Molecular genetics, seed morphology and fatty acids diversity in castor (Ricinus communis L., Euphorbiaceae) Iranian populations.

BACKGROUND: Castor (Ricinus communis L.) seeds contain a large amount of oil that has several biological activities. In the current research, phytogeographic distribution, seed morphological characteristics, molecular genetic diversity and structure, and fatty acid composition were investigated in nine Iranian castor populations. METHODS AND RESULTS: The cetyltrimethylammonium bromide (CTAB) protocol was used to extract the nuclear genomes. These were later amplified using 13 SCoT molecular primers. The phytogeographic distribution was determined based on the Zohary mapping, GC apparatus determined the fatty acid composition of the seeds. GenAlex, STRUCTURE, GenoDive, PopGene, and PopART software were used for the statistical analyzes. On phytogeographic mapping, the harvested populations belonged to different districts of the Euro-Siberian and Irano-Turanian regions (Holarctic kingdom). Most of the quantitative morphological traits of the seeds differed significantly (P ≤ 0.05) between the populations. The AMOVA test demonstrated a large proportion of significant genetic diversity assigned among populations, which were approved by some estimated parameters of genetic diversity such as Nm, Ht, Hs, and Gst. Nei's genetic distance and structure analysis confirmed the existence of two main genotype groups and some intermediates. However, there was no isolation by distance between the genotypes. Unsaturated fatty acids were detected as the main component of seed oil with linoleic and ricinoleic acids. Significant correlations were detected between the main fatty acids of seed oil with seed morphological traits, geographic distance and the geographic parameters of habitats. According to the composition of the seed fatty acids, four chemotypes groups were detected. CONCLUSIONS: The classification patterns of the populations based on molecular genetic data, fatty acid composition, and phytogeographic mapping were not identical. These findings indicated that Iranian castor populations had unusual seed fatty acid composition which strongly depended on habitat geographic factors and seed morphological traits. However, the identified chemotypes and genotypes can be used in future breeding programs.

Aquaporin3 expression and the potential role of aquaporins in motility and mitochondrial membrane potential in human spermatozoa.

Aquaporins are water selective channels which play important roles in cell volume regulation during the transmission of spermatozoa to female tract. This study investigated the expression of aquaporin3 and determined the role of aquaporins in human sperm motility and mitochondrial membrane potential (MMP). RT-PCR and flow cytometry analysis were done to investigate aquaporin3 expression levels, and immunolocalisation of aquaporin3 in the spermatozoa was detected using immunocytochemical analysis. The sperm suspension was divided into four groups of spermatozoa: (a) Spermatozoa at 0 hr, (b) spermatozoa in control group, (c) spermatozoa treated with HgCl2 (as an aquaporin inhibitor) and (d) spermatozoa treated with HgCl2 + and 2-mercaptoethanol. The sperm samples were examined in terms of sperm motility and mitochondrial membrane potential. Results confirmed aquaporin3 expression in human spermatozoa and immunocytochemistry results showed an intense immunoreactivity in whole sperm tail. After 60 min, HgCl2 showed a significant decrease in motility and MMP compared to the control group. At this time point, 2-mercaptoethanol in the HgCl2 + 2-mercaptoethanol group reversed the effects of HgCl2 as compared to the HgCl2 group. Present study showed the expression and immunolocalisation of AQP3 in human spermatozoa and the potential role of AQPs in the sperm motility and MMP.

Efficient superantioxidant and biofuel production from microalga Haematococcus pluvialis via a biorefinery approach.

A biorefinery approach was implemented to produce a superantixoident, i.e., astaxanthin, and biofuels, i.e., ethanol and biogas, from the biomass of microalga Haematococcus pluvialis. The hydrolysis of residual biomass obtained from astaxanthin extraction was conducted using α-amylase and glucoamylase for hydrolysis of α-glucans and a mixture of cellulases for ß-glucan hydrolysis. Four different hyudrolysis processes were employed and the efficiency of 97.2% over the total residual glucan was obtained, which was then fermented to produce 0.21 g ethanol/g residual biomass. The residuals obtained from astaxanthin extraction and fermentation were anaerobically digested to produce biomethane. The yield of biomethane was 264.8 ml/g volatile solids, 2.9 fold greater than methane yield from raw microalgal biomass. Overall, the process of astaxanthin extraction and consecutive production of ethanol and biogas from H. pluvialis biomass was recognized as a promising process to produce 45.8 g astaxanthin and 7095.3 KJ energy per Kg of raw biomass.

Study of the effect of nickel heavy metals on some physiological parameters of Catharanthus roseus.

Plants, in their life cycle, are usually exposed to various kinds of non-biological stresses including heavy metals. One of these heavy metals is nickel which affects many physiological processes of plants. Studies have shown that the changes in planting conditions can affect the qualitative and quantitative features of Catharanthus roseus; therefore, creating stressful conditions (e.g. NiCl2) can be an effective way to investigate the changes. In this research, we investigated the effect of 0, 2.5, 5, 10, 25 and 50 mM concentrations of NiCl2 on the degree of catalase enzyme activity, amount of proline aggregation and photosynthetic parameters on seeds of pink variety of C. roseus. The results indicated that the degree of catalase enzyme activity and the amount of proline aggregation increased in plants which were exposed to NiCl2 treatments, especially in high concentrations, while the total protein decreased. The stress of Ni also affected photosynthetic parameters, and decreased the amount of pigments, as well as the efficiency of photosystem II.

