The karyotype of the great sculpin, <Emphasis Type="Italic">Myoxocephalus polyacanthocephalus</Emphasis> (Pallas, 1814) (Pisces: Cottidae), from the Russian part of the species range

The karyotype of the great sculpin, Myoxocephalus polyacanthocephalus (Pallas, 1814) (Pisces: Cottidae) from the Sea of Okhotsk and the Sea of Japan has been studied for the first time. The karyotype is stable; it consists of 40 chromosomes (4 metacentric, 2 submeta-subtelocentric, 20 subtelocentric, and 14 acrocentric chromosomes); the number of chromosomal arms is 44 + 2. Nucleolar organizer regions (NOR) are found in the telomeric region of the arm in one homologue of a pair of small metacentric chromosomes, using the Ag-NOR banding technique. A comparative analysis of the karyotype of M. polyacanthocephalus and the karyotypes of other Myoxocephalus species (M. stelleri, M. brandtii, M. jaok, M. ochotensis, and M. scorpius) has been carried out based on the main karyotype characters, as well as on the number and localization of NORs. The identified differences make it possible to differentiate the studied species, whereas the general traits indicate their taxonomic proximity.     

Cytogenetic analyses of eight species in the genus <Emphasis Type="Italic">Leptodactylus</Emphasis> Fitzinger, 1843 (Amphibia,Anura, Leptodactylidae), including a new diploid number and a karyotype with multiple translocations

Background

The karyotypes of Leptodactylus species usually consist of 22 bi-armed chromosomes, but morphological variations in some chromosomes and even differences in the 2n have been reported. To better understand the mechanisms responsible for these differences, eight species were analysed using classical and molecular cytogenetic techniques, including replication banding with BrdU incorporation.

Results

Distinct chromosome numbers were found: 2n = 22 in Leptodactylus chaquensis, L. labyrinthicus, L. pentadactylus, L. petersii, L. podicipinus, and L. rhodomystax; 2n = 20 in Leptodactylus sp. (aff. podicipinus); and 2n = 24 in L. marmoratus. Among the species with 2n = 22, only three had the same basic karyotype. Leptodactylus pentadactylus presented multiple translocations, L. petersii displayed chromosome morphological discrepancy, and L. podicipinus had four pairs of telocentric chromosomes. Replication banding was crucial for characterising this variability and for explaining the reduced 2n in Leptodactylus sp. (aff. podicipinus). Leptodactylus marmoratus had few chromosomes with a similar banding patterns to the 2n = 22 karyotypes. The majority of the species presented a single NOR-bearing pair, which was confirmed using Ag-impregnation and FISH with an rDNA probe. In general, the NOR-bearing chromosomes corresponded to chromosome 8, but NORs were found on chromosome 3 or 4 in some species. Leptodactylus marmoratus had NORs on chromosome pairs 6 and 8. The data from C-banding, fluorochrome staining, and FISH using the telomeric probe helped in characterising the repetitive sequences. Even though hybridisation did occur on the chromosome ends, telomere-like repetitive sequences outside of the telomere region were identified. Metaphase I cells from L. pentadactylus confirmed its complex karyotype constitution because 12 chromosomes appeared as ring-shaped chain in addition to five bivalents.

Conclusions

Species of Leptodactylus exhibited both major and minor karyotypic differences which were identified by classical and molecular cytogenetic techniques. Replication banding, which is a unique procedure that has been used to obtain longitudinal multiple band patterns in amphibian chromosomes, allowed us to outline the general mechanisms responsible for these karyotype differences. The findings also suggested that L. marmoratus, which was formerly included in the genus Adenomera, may have undergone great chromosomal repatterning.

     

Karyotype of the sculpin <Emphasis Type="Italic">Myoxocephalus jaok</Emphasis> (Pisces: Cottidae) from Peter the Great Bay,Sea of Japan

The karyotype of the sculpin Myoxocephalus jaok from the Ussuriisky, Amursky, and Vostok Bays was studied. It was found that 2n = 24, among the chromosomes there were 16 metacentric, 4 submetacentric, and 4 acrocentric, NF = 44. There was no variation in the number of chromosomes, and no differences between male and female karyotypes were revealed. A comparison of Myoxocephalus jaok, M. brandti and M. stelleri karyotypes was performed. The pronounced distinction of Myoxocephalus jaok karyotype resulting from chromosomal rearrangements was shown.     

