Physiological responses to drought stress in wild relatives of wheat: implications for wheat improvement

Wild progenitors of common wheat are a potential source of tolerance to biotic and abiotic stresses. We conducted a glasshouse pot experiment to study genotypic differences in response to drought stress in a collection of 180 accessions of Aegilops and Triticum along with one tolerant and one sensitive control variety. Several physiological traits and chlorophyll fluorescence parameters were evaluated. Our findings indicated that drought significantly reduced shoot fresh (59.45%) and dry (50.83%) weights, stomatal conductance (41.52%) and maximum photosynthetic capacity (41.06%), but increased initial fluorescence (28.10%). Drought stress also decreased the chlorophyll content, relative water content and maximum quantum efficiency by 14.90, 12.13 and 11.42%, respectively. Principal component analysis of the 182 individuals identified three components that explained 57.61 and 61.68% of the total variation in physiological and photosynthetic traits under control and stress conditions, respectively. When grouped into the 12 species tested, the three top components explained 78.22% of the total variation under drought. The means comparison, stress tolerance index and biplot analysis identified five accessions with superior tolerance to drought. Remarkably, four species of wild relatives—Ae. cylindrica (DC genome), Ae. crassa (DM genome), Ae. caudata (C genome) and T. urartu (A^u genome)—responded well to drought stress with a lower percentage decline for most traits and high values for the first two components. The potential of these species offers further opportunities for analysis at the molecular and cellular levels to confront with drought stress through a physiological mechanism.     

Transient expression of recombinant tissue plasminogen activator (rt-PA) gene in cucurbit plants using viral vector

Objective

To use a transient expression system to express a truncated human tissue plasminogen activator (K2S) gene in cucurbit plants.

Results

The recombinant tissue plasminogen activator protein (K2S form) was expressed in active form in cucurbit plants. Its molecular weight was 43 kDa. The plant-derived rt-PA was determined using goat anti-rabbit antibody by western blotting. Among the infected lines, the highest expression of rt-PA was 62 ng/100 mg per leaf tissue as measured by ELISA. The enzymatic activity of the plant-derived rt-PA was 0.8 IU/ml.

Conclusions

The K25 form of rt-PA was expressed for the first time using the viral expression system. Plant-derived rt-PA showed similar potency to commercially-available PA.

     

Long-term storage of sexual and asexual Trichogramma brassicae (Hymenoptera: Trichogrammatidae)

The effect of exposure duration to pre-storage (representing fall conditions) and storage (representing winter conditions) temperatures on the emergence rate in sexual and asexual Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) was studied under controlled laboratory conditions. Asexual T. brassicae was infected by Wolbachia, an endosymbiont bacterium. We considered 0, 30, 40, 50 and 60 days as exposure duration at 10°C and 0, 30, 60, 90 followed by 180 days as exposure duration at 4°C for both T. brassicae strains. Emergence rate was significantly affected by the presence of Wolbachia, the duration of exposure to 10°C, the duration of storage at 4°C and their interactions, but not by the interaction between strain × storage duration at 4°C. Emergence rate of adults was positively correlated with exposure duration at 10°C, but it gradually decreased as the cold storage duration (4°C) increased in both strains. In conclusion, we are able to store both asexual and sexual strains for longer periods of time at 4°C, but the emergence rate of sexual T. brassicae was greater than asexual in all the treatments. The presence of Wolbachia could have a negative effect on fitness of T. brassicae and reduces its emergence rate after long-term storage.     

The critically endangered Asiatic cheetah <Emphasis Type="Italic">Acinonyx jubatus venaticus</Emphasis> in Iran: a review of recent distribution,and conservation status

Considerable effort has been put into conservation of the critically endangered Asiatic cheetah Acinonyx jubatus venaticus in Iran during the past few decades, and a thorough review of the species’ status, demography, range and conservation is provided here. We collated a large dataset of all verified occurrence data, photographic records and mortality cases since 1980 throughout the species’ range in Iran. Currently, the cheetah is distributed throughout the arid landscapes of the eastern half of Iran, but the limits of its current and past range as well as population trends are uncertain. Surveys of nearly 40 different areas resulted in 18 localities with confirmed presence of cheetahs in recent years. Camera trapping has been an effective tool to provide evidence of presence and status of cheetahs, revealing the species’ extremely low density and long inter-reserve movements. Together with photographic records, a total of 82 different cheetahs were detected during the 2000s in Iran. Protection status in most areas has been elevated by the Iran government. Asiatic cheetahs are highly vulnerable to extinction, mainly due to causalities mediated by herder persecution, poaching and road collisions as well as prey and habitat loss. Some efforts have been made to address these threats, but range expansion in recent years is a result of greater survey effort, rather than population recovery. We suggest that, despite conservation investment of the last 15 years, the species remains critically endangered on the verge of extinction.     

Haplotypes inside the beta-globin gene: use as new biomarkers for beta-thalassemia prenatal diagnosis in north of Iran

Background

Beta-thalassemia is common in the Mediterranean area as well as the Middle East and India. Official report in Iran revealed the average prevalence rate of carriers about 4%. More than 20 restriction fragment length polymorphisms (RFLPs) are known in the beta-globin gene cluster and used in the prenatal diagnosis (PND) services. Some of these locations may have low allele frequency and are not informative in the prenatal diagnosis. The current study aims to find new haplotypes and polymorphisms with high allele frequency in the local population.