The high potential of Pelargonium roseum plant for phytoremediation of heavy metals.

The major objective of this investigation was to evaluate the potential of scented geraniums, Pelargonium roseum, to uptake and accumulate heavy metals nickel (Ni), cadmium (Cd), or lead (Pb). For this, plants were grown in an artificial soil system and exposed to a range of metal concentrations over a 14-day treatment period. Then, metals from the entire biomass were extracted. The results showed that scented geranium plants accumulated in excess of 20,055 mg of Ni kg(-1) dry weight (DW) of root and 10,889 mg of Ni kg(-1) DW of shoot, and in excess of 86,566 mg of Pb kg(-1) DW for roots and 4,416 mg of Pb kg(-1) DW for shoots within 14 days. Also, the uptake and accumulation of cadmium in roots of scented geranium plants increased with the exposure at low (250, 500 mg L(-1)) and medium level (750 mg L(-1)) followed by a decline at the highest level (1,000 mg L(-1)). The highest accumulation in roots (31,267 mg kg(-1) DW) was observed in 750 mg L(-1) cadmium treatment. In the shoots of scented geraniums, the highest amount of metal accumulation (1,957 mg kg(-1) DW) was detected at 750 and 1,000 mg L(-1) of cadmium in the culture solution. Finally, since the high concentrations of Ni or Pb accumulated in shoots of scented geranium has far exceeded 0.1 % DW and for Cd has far exceeded 0.01 % DW, P. roseum is a new hyperaccumulator species for these metals and can be used in phytoremediation industry.

Abscisic acid regulates root hydraulic conductance via aquaporin expression modulation in Nicotiana tabacum.

Abscisic acid (ABA) modifies the hydraulic properties of roots by increasing root water flux. The effects of ABA on aquaporin content and root hydraulic conductance are controversial. We addressed these effects via a combination of experiments. Tobacco (Nicotiana tabacum) plants were grown hydroponically, and ABA (1 microM) was exogenously applied to the roots. Then, the water transport properties of tobacco roots and expression of PIP-type aquaporins were examined. ABA increased the sap flow rate (Jv) and also the osmotic root hydraulic conductance (Lp(r-o)) of excised tobacco roots after 24h. The expression of three aquaporin PIP-type genes and PIP1s proteins abundance in tobacco roots were analyzed by real-time PCR and protein gel blot analysis, respectively. Interestingly, the accumulation of NtAQP1, NtPIP1;1 and NtPIP2;1 transcripts and NtPIP1;1 and NtAQP1 proteins abundance was significantly increased. Although the antibody used recognize NtPIP1;1 and NtAQP1, most probably it also recognizes other PIP1 proteins present in tobacco. Thus, the increase in the expression of the three PIP-type genes and other PIP1s proteins abundance caused by ABA were correlated with an increase in Lp(r-o) and Jv. ABA therefore facilitated the cell-to-cell component of water transport across the root cylinder. The subcellular localization of NtPIP1;1- and NtPIP2;1-GFP was investigated by protoplast transformation with chimeric gene, showing NtPIP2;1 localization in plasma membrane and NtPIP1;1 retention in the endoplasmic reticulum (ER). However, ABA did not change subcellular localization of NtPIP1;1 from ER to plasma membrane.

Drought stress alters water relations and expression of PIP-type aquaporin genes in Nicotiana tabacum plants.

Plasma membrane intrinsic proteins (PIPs), a type of aquaporins, mediate water transport in many plant species. In this study, we investigated the relationship between the functions of PIP-type water channels and water relations of tobacco plants (Nicotiana tabacum cv. Samsun) under drought stress. Drought stress treatments have led to reductions in the stomatal conductance, transpiration, water potential and turgor pressure in leaves, and also the sap flow rate and osmotic hydraulic conductance in roots. In contrast, leaf osmotic pressure was increased in response to drought stress. Interestingly, the accumulation of NtPIP1;1 and NtPIP2;1 transcripts was significantly decreased, but only that of the NtAQP1 transcript was increased under drought stress. Functional analysis using Xenopus laevis oocytes revealed that NtPIP2;1 shows marked water transport activity, but the activities of NtAQP1 and NtPIP1;1 are weak or almost negligible, respectively, when expressed alone. However, co-expression of NtPIP1;1 with NtPIP2;1 significantly enhanced water transport activity compared with that of NtPIP1;1- or NtPIP2;1-expressing oocytes, suggesting that these two aquaporins may function as a water channel, forming a heterotetramer. Heteromerization of NtPIP1;1 and NtPIP2;1 was also suggested by co-expression analyses of NtPIP1;1-GFP (green fluorescent protein) and NtPIP2;1 in Xenopus oocytes. Re-watering treatments recovered water relation parameters and the accumulation of the three NtPIP transcripts to levels similar to control conditions. These results suggest that NtPIP1;1 and NtPIP2;1 play an important role in water transport in roots, and that expression of NtPIP1;1 and NtPIP2;1 is down-regulated in order to reduce osmotic hydraulic conductance in the roots of tobacco plants under drought stress.