Molecular genetic and karyological analysis of antlered sculpins of <Emphasis Type="Italic">Enophrys diceraus</Emphasis> group (Cottidae)

Molecular genetic and karyological analyses of antlered sculpin, Enophrys diceraus, from the Sea of Japan and the Sea of Okhotsk were carried out. The karyotype of this species was studied for the first time. On the basis of karyological analysis, it was established that E. diceraus from the Sea of Japan and the Sea of Okhotsk was polymorphic in terms of the number of chromosomes and their morphology (2n = 36, 35, and 37, NF = 40). It was suggested that the karyotype with 35 chromosomes could have been produced as a result of Robertsonian translocation; the karyotype with 37 chromosomes could have been produced by crossing of individuals with different number of chromosomes. On the basis of the molecular genetic analysis of the mitochondrial COI and 16S rRNA genes, considerable differences between E. diceraus from the Sea of Japan and the Sea of Okhotsk corresponding to the level of interspecies genetic variability were established. It is concluded that E. diceraus from the Sea of Japan belongs to another species, most likely, E. namiyei.     

A PCR-based analysis of plant DNA reveals the feeding preferences of <Emphasis Type="Italic">Apolygus lucorum</Emphasis> (Heteroptera: Miridae)

The mirid bug Apolygus lucorum (Meyer-Dür) (Heteroptera: Miridae) is a severe pest of cotton and other crops in China. The feeding preferences of this pest are unclear due to its frequent movement among different host plants and the inconspicuous signs of its feeding. Here, we present results of a field trial that used direct observation of bug densities and a PCR-based molecular detection assay to detect plant DNA in bugs to explore relationships between A. lucorum population abundance and its feeding preference between two host plants, Humulus scandens (Loureiro) Merrill and Medicago sativa L. The field-plot samples showed that A. lucorum adults generally prefer flowering host plants. Its density was significantly higher on flowering H. scandens than on seedlings of M. sativa, and a similarly higher bug density was observed on flowering M. sativa than on seedlings of H. scandens. In the laboratory, we designed two pairs of species-specific primers targeting the trnL-F region for H. scandens and M. sativa, respectively. The detectability of plant DNA generally decreased with time post-feeding, and the half-life of plant DNA detection (DS₅₀) in the gut was estimated as 6.26 h for H. scandens and 3.79 h for M. sativa with significant differences between each other. In mirid bugs exposed to seedlings of H. scandens and flowering M. sativa, the detection rate of M. sativa DNA was significantly higher than that of H. scandens. Meanwhile, in mirid bugs exposed to seedlings of M. sativa and flowering H. scandens, a significantly higher detection rate of H. scandens DNA was found. We developed a useful tool to detect the remaining plant food species specifically from the gut of A. lucorum in the current study. We provided direct evidence of its feeding preference between H. scandens and M. sativa at different growth stages, which strongly supported a positive correlation between population abundance and feeding preference of A. lucorum on different plants under field conditions. The findings provide new insights into the understanding of A. lucorum’s feeding preference, and are helpful for developing the strategies to control this pest.     

The Karyotype of <Emphasis Type="Italic">Amoeba borokensis</Emphasis> from a “<Emphasis Type="Italic">proteus</Emphasis>-like” Amoeba Group (Amoebozoa: Euamoebida)

The karyotype of Amoeba borokensis was studied for the first time. At the metaphase of mitosis, this species has a haploid set of chromosomes (n = 27). This is exactly half of the diploid karyotype in Amoeba proteus (strain B). At first glance, it confirms the idea that has recently appeared that one species arises from another via multiple changes in chromosome number. However, comparative cytogenetic analysis revealed that four orthologous chromosomes from haploid sets of these two species were not distinguished by the pattern of DAPI-stained bands. It shows that the genetic distance between A. proteus and A. borokensis is higher than was believed earlier and these two species have diverged from each other. Analysis of data on the life cycles of A. proteus and A. borokensis shows that a kind of so-called “cyclic polyploidy” takes place in “proteus-like” amoebae. “Cyclic polyploidy” has recently been considered as an alternative to the sexual process for genetic recombination in agamic protists from different macrotaxons.     

