Mapping QTLs for physiological and biochemical traits related to grain yield under control and terminal heat stress conditions in bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

In order to detect genomic regions with different effects for some of the physiological and biochemical traits of wheat, four experiments were conducted at Research Farm of Agricultural and Natural Resources Research Center of Zabol in 2015–2016 and 2016–2017 growing seasons. The experiments were carried out using four alpha lattice designs with two replications under non-stress and terminal heat stress conditions. Plant materials used in this study included 167 recombinant inbred lines and their parents (‘SeriM82’ and ‘Babax’). Six traits including grain yield (GY), proline content (PRO), water soluble carbohydrates (WSC), maximum efficiency of photosystem II (Fv/Fm), cytoplasmic membrane stability (CMS) and chlorophyll content (CHL) were evaluated. Genetic linkage map consisted of 211 AFLP marker, 120 SSR marker and 144 DArT markers with 1864 cm length and 4.4 cm mean distance. QTL analysis was carried out using a mixed-model-based composite interval mapping (MCIM) method. By the combined analysis of normal phenotypic values, 27 additive QTLs and five pairs of epistatic effects were identified for studied traits, among which two additive and one epistatic QTL showed significant QTL?×?environment interactions. By the combined analysis of stress phenotypic values, a total of 26 QTLs with additive effects and 5 epistatic QTLs were detected, among which one additive and one epistatic QTL showed QTL?×?environment interactions. Six QTLs with major effects (QGY-2B, QGY-2D, QPro-5B, QWSC-4A, QFv/Fm-6A and QCMS-4B), which were common between two conditions could be useful for marker-assisted selection (MAS) in order to develop heat tolerant and high-performance wheat varieties.     

Physiological and biochemical parameters: new tools to screen barley root exudate allelopathic potential (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L. subsp. <Emphasis Type="Italic">vulgare</Emphasis>)

Morphological markers/traits are often used in the detection of allelopathic stress, but optical signals including chlorophyll a fluorescence emission could be useful in developing new screening techniques. In this context, the allelopathic effect of barley (Hordeum vulgare subsp. vulgare) root exudates (three modern varieties and three landraces) were assessed on the morphological (root and shoot length, biomass accumulation), physiological (F_v/F_m and F₀), and biochemical (chlorophyll and protein contents) variables of great brome (Bromus diandrus Roth., syn. Bromus rigidus Roth. subsp. gussonii Parl.). All the measured traits were affected when great brome was grown in a soil substrate in which barley plants had previously developed for 30 days before being removed. The response of receiver plants was affected by treatment with activated charcoal, dependent on barley genotype and on the nature of the growing substrate. The inhibitory effect was lower with the addition of the activated charcoal suggesting the release of putative allelochemicals from barley roots into the soil. The barley landraces were more toxic than modern varieties and their effect was more pronounced in sandy substrate than in silty clay sand substrate. In our investigation, the chlorophyll content and F_v/F_m were the most correlated variables with barley allelopathic potential. These two parameters might be considered as effective tools to quantify susceptibility to allelochemical inhibitors in higher plants.     

Inheritance of the <Emphasis Type="Italic">ps</Emphasis> mutation in sugar beet

Genetic analysis of the inheritance of mutation ps in sugar beet was conducted. This mutation causes the meiotic abnormalities leading to the development of diploid pollen grains and influences several other morphological traits, namely, annual or biennial habit, stem color, and aggregation of pollen grains into tetrads, which are controlled by the genes B, Stc, and ap, respectively. The literature data on the linkage of genes B and Stc were confirmed; the obtained recombination coefficient between these genes amounts to 15.0 ± 3.6%. It was demonstrated that gene ap was inherited independently of genes B and Stc. Statistical analysis of the data shows that the mutation ps is recessive and is inherited independently of the mutation ap but in a linked manner with the traits development habit and stem color. The conclusion is made that a gene with a strong phenotypic effect that determines the development of the phenotype characteristic of mutation ps is located in the first linkage group near genes B and Stc.     

