Beta-cyanoalanine synthase as a molecular marker for induced resistance by fungal glycoprotein elicitor and commercial plant activators

ABSTRACT The biocontrol agent Pythium oligandrum produces glycoprotein elicitor in the cell wall fraction, designated CWP, and induces resistance to a broad range of pathogens. To understand the mechanism of CWP-induced resistance to pathogens, gene expression at the early stage of CWP treatment in tomato roots was analyzed using a cDNA array. At 4 h after CWP treatment, 144 genes were up-regulated and 99 genes were down-regulated. In the 144 up-regulated genes, nine genes exhibited about eightfold increased expression. Analysis of the response of these nine genes to three commercial plant activators indicated that a high level of one gene, beta-cyanoalanine synthase gene (LeCAS) encoding hydrogen cyanide (HCN) detoxification enzyme, was stably induced in tomato roots by such treatment. However, expression of LeCAS was not significantly induced in tomato roots at 4 h by abiotic stresses, whereas only a very low level of induction of such expression by cold stress was observed. This LeCAS expression was also induced after exogenous treatment with a low level of 1-amino-cyclopropane-1-carboxylate as the precursor of ethylene, but not with either salicylic acid or methyl jas-monate. The induction of LeCAS expression in CWP-treated and plant activator-treated roots is likely to be caused by the detoxification of HCN during ethylene production. Transient activation of LeCAS expression caused by ethylene production in tomato roots may be a general phenomenon in fungal elicitor-induced and synthetic plant activator-induced resistance. LeCAS seems to be useful for screening possible novel plant activators for plant protection against pathogens.     

Detection of candidate polymorphisms around the QTL for fat area ratio to rib eye area on BTA7 using whole‐genome resequencing in Japanese Black cattle

In our previous study, we performed genome‐wide association study (GWAS) to identify the genomic region associated with Fat area ratio to rib eye area (FAR) and detected a candidate in BTA7 at 10–30 Mbp. The present study aims to comprehensively detect all polymorphisms in the candidate region using whole‐genome resequencing data. Based on whole‐genome resequencing of eight animals, we detected 127,090 polymorphisms within the region. Of these, 31,945 were located within the genes. We further narrowed the polymorphisms to 6,044 with more than five allele differences between the high and low FAR groups that were located within 179 genes. We subsequently investigated the functions of these genes and selected 170 polymorphisms in eight genes as possible candidate polymorphisms. We focused on SLC27A6 K81M as a putative candidate polymorphism. We genotyped the SNP in a Japanese Black population (n = 904) to investigate the effect on FAR. Analysis of variance revealed that SLC27A6 K81M had a lower p‐value (p = .0009) than the most significant SNP in GWAS (p = .0049). Although only SLC27A6 K81M was verified in the present study, subsequent verification of the remaining candidate genes and polymorphisms could lead to the identification of genes and polymorphisms responsible for FAR.     

Equine herpesvirus type 1 tegument protein VP22 is not essential for pathogenicity in a hamster model,but is required for efficient viral growth in cultured cells

VP22 is a major tegument protein of Equine herpesvirus type 1 (EHV-1) that is a conserved protein among alphaherpesviruses. However, the roles of VP22 differ among each virus, and the roles of EHV-1 VP22 are still unclear. Here, we constructed an EHV-1 VP22 deletion mutant and a revertant virus to clarify the role of VP22. We found that EHV-1 VP22 was required for efficient viral growth in cultured cells, but not for virulence in a hamster model.     

Vitrification procedure decreases inositol 1,4,5‐trisphophate receptor expression,resulting in low fertility of pig oocytes

Although cryopreservation of mammalian oocytes is an important technology, it is well known that unfertilized oocytes, especially in pigs, are highly sensitive to low temperature and that cryopreserved oocytes show low fertility and developmental ability. The aim of the present study was to clarify why porcine in vitro matured (IVM) oocytes at the metaphase II (MII) stage showed low fertility and developmental ability after vitrification. In vitro matured cumulus oocyte complexes (COCs) were vitrified with Cryotop and then evaluated for fertility through in vitro fertilization (IVF). Although sperm‐penetrated oocytes were observed to some extent (30–40%), the rate of pronuclear formation was low (9%) and none of them progressed to the two‐cell stage. The results suggest that activation ability of cryopreserved oocytes was decreased by vitrification. We examined the localization and expression level of the type 1 inositol 1,4,5 trisphosphate receptor (IP₃R1), the channel responsible for Ca²⁺ release during IVF in porcine oocytes. Localization of IP₃R1 close to the plasma membrane and total expression level of IP₃R1 protein were both decreased by vitrification. In conclusion, our present study indicates that vitrified‐warmed porcine COCs showed a high survival rate but low fertility after IVF. This low fertility seems to be due to the decrease in IP₃R1 by the vitrification procedure.     