Weitere Untersuchungen über Chromosomenverhältnisse und DNS-Gehalt bei Anuren (Amphibia)

The karyotypes of the toad Bufo marinus L. (2n=22) and the frogs Limnodynastes tasmaniensis Gthr. (2n=24), Rana temporaria L., R. esculenta L. (both 2n=26) and R. arvalis Nills. (2n=24) were analysed in colchicine treated leukocyte and spermatogonial metaphases and/or embryonic and larval mitoses. The DNA content of Feulgen stained erythrocyte nuclei was measured microspectrophotometrically. Heteromorphic sex chromosomes are absent in all species. L. tasmaniensis has the lowest DNA content among these species. The south American toad B. marinus shows a karyotype similar to the other known toad species and contains the same amount of DNA as the European species B. calamita with the lowest DNA amount among the European toads. In southern German populations of R. temporaria besides animals with the “standard”-karyotype (2n=26) individuals with 1 or 2, in rare cases with 3 or 4 supernumerary chromosomes have been found. The supernumeraries are heterochromatic and smaller than the smallest chromosome of the “standard”-karyotype. If only 1 or 2 supernumerary chromosomes are present, they seem to show normal mendelian inheritance as a rule. The observation of a few tadpoles with intraindividual different numbers of supernumeraries points to the occurrence of unequal distribution of these chromosomes in individuals containing a higher number of supernumerary chromosomes. The karyotype of R. esculenta is very similar to the “standard”-karyotype of R. temporaria, but the chromosomes of R. esculenta are somewhat longer than those of R. temporaria. R. esculenta contains about 54% more DNA than R. temporaria in the erythrocyte nuclei, so that it must be assumed that all chromosomes of R. esculenta contain more DNA than their homologues in R. temporaria. R. arvalis possesses about 28% more DNA than R. temporaria. It is supposed that these interspecific differences in DNA content of the Rana species — as observed earlier in Bufo species — are not a consequence of differential polyteny but are caused during evolutionary processes by local increase in DNA in the chromosomes of R. esculenta and R. arvalis.     

New insights into sex chromosome evolution in anole lizards (Reptilia,Dactyloidae)

Anoles are a clade of iguanian lizards that underwent an extensive radiation between 125 and 65 million years ago. Their karyotypes show wide variation in diploid number spanning from 26 (Anolis evermanni) to 44 (A. insolitus). This chromosomal variation involves their sex chromosomes, ranging from simple systems (XX/XY), with heterochromosomes represented by either micro- or macrochromosomes, to multiple systems (X₁X₁X₂X₂/X₁X₂Y). Here, for the first time, the homology relationships of sex chromosomes have been investigated in nine anole lizards at the whole chromosome level. Cross-species chromosome painting using sex chromosome paints from A. carolinensis, Ctenonotus pogus and Norops sagrei and gene mapping of X-linked genes demonstrated that the anole ancestral sex chromosome system constituted by microchromosomes is retained in all the species with the ancestral karyotype (2n?=?36, 12 macro- and 24 microchromosomes). On the contrary, species with a derived karyotype, namely those belonging to genera Ctenonotus and Norops, show a series of rearrangements (fusions/fissions) involving autosomes/microchromosomes that led to the formation of their current sex chromosome systems. These results demonstrate that different autosomes were involved in translocations with sex chromosomes in closely related lineages of anole lizards and that several sequential microautosome/sex chromosome fusions lead to a remarkable increase in size of Norops sagrei sex chromosomes.     