Polymorphism of the prolactin gene and its effect on fiber traits in goat

The prolactin gene (PRL) is a potential candidate gene for the goat cashmere traits in markerassisted selection. Thus, the aim of this study was to detect PRL gene polymorphism and its association with fiber traits in 200 Raini cashmere goats native to the south-east of Iran. A 196-bp fragment encoding exon 5 within the goat PRL gene was amplified using PCR specific primers. The amplification products were subjected to the single stranded conformation polymorphism (SSCP) analysis. Three different SSCP banding patterns (CC, AC, and AA) were observed in exon 5 of the caprine PRL gene. The pattern frequencies for CC, AC, and AA were 0.39, 0.38, and 0.23 and frequencies of the A and C alleles were 0.42 and 0.58, respectively. The genotypic distributions did not deviate from the Hardy–Weinberg equilibrium (P > 0.05). The number of observed alleles, number of effective alleles, expected heterozygosity, observed heterozygosity, mean of heterozygosity, expected homozygosity, observed homozygosity, Nei’s index and Shanon’s index were 2.0, 1.9, 0.48, 0.38, 0.48, 0.51, 0.61, 0.48, and 0.68, respectively. Results of association between genotypes and fiber traits indicated that the CC genotype had the highest fiber length compared with the AA and AC genotypes (P > 0.05) while there was no significant association between the PRL gene genotypes and fiber diameter. These results imply that the PRL gene polymorphism can be used as a molecular marker to improve fiber production without a negative effect on fiber diameter.     

Expression of <Emphasis Type="Italic">IPT</Emphasis> in Asakura-sanshoo (<Emphasis Type="Italic">Zanthoxylum piperitum</Emphasis> (L.) DC. f. <Emphasis Type="Italic">inerme</Emphasis> Makino) Alters Tree Architecture,Delays Leaf Senescence,and Changes Leaf Essential Oil Composition

The IPT gene encodes isopentenyl pyrophosphate transferase, a key enzyme in cytokinin biosynthesis. We introduced IPT under the control of the CaMV35S promoter into Asakura-sanshoo (Zanthoxylum piperitum (L.) DC. f. inerme Makino) via stable Agrobacterium tumefaciens-mediated transformation. Three of 3-year-old transgenic Asakura-sanshoo lines Y5, Y16, and Y17 were used to evaluate the effects of IPT expression on the morphological characteristics, leaf senescence, and essential oil composition. Introduced IPT into Asakura-sanshoo stimulated an increase in cytokinin content and a decrease in auxin level. The increase in the cytokinin/auxin ratio affected the tree architecture in 3-year-old transgenic lines. The phenotypes of transgenic lines included reduced stem elongation, decreased leaf surface area, increased branching, and delayed leaf senescence. The expression of IPT in Asakura-sanshoo also affected the leaf essential oil composition. The amount of oxygenated sesquiterpenoid compounds in Y5 and Y16 was 21.1 and 15.8 % higher, respectively, than that in wild type (WT). The amount of aromatic compounds in Y5 and Y16 was 2.9 and 24.6 % lower, respectively, than that in WT. These results show that ipt expression in Asakura-sanshoo conferred desirable traits, including a dwarf growth habit, delayed senescence, and increased concentrations of some sesquiterpenoid compounds.     

Genetic Diversity of Apple Cultivars Growing in Kazakhstan

Identification of the varieties is the primary requirement for characterization of the gene pool in agricultural production and implementation of breeding programs. In the present work, a set of six SSR markers was used for identification of cultural material collected on various horticultural farms in Kazakhstan: 30 varieties of Kazakhstani selection, 40 foreign varieties, and 16 Dzhangaliev’s apple clones selected in wild apple populations. Values of expected (H_e) and observed (H_o) heterozygosity in groups of all analyzed varieties were high: from 0.735 to 0.812 and from 0.661 to 0.721 respectively. Cluster analysis and analysis of genetic distances (STRUCTURE, UPGMA) showed a distribution of all samples into four major groups with a set of small subgroups caused by origin diversity. The first group included Kazakhstani varieties originating from Reneitte Burchardt, the second group included varieties with Aporta in parentage, the third group was represented by subclusters with a majority of foreign varieties, and the last group was composed of Dzhangaliev’s apple clones and Kazakhstani varieties with wild apple as their ancestor. Genotyping revealed inconsistencies in individual samples (and/or parentage) with claimed names. Analysis by markers of the Md-ACS1 and Md-ACO1 genes responsible for ethylene levels in fruits, which according to the literature correlates with fruit hardness and storability, did not reveal among Kazakhstani varieties any ACS1-2/2 homozygotes, the genotype with the highest expression of these traits. A quarter of Kazakhstani varieties and about a half of foreign varieties were heterozygous in ACS1, an indication of medium hardness and relatively long period of fruit storage. In two Kazakhstani and two foreign varieties heterozygous in ACS1, an improvement of the traits is possible owing to homozygosity in ACO1-1/1.     

