Over half of all organisms living on Earth today are parasites, and there are hardly any species which are free from them. How can the “wild immunology” approach help us understand them better?
The resistance of winter wheat varieties to Puccinia recondite f. sp. tritici was investigated at the Lithuanian Institute of Agriculture during 2001–2003. Effectiveness of resistance genes was investigated at seedling, tillering and adult plant stages. Virulence tests done during the 2000–2003 period showed that the majority of Lr genes used in European wheat were not sufficiently efficient. However, testing of cultivars at the first leaf stage revealed that the Lr37 gene in combination with the other genes was very effective. The experimental cultivars were sown in 2 times: in autumn and spring, without vernalization. The main task of spring-sown nursery was to improve the effectiveness of the experiment and investigate the effect of different Lr genes of non-vernalized plants at tillering growth stage. The Lr37 gene was found to be the most effective at both adult plant stage and tillering growth stage. Disease severity and plant resistance type at tillering stage were stable in all experimental years, which is important for the breeding program. The investigations revealed that the correlations between resistance at seedling and the other two stages were up to r = 0.81 (significant at p = 0.01**). The correlations between leaf rust severity and varietal resistance type at tillering were very high (r = 0.86–0.91**) in the same year. The correlation of leaf rust severity at adult plant stage was strong (r = 0.78**) between 2001 and 2002, but too low for reliable selection of resistant cultivars in the other years. Spring-sown nursery was complementary to collect resistance data in the years unfavourable for leaf rust development.
The excessive use of pesticides is a problem in most parts of the world today because of their broad and unspecific target range that is considerably harmful. The accumulation of several chemical insecticide residues based on chlorpyrifos-methyl, organochlorine, different isomers of HCH, DDT etc., in Triticum aestivum L. plants can be dangerous. Hence, there is an urgent need to develop potential and safer alternative measures. Wheat (Triticum aestivum L.) is a major cereal crop grown and used for food, animal feed, beverages and furniture accessories in most parts of the world. It also serves as a host to various insect pests. Our previous studies showed the insecticidal potency and specificity of short ssDNA oligonucleotides from the inhibitor of apoptosis (IAP-2 and IAP-3) genes of Lymantria dispar multicapsid nuclear polyhedrosis virus (LdMNPV) against gypsy moth (L. dispar) larvae, a possible insect pest of non-host plants like wheat. Consequently, the present study analyzes the effects of ssDNA oligonucleotides used as DNA insecticides on wheat (T. aestivum) plant biomass, plant organs and some biochemical parameters as a marker of the safety margin on non-target organisms. The results obtained on plant biomass showed that groups treated with ssDNA oligonucleotides at concentrations of 0.01 pmol · μl−1, 0.1 pmol · μl−1 and 1 pmol · μl−1 varied in comparison with the control group, but remained harmless to plant growth and development, while the treatment concentration of 0.001 pmol · μl−1 did not affect the plant biomass. The glucose, protein and phosphorous biochemical parameters, analyzed after 21 days, showed that the ssDNA oligonucleotides used were equally safe. The data obtained for the plant organs (leaves and root lengths) indicate that the phenomenon of DNA insecticides can be further studied and developed for plant protection while improving the growth of plant organs even for a non-target organism such as wheat T. aestivum plants.