Identification and fine mapping of <Emphasis Type="Italic">qWBPH11</Emphasis> conferring resistance to whitebacked planthopper (<Emphasis Type="Italic">Sogatella furcifera</Emphasis> Horvath) in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

The whitebacked planthopper (WBPH), Sogatella furcifera Horvath, is one of the most destructive pests in rice (Oryza sativa L.) production. Host-plant resistance has been considered as an efficient and eco-friendly strategy to reduce yield losses caused by WBPH. In this study, we found that an indica rice cultivar IR54751-2-44-15-24-2 (IR54751) displayed high resistance to WBPH at both seedling and tillering stages. The resistance of IR54751 was mainly contributed by antixenosis and tolerance rather than antibiosis. An F₂ population derived from a cross between IR54751 and a susceptible japonica cultivar 02428 was constructed to detect the quantitative trait loci (QTLs) conferring the resistance to WBPH. In total, four QTLs including qWBPH3.1, qWBPH3.2, qWBPH11, and qWBPH12 were identified and distributed on three different chromosomes. The four QTLs had LOD scores of 3.8, 8.2, 5.8, and 3.9, accounting for 8.2, 21.5, 13.9, and 10.4% of the phenotypic variation, respectively. Except for qWBPH3.1, the resistance alleles of the other three QTLs were all from IR54751. Further, a secondary population harboring only single qWBPH11 locus was developed from the F₂ population by marker-assisted selection. Finally, qWBPH11 was delimited in a 450-kb region between markers DJ53973 and SNP56. The identification of WBPH resistance QTLs and the fine mapping of qWBPH11 will be helpful for cloning resistance genes and breeding resistant rice cultivars.     

Chromosomal studies in <Emphasis Type="Italic">Crenicichla lepidota</Emphasis> and <Emphasis Type="Italic">Australoheros facetus</Emphasis> (Cichlidae,Perciformes) from extreme Southern Brazil

Fishes of the family Cichlidae generally show low karyotype variability. Nevertheless, karyotype variants have been identified within some genera, providing information about their evolutionary history. In the present study, karyotype characteristics of Crenicichla lepidota and Australoheros facetus, two sympatric species found in the São Gonçalo-Mangueira basin, were studied. Besides conventional procedures, double fluorochromes staining chromomycin A₃/DAPI and fluorescent in situ hybridization (FISH) with rDNA probes were also used. Both species presented 2n = 48 chromosomes, but karyotypes were differentiated by fundamental number, which was equal to 70 in A. facetus and 56 in C. lepidota. Similar heterochromatin distribution patterns were also observed on the pericentromeric region of most chromosomes, although C. lepidota presented an additional heterochromatic block in the first pair. The Ag-NORs, 18S rDNA probe and CMA₃/DAPI were coincident in location on the first and second pairs of C. lepidota and A. facetus, respectively. The minor rDNA loci (5S rDNA) were found in four sites located on two distinct chromosomal pairs in C. lepidota. Although the data obtained here to C. lepidota and to A. facetus show chromosomal characteristics considered ancestral to the family, new data are presented to both species. Additionally, this study corroborates the hypothesis in which evolutionary processes like non-Robertsonian rearrangements are involved in the diversification of the major groups of Neotropical Cichlidae. Thus, the karyotype diversification observed in A. facetus have the high fundamental number pathway while C. lepidota has others evolutionary chromosomal mechanisms.     

Karyological studies of Iranian <Emphasis Type="Italic">Allium</Emphasis> L. (Amaryllidaceae) species with focus on sect. <Emphasis Type="Italic">Acanthoprason</Emphasis>. 1. Mitotic chromosomes