Root-exudate flux variations among four co-existing canopy species in a temperate forest,Japan

Plants allocate carbon to root exudates to mine nitrogen (N) from soil organic matter (SOM). Little is known about how the root-exudation rate varies among co-existing woody species. We conducted an in situ experiment in a warm temperate forest on two dominant species, Quercus serrata and Ilex pedunculosa, and two of their congeneric species, Quercus glauca and Ilex macropoda, respectively. We hypothesized that the root-exudation rate varies among these species because of their distinct functional traits and N demands. Root-exudation rates were measured using a non-soil culture method during the growing season from June 2013 to May 2014. We also measured foliar N concentrations and the activities of N-degrading enzymes in the rhizosphere soils. The annual demand for N was calculated from the growth rate and allometric equations for biomass. The root-exudation rates of Q. serrata and I. macropoda were consistently greater than those of their congeneric evergreen species on root-length, root-weight, and individual-tree bases. The variations of the annual N demand of these species mirrored this pattern. Within a species, root-exudation rates correlated positively to leaf N contents, suggesting a physiological linkage between photosynthetic capacities and belowground carbon allocation. Root-exudation rates also correlated positively to the activities of polyphenol oxidase, an enzyme that decomposes N from recalcitrant SOM. Our results suggest that the variations of the root-exudation among co-existing species relate to their functional traits and demand for N.     

Intestinal <Emphasis Type="Italic">Lactobacillus</Emphasis> community structure and its correlation with diet of Southern Chinese elderly subjects

This study aimed to investigate the relationship between the intestinal Lactobacillus species and diet of elderly subjects in a longevity area in Southern China. Healthy elderly subjects ranging from 80 to 99 years old were respectively selected from the regions of Bama and Nanning, Guangxi, China. The nested polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) technology was used to analyze the intestinal Lactobacillus community structure. Results showed that Weissella confusa, L. mucosae, L. crispatus, L. salivarius, and L. delbrueckii were the representative Lactobacillus of elderly subjects. Among them, L. crispatus and L. delbrueckii were the dominant Lactobacillus of all species. In comparison to Nanning elderly subjects, the detection frequencies of W. confusa and L. salivarius were significantly increased in Bama elderly subjects (P < 0.01), whereas L. mucosae was significantly decreased (P < 0.01). Interestingly, it was also found that there were 4 kinds of representative Lactobacillus, which were significantly correlated with dietary fiber. W. confusa (P < 0.01) and L. salivarius (P < 0.05) were significantly positively correlated with the intake of dietary fiber, while L. mucosae (P < 0.01) and L. crispatus (P < 0.05) were significantly negatively correlated with the intake of dietary fiber, respectively. Results confirmed that different diets had obvious effects on the intestinal Lactobacillus community structure of elderly subjects in Southern China, which may provide a certain theoretical basis for the elderly’s healthy food strategic design and probiotics product development.     

Small genome size variation across the range of European beech (<Emphasis Type="Italic">Fagus sylvatica</Emphasis>)

Interpopulation variation of relative and absolute genome size was studied in Fagus sylvatica subsp. sylvatica and subsp. orientalis. The study included 18 populations of beech planted in a common-garden experiment in central Slovakia and three additional populations from the Caucasus. Nuclear DNA content was determined by means of flow cytometry using the AT-specific fluorochrome 4′,6-diamidino-2-phenylindole and non-specific propidium iodide, and its associations with climate, growth, phenology and physiological traits were assessed. The approximate average nuclear DNA content (2C) across all samples was 1.178 ± 0.020 pg. The lowest mean relative genome sizes were observed in the Alpine range, whereas they increased toward the range margins; no clear trend was observed for 2C values. Temperature seasonality and temperature annual range were found to be negatively associated with genome size. Among phenotypic traits, the maximum chlorophyll a fluorescence yield (Fv/Fm) was found to be negatively correlated with relative genome size, whereas phenology and some photosynthetic parameters were correlated with the 2C values.     