The whitefly, Bemisia tabaci, an insect of the order Hemiptera which attacks more than 600 species of plants, is one of the most important agricultural pests around the world. The insecticidal Cry proteins from Bacillus thuringiensis (Bt) are useful biological pesticides, and some are toxic to Hemipteran insects. In this study, Colombian native isolates of Bt were functionally characterized at molecular and biological levels. The strains contained between one and five different crystal shapes: round, triangular, amorphous, bipyramidal and squared. The strains presented between three to seven bands of proteins in their electrophoretic pattern that were organized into six groups according to their possible biological activity on insect pests. Cry1Aa, cry1Ab, cry1Ac, cry1B and cry1C genes were identified for PCR in the different Bt isolates. Bioassays were performed on tomato leaves whose surface was spread with 3 μg · ml−1 crude extract of Bt toxins. Second instar larvae of whitefly, which were placed on top of leaves and exposed to the toxins for 7 days, exhibited mortalities from 18 to 69%. The lethal concentration 50 (LC50) of ZBUJTL39, Bt kurstaki HD1 and ZCUJTL9 strains were 1.83, 1.85 and 2.16 μg · ml−1, respectively (p < 0.05). These results show that the native Bt strain ZBUJTL39, which contained the genes cry1Aa, cry1Ab, cryCa and cryBa could eventually be used for the development of an integrated management program together with other tools for the control of B. tabaci.
Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most important foliar diseases of cereals. Infection by this pathogen on triticale has intensified in Poland in the last few years. In this study we examined resistance to powdery mildew in triticale hybrids possessing resistance genes Pm4b and Pm6 introduced from common wheat. The materials tested were hybrids derived from triticale crosses with common wheat cultivars carrying the desired resistance genes. The presence of the transferred genes was reflected in increased field resistance and shown by the use of molecular markers. The paper discusses the potential introduction of the genes to improve powdery mildew resistance.
Gene postulation is one of the fastest and most cost-effective methods for identifying seedling leaf rust resistance genes in wheat cultivars. Many researchers use this approach to identify Lr genes in wheat cultivars. The purpose of our research was to identify seedling leaf rust resistance genes in 20 wheat cultivars from different breeding centers of Russia, Ukraine and Germany. Forty-two near isogenic Thatcher lines and 10 Puccinia triticina isolates were used for gene postulation. When assessing the infection types to cultivars and lines, a scale was used, according to Oelke and Kolmer. In 20 wheat cultivars 19 Lr genes were postulated: 2c, 3, 10, 3bg, 3ka, 14a, 17, 18, 23, 25, 26, 30, 33, 40, 44, 50, B, Exch, Kanred. The most common for cultivars was the Lr10 gene. In five cultivars, showing high field resistance, most postulated seedling genes (Lr2c, Lr3, Lr10, Lr14а, Lr26, Lr33) were not effective in the adult stage. It is possible that resistance of such cultivars is associated with APR genes, the postulation of which requires an expansion in the number and spectrum of P. triticina isolate virulence. Most of the studied cultivars (60%) have recently been entered into the register (2015–2019) and in the field show a stable or moderately susceptible response to P. triticina infection, despite the fact that the Lr genes postulated in them were not effective in the adult stage. The data obtained indicated a variety of genotypes of the studied cultivars, as well as the tendency of breeders to use the effect of pyramiding ineffective genes, which can prolong the resistance of the cultivar. Annual monitoring of varieties is necessary in each region, especially when reacting with a medium susceptible type (MS), which may indicate the initial stage of resistance loss.
The aim of the study was to develop a reliable and cost-effective method for detection of nonsense mutation in APAF1 gene causing lethal effect called HH1 (Holstein Haplotype1) and to evaluate its prevalence in a sample of Polish Holstein-Friesian bulls. One hundred seventy eight bulls born between 1996 and 2017 were included in the analysis. They were kept in four artificial insemination centers and have in the pedigree the known carrier of HH1. All bulls were diagnosed by novel PCR-SSCP technique. Specific amplicons of 261 bp APAF1 gene fragment were used to detect changes in single stranded conformation (SSCP) caused by nonsense mutation C/T responsible for HH1. Each new carrier was used to trace another potential carriers among their offspring available in Polish Holstein Bull Repository Database. Among 178 bulls, 85 HH1 carriers were found. Our results show that nonsense mutation in APAF1 gene is already transmitted and segregating in Polish Holstein-Friesian cattle and its frequency may increase if no action will be undertaken against actual carriers.