Eighteen species and subspecies (34 accessions) of Allium sect. Acanthoprason and 11 species (17 accessions) belonging to other subgenera and sections of Allium were karyologically investigated and include first reports for 12 species. The examined plants of 47 accessions were diploid, three accessions of two species were tetraploid, and in the A. bisotunense accession, we found a mix of di- and triploid individuals. B chromosomes were found in 10 accessions. A basic chromosome number of x = 8 was confirmed for all investigated members of subg. Melanocrommyum and subg. Allium, and x = 9 for Allium tripedale of subg. Nectaroscordum. Idiograms were drawn for each accession, and metaphase images are presented illustrating observed chromosomal variations. Also, karyotype features and asymmetry parameters were calculated for all accessions. Chromosomal aberrations, e.g. aneuploid cells or loss of whole or parts of chromosome arms, were rarely observed. In general, the karyotypes showed low variation in inter- and intrachromosomal asymmetry especially inside of the taxonomic groups, though satellited chromosomes were good markers for subgenera and even specific for two studied sections of subg. Allium. Six different types of satellites were recognized, two of them were newly described: Type P was prevalent in subg. Melanocrommyum, and type O in sect. Codonoprasum. Statistical analyses were performed on five karyological parameters to test correct relationships and also to test previous grouping hypotheses. Although our data confirm distinct karyological characters for the subgenera investigated, the remarkable morphological diversity inside of subg. Melanocrommyum is not mirrored by striking karyological differences.     

Bidirectional backcrosses between wild and cultivated lettuce identify loci involved in nonhost resistance to downy mildew

Key message

The nonhost resistance of wild lettuce to lettuce downy mildew seems explained by four components of a putative set of epistatic genes.

Abstract

The commonplace observation that plants are immune to most potential pathogens is known as nonhost resistance (NHR). The genetic basis of NHR is poorly understood. Inheritance studies of NHR require crosses of nonhost species with a host, but these crosses are usually unsuccessful. The plant-pathosystem of lettuce and downy mildew, Bremia lactucae, provides a rare opportunity to study the inheritance of NHR, because the nonhost wild lettuce species Lactuca saligna is sufficiently cross-compatible with the cultivated host Lactuca sativa. Our previous studies on NHR in one L. saligna accession led to the hypothesis that multi-locus epistatic interactions might explain NHR. Here, we studied NHR at the species level in nine accessions. Besides the commonly used approach of studying a target trait from a wild donor species in a cultivar genetic background, we also explored the opposite, complementary approach of cultivar introgression in a wild species background. This bidirectional approach encompassed (1) nonhost into host introgression: identification of L. saligna derived chromosome regions that were overrepresented in highly resistant BC1 plants (F1?×?L. sativa), (2) host into nonhost introgression: identification of L. sativa derived chromosome regions that were overrepresented in BC1 inbred lines (F1?×?L. saligna) with relatively high infection levels. We demonstrated that NHR is based on resistance factors from L. saligna and the genetic dose for NHR differs between accessions. NHR seemed explained by combinations of epistatic genes on three or four chromosome segments, of which one chromosome segment was validated by the host into nonhost approach.

     

Identification of quantitative trait loci conferring resistance to tan spot in a biparental population derived from two Nebraska hard red winter wheat cultivars

Tan spot, caused by Pyrenophora tritici-repentis (Ptr), is a destructive foliar disease in all types of cultivated wheat worldwide. Genetics of tan spot resistance in wheat is complex, involving insensitivity to fungal-produced necrotrophic effectors (NEs), major resistance genes, and quantitative trait loci (QTL) conferring race-nonspecific and race-specific resistance. The Nebraska hard red winter wheat (HRWW) cultivar ‘Wesley’ is insensitive to Ptr ToxA and highly resistant to multiple Ptr races, but the genetics of resistance in this cultivar is unknown. In this study, we used a recombinant inbred line (RIL) population derived from a cross between Wesley and another Nebraska cultivar ‘Harry’ (Ptr ToxA sensitive and highly susceptible) to identify QTL associated with reaction to tan spot caused by multiple races/isolates. Sensitivity to Ptr ToxA conferred by the Tsn1 gene was mapped to chromosome 5B as expected. The Tsn1 locus was a major susceptibility QTL for the race 1 and race 2 isolates, but not for the race 2 isolate with the ToxA gene deleted. A second major susceptibility QTL was identified for all the Ptr ToxC-producing isolates and located to the distal end of the chromosome 1A, which likely corresponds to the Tsc1 locus. Three additional QTL with minor effects were identified on chromosomes 7A, 7B, and 7D. This work indicates that both Ptr ToxA-Tsn1 and Ptr ToxC-Tsc1 interactions are important for tan spot development in winter wheat, and Wesley is highly resistant largely due to the absence of the two tan spot sensitivity genes.     

