Whole Exome Sequencing-Based Identification of a Novel Gene Involved in Root Hair Development in Barley (Hordeum vulgare L.)

Root hairs play a crucial role in anchoring plants in soil, interaction with microorganisms and nutrient uptake from the rhizosphere. In contrast to Arabidopsis, there is a limited knowledge of root hair morphogenesis in monocots, including barley (Hordeum vulgare L.). We have isolated barley mutant rhp1.e with an abnormal root hair phenotype after chemical mutagenesis of spring cultivar ‘Sebastian’. The development of root hairs was initiated in the mutant but inhibited at the very early stage of tip growth. The length of root hairs reached only 3% of the length of parent cultivar. Using a whole exome sequencing (WES) approach, we identified G1674A mutation in the HORVU1Hr1G077230 gene, located on chromosome 1HL and encoding a cellulose synthase-like C1 protein (HvCSLC1) that might be involved in the xyloglucan (XyG) synthesis in root hairs. The identified mutation led to the retention of the second intron and premature termination of the HvCSLC1 protein. The mutation co-segregated with the abnormal root hair phenotype in the F2 progeny of rhp1.e mutant and its wild-type parent. Additionally, different substitutions in HORVU1Hr1G077230 were found in four other allelic mutants with the same root hair phenotype. Here, we discuss the putative role of HvCSLC1 protein in root hair tube elongation in barley.

Complete Genome Sequencing of the Attenuated Strain Mycoplasma synoviae 5-9

Here, we present the complete genome sequence of Mycoplasma synoviae strain 5-9. Strain 5-9 was attenuated by chemical mutagenesis from a field strain isolated from egg breeders in Ningxia, China. It was completely sequenced and its genome annotated; it is presented with the relevant data as a potential vaccine candidate.

Rice Brittle Culm19 Encoding Cellulose Synthase Subunit CESA4 Causes Dominant Brittle Phenotype But has No Distinct Influence on Growth and Grain Yield

Background Mechanical strength is a crucial agronomic trait in rice (Oryza sativa), and brittle mutants are thought suitable materials to investigate the mechanism of cell wall formation. So far, almost all brittle mutants are recessive, and most of them are defected in multiple morphologies and/or grain yield, limiting their application in hybrid breeding and in rice straw recycling. Results We identified a semi-dominant brittle mutant Brittle culm19 (Bc19) isolated from the japonica variety Nipponbare through chemical mutagenesis. The mutant showed the same apparent morphologies and grain yield to the wild type plant except for its weak mechanical strength. Its development of secondary cell wall in sclerenchyma cells was affected, along with reduced contents of cellulose, hemicellulose, lignin and sugars in culms and leaves. Positional cloning suggested that the Bc19 gene was allelic to OsCESA4, encoding one of the cellulose synthase A (CESA) catalytic subunits. In this mutant, a C-to-T substitution occurred in the coding sequence of BC19, causing the P507S missense mutation in its encoded product, which was located in the second cytoplasmic region of the OsCESA4 protein. Furthermore, introducing mutant gene Bc19 into the wild-type plant resulted in brittle plants, confirming that the P507S point mutation in OsCESA4 protein was responsible for the semi-dominant brittle phenotype of Bc19 mutant. Reverse correlation was revealed between cellulose contents and expression levels of mutant gene Bc19 among the homozygous mutant, the hybrid F1 plant, and the Bc19 overexpression transgenic plants, implying that gene Bc19 might affect cellulose synthesis in a dosage-dependent manner. Conclusions Bc19, a semi-dominant brittle mutant allele of gene OsCESA4, was identified using map-based cloning approach. The mutated protein of Bc19 possessing the P507S missense mutation behaved in a dosage-dependent semi-dominant manner. Unique brittle effect on phenotype and semi-dominant genetic quality of gene Bc19 indicated its potential application in grain-straw dual-purpose hybrid rice breeding.

Enhanced phytase production by Aspergillus niger mutants in solid state fermentation

The present research work was conducted to improve the phytase production by genetic alteration of Aspergillus niger with induced mutagenesis using solid state fermentation. Strain improvement was carried out in the presence of ultra violet (UV) irradiation and ethylmethane sulphonate (EMS) [0.5% v/v] treatments for various time intervals. We reported an improved strain of Aspergillus niger designated as UV-3 mutant producing a zone of hydrolysis of about 40 mm, in comparison to wild strain (26 mm). The highest enzyme activity was found to be 547.64 IU/g for UV-3 mutant followed by EMS-4 mutant (492.23 IU/g)compared to wild strain which showed 406.45 IU/g of enzyme activity. There was 1.35 fold increase in phytase production after mutation studies of Aspergillus niger. Phytase was applied as poultry feed additive and given to broiler chickens for 5 weeks. The results exhibited that there was increase in body weight gain (BWG) of chicks for experimental group (2028 g) in comparison to control group (1903 g). Thus, physical and chemical mutagenesis was proved as an effective technique for the improvement of strain and ultimately for enhanced and economical phytase production for different industrial applications.

