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Ancient wheats are increasingly considered as valuable resources for genes of interest which could be analyzed and introduced into cultivated varieties by genetic engineering technologies. The first stage of biotechnological crop improvement consists of successful in vitro plant regeneration. Twelve wheat germplasms with different genomic formulas (AA, AABB, AAGG, AABBDD, AADDGG genomes) were examined with the use of two explant types (immature vs. mature embryos). All of the tested germplasms were able to regenerate plants, although the morphogenic ability of immature embryos was higher. The highest rate of embryogenic/regenerable structure formation was found in immature embryo cultures of tetraploid species (T. polonicum, T. turgidum, T. carthlicum, and T. dicoccum) as well as of hexaploid T. spelta. At the same time, diploid einkorn wheat (T. monococcum) and polyploid species with G chromosomes (T. timopheevii and T. kiharae) were characterized by low embryogenesis and by the presence of albino plantlets among shoots. [ABSTRACT FROM AUTHOR]

Recently, it has been found that bacteria secrete short RNAs able to affect gene expression in eukaryotic cells, while certain mammalian microRNAs shape the gut microbiome altering bacterial transcriptome. The involvement of bacterial RNAs in communication with other bacteria is also expected, but has not been documented yet. Here, we compared the fractions of extremely short (12–22 nucleotides) RNAs secreted by Escherichia coli grown in a pure culture and jointly with bacteria of the Paenibacillus genus. Besides fragments of rRNAs and tRNAs, abundant in all samples, secreted oligonucleotides (exoRNAs) predominantly contained GC-rich fragments of messenger and antisense RNAs processed from regions with stable secondary structures. They differed in composition from oligonucleotides of intracellular fraction, where fragments of small regulatory RNAs were prevalent. Both fractions contained RNAs capable of forming complementary duplexes, while for exoRNA samples a higher percentage of 3΄-end modified RNAs and different endonuclease cleavage were detected. The presence of a cohabiting bacterium altered the spectrum of E. coli exoRNAs, indicating a population-dependent control over their composition. Possible mechanisms of this effect are discussed. [ABSTRACT FROM AUTHOR]