure. Asymmetric somatic hybrids provide a worthwhile model to further investigate the nature of genomic shock induced genetic variation.

Agro-physiological and growth response to reduced water supply of somatic hybrid potato plants (Solanum tuberosum L.) cultivated under greenhouse conditions

Potato seed production from in vitro multiplication processes requires different steps, starting from greenhouse cultivation of plants and production of the first generation of tubers (minitubers). These tubers are then used as seeds in the first field culture conditions, which is followed by a second field culture using the previous tubers as seeds. The insect-proof greenhouse culture of potato plants requires regular watering and an adequate fertilization process. In this context, we focused in this report on the greenhouse culture conditions of two intraspecific somatic hybrids that previously showed improved resistance to Potato Virus Y and to Pythium aphanidermatum infection. Three different culture conditions were tested: a seasonal culture submitted to full irrigation (IR100) or to 50% irrigation (IR50) and off-seasonal culture. The effects of the moderate water deficit during the culture period on plant growth and tuber yield were investigated. During the different culture periods, physiological, biochemical and agronomical parameters were followed. The greenhouse experiments were applied on two commercial varieties (Nicola and Spunta) used as control in addition to the two somatic hybrid lines (CN1 and CN2). Hybrid plants exhibited better plant growth and higher yields of tubers than the commercial varieties. Under moderate water supply plants from hybrid lines showed higher tuber quality than commercial lines. Indeed, the highest levels of dry matter, starch, protein and lipid contents were measured in CN1 tubers in the full irrigation regime. Similarly, in the off-seasonal culture, the CN1 and CN2 tubers exhibited the highest dry matter content. The 50% reduction of irrigation rate slightly affected the starch, protein and lipid contents of the different plant lines. However, the CN1 hybrid tuber content in starch and reduced sugars remained higher than the other tubers.

Nutritional quality assessment of two potato intraspecific somatic hybrid lines

The nutritional quality of new potatoes from intraspecific somatic hybrids called CN1 and CN2 was investigated and compared to that of the conventional Nicola and BF15 varieties. The chemical composition of tubers was determined to ascertain substantial equivalence. No significant difference in ash and mineral levels was noticed between all the potato samples. However, some differences were observed in dry matter, starch, soluble sugar, protein and lipid contents between hybrid potatoes and commercial varieties, but all values were within the normal ranges reported in the literature. The hybrid potatoes as well as the Nicola and BF15 varieties were then separately added to rat diet at a level of 30% (w/w). Animals were divided into five groups of 5 rats each. The rat group fed the standard diet served as control. The responses of rats fed diets containing hybrid potatoes were compared to those fed conventional potato varieties. Overall health, weight gain, food consumption and digestibility, aspects and r...

Somatic Hybrids Between Potato and S. berthaultii Show Partial Resistance to Soil‐Borne Fungi and Potato Virus Y

AbstractThree tetraploid somatic hybrid lines produced by protoplast fusion between a dihaploid potato, Solanum tuberosum, cultivar BF15 and the wild potato species Solanum berthaultii were evaluated here for their response to different soil‐borne pathogens, that is Fusarium solani, Pythium aphanidermatum and Rhizoctonia solani as well as to infection by potato virus Y (PVY). Both hybrid and BF15 plants grown in vitro were inoculated with the tested pathogen strains, that is R. solani, P. aphanidermatum, or F. solani. The growth level and disease severity index of these plants were compared to the susceptible commercial cultivar Spunta. A better growth of inoculated hybrid plants and restricted disease symptoms were observed in comparison with the commercial plants. Under glasshouse conditions and after inoculation with R. solani and P. aphanidermatum, improved resistance of the hybrid plants to these pathogens was confirmed. Indeed, these plants showed no significant damage following inoculation and a better development in R. solani‐infected plants. The susceptibility of the hybrid tubers to R. solani, P. aphanidermatum, and to F. solani infection was also determined. A significant reduction of tissue colonisation was observed in all the hybrid lines compared to the cultivated cultivars. The STBc and STBd hybrids also showed improved resistance to the PVY ordinary strain (PVYo) under glasshouse conditions.

