Population genetic structure of four regional populations of the barley pathogen Pyrenophora teres f. maculata in Iran is characterized by high genetic diversity and sexual recombination

The leaf spot form of the barley disease net blotch, caused by the fungus Pyrenophora teres f. maculata (PTM), is an increasingly important foliar disease of barley. Studies of population genetic structure and reproductive mode are necessary to make predictions of the evolutionary potential of the pathogen. Sources of resistance to PTM have been found in Iranian landraces, which may have the potential to improve plant breeding efforts. However, little is known about the population genetic structure of this fungus in Iran. In this study, we analysed the frequency of the mating type genes to assess the potential for sexual mating of PTM collected from four provinces—Khuzestan, Hamadan, Golestan, and East Azerbaijan—and we investigated the population genetic structure using seven simple sequence repeat markers. High genotype diversity, linkage equilibrium, and equal ratios of mating types frequencies in the PTM populations at Khuzestan and Hamadan support the occurrence of sexual reproduction in these populations, while in Golestan and East Azerbaijan populations, significant gametic disequilibrium and relatively low genotype diversity suggest a higher incidence of clonality or different demographic histories. Unequal mating type frequencies in Golestan confirm a predominance of asexual reproduction. Finally, we found significant evidence for strong population structure with most of the genetic variation represented within regional populations (89%). Overall, our study provides evidence for high genetic variation in Iranian PTM populations, which may be the basis for rapid adaptive evolution in this pathosystem. This highlights the need for integrated efforts to control the disease.     

Induction of transgenic hairy roots in Trigonella foenum-graceum co-cultivated with Agrobacterium rhizogenes harboring a GFP gene

An important feature of A. rhizogenes-induced hairy roots is their unique ability for investigation of gene function and production of secondary metabolites such as diosgenin in fenugreek. In order to evaluate the transformation frequency and the efficiency of transgenic hairy root induction, leaf and stem explants from two fenugreek ecotypes, Karaj and Bushehr, were infected with three concentrations of OD₆₀₀= 0.8, 1.2, and 1.6 of A. rhizogenes strain K599 harboring a GFP gene. Regardless of ecotype, the ability of stem explants for the induction of hairy roots (8.09) and the transformation frequency (81.3%) was higher compared with leaf explants with the values of 5.97 and 71.88%, respectively. The number of transgenic GFP-positive hairy roots ranged from 4.2 to 13.5 in the Karaj ecotype and 3.8 to 9.9 in Bushehr. The highest transgenic hairy root (8.76), the transformation frequency (79.76%), and the growth rate of transgenic roots (0.77 d^?1) were obtained from infection with K599 at OD₆₀₀= 1.2, while the lowest belonged to the bacterial concentration of OD₆₀₀=1.6. Although the ecotype Bushehr had lower total roots (7.53) and transgenic hairy roots (6.08), it showed higher transformation frequency (79.56%) than Karaj (73.63%). Therefore, the results indicate the importance of genotype, type of explant and bacterial concentration in breeding for induction of transgenic hairy roots and consequently, production of secondary metabolites in fenugreek.     

Morphological, physiological and antioxidant responses of some Iranian grapevine cultivars to methyl jasmonate application

The role of exogenously applied Methyl jasmonate (MeJA) in morphological responses, photochemical efficiency, changes of malondialdehyde content, and the activities of some antioxidant enzymes were investigated in four Iranian grapevine cultivars. MeJA improved morphological traits containing dry and fresh weight, node number, and shoot length. MeJA induced an oxidative stress, as shown by an increase in lipid peroxidation. Activities of catalase, peroxidase, and ascorbate peroxidase were higher in MeJA-treated grapevines than in controls while the relative water content and leaf water loss of grapevine cultivars demonstrated a non-significant difference between the control and varying levels of MeJA. MeJA was positively affected in recovery of the leaf chlorophyll fluorescence (photochemical efficiency) of grapevine cultivars, although the mean proline content of MeJA-treated grapevines indicated a significant decrease when compared with those of the controls. These results suggest that MeJA could act as an intervener in grapevine responses by the enhancing the activity of antioxidants and recovery of photochemical efficiency, leading to enhanced grapevine performance.     