Influence of Different Rice Cultivars on <Emphasis Type="Italic">Schizotetranychus oryzae</Emphasis> Development

Schizotetranychus oryzae Rossi de Simons (Acari: Tetranychidae) is considered one of the most important phytophagous mite in rice cultivation in the Americas South, Central, and North. This study aimed to examine some biological aspects of S. oryzae developing on leaves of three different cultivars of rice [Oryza sativa (L.)—Poaceae] produced in the state of Rio Grande do Sul, Brasil. The plants were kept in a room at 25?±?1°C, with natural light (photophase of approximately 14 h) and 70?±?5% relative humidity. During the immature stages, observations were carried out daily at 7 am, 1 pm, and 7 pm. The results showed that the mean duration of the egg–adult period in days were similar between cultivars evaluated (Irga 424, 11.27?±?0.13; Taim, 11.21?±?0.14 and Sinuelo, 11.13?±?0.15). Egg–adult viability on Irga 424, Sinuelo, and Taim was 61.9, 85.71, and 90.48%, respectively, being lowest on Irga 424 (χ2?=?28.62, p?<?0.0001). The duration of the immature stages was not affected by cultivar, but on Irga 424, egg–adult viability and female longevity were lower. The results of this study can help select O. sativa cultivar resistant to S. oryzae. However, historically, the IRGA 424 has lower populations of S. oryzae in field conditions.     

Karyotype and Relationships of the Endemic Char <Emphasis Type="Italic">Salvelinus krogiusae</Emphasis> from Dal'nee Lake (Kamchatka)

Resident (lacustrine) chars, inhabiting many lakes of Kamchatka, Chukotka, and continental coast of the Sea of Okhotsk, are of particular interest for understanding the mechanisms of speciation and evolution of Salvelinus chars. Since one of these, the char from Dal'nee Lake (Paratunka River basin, southeastern Kamchatka), is substantially different from lacustrine-riverine and anadromous chars from the Paratunka River basin in several morphological traits, hemoglobin spectrum, ecology, and reproduction, it is considered an isolated species Salvelinus krogiusae. The karyotype of the resident char from Dal'nee Lake was shown to be variable in most individuals, containing 76 to 80 chromosomes in different cells, with NF = 98. This suggests that the variability of the chromosome number in this char form is explained by Robertsonian translocations. In females and males, cells with respectively 2n = 78 and 2n = 77 prevailed. Heteromorphic sex chromosomes were not found in the karyotype of this char species. Nucleolar-organizing regions (NORs) were mostly detected in the telomeric regions of short arms of large submetacentric chromosomes. These features of the Krogius char karyotype demonstrate that this species is isolated from other Kamchatka chars, being similar to Taranetz char S. taranetzi from Chukotka Peninsula, which is in good agreement with morphological data.     

The <Emphasis Type="Italic">Agropyron cristatum</Emphasis> karyotype,chromosome structure and cross-genome homoeology as revealed by fluorescence in situ hybridization with tandem repeats and wheat single-gene probes

Key message

Fluorescence in situ hybridization with probes for 45 cDNAs and five tandem repeats revealed homoeologous relationships of Agropyron cristatum with wheat. The results will contribute to alien gene introgression in wheat improvement.

