Molecular Diversity of Mycobacterium avium subsp. paratuberculosis in Four Dairy Goat Herds from Thuringia (Germany)

This study investigated the intra- and inter-herd diversity of Mycobacterium avium subsp. paratuberculosis (MAP) isolates from four goat herds in Thuringia (Germany) that were affected by paratuberculosis for several years. The main focus was on the characterization and distribution of genotypes among animals and the environment of goat herd 1. This study included 196 isolates from the feces of 121 infected goats, various tissues from 13 clinically diseased goats, 29 environmental samples from herd 1, and additionally, 22 isolates of different origin from herds 2 to 4. The isolates, sampled between 2018 and 2022, were genotyped using short-sequence-repeat (SSR) analysis, mycobacterial-interspersed repetitive units-variable-number tandem repeat (MIRU-VNTR) analysis, and a single nucleotide polymorphism (SNP)-based assay for phylogenetic grouping. All the isolates belonged to the MAP-C group. In herd 1, one predominant genotype was determined, while two other genotypes were identified very rarely and only in fecal and environmental samples. One of three further genotypes was found in each of herds 2 to 4. The assignment of genotypes to different phylogenetic clades suggested six different infection strains. The results indicated no epidemiological links between the examined herds. Based on the current MAP genotyping data from Germany, possible sources of infection are MAP-contaminated barns previously used by infected cattle and the purchase of sub-clinically infected goats.

Molecular cytological analysis of alien introgressions in common wheat lines created by crossing of Triticum aestivum with T. dicoccoides and T. dicoccum

Wild and domesticated emmer (ВВАА, 2n = 28) are of significant interest for expanding the genetic diversity of common wheat as sources of a high protein and microelement grain content, resistance to many biotic and abiotic factors. Particular interest in these species is also determined by their close relationship with Triticum aestivum L., which facilitates interspecific hybridization. The objective of this work was to analyze the nature of alien introgressions in hybrid lines from crossing common wheat varieties with T. dicoccoides and T. dicoccum, and to assess the effect of their genome fragments on the cytological stability of introgression lines. A C-banding technique and genotyping with SNP and SSR markers were used to determine localization and length of introgression fragments. Assessment of cytological stability was carried out on the basis of chromosome behavior in microsporogenesis. A molecular cytogenetic analysis of introgression wheat lines indicated that the inclusion of the genetic material of wild and domesticated emmer was carried out mainly in the form of whole arms or large fragments in the chromosomes of the B genome and less extended inserts in the A genome. At the same time, the highest frequency of introgressions of the emmer genome was observed in chromosomes 1A, 1B, 2B, and 3B. The analysis of the final stage of meiosis showed a high level of cytological stability in the vast majority of introgression wheat lines (meiotic index was 83.0-99.0 %), which ensures the formation of functional gametes in an amount sufficient for successful reproduction. These lines are of interest for the selection of promising material with agronomically valuable traits and their subsequent inclusion in the breeding process.

Molecular cytological analysis of alien introgressions in common wheat lines derived from the cross of TRITICUM AESTIVUM with T. kiharae

BACKGROUND

Triticum kiharae (A^tA^tGGDD, 2n = 42) is of interest for the improvement of bread wheat as a source of high grain protein and gluten content, as well as resistance to many diseases. The use of T. kiharae for the improvement of T. aestivum L. is complicated by the fact that the homology degree of their genomes is low and this leads to an unbalanced set of chromosomes in the gametes of its first generations and the elimination of some genotypes. The aim of this study was to analyze the nature of alien introgressions and their effect on the cytological stability of hybrids obtained from crossing of bread wheat varieties with T. kiharae.

RESULTS

Using C-banding, the presence of entire chromosomes of T. kiharae in the karyotypes of hybrid lines (intergenomic substitution 2G/2B), chromosome arms (centric translocation Т2A^tS:2AL) and large inserts in the form of terminal translocations involving chromosomes of 1st, 3rd and 5th homoeologous groups of B- and G-genomes were found. Molecular markers revealed short introgression of T. kiharae into the genome of common wheat varieties. The highest introgression frequency was shown for 1A, 1B, 2A, 5B, and 6A chromosomes, while no foreign chromatin was detected in 4A and 4B chromosomes. A high level of cytological stability (a meiotic index of 88.18-93.0%) was noted for the majority of introgression lines. An exception was found for the lines containing the structural reorganization of chromosome 5B, affecting the main genes of chromosome synapsis in terms of their functioning.

CONCLUSIONS

During the stabilization of hybrid karyotypes, the introgression of genetic material from T. kiharae into the genome of T. aestivum occurs in the form of short fragments detectable only by molecular markers and in the form of whole chromosomes (intergenomic substitution) and their large fragments (centric and terminal translocations). The level of cytological stability achieved in F₁₀ by the majority of introgression lines ensures the formation of functional gametes sufficient for the successful reproduction of the obtained hybrids.

[Genome survey analysis and SSR loci mining of Bupleurum falcatum]

Buplewrum falcatum is a traditional Chinese medicine,which is mainly used for the treatment of cold and liver protection. B. falcatum is dominantly cultivated in Japan as well as planted in China,Korea and other countries and regions. In order to determine the appropriate sequencing strategy,the genome survey before large-scale genome sequencing is needed. This survey can provide information about the size and complexity of the whole genome of the target species. In the present study,the next generation sequencing technology( Illumina Hiseq 2000) was used to analyze the genome size and complexity of B. falcatum. In addition,SSR loci were analyzed from the sequenced data. Primer 3 was used to design specific primers and 33 pairs of primers were randomly selected for PCR with template DNA of B. falcatum,and the PCR system and optimal annealing temperature were screened. A total of 288. 64 G genome sequence data was obtained,and the estimated genome size of B. falcatum was 2 119. 58 Mb. The measured genome data depth was138×; the rate of heterozygosity was 1. 84%; and the ratio of repeat sequence was 83. 89%. It is speculated that the genome of B. falcatum is complex. The preliminary assembly was performed with K-mer = 41,and the contig N50 was 224 bp,the total length 896. 97 Mb,the scaffold N50 313 bp,and the total length was 922. 67 Mb. A total of 91 377 SSR sequences were detected in the sequenced genome data which were distributed in 70 809 unigenes.The main type is dinucleotide repeats,with 49 680 sequences,accounting for70. 16%. Among the 33 pairs of primers randomly synthesized according to the obtained SSR sequences,21 pairs were successfully amplifying the target sequences. The results will be helpful for later large scale genome sequencing and SSR molecular markers development for germplasm identification and trait mapping.