Associations between teat injuries and fistula formation in lactating dairy cows treated with surgery

OBJECTIVE: To determine associations between rate of fistula formation and parity, lactation period, wound age, wound location, and shape of teat injuries in surgically treated teats in dairy cows. STUDY DESIGN: Prospective clinical study. ANIMALS: 106 lactating dairy cows with teat lacerations. PROCEDURES: Lacerations were classified via shape, location, and age. Associations between potential risk factors and fistula formation were analyzed. Seasonal distribution, type of injured teat, parity, and days in lactation were determined. RESULTS:Cows with teat injury in their first and second parity had 4.1 times the odds of fistula formation, compared with cows with parity >or= 3.Teats sutured within 48 to 72 hours of injury had 8.3 times the odds of fistula formation, compared with teats sutured within the first 24 hours. Cows in early lactation stage (first 60 days of lactation) were more susceptible to teat injuries. Occurrence of teat injury was greater at the third, fourth, and fifth parity. CONCLUSIONS AND CLINICAL RELEVANCE: Season, parity, and lactation period were associated with prevalence of teat injury in lactating dairy cows in a range system. Neither the type of suture material used nor the suturing technique was associated with effects on healing of the operated full-thickness teat wounds. Factors such as parity and age of the wound can be associated with delay in the healing process, which may result in fistula formation.     

Changes of vitellogenin and Lipase in captive Sterlet sturgeon <Emphasis Type="Italic">Acipenser ruthenus</Emphasis> females during previtellogenesis to early atresia

Plasma chemistry, lipid metabolism and vitellogenin gene expression of captive Sterlet sturgeon Acipenser ruthenus were studied in different maturity stages. A total of 32 fish were sampled, and maturity stages were identified on the basis of histological criteria and direct observation. Females were classified to four groups: previtellogenic, vitellogenic, post-vitellogenic, and atresia. Blood, gonad and liver tissue samples were taken through non-lethal biopsy. Our results showed that plasma levels of glucose, cholesterol, triacylglycerol, high-density lipoprotein, low-density lipoprotein, very low-density lipoprotein, calcium, phosphorus, alkaline phosphatase activity, albumin and total protein increased during ovarian development and were highest at post-vitellogenic stage. The lowest amounts in atresia stage demonstrate that lipid and energy imbalance was related to reabsorption and digestion of the yolk. These results suggested that the VLDL was the main plasma lipoprotein component of Sterlet. We determined that lipoprotein lipase and hepatic lipase activity increased during vitellogenesis process which suggested the role of lipase enzymes in regulating blood lipid metabolism. RT-PCR analysis indicates that Vitellogenin (VTG) mRNA could be detected both in livers and ovaries of female Sterlet. Throughout the study, the expression level of VTG gene showed an increase both in ovaries and in livers reaching its peak at late vitellogenesis stage. This strongly indicated a relation between VTG mRNA and ovarian development.     

Crustacean-acanthocephalan interaction and host cell-mediated immunity: parasite encapsulation and melanization

Host-parasite interactions of Pomphorhynchus laevis (Müller, 1776) in naturally infected amphipod, Echinogammarus stammeri (Karaman), from the Brenta River (northern Italy) are described. A fully developed acanthocephalan larva occupies a large portion of an amphipod's haemocoelic space; thus, the parasite frequently induces displacement of host digestive tract and other internal organs. However, no apparent damage to the host's internal structures was observed. Within the haemocoel of E. stammeri, each larva of P. laevis is surrounded with a membranous layer, formed by microvilli, which maintains intimate contact with the amphipod's internal organs and haemocytes. Three types of circulatory haemocytes were identified based upon their distinct appearance: hyaline cell, semi-granular cell and granular cell. Echinogammarus stammeri haemocytes surrounded acanthocephalan larvae and in some instances a partially and/or totally melanized P. laevis larva was noticed. Interestingly, no melanized larvae were found in E. stammeri parasitized with other acanthocephalans namely Echinorhynchus truttae (Schrank, 1788), Polymorphus minutus (Goeze, 1782) and Acanthocephalus clavula (Dujardin, 1845).     

Independent and combined effects of heat and drought stress in the Seri M82 × Babax bread wheat population

Heat and drought are the most important wheat production constraints worldwide. The objectives of this research were to evaluate the independent and combined effects of drought and heat in SeriM82/Babax population. Genotypes showed 11, 38 and 52% losses in grain yield (YLD) in 2010–11 and 18, 25 and 48% in 2011–12 under heat, drought and combined stress, respectively. Seri M82 had higher YLD than Babax under heat and combined stress. Grain per spike and canopy temperature at vegetative stage (CTv) in irrigated, day to heading and CT at grain‐filling stage (CTg) in drought, CTg and thousand‐grain weight (TGW) in heat and in combined trials were the best predictors of YLD. Results indicated that due to genotype by environment interactions not all stress‐adaptive traits could be accumulated in a single genotype. In general, day to heading, CTg and grain weight are suggested as indirect selection criteria for increasing YLD under heat and drought stresses. In particular, CTg could be used as a rapid and effective criterion for screening a high number of genotypes.