Accumulation of dehydrin-like proteins in the mitochondria of cereals in response to cold, freezing, drought and ABA treatment

BACKGROUND: Dehydrins are known as Group II late embryogenesis abundant proteins. Their high hydrophilicity and thermostability suggest that they may be structure stabilizers with detergent and chaperone-like properties. They are localised in the nucleus, cytoplasm, and plasma membrane. We have recently found putative dehydrins in the mitochondria of some cereals in response to cold. It is not known whether dehydrin-like proteins accumulate in plant mitochondria in response to stimuli other than cold stress. RESULTS: We have found five putative dehydrins in the mitochondria of winter wheat, rye and maize seedlings. Two of these polypeptides had the same molecular masses in all three species (63 and 52 kD) and were thermostable. Drought, freezing, cold, and exogenous ABA treatment led to higher accumulation of dehydrin-like protein (dlp) 63 kD in the rye and wheat mitochondria. Protein 52 kD was induced by cold adaptation and ABA. Some accumulation of these proteins in the maize mitochondria was found after cold exposition only. The other three proteins appeared to be heat-sensitive and were either slightly induced or not induced at all by all treatments used. CONCLUSIONS: We have found that, not only cold, but also drought, freezing and exogenous ABA treatment result in accumulation of the thermostable dehydrins in plant mitochondria. Most cryotolerant species such as wheat and rye accumulate more heat-stable dehydrins than cryosensitive species such as maize. It has been supposed that their function is to stabilize proteins in the membrane or in the matrix. Heat-sensitive putative dehydrins probably are not involved in the stress reaction and adaptation of plants

Lines resistant to downy mildew in the sunflower genetic collection at VIR

Background. Downy mildew (DM) caused by the fungus Plasmopara halstedii (Farl) Berl. & De Toni) is one of the most harmful diseases of sunflower (Helianthus annuus L.). Due to the pathogen’s attacks, annual seed harvest losses range between 30% and 70%. Lines resistant to new races of the pathogen should be obtained for the development of commercial sunflower hybrids.Materials and methods. Downy mildew resistance of 323 lines and 10 cultivars from the sunflower collection was assessed in the field at the Kuban Experiment Station of VIR in 2017–2018. Line VIR 845, susceptible during all years of observations, was used as a control. Resistance genes were identified by means of the molecular analysis using diagnostic markers of the Plarg, Pl6 and Pl8 genes that confer resistance to many known P. halstedii races.Results. The founder varieties of VIR’s lines were susceptible to a varying extent. Thirty-nine lines were resistant in 2016 and 2018; among those, 36 lines were susceptible in 2017. Presumably, a more virulent P. halstedii race became widespread in 2017, compared to the races that prevailed in 2016 and 2018, so the genes that determined resistance in 2016 and 2018 turned out to be ineffective. Lines ТА 716-18, VIR 768, and VIR 800, having originated from interspecific hybrids, exhibited absence of pathogenic damage during 3 years of the trials. Molecular markers of the Plarg, Pl6 and Pl8 genes were detected in most lines that demonstrated resistance in 2016 and 2018. There were no markers in lines VIR 768 and VIR 800, whereas in ТА 716-18 the markers of Plarg and Pl8 were present.Conclusion. As a result of the long-term studies, a trait-specific genetic collection was established for sunflower. It comprises genotyped lines with various effective DM resistance genes. Lines ТА 716-18, VIR 768 and VIR 800 appeared highly resistant to the pathogen and probably possess new resistance genes/alleles introgressed from wild species

The trait-specific collection of large-seeded sunflower at VIR: ba source for breeding cultivars and hybrids