Methods

Two thousand three hundred fifty samples (1,321 male and 1,029 female) from the northern Iran, whom suspected to be the carriers either for alpha or beta thalassemia and referred to the local diagnostic laboratory as a routine services were investigated during five years, (2010–2015). The beta-globin gene was sequenced for all samples.

Results

Heterozygosity for five SNPs in the beta-globin gene was calculated separately. 383 individuals (16.29%) showed no sign of nucleotide change in the beta-globin gene sequence. In total, codon2 (C/T) 31.72%, IVSII-16 (C/G) 31.72%, IVSII-74 (G/T) 54.71%, IVSII-81 (C/T) 19.47%, and IVSII-666 (T/C) 31.72% were seen respectively. Although all five polymorphisms showed reasonably high heterozygosity, IVSII-74 (G/T) [GG wild type (36.5%), G/T (54.71%) and TT (8.8%)] revealed the highest heterozygosity rate. Four combinations of these five SNPs were defined as new haplotypes named M1 to M4. ARMS-PCR also were designed and applied to detect IVSII-74 (G/T) nucleotide position.

Conclusions

This study represents an intragenic polymorphism, IVSII-74, a reliable position with high heterozygosity rates in Iranian population for PND analysis.

Trial registration

Retrospectively registered.

     

The delayed effect of mustard gas on housekeeping gene expression in lung biopsy of chemical injuries

ObjectiveSulfur mustard (SM) was used as a chemical weapon in Iraq-Iran war. Exposed people have major complications in important organs such as pulmonary system. Some studies have shown that SM could affect the expression of endogenous genes and non-housekeeping genes, time dependently. To understand the accurate molecular mechanism of the delayed effect of SM, the identification of the gene expression pattern in these patients is essential. Hence, we have evaluated mRNA expression of four common housekeeping genes (ACTIN, PGK1, β2m, GAPDH) in SM-exposed and non-exposed (control) formalin-fixed, paraffin-embedded (FFPE) human lung tissues.MethodParaffin block of lung biopsy of SM-exposed people (11 cases) and people without exposure to SM as control group (9 cases) have been selected. The mRNA expression of four endogenous control genes has been evaluated by qRT-PCR. The stability value of each gene was calculated by different methods.ResultIt was found that ACTIN mRNA has the highest expression (30.26±2.87) and PGK1 has the lowest standard deviation (SD) (30.885±2.215) between pooled groups. The best correlation was between ACTIN and PGK1 expressions. The M value has shown that ACTIN and then PGK1 are the most stable housekeeping genes among. The results obtained from the GeNorm and NormFinder have indicated that the pair ACTIN- PGK1 is the most suitable choice for endogenous control genes.ConclusionACTIN and PGK1 genes are stable in studied lung tissues and are the better than two other housekeeping genes. In addition, mustard gas does not affect their expression in long term.     

Functional studies on the ATM intronic splicing processing element

In disease-associated genes, the understanding of the functional significance of deep intronic nucleotide variants may represent a difficult challenge. We have previously reported a new disease-causing mechanism that involves an intronic splicing processing element (ISPE) in ATM, composed of adjacent consensus 5′ and 3′ splice sites. A GTAA deletion within ISPE maintains potential adjacent splice sites, disrupts a non-canonical U1 snRNP interaction and activates an aberrant exon. In this paper, we demonstrate that binding of U1 snRNA through complementarity within a ~40 nt window downstream of the ISPE prevents aberrant splicing. By selective mutagenesis at the adjacent consensus ISPE splice sites, we show that this effect is not due to a resplicing process occurring at the ISPE. Functional comparison of the ATM mouse counterpart and evaluation of the pre-mRNA splicing intermediates derived from affected cell lines and hybrid minigene assays indicate that U1 snRNP binding at the ISPE interferes with the cryptic acceptor site. Activation of this site results in a stringent 5′–3′ order of intron sequence removal around the cryptic exon. Artificial U1 snRNA loading by complementarity to heterologous exonic sequences represents a potential therapeutic method to prevent the usage of an aberrant CFTR cryptic exon. Our results suggest that ISPE-like intronic elements binding U1 snRNPs may regulate correct intron processing.     

Coexistence of atrioventricular nodal reentrant tachycardia and idiopathic left ventricular outflow-tract tachycardia

Double tachycardia is a relatively rare condition. We describe a 21 year old woman with history of frequent palpitations. In one of these episodes, she had wide complex tachycardia with right bundle branch and inferior axis morphology. A typical atrioventricular nodal tachycardia was induced during electrophysiologic study, aimed at induction of clinically documented tachycardia. Initially no ventricular tachycardia was inducible. After successful ablation of slow pathway, a wide complex tachycardia was induced by programmed stimulation from right ventricular outflow tract. Mapping localized the focus of tachycardia in left ventricular outflow tract and successfully ablated via retrograde aortic approach. During 7 month's follow-up, she has been symptom free with no recurrence. This work describes successful ablation of rare combination of typical atrioventricular nodal tachycardia and left ventricular outflow tract tachycardia in the same patient during one session.