Application of gamma irradiation on morphological, biochemical, and molecular aspects of wheat (Triticum aestivum L.) under different seed moisture contents.

Nuclear technology is currently used as a tool in mutation breeding to improve crops by increasing genetic variation. The ionization of gamma rays produces large amounts of free radicals, simulating stressors in the natural environment. To avoid gamma-ray-induced oxidative stress, plants use antioxidant defense systems. Exposure of plants to irradiation can affect the germination, growth, and production of metabolites. Plants' sensitivity to irradiation depends on genetic and environmental factors such as moisture content. For this purpose, the effects of different gamma irradiation doses [0, 100, 200, 300, and 400 Gray (Gy)] and different seed moisture contents (7, 13, and 19%) on traits such as seed germination, seedling growth, molecular and biochemical alterations in antioxidant enzymes were examined in the current study. Based on the results, the highest seed germination percentage was observed in the interaction effect of seed moisture at 13% with an irradiation dose of 400 Gy (98.89%). Seedling survival percent and seedling length decreased with increasing doses of gamma irradiation at different seed moisture contents. Increasing gamma irradiation doses were reduced root and stem fresh and dry weight, and root and stem length. The highest level of catalase enzyme activity and expression was observed at 200 and 300 Gy irradiation doses at different moisture contents. The peroxidase and polyphenol oxidase gene expression were reduced at all contents of gamma irradiation doses and seed moisture compared to the control. It can be concluded that the dose of 200-300 Gy of gamma irradiation reduced plant growth by 30% in terms of fresh and dry weight and length of plants, as well as enhanced the expression of antioxidant enzymes. The results of this study could help plant breeders select an appropriate dose rate in wheat for further research.

Application of gamma rays on salinity tolerance of wheat (Triticum aestivum L.) and expression of genes related to biosynthesis of proline, glycine betaine and antioxidant enzymes.

We investigated the effects of salinity stress and gamma radiation on salinity tolerance in wheat crops. To this end, mutant lines were generated by exposing Arg and Bam wheat varieties at the primordial state to 150 and 200 gamma radiation doses in the field. The top 15 mutant lines were specified for cultivation in the fifth-generation under two conditions, including non-stress and salinity stress. According to Fernandez's model, the three mutant lines had high yields under both conditions. The three mutant lines were selected with their two parents, and then, cultivated in a completely randomized factorial design in a greenhouse under non-stress and salinity conditions. The mutant lines showed significantly higher osmotic adjustment, leaf relative water content (RWC), potassium ion concentration, soluble sugar content and lower proline (Pro), and glycine betaine (GB) content than the parents at both the vegetative (VEG) and reproductive (REP) stages under salinity conditions. The expression of genes involved in the Pro biosynthesis pathway, P5CS and P5CR genes, in mutant lines were less than their parents, and conversely, P5CDH in mutant lines was more than their parents. The changes in the expression of CMO and BADH genes involved in the GB synthesis pathway indicated that the mutant lines had less gene expression compared to their parent genotypes of Arg and Bam. The results indicated an increase in antioxidant activity in the mutant lines compared to their parents. Consequently, irradiated plants have probably adapted to the salinity stress by increasing the osmotic adjustment, RWC, potassium ion concentration, and soluble sugar content, as well as activating antioxidant enzymes.

Ultrasound-assisted preparation of flaxseed oil nanoemulsions coated with alginate-whey protein for targeted delivery of omega-3 fatty acids into the lower sections of gastrointestinal tract to enrich broiler meat.

Flaxseed oil is one of the richest sources of α-linolenic acid (ALA). However, the susceptibility of ALA to oxidation and also lack of the convenient methods to deliver these invaluable compound into the lower sections of gastrointestinal tract (GIT) are still unknown. The objective of the current study was to establish a method for ALA targeted delivery into the lower sections of GIT to enrich broiler meat. An in vitro study was performed to use ultrasound to produce oil-in-water nanoemulsions of flaxseed oil stabilized by different wall materials for controlled release of ALA in GIT. The fabricated nanoemulsions were assessed in terms of particle size distribution, zeta-potential, encapsulation efficiency, field emission scanning electron microscopy (FESEM), and in vitro gastric and intestinal digestions. Results indicated that the nanoemulsions coated by a combination of whey protein-sodium alginate (WP/SA) had a relatively uniform distribution and all particles distributed in less than 1000 nm. The values of zeta-potential for nanoemulsions stabilized by whey protein (WP), sodium alginate (SA) and WP/SA were -31.4, -29.3 and -45.5 mV, respectively. The wall combination of WP/SA showed the best encapsulation efficiency followed by WP. The FESEM results indicated spherical and non-aggregated structures for three types of nanoemulsions. The nanoemulsions stabilized by WP/SA showed a high resistance to in vitro gastric digestion but a relatively rapid release during intestinal digestion. An in vivo study was conducted to enrich broiler meat with ALA, using the best wall material from the in vitro study. In total, 300 one-day-old broilers (Ross, 308) were assigned into 5 experimental treatments including: basal diet (BD), basal diet plus flaxseed oil (BD + FO, 1 mL/kg body weight), basal diet plus ultrasonicated flaxseed oil nanoemulsions stabilized by WP/SA (BD + FON, 1 mL/kg body weight), basal diet plus flaxseed oil and vitamin E (BD + FO + E, 1 mL/kg body weight and 200 mg/kg diet vitamin E) and basal diet plus ultrasonicated flaxseed oil nanoemulsions stabilized by WP/SA and vitamin E (BD + FON + E, 1 mL/kg body weight of nanoemulsion and 200 mg/kg diet vitamin E). Each experimental treatment included 4 replicates in a completely randomized design. Results showed a better feed conversion ratio (FCR) in birds treated with dietary treatments compared with those received basal diet. A greater incorporation of ALA and total poly unsaturated fatty acids (PUFA) omega-3 were observed in thigh and breast meat of birds fed by ultrasonicated flaxseed oil nanoemulsions. In comparison to birds fed with BD, a favourably lower PUFA omega-6/omega-3 ratio was observed in birds received nanoemulsions of flaxseed oil. In general, the current study showed that using ultrasound to produce nanoemulsions stabilized by WP/SA has potential to protect ALA of flaxseed oil from gastric digestion and could be used as delivery carriers of ALA omega-3 fatty acid to the posterior sections of chicken GIT. Moreover, ultrasonic fabrication of nanoemulsion has potential to enrich broiler meat by ALA fatty acid.