Genome Instability In Fruit Body Derived Lines Generated From Fruiting Pfle Somatic Hybrid Lines And Development Of Hybrid Strain Specific Scar Marker In Edible Mushroom

Abstract Six fruit body derived lines (pfle FB) generated from six fruiting pfle somatic hybrid mushroom lines showed genetic diversity analysed by fruit body morphology and inter simple sequence repeat (ISSR) markers. Stipe length, pelius diameter and bioefficiency % (BE%) of all the strains showed variations between each other with respect to Pleurotus florida parent. Hybrid pfle 1v and pfle 1q showed the highest value of stipe length and pelius diameter, respectively, compared with parent P. florida. Four ISSR primers amplified a total of 47 reproducible fragments with 82.9% polymorphism in which primer ISSR-03 produced the highest number of amplicons. Unweighted pair group method with arithmetic mean (UPGMA) based dendrogram exhibited two major groups in which hybrids pfle 1r and pfle 1q showed genetical closeness to parents P. florida and Lentinula edodes, respectively. Tissue culture generated line from fruit body of pfle 1r hybrid showed maximum BE% compared with the other hybrids and P. florida parent. For identification of this line, a pair of hybrid strain-specific SCAR marker (RFB2F and RFB2R) was developed based on an unique 813 bp RAPD amplicon.

New food from a potato somatic hybrid: nutritional equivalence and safety assessment by a feeding study on rats

Potato tubers from the STBd somatic hybrid line that exhibited improved tolerance to salinity and resistance to fungal and PVY infections were characterised. They were compared for their chemical composition to the Spunta variety produced by conventional agronomic practices. This study aimed to compare nutritional value and safety by feeding rats with STBd or commercial tubers added to the standard diet (20/80 w/w). The analysis of soluble sugar, fat, fibre and ash content of tubers did not reveal any significant differences between the hybrid line and the control Spunta variety. Small differences were observed in dry matter, starch and protein content of hybrid potatoes in comparison to controls. However, all values were within normal ranges reported in the literature. The feeding study on rats showed that overall health, weight gain, food consumption, morphological aspects and weights of organs were comparable between rat groups fed the STBd hybrid and the Spunta variety. Taken together, 28 days of consumption of STBd hybrid potato did not exert any adverse effect on rats compared with commercial Spunta potato. The STBd potato line was therefore considered to be as safe for food utilisation as the commercial variety.

Production and characterization of somatic hybrids raised through protoplast fusion between edible mushroom strains Volvariella volvacea and Pleurotus florida

Twelve somatic hybrid lines were raised through polyethylene glycol-mediated intergeneric protoplast fusion between Volvariella volvacea and Pleurotus florida using a double selection method. Four hybrid lines belonging to two distinct colony morphology types could be maintained in culture. Basidiocarps could be generated from two hybrid lines, one of which showed resemblance to the P. florida parent while the other showed intermediate parental morphology. Hybridity of the fusant lines was established on the basis of colony morphology, mycelial growth rate, hyphal traits, fruit body morphology, isozyme and RAPD analysis. Four isozyme activities were analyzed to provide biochemical criteria for detection of polymorphism among the hybrids and their parents. Using 20 random decamers a total of 203 RAPD bands ranging from 0.09 to 1.6 kb were observed. The UPGMA method of clustering exhibited two major phylogenetic clusters, the first of which comprised of the parents, two fruit body generating hybrid lines and their subsequent fruit body derived lines, while the two non-fruit body generating hybrid lines formed the out group of the first major cluster. Screening of a Pleurotus type hybrid line having high biological efficiency and generation of a temperature tolerant Pleurotus type line through backcross mating between a non-fruit body generating somatic hybrid and V. volvacea parent are the key achievements of this fusion programme.

Interspecific potato somatic hybrids between Solanum berthaultii and Solanum tuberosum L. showed recombinant plastome and improved tolerance to salinity

In this study three somatic hybrid lines originating from protoplast fusion between Solanum tuberosum cv. BF15 and Solanum berthaultii were subjected to a detailed molecular analysis using the I-SSR-PCR technique based on 5′-anchored microsatellite primers. The data obtained revealed a polymorphism between the different lines, suggesting that they correspond to symmetric hybrids. The analysis of chloroplast genome of these hybrids showed that they are resulting from a recombination between parental plastomes. When transferred to a greenhouse, these hybrid lines displayed an improved vigour compared to the cultivated potato BF15 parent. Indeed, an important growth rate and high tuber yield and weight were obtained for these hybrids compared to the parent. Some of these hybrids showed also an improved ion homeostasis control and they seem to display a better tolerance to salt stress compared to the potato BF15 parent.