Hop-like alfalfa as an object of introduction into culture

It was found that the most promising strains of nodule bacteria XM1 and 412b are the most promising for inoculation of the Mira variety, the former increased the collection of dry matter by 96%, the latter by 81%, seeds by 115 and 73%. Strain XM1 was isolated from the nodules of the same wild population of alfalfa in the hop-like Moscow region from which the variety Mira was formed by the method of chemical mutagenesis. Strains 412b and XM 1 can be recommended for pre-sowing inoculation of the Mira variety when cultivated for feed and seeds, and the XM6 strain - when cultivated for seeds. The latter increases the seed yield by 84%, and the green mass by only 31%. Strains XM2, XM5 and XM6 shift the metabolism of the alfalfa-rhizobial system towards an increase in the number of seeds. The proportion of seeds increases to 24-31% of the mass of the entire plant, in other symbiotic systems this figure is 19-22%. A promising breeding number of hop alfalfa VIC 26 has been created, which is 58% more productive than the Mira variety when grown in the traditional way and by 65% when inoculated with the A2 strain.

Mutation Breeding in Ornamentals

The promising possibilities of mutation breeding in ornamental plants have led to a great interest in effective mutagenic treatment protocols for various species. This review discusses mutagenic treatments of a large number of ornamental genera, the advantages and disadvantages of various techniques, and the possibilities of improving the associated protocols. A number of nontargeted mutagenesis methods are available, ranging from chemical treatment with alkylating agents to irradiation with X-rays, gamma rays, and neutron or heavy ion beams at various doses. These are all relatively inexpensive and have been proven to be effective mutagens in a large number of diverse species. Genetic engineering, however, remains mostly impractical for many ornamental breeding operations because of the high cost and lack of knowledge necessary to successfully transform and regenerate ornamental crops. Of the available nontargeted mutagens, irradiation with gamma rays is still the most popular. It provides high consistency compared with chemical mutagens, albeit at a seemingly lower mutagenic efficiency. Changes in the radiation dose rate may increase the efficiency, although chronic irradiation over a longer period causes fewer deleterious mutations than the commonly used acute irradiation protocols. Heavy ion beam irradiation may also provide highly consistent mutation induction at higher efficiencies because of the high particle energy associated with these treatments. There are also opportunities to improve chemical mutagenesis. Although the required knowledge of specific gene functions in many ornamentals is still lacking, combination mutagenesis with ethyl methanesulfontate with genetic screening in a process known as TILLING (Targeting Induced Local Lesions IN Genomes) may lead to a powerful mutation breeding tool in the future. Mutation breeding is still very useful, and many opportunities are available to improve the existing methods.

Assessment of Morphological Mutations and Genetic Components in MMS and EMS Induced Chilli Cultivars, NS 1101 and NS 1701DG

A change in the genetic makeup of a plant is an essential prerequisite for the breeding programs and induce mutagenesis is an important approach to create the variations within crop germplasm. The main objective of this study is to find the mutants in chemically treated M2 chilli plant populations. Since, mutagenesis in chilli plants was induced through EMS and Cd to increase the genetic variability that results in thirteen mutant plants at M2 generation from the genetic background of chilli varieties NS 1101 and NS 1701 DG, respectively. Most of the mutant phenotypes observed felled within qualitative and quantitative characteristics the seven major categories including plant height, leaf shape, leaf color, branch, and flower color, fruits, 1000 seed weight, yield, and root length. The inter-population differences were carried out through analysis of variance of quantitative traits of chemically treated chilli populations. Results reflect increased mean value in quantitative traits that could validate the improvement over the parental lines. Fruit number and seed weight were the main priority traits in the selection of high yield plants and these quantitative traits have a strong association with the yield of the plant. Genetic variability induced by chemical mutagens in chilli can integrate into further chilli breeding programs as new crop germplasm with improved agronomic traits. Mutants selected from 0.2% treated chilli populations can be used to develop an efficient and fast crop variety of chilli with desirable traits. The present study about the genetic variability induced by chemical mutagenesis provides more opportunities to bring diversity in the genetic makeup of chilli plant for improvement of the desirable traits.