Membrane fatty acid compositions and cold-induced responses in tetraploid and hexaploid wheats.

Plant cells often increase cold tolerance by reprogramming their genes expression which results in adjusted metabolic alternations, a process enhanced under cold acclimation. In present study, we assessed the changes of membrane fatty acid compositions along with physio-biochemical indices like H2O2 and malondialdehyde (MDA) contents and lipoxygenase (LOX) activity during cold stress (CS) phases in acclimated and non-acclimated durum (SRN and Gerdish) and bread (Norstar) wheat genotypes. During thermal treatments, MDA was an end product of lipid peroxidation via oxidative stress (H2O2 content) rather than LOX activity. LOX activity plays a double role in mechanism of cold tolerance in wheat, particularly at severe stress. With increase in severity of CS especially in non-acclimated plants, LOX activity decreased along with an increase in MDA and other responses helped increase or maintaine unsaturated fatty acids (FAs) whereas in acclimated plants (moderate CS), increasing of LOX activity along with a decrease in MDA indicates probably its role in secondary metabolites like jasmonic acid signaling pathway. Significant increase of total FAs and particularly unsaturated FAs showed distinct cell endeavor to protect against CS in Norstar and Gerdish compared to SRN genotype. Results showed that an increase in double bond index and LOX activity and low MDA under CS could be reasons for plant cold tolerance.

Comparative analysis of physio-biochemical responses to cold stress in tetraploid and hexaploid wheat.

The cellular changes induced by cold stress (CS) include responses that lead to oxidative stress and limits plant growth, metabolism, and productivity. In this study, responses of physio-biochemical to CS phases were comparatively studied in three genotypes of bread and durum wheats differing in sensitivity, two of them (Norstar, bread wheat and Gerdish, durum wheat) were tolerant to CS and the other one, SRN (durum wheat) was sensitive to CS. 14-day-old seedlings were subjected to CS (12 and 24 h) with or without cold acclimation (CA) phase. During CS, the elevated levels of electrolyte leakage index, contents of hydrogen peroxide (H2O2), and malondialdehyde in Norstar and Gerdish were lower than that of SRN plants. Positive correlation and co-regulation of reactive oxygen species (ROS) scavenging systems, superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, and proline especially after CA phase suggested crucial role for holding back toxic ROS levels in CS phase. However, different activities of this system resulted in different intensities of oxidative stress in acclimated and non-acclimated plants. Our results showed that a CA phase induced oxidative stress tolerance by modulating antioxidative systems. These responses confirmed the existence of wide range of genetic capacity in durum wheat to increase cold tolerance particularly in Gerdish so that the sensitivity of SRN plants to CS was linearly correlated with the more decrease of antioxidant systems. These general responses may be a sign for associating other metabolites or enzymes activities to create partly tolerance against cold-induced oxidative stress. Eventually, assessing the dynamic of cell responses in short intervals after CS without CA phases profitably could be a novel path in plant stress response investigations in a short period of time.

Developmental transcription of genes putatively associated with growth in two sturgeon species of different growth rate.

In the present study, we surveyed developmental changes in the transcription of growth hormone (gh), insulin-like growth factor-I (igf-I), ghrelin (ghrl) and vascular endothelial growth factor (vegf) genes in the largest freshwater fish, European sturgeon (Beluga, Huso huso) and compared the same parameters to that of its phylogenically close moderate-sized species, Persian sturgeon (Acipenser persicus). The transcripts of gh, igf-I, ghrl and vegf were detected at all developmental time-points of Persian sturgeon and Beluga from embryos to juvenile fish. Changes in normalized gh, igf-I, ghrl and vegf transcription by using the geometric average of genes encoding ribosomal protein L6 (RPL6) and elongation factor (EF1A) over the time of development of Persian sturgeon and Beluga were statistically significant (P<0.05). Our results showed that the mRNA expression levels of both igf-I and ghrl were low during early larval development and then increased significantly to the late larval time-points when larvae started exogenous feeding. In both Beluga and Persian sturgeon, after a low mRNA expression during the embryonic stage, the transcript levels of vegf displayed an increasing trend during yolk-sac fry, consistent with organogenesis. The vegf level remained constantly high in the time of exogenous feeding. The highest detection of gh transcripts coincided with the end of the embryonic stage (hatching time) in Persian sturgeon and 3 days-post-hatching (dph) in Beluga. In Persian sturgeon, the gh transcript started to decrease to the rest of the developmental time-points, whereas in Beluga gh transcript had a marked second increase from the time of exogenous feeding (20-dph). This Beluga specific increase in gh transcription may be associated with the marked growth rate and extraordinary size of this fish species.