Genetic Characteristic of High Molecular Weight Glutenin Subunits in Somatic Hybrid Wheat LinesPotential Application to Wheat Breeding

Analysis of 17 derivatives from a somatic fusion between common wheat (Triticum aestivum) and tall wheat grass (Thinopyrum ponticum) showed a diversity of high molecular weight glutenin subunit (HMW-GS) compositions. On the basis of the inheritance of HMW-GS patterns, the derivatives were either (i) bred true over four successive generations, (ii) generated a few novel HMW-GS combinations at each generation, or (iii) showed highly unstable HMW-GS compositions. HMW-GS analysis of F(5) seed and each single seed-generated F(6) progenies further revealed that most of the HMW-GS had genetic stability. The variations of HMW-GS were inferred to occur in early generations and were maintained thereafter. Low molecular weight glutenin subunits (LMW-GS) in hybrid lines with high or low bread-making quality, classified into the first pattern, were compared. The result showed that hybrid lines with the uniform HMW-GS patterns also have identical LMW-GS patterns. The Glu-1 quality score was inferred to be relatively significant to the sodium dodecyl dulfate sedimentation value, as well as to correlate with the gluten exponent and contents of dry gluten and proteins. Sexual hybridization between high-quality somatic hybrid progeny II-12 and Chinese Spring (CS) showed that these high-quality HMW-GS genes could entail progenies. There was not subunit variation in the progenies of II-12 x CS. Therefore, sexual hybridization between somatic hybrid line and cultivars can transfer novel high-quality HMW-GS of somatic hybrids and benefit wheat breeding.

Two quality-associated HMW glutenin subunits in a somatic hybrid line between Triticum aestivum and Agropyron elongatum.

High-molecular-weight glutenin subunits (HMW-GSs) from hybrid line II-12 between wheat (Triticum aestivum L.) and Agropyron elongatum (Host) Nivski were characterized with SDS-PAGE. Out of these HMW-GSs, two subunits, h1Bx and h1By, had mobilities similar to the subunits 1Bx13 and 1By16 from common wheat 4072, which was used as control. Polyclonal antibodies (pAbs) of h1Bx and h1By were prepared, and Western blotting showed that the pAbs had strong affinities for h1Bx and h1By, separately. The specificity of h1Bx-pAb was further checked; it preferentially recognized subunits h1Bx and 1Bx13. HMW-GS gene coding sequences were amplified by genomic polymerase chain reaction from hybrid II-12. Two of the five amplicons, marked II2a and II31b, were sequenced. Their coding sequences are clustered to Glu-1Bx7 and Glu-1By9 of common wheat. Three discrepant regions in deduced amino acid sequences of II2a and 31b repeated one time more than Glu-1Bx7 and Glu-1By9. N-terminal sequences of h1Bx and h1By were determined, which were identical to the published sequences of 1Bx13 and 1By16 and in agreement with that deduced from II2a and II31b, respectively. These results indicated that the two novel genes separated from the hybrid wheat derived from the allelic variation of 1Bx7 and 1By9 of the parent wheat. There is an additional cysteine residue positioned at 271st amino acid of the mature peptide of II2a, which may be related to the high quality of the flour.

Transfer of small chromosome fragments of Agropyron elongatum to wheat chromosome via asymmetric somatic hybridization

The chromosome constitution of hybrids and chromatin patterns of Agropyron elongatum (Host)Neviski in F5 somatic hybrid lines II -1-3 and I-1-9 between Triticum aestivum L. and A. elongatum were analyzed. Based on the statistic data of pollen mother cells, F5 I-1-9 and II-1-3 had 20-21 bivalents with a frequency of 84.66% and 85.28%, of which, 89.83% and 89.57% were ring bivalents. The result indicated that both hybrid lines were basically stable in the chromosome constitution and behavior. RAPD analysis showed that the two hybrids contained biparental and integrated DNA. GISH (Genome in situ hybridization) revealed that in the form of small chromosome segments, A. elongatum chromatin was scattered on 4-6 wheat chromosomes near by the region of centromere and telomere in the two hybrid lines. SSR analysis indicated that A. elongatum DNA segments were distributed on the 2A, 5B, 6B and 2D wheat chromosomes in the hybrids, which was in accordance with the GISH results that small-segments intercalated poly-site.

A somatic hybrid between Solanum integrifolium and Solanum violaceum that is resistant to bacterial wilt caused by Ralstonia solanacearum

Protoplast fusion was performed between a commercial rootstock variety of Solanum integrifolium that is widely used in the cultivation of edible eggplant, and Solanum violaceum, a wild eggplant species tolerant to bacterial wilt. One of the somatic hybrid lines (27–14) obtained showed morphological traits intermediate between those of its parents. Its hybrid nature was confirmed by analysis of random amplified polymorphic DNA and restriction fragment length polymorphism patterns. Microscopic observation revealed that the line was amphidiploid. The hybrid line and both parent species were infected with a virulent strain of Ralstonia solanacearum by the root cutting method. Line 27–14 developed much less severe symptoms of bacterial wilt than the susceptible S. integrifolium. Twenty days after inoculation, the bacterial density in the shoot apex tissue was significantly lower in the hybrid than in S. integrifolium, suggesting that the multiplication of bacteria was inhibited in line 27–14.