Abstract

Crested wheatgrass (Agropyron cristatum L. Gaertn.) is a wild relative of wheat and a promising source of novel genes for wheat improvement. To date, identification of A. cristatum chromosomes has not been possible, and its molecular karyotype has not been available. Furthermore, homoeologous relationship between the genomes of A. cristatum and wheat has not been determined. To develop chromosome-specific landmarks, A. cristatum genomic DNA was sequenced, and new tandem repeats were discovered. Their distribution on mitotic chromosomes was studied by fluorescence in situ hybridization (FISH), which revealed specific patterns for five repeats in addition to 5S and 45S ribosomal DNA and rye subtelomeric repeats pSc119.2 and pSc200. FISH with one tandem repeat together with 45S rDNA enabled identification of all A. cristatum chromosomes. To analyze the structure and cross-species homoeology of A. cristatum chromosomes with wheat, probes for 45 mapped wheat cDNAs covering all seven chromosome groups were localized by FISH. Thirty-four cDNAs hybridized to homoeologous chromosomes of A. cristatum, nine hybridized to homoeologous and non-homoeologous chromosomes, and two hybridized to unique positions on non-homoeologous chromosomes. FISH using single-gene probes revealed that the wheat-A. cristatum collinearity was distorted, and important structural rearrangements were observed for chromosomes 2P, 4P, 5P, 6P and 7P. Chromosomal inversions were found for pericentric region of 4P and whole chromosome arm 6PL. Furthermore, reciprocal translocations between 2PS and 4PL were detected. These results provide new insights into the genome evolution within Triticeae and will facilitate the use of crested wheatgrass in alien gene introgression into wheat.

     

The effect of intercultivar substitution of wheat <Emphasis Type="Italic">Triticum aestivum</Emphasis> L. chromosomes on lipoxygenase activity and its correlation with the technological properties of flour

The effects of intercultivar substitution of individual chromosome pairs (except for 1B, 6D, and 7A) in the wheat cultivars Saratovskaya 29 and Janetzkis Probat, differing in quality, on specific lipoxygenase activity, the grain yield per spike, and the main technological properties of flour and dough were studied. It was demonstrated that the substitution of individual chromosomes of the recipient cultivar Saratovskaya 29 with the homologous chromosomes of the donor cultivar Janetzkis Probat caused significant changes in lipoxygenase activity and several other quality characteristics. The correlations between the lipoxygenase activity and the parameters of physical dough properties were determined. Three molecular forms of lipoxygenase (Lpx-1, Lpx-2, and Lpx-3), differing in the value of surface charge and enzymatic activity, were detected by native PAGE.     

Two new cytotypes reinforce that <Emphasis Type="Italic">Micronycteris hirsuta</Emphasis> Peters, 1869 does not represent a monotypic taxon

Background

The genus Micronycteris is a diverse group of phyllostomid bats currently comprising 11 species, with diploid number (2n) ranging from 26 to 40 chromosomes. The karyotypic relationships within Micronycteris and between Micronycteris and other phyllostomids remain poorly understood. The karyotype of Micronycteris hirsuta is of particular interest: three different diploid numbers were reported for this species in South and Central Americas with 2n?=?26, 28 and 30 chromosomes. Although current evidence suggests some geographic differentiation among populations of M. hirsuta based on chromosomal, morphological, and nuclear and mitochondrial DNA markers, the recognition of new species or subspecies has been avoided due to the need for additional data, mainly chromosomal data.

Results

We describe two new cytotypes for Micronycteris hirsuta (MHI) (2n?=?26 and 25, NF?=?32), whose differences in diploid number are interpreted as the products of Robertsonian rearrangements. C-banding revealed a small amount of constitutive heterochromatin at the centromere and the NOR was located in the interstitial portion of the short arm of a second pair, confirmed by FISH. Telomeric probes hybridized to the centromeric regions and weakly to telomeric regions of most chromosomes. The G-banding analysis and chromosome painting with whole chromosome probes from Carollia brevicauda (CBR) and Phyllostomus hastatus (PHA) enabled the establishment of genome-wide homologies between MHI, CBR and PHA.

Conclusions

The karyotypes of Brazilian specimens of Micronycteris hirsuta described here are new to Micronycteris and reinforce that M. hirsuta does not represent a monotypic taxon. Our results corroborate the hypothesis of karyotypic megaevolution within Micronycteris, and strong evidence for this is that the entire chromosome complement of M. hirsuta was shown to be derivative with respect to species compared in this study.