Background. In recent years, an increase has been observed in the share of sunflower seeds in the confectionery and food industries. There are 30 cultivars and only 3 hybrids for confectionery use among 839 zoned sunflower cultivars and hybrids listed in the State Register for Selection Achievements Admitted for Usage in 2023. Thus, the development of source material for breeding large-seeded cultivars and hybrids remains a relevant task.Materials and methods. The studied material included 90 accessions selected for their large seed size from VIR’s sunflower collection. The following characters were assessed: 1000 seed weight, days from sprouting to maturation, plant height, head diameter, cypsela color and size, and resistance to downy mildew. DNA markers were used to identify accessions with the Rf1 gene and CMS.Results. Accessions k-2818 (Primorsky Territory), k-3633, k-3748, k-3782 (China), and k-3578 (Ukraine) were the best in 1000 seed weight. Russian cvs. ‘Alekseyevsky Krupnoplodny 2’ (k-3552), ‘Gyar-Gyar’ (k-1589), ‘SPK’ (k-3426), and ‘Lakomka’ (k-3526) confirmed their large seed size. The sterile type of cytoplasm was identified in 12 accessions. Fourteen accessions with fertile cytoplasm had diagnostic markers of the nuclear Rf1 gene.Conclusion. The large-seeded cultivars developed at VNIIMK, ‘SPK’, ‘Lakomka’, and k-3782 from China were the best not only in their large seed size but also in downy mildew resistance. As a result of long-term studies, a trait-specific collection was established for the large seed size trait. It included 90 accessions that can be used in the development of confectionery cultivars. Large-seeded sunflower accessions carrying the Rf1 gene were identified. Some of them became the ancestors of donor lines for both pollen fertility restoration genes and large seed size

Sunflower lines originated from varieties with high oil content in their seed

Background. Sunflower as an oilseed crop originated from Russia. It was in this country that single-headed highly productive forms were obtained, industrial oil production was invented, first local varieties were developed, accessions with increased oil content in seeds were identified by V. S. Pustovoit and his associates, and the first high-yielding cultivars ('Peredovik', 'VNIIMK 8883') with high oil content in seeds (50-60%) were produced. Mutants with modified fatty acid composition were obtained, and high oleic cultivar 'Pervenets' was created. Soviet varieties formed the basis for the world's sunflower breeding, and further for breeding commercial hybrids using the effect of heterosis. In the article, the genetic diversity of lines originated from domestic varieties is demonstrated. The genealogy of many domestic lines and also of the American line HA89 which served as the reference in breeding trials and genetic experiments is discussed. The information on the lines developed by the researchers of VIR at Kuban Experiment Station in the years 1970-2015 as well as the available data of foreign researchers on the lines obtained from domestic varieties are presented.Materials and methods. The lines were developed using repeated self pollination of the varieties and selection by morphological characters, CMS, pollen fertility restoration ability, duration of the growing season, and downy mildew resistance in each inbred generation. As a rule, lines were homogeneous after 7-8 generations.Results and discussion. The information on the genealogy of 38 lines developed by the researches of VIR, two VNIIMK lines, 16 foreign lines, and also the data on the origin of the CMS PET1 source are analyzed. The genealogical overview of the lines has allowed us to draw a conclusion on the origin of the high oil content and high oleic content traits. It is these characters that in the first place distinguish cultivated sunflower from the wild species of the genus Helianthus L. Lines originated from one and the same variety can differ by the presence of diagnostic markers of the Rf1 gene controlling pollen fertility restoration in forms with cytoplasmic male sterility, and also by allelic variants of storage protein genes and morphological characters

FIGURE 2.A in Molecular analysis of the Pygospio elegans group of species (Annelida: Spionidae)

FIGURE 2.A, majority rule consensus tree of the Bayesian inference analysis of2450 bptotal of 16S (265 bp), 18S (1577 bp), 28S (293 bp), and Histone 3 (315 bp) of Pygospio, Boccardia, and Spio sequences rooted with sequences of Rhynchospio. B, majority rule consensus tree of the Bayesian inference analysis of 2576 bp total of 16S (296 bp), 18S (1667 bp), 28S (295 bp), and Histone 3 (318 bp) of the only-Pygospio sequences. Posterior probabilities are shown on the branches. Species names are followed by the names of the collecting locations (in parentheses)