Comparative study of symmetric and asymmetric somatic hybridization between common wheat andHaynaldia villosa

Symmetric and asymmetric protoplast fusion between long term cell suspension-derived protoplasts ofTriticum aestivum (cv. Jinan 177) and protoplasts ofHaynaldia villosa prepared from one-year-old embryogeneric calli was performed by PEG method. In asymmetric fusion, donor calli were treated with gamma ray at a dose of 40, 60, 80 Gy (1.3 Gy/min) respectively and then used to isolate protoplasts. Results of morphological, cytological, biochemical (isozyme) and 5S rDNA spacer sequence analysis revealed that we obtained somatic hybrid lines at high frequency from both symmetric and asymmetric fusion. Hybrid plants were recovered from symmetric and low dose gamma-fusion combinations. GISH (genomicin situ hybridization) analysis proved exactly the existence of both parental chromosomes and the common occurrence of several kinds of translocation between them in the hybrid clones regenerated from symmetric and asymmetric fusion. And the elimination of donor DNA in hybrid clones regenerated from asymmetric fusion combinations was found to increase with the increasing gamma doses. It is concluded that transference and recombination of nuclear DNA can be achieved effectively by symmetric and asymmetric fusion, hybrids with small fragment translocation which are valuable in plant breeding can be obtained directly by asymmetric fusion.

Fertile Solanum tuberosum+S. commersonii somatic hybrids as sources of resistance to bacterial wilt caused by Ralstonia solanacearum

The wild potato relative Solanum commersonii is reported to carry resistance to bacterial wilt disease caused by Ralstonia solanacearum. To overcome sexual incompatibilites due to differences in ploidy and endosperm balance numbers, somatic hybrids were made that combine the S. tuberosum and S. commersonii genomes. The resulting somatic hybrid plants are vigorous, but their disease resistance level and their fertility was unknown. We therefore tested the S. commersonii and S. tuberosum source material cv Superior, potato cv Atlantic and six somatic hybrid lines for resistance to a virulent strain of R. solanacearum (race 3, biovar 2) at 28°C. As expected, S. commersonii was significantly more wilt-resistant than the cultivated potatoes. In five of the six somatic hybrid lines, disease resistance levels were similar to that of the resistant S. commersonii parent. The resistance level of the sixth somatic hybrid was intermediate, significantly different from both S. commersonii and S. tuberosum. In controlled crosses, the somatic hybrids in this study proved both to be male- and female-fertile and were self-compatible. More importantly, the somatic hybrids can be crossed with S. tuberosum to produce viable seeds.

DNA analysis of potato + Solanum brevidens somatic hybrid lines

Three somatic hybrid lines between potato (cv. While Lady line no. Ke 79, 2n = 2x = 48) + Solanum brevidens (PI 218228, 2n = 2x = 24) were evaluated using randomly amplified polymorphic DNA (RAPD) markers. The lines originated from the same callus but showed different reactions to Erwinia carotovora ssp. carotovora, the cause of potato soft rot. By the use of 48 oligomer primers producing 99 scorable bands, DNA polymorphism were detected on 7 of 12 S. brevidens chromosomes. Loss of certain DNA segments on chromosome 5, 6, 9 and 11 were observed. Some of the variations could have taken place in early callus stage of development; others may have occurred after initiation of individual shoot regeneration. The possible involvement of missing RAPD products specific to one somatic hybrid that shows decreased resistance to bacterial soft rot is discussed.

Variation in the growth and alkaloid production capability of the hairy roots of Hyoscyamus albus, H. muticus and their somatic hybrid

Hairy root cultures have been established by inoculating the somatic hybrid ( Hyoscyamus muticus + H. albus) as well as parent leaf explants with two strains of Agrobacterium rhizogenes (A4 and LBA 9402). The transformation frequency obtained with the A4 strain was found to be better than that of the LBA 9402 strain in all three test systems. Six lines each of H. albus and H. muticus, and four lines of the hybrid were studied for their growth and secondary metabolite production after 30 days of culture. Great variation was observed among the various lines induced by the two strains of bacteria. The maximum biomass had been noted in the somatic hybrid line 2D of A4 origin which is 1.26 and 1.55 times higher than that of the maximum biomass yielding lines 3M and 43A of H. muticus and H. albus respectively of the same bacterial origin. The somatic hybrid hairy root line 1D induced by A4 strain revealed maximum yield of atropine (9.73mg/culture) which was 9.18 times and 1.45 times higher than that of the highest atropine yielding hairy root line of H. muticus (35M) and H. albus (28A) respectively, of A4 origin. The scopolamine content of the same somatic hybrid line was found to be 1.13 times higher than that of the maximum scopolamine yielding H. albus line (28A).