Quantification of phosphatidic acid in foodstuffs using a thin-layer-chromatography-imaging technique

Apical application of lysophosphatidic acid (LPA), a growth-factor-like phospholipid, was shown to prevent or restore gastrointestinal (GI) disorders, such as diarrhea and stomach ulcer, in experimental animals. Because LPA is formed from phosphatidic acid (PA) by the activity of digestive phospholipase A(2), PA is a potential component for dietary treatment of such GI disorders. Here, we quantified PA contained in 38 foodstuffs and 3 herbs by a thin-layer-chromatography-imaging technique. Vegetables belonging to Brassicaceae, such as cabbage leaves (700 nmol/g of wet weight) and Japanese radish leaves (570 nmol/g), contained higher amounts of PA than other foodstuffs. Amounts of PA in fruits, cereals, and starchy root vegetables were below 300 nmol/g. Animal foodstuffs contained low amounts of PA (<60 nmol/g). Interestingly, leaves of Mallotus japonicas, a Japanese edible herb used for treatment of stomach ulcer, had the highest PA (1410 nmol/g) among those examined. The data shown here will be useful for the development of dietary treatment for a damaged GI tract.     

First report of phytophthora rot on <Emphasis Type="Italic">Wasabia japonica</Emphasis> caused by <Emphasis Type="Italic">Phytophthora drechsleri</Emphasis> in Japan

In September 2014, Phytophthora rot on wasabi plants [Wasabia japonica (Miq.) Matsum.] was found for the first time in the city of Okutama, Tokyo, Japan. A Phytophthora sp. strain was constantly isolated from brown stem bases and rhizomes of infected plants. The same symptoms as those observed in the field were produced in vitro through inoculation of test plants with the isolated Phytophthora sp. The fungus was identified as Phytophthora drechsleri based on morphological and DNA sequence comparison. Phytophthora rot, “eki-byo” in Japanese, is proposed for this disease common name.     

Influence of riders’ skill on plasma cortisol levels of horses walking on forest and field trekking courses

The aim of this study was to evaluate the influence of rider's skill on the plasma cortisol levels of trekking horses on two courses, walking on field and forest courses (about 4.5 to 5.1 km each). Three riders of different skills did horse trekking (HT) in a tandem line under a fixed order: advanced‐leading, beginner‐second and intermediate‐last. A total of six horses were used and they experienced all positions in both courses; a total of 12 experiments were done. Blood samples were obtained before HT, immediately after and 2 h after HT. As a control, additional blood samples were obtained from the same horses on non‐riding days. Irrespective of the course and the rider's skill, the cortisol level before HT was higher than that of control (P < 0.05). In both courses, the cortisol levels immediately after HT ridden by the advanced rider were higher than that of control (P < 0.05). However, in every case, the cortisol level 2 h after HT was closely similar to the level of the control. Thus, we concluded the stress of trekking horse was not sufficient to disturb the circadian rhythm of the cortisol level, irrespective of the course and the rider's skill.     

Direct experimental evidence for the contribution of lime to CO2 release from managed peat soil

Liming is a common management practice used to achieve optimum pH for plant growth in agricultural soils. Addition of lime to the soil, however, may cause CO₂ release when the carbonates in lime dissolve in water. Although lime may thereby constitute a significant carbon source, especially under acidic soil conditions, experimental data on the CO₂ release are lacking so far. We conducted a split-plot experiment within a cut-away peatland cultivated with a bioenergy crop (reed canary grass, Phalaris arundinacea L.) with lime and fertilizer treatments to determine effects of lime on the CO₂ emissions from soil and to better understand mechanisms underlying liming effects. Carbon dioxide release was measured over two growing seasons in the field after liming, and complementary laboratory studies were conducted. To differentiate CO₂ derived from lime and biotic respiration the δ¹³C of CO₂ released was determined and the two-pool mixing model was applied. The results showed that lime may contribute significantly to CO₂ release from the soil. In the laboratory, more than 50% of CO₂ release was attributable to lime-carbonates during short-term incubation. Lime-derived CO₂ emissions were much lower in the field, and were only detected during the first (2–4) months after the application. However, a maximum of 12% of monthly CO₂ emissions from the cultivated peatland originated from the lime. Biotic respiration rates were similar in limed and unlimed soils, suggesting that higher pH did not, at least in the short-term, increase carbon losses from cultivated peat soils. Additional fertilization and acidification did not contribute to further CO₂ release from the lime. According to our first estimations about one sixth of the lime applied would be released as CO₂ from the managed peatland, with all lime-derived emissions occurring during the first year of application (equivalent to about 4.6% of the total annual CO₂ losses from the soil in the first year). This suggests that the mass-balance approach as proposed by the IPCC Tier 1 methodology, which assumes that all carbon in lime ends up as CO₂ in the atmosphere, overestimates the emissions from lime. Our study further shows that there is a great risk to overestimate heterotrophic microbial activity in limed soils by measuring the CO₂ release without separating abiotic and biotic CO₂ production.