Diversity and symbiotic divergence of endophytic and non-endophytic rhizobia of <Emphasis Type="Italic">Medicago sativa</Emphasis>

Knowledge of rhizobium diversity is helping to enable the utilization of rhizobial resources. To analyze the phenotypic and genetic diversity and the symbiotic divergence of rhizobia of Medicago sativa, 30 endophytic and non-endophytic isolates were collected from different parts of five alfalfa varieties in three geographic locations in Gansu, China. Numerical analyses based on 72 phenotypic properties and restriction fragment length polymorphism (RFLP) fingerprinting indicated the abundant phenotypic and genetic diversity of the tested strains. According to the phylogenetic analysis of 16S RNA, atpD, glnII, and recA gene sequences, Rhizobium and Ensifer were further classified into four different genotypes: Rhizobium radiobacter, Rhizobium sp., Rhizobium rosettiformans, and Ensifer meliloti. The differences in architecture and functioning of the rhizobial genomes and, to a lesser extent, environment diversification helped explain the diversity of tested strains. The tested strains exhibited similar symbiotic feature when inoculated onto M. sativa cvs. Gannong Nos. 3 and 9 and Qingshui plants for the clustering feature of their parameter values. An obvious symbiotic divergence of rhizobial strains was observed in M. sativa cvs. Longzhong and WL168HQ plants because of the scattered parameter values. Their symbiotic divergence differed according to alfalfa varieties, which indicated that the sensitivity of different alfalfa varieties to rhizobial strains may differ. Most of the tested strains exhibited plant growth-promoting traits including phosphate solubilization and production of indole-3-acetic acid (IAA) when colonizing plant tissues and soil.     

Interactive effects of multiple vernalization (<Emphasis Type="Italic">Vrn-1</Emphasis>)- and photoperiod (<Emphasis Type="Italic">Ppd-1</Emphasis>)-related genes on the growth habit of bread wheat and their association with heading and flowering time

Background

The precise identification of Winterness/Springness (growth habit) for bread wheat, which is determined by genes involved in vernalization and photoperiod, will contribute to the effective utilization of bread wheat varieties. Here, 198 varieties from the Yellow and Huai wheat production region (YHW) in China were collected to identify their vernalization (Vrn-1) and photoperiod (Ppd-1) gene composition via a series of functional markers and their association with vernalization and photoperiod requirements at three locations during two years of experiments. The growth habits were measured during the spring sowing season.

Results

The results showed that the semi-winter varieties (grades1–4) were most prevalent in the population. The relative effects of single Vrn alleles on the growth period, such as heading date (HD) and/or flowering date (FD), were as follows: Vrn-B1b?>?Vrn-B1a?>?Vrn-D1b?>?Vrn-D1a?>?vrn-D1?=?vrn-B1. The interactive effects of Vrn-B1 and Vrn-D1 on HD and FD were identical to those of Vrn-B1b. Approximately 35.3% of the cultivars carried Ppd-B1a (photoperiod-insensitive) and exhibited the earliest HD and FD. The Ppd-D1a-insensitive allele (Hapl II) was carried by just 0.5% of the varieties; however, the other two sensitive alleles were present at a higher frequency, and their effects were slightly weaker than those of Ppd-B1a. In addition, strong interactive effects between Ppd-B1 and Ppd-D1 were detected. In terms of mean values among various genotypes, the effects followed the order of Vrn-1?>?Ppd-1.

Conclusions

According to the results of ANOVA and least significant range (LSR) tests, we can conclude that Vrn-1 rather than Ppd-1 played a major role in controlling vernalization and photoperiod responses in this region. This research will be helpful for precisely characterizing and evaluating the HD, FD and even growth habit of varieties in the YHW at molecular levels.

     

Physical and biochemical aspects of host plant resistance to mustard aphid, <Emphasis Type="Italic">Lipaphis erysimi</Emphasis> (Kaltenbach) in rapeseed-mustard

Mustard aphid, Lipaphis erysimi (Kaltenbach) is a major constraint in increasing the yield of rapeseed-mustard crops in India. Resistance to mustard aphid infestation and its correlation to some physiological and biochemical traits in selected varieties of different Brassica species were studied. Yield and oil content losses of up to 29.4% and 2.84%, respectively, were observed due to aphid infestation. Eruca sativa var. T-27 and Brassica carinata var. DLSC-2 were less susceptible to aphid infestation and had minimal yield losses. Surface wax, total glucosinolate, and phenol contents were found to correlate negatively with the aphid infestation, whereas the opposite relationship was obtained for the sugar content. The study suggests that physical and chemical barriers potentially play an important role in resistance against aphid infestation.     