In our previous Genome-wise Association Study we found that Cystic Fibrosis Transmem- brane Conductance Regulator gene (CFTR) is a candidate gene for sperm motility in fresh semen of Holstein-Friesian bulls. Since in cows thawed semen is commonly used for the artificial insem- ination (AI) we have decided to find out whether functional polymorphism within CFTR gene coding sequence is associated with selected parameters of thawed sperm, including their motility evaluated by computer-assisted sperm analysis (CASA), the activity of three antioxidant enzymes: glutathione peroxidase (GPx) catalase (CAT), superoxide dismutase (SOD), ATP con- tent and integrity of sperm membranes. One hundred twenty Holstein Friesian bulls kept in uni- form environmental conditions (one AI company) were included in the study. Significant associ- ations between genotypes of missense mutation within exon 11 of the CFTR gene (Met468Leu) and the activity of antioxidant enzymes and sperm mitochondrial function were revealed. No effect of CFTR genotypes on sperm motility was observed. Significant differences in CAT and SOD activity were found between AA and TT homozygous individuals. Bulls with TT genotype had the lowest activity of both antioxidant enzymes. The same bulls also showed the lowest num- ber of sperm with active mitochondria. Our results demonstrate that missense mutation Met468Leu within CFTR gene is associated with antioxidant enzyme activity and mitochondrial function of bovine thawed sperm without affecting their motility.
The aim of the study was to find out whether carriers of new lethal mutation in SDE2 gene occur in the population of Polish Holstein-Friesian bulls. Eighty seven bulls were included in the analysis. Bulls were selected as having in the pedigree known carrier of SDE2 mutation (bull Mountain USAM000002070579). All bulls were diagnosed by PCR amplification of 524 bp fragment of SDE2 gene followed by digestion of Bcc I restriction enzyme. Heterozygotes (carriers) were confirmed by sequencing. Each new carrier was used to trace another potential carriers among its offspring available in Polish Holstein Bull Repository Database. Among 87 bulls, 50 new SDE2 carriers were found. The study has shown that mutation in SDE2 gene causing early embryo mortality is already transmitted to Polish Holstein-Friesian cattle. The results are sufficient to initiate the screening program to reveal new carriers and to avoid further spreading of SDE2 lethal mutation.
Clarifying the genetic background of the drought-tolerance trait is a crucial task that may help to improve plant performance under stress by a genetic engineering approach. Dehydration-responsive element-binding protein (DREB) is a transcription factor family which modulates many stress-responsive genes. In this study, we isolated a DREB homolog gene named ZmDREBtv from Zea mays var. Tevang-1. Using bioinformatic tools, a number of InDels and SNPs in ZmDREBtv sequence different from the reference accession were identified. In addition, based on deduced protein sequence similarity, ZmDREBtv was assigned to transcription factor DREB2 class as featured by a conserved DNA binding domain - AP2. The ZmDREBtv construct under thecontrol of the rd29A promoter was transformed into a drought-sensitive maize plant, K7 line. The transgenic plants were assessed with reference to molecular and phenotypic characteristics related to the drought-tolenrance trait. The results proved that the maize plants carrying ZmDREBtv gene showed enhanced tolerance and better performance to the water-deficit environment at different stages, compared to the wild-type plants.
Cells of a multicellular organism are genetically identical but differ in structure and function. This heterogeneity is created by several epigenetic mechanisms during the development of the organism. The epigenetic changes- including DNA methylation, histone post-translational modifications, chromatin remodeling and RNA interference have all been shown to control chromatin structure and regulate a plethora of cellular and organismal processes. There is a strong evidence that epigenetics play a crucial role in the development of diseases such as cancer, schizophrenia or metabolic disorders. The epigenetic regulation underlie memory formation or adaptation to external stimuli. The extent to which environmental effects can provoke epigenetic responses represents an exciting area of future research. Here we review the current knowledge about the epigenetic mechanisms and their relation to the human health and disease.
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