Fine mapping and candidate gene analysis of <Emphasis Type="Italic">qFL-chr1</Emphasis>, a fiber length QTL in cotton

Key message

A fiber length QTL, qFL-chr1, was fine mapped to a 0.9 cM interval of cotton chromosome 1. Two positional candidate genes showed positive correlation between gene expression level and fiber length.

Abstract

Prior analysis of a backcross-self mapping population derived from a cross between Gossypium hirsutum L. and G. barbadense L. revealed a QTL on chromosome 1 associated with increased fiber length (qFL-chr1), which was confirmed in three independent populations of near-isogenic introgression lines (NIILs). Here, a single NIIL, R01-40-08, was used to develop a large population segregating for the target region. Twenty-two PCR-based polymorphic markers used to genotype 1672 BC₄F₂ plants identified 432 recombinants containing breakpoints in the target region. Substitution mapping using 141 informative recombinants narrowed the position of qFL-chr1 to a 1.0-cM interval between SSR markers MUSS084 and CIR018. To exclude possible effects of non-target introgressions on fiber length, different heterozygous BC₄F₃ plants introgressed between SSR markers NAU3384 and CGR5144 were selected to develop sub-NILs. The qFL-chr1 was further mapped at 0.9-cM interval between MUSS422 and CIR018 by comparisons of sub-NIL phenotype, and increased fiber length by ~1 mm. The 2.38-Mb region between MUSS422 and CIR018 in G. barbadense contained 19 annotated genes. Expression levels of two of these genes, GOBAR07705 (encoding 1-aminocyclopropane-1-carboxylate synthase) and GOBAR25992 (encoding amino acid permease), were positively correlated with fiber length in a small F₂ population, supporting these genes as candidates for qFL-chr1.

     

Conspecific tolerance and heterospecific competition as mechanisms for overcoming resistance to invasion by an intertidal crab

The success of the invasive Asian shore crab, Hemigrapsus sanguineus, stems partly from its ability to exclude established crab species from preferred rocky and cobble intertidal habitat. Here, we assessed preference and competition for habitat types (cobble vs. sand) for H. sanguineus and two competitor species; the previous invasive green crab, Carcinus maenas, and the native rock crab, Cancer irroratus, in New England. In simple laboratory experiments, we paired similarly sized heterospecifics and conspecifics from each species, and also grouped combinations of C. maenas and H. sanguineus in a series of four-individual sets in order to dissect the outcome of intra- and inter-specific competition at different densities. Individually, all three species preferred cobble substrate. With paired conspecifics, H. sanguineus individuals would cohabitate in cobble, whereas C. maenas and C. irroratus individuals each excluded conspecifics from cobble. In heterospecific pairs, H. sanguineus excluded both C. maenas and C. irroratus from cobble. C. maenas and C. irroratus, were equally likely to exclude the other species, but rarely excluded H. sanguineus. In larger assemblages, H. sanguineus preferentially grouped under cobble, whereas C. maenas were more evenly distributed among habitat types. These observations demonstrate that conspecific tolerance and heterospecific competition can be effective, complementary mechanisms for overcoming invasion resistance. Such mechanisms help explain the well-studied success of H. sanguineus following its introduction into New England coastal habitats, and the resulting exclusion of preexisting crab species.     

Effect of <Emphasis Type="Italic">UCP2</Emphasis> and <Emphasis Type="Italic">UCP3</Emphasis> Genes Polymorphisms on Functional Traits in Dairy Cattle

The aim of this study was to investigate associations between genotypes of UCP2 and UCP3 genes, milk, and reproduction traits in dairy cattle. The study included two herds: Jersey cows and Polish Holstein-Friesian (Red and White strain) cows. All cows were genotyped using the PCR-RFLP method and allele frequencies were determined. Statistical analysis showed a significant association between polymorphism in the UCP3 gene and the milk yield and fat content of milk (P ≤ 0.05, P ≤ 0.01) and between the UCP2 gene and the calving interval (P ≤ 0.05). Information contained in this study may be useful in further analysis to define the role of analysed genes in relation to functional traits in dairy cattle, nevertheless, the obtained results should be verified by conducting research on a larger group of animals and various cattle breeds.