Developmental role of phenylalanine-ammonia-lyase (PAL) and cinnamate 4-hydroxylase (C4H) genes during adventitious rooting of Juglans regia L. microshoots

Phenylalanine-ammonia-lyase and cinnamate-4-hydroxylase play important role in the phenylpropanoid pathway, which produces many biologically important secondary metabolites participating in normal plant development. Flavonol quercetin is the main representant of these compounds that has been identified in numerous Juglans spp. In this survey, the developmental expression patterns of PAL and C4H genes during in vitro rooting of two walnut cultivars ‘Sunland’ and ‘Howard’ was examined by RT-PCR. To understand the potential role in rooting, the changing pattern of endogenous content of quercetin was also analyzed by HPLC. The ‘Sunland’ with better capacity to root had more quercetin content during the “inductive phase” of rooting than ‘Howard’. In each cultivar, the level of PAL transcripts showed the same behavior with the changing patterns of quercetin during root formation of microshoots. The positive correlation between the changes of quercetin and PAL-mRNA indicated that PAL gene may have an immediate effect on flavonoid pathway metabolites including quercetin. Although the behavioral change of C4H expression was similar in both cultivars during root formation (with significantly more level for ‘Howard’), it was not coincide with the changes of quercerin concentrations. Our results showed that C4H function is important for the normal development, but its transcriptional regulation does not correlate with quercetin as an efficient phenolic compound for walnut rhizogenesis

The allelopathic effect of apricot (Prunus armeniaca L.) leaf on some morphological and biochemical characteristics of monocot and dicot crops and weeds

An experiment trial run to determine the allelopathic effects of apricot leaves on corn, bean, rye and pigweed. This experiment was done with apricot aqueous leaf extract (75% w/v) and leaf powder (3% w/w) treatments and control (without any treats with leaf extract and powder and irrigated with distilled water) during seedling stage. This experiment was carried out as a factorial experiment in complete randomized design with 3 replicates. According to the results, the lowest and the highest loss percentage of shoot and root dry weight, and stem and root length was observed in corn and pigweed under the treats of apricot leaf extract and powder. Electrolyte leakage increased significantly in bean under leaf extract and powder treats and in rye treated with extract compared to control. Both treats of apricot leaf decreased the content of chlorophyll a and b in bean and pigweed, although these pigments increased in corn and rye under mentioned treatments. Increased soluble sugars of bean and corn under leaf aqueous extract and powder and of rye and pigweed under leaf aqueous extract were significantly more than control. However, treatment with aqueous extract increased proline content in all studied plants, but the content of this amino acid increased only in the bean treated with apricot extract powder. A little changes of superoxide dismutase activity were not significant in corn, bean, rye and pigweed treated with aqueous extract and powder compared to the control

Evaluation of antifungal activity of nano and bulk forms of copper oxide in wheat (Roshan cultivar)

Wheat (Triticum aestivum L.), as one of the most important cultivated crops in the world and Iran, is constantly threatened by many diseases, including Fusarium contamination. Due to the unique characteristics of nanoparticles, copper oxide nanoparticles show high antibacterial and antifungal properties. The purpose of this research was to comparatively investigate the antifungal effects of copper oxide nanoparticles and its bulk form on the suppression of Fusarium calmorum in wheat. For this purpose, a pot experiment was done with four levels (10, 250, 500, and 1000 mg L-1) of nanoparticles and bulk form of copper oxide treatments in wheat (Roshan cultivar). The results showed that the maximum inhibition of root pathogenicity was observed in a high concentration of nanoparticles as compared to bulk form. The 250 and 500 mg L-1 concentrations of copper oxide nanoparticles caused the highest stem and root length and the highest dry weight of the aerial part and root, respectively. Treatment with 10 and 250 mg L-1 nanoparticles also increased the content of chlorophyll a, total chlorophyll, carotenoid, chlorophyll stability index, membrane stability coefficient, and relative leaf water content. While the content of chlorophyll b, malondialdehyde, hydrogen peroxide, and proline increased with the increasing concentration of both nanoparticle and bulk forms. The results of this research showed that the low and medium concentrations of nanoparticles were more successful in inhibiting the aforementioned fungus than the bulk form

Exogenous arginine treatment additively enhances growth and tolerance of Salicornia europaea seedlings under salinity

The effects of foliar application of 5 mM arginine (Arg) on the growth and control of salinity-induced osmotic and oxidative stresses (0, 200, 400 and 600 mM NaCl) in Salicornia europaea seedlings were investigated. Despite higher levels of lipid peroxidation, lower membrane stability index (MSI), decreased pigment content and phenolic compounds, and reduced activity of antioxidant enzymes observed under salinity, seedling growth indices, including plant height and biomass, increased significantly, and some protective and antioxidant molecules such as proline and flavonoids accumulated. Soluble protein level increased at the low salt concentration (200 mM) but decreased at other doses. Exogenous Arg treatment alone had less or no effect on plant biomass and other metabolites, but in combination with salt, further enhanced growth parameters, MSI and accumulation of soluble protein, phenolic compounds and proline. Arg-induced changes under salinity were associated with decreased lipid peroxidation, flavonoids content and antioxidant enzymes activity. These results show that S. europaea seedlings are well tolerant to applied salt doses. The treatment with exogenous Arg alone affects plant growth slightly, but in combination with salt, synergistically increases growth and salt tolerance of these plants by enhancing the accumulation of proline and antioxidant molecules instead of enzymatic antioxidant

Evaluation of resistance to drought stress in seedlings of two lines of Triticale (Triticosecale × Wittmack) with emphasis on some enzymatic and non-enzymatic antioxidants

Drought is one of the most important factors that limit plant growth and development. In order to study the effect of drought stress in two lines of Triticale Sanabad and ET83-20 as the new man-made cereal, a greenhouse experiment was arranged in a three-replicate completely randomized factorial design. Drought stress was applied as limited irrigation by 30% and 60% of field capacity as a drought condition and 90% of field capacity as a control. One week after applying the stress, some growth criterions and biochemical parameters were evaluated for seedlings. Results of statistical analysis showed that drought stress reduced growth parameters (including dry weight of root and shoot, root length and diameter, root and leaf area) and increased the levels of chlorophyll a, b, total chlorophyll and carotenoid in both lines. However, the pigments contentof ET83-20 had a further increase than the other. The results also showed that proline content as non-enzymatic antioxidant and soluble sugars as osmolytes and antioxidant enzyme activities of superoxide dismutase and guaiacol peroxidase increased under drought stress. However, these increases were more significant in line Sanabad. The damage levels of growth criterions and defence mechanisms show that ET83-20 is less resistance to drought stress than Sanabad. So the line Sanabad could be introduced as a better alternative to wheat bread

An investigation on callogenesis and antioxidant capacity of different explants of Teucrium polium

Kalpoureh (Teucrium polium L.) as a medicinal plant belongs to family Lamiaceae. This plant has short growth period and endangered, so it seems the method of plant tissue culture is efficient for that. On the other hand Teucrium polium with high antioxidant properties has many health benefits. In this study, the effect of culture medium, different concentrations of 2, 4-D and the type of explants on callus induction were evaluated. It was found that effective treatment for more fresh weight of callus was the leaf explants on B5 culture with concentrations 1 and 0.5 mg L-1 of 2,4-D. In no hormone treatments, the percentage of callus induction was lower than others and the highest percentage of callus induction was on medium containing higher levels of the hormone. Analysis of biochemical properties (total phenolic content, antioxidant capacity based on two tests; DPPH and PPM) was also concluded that callus of terminal bud on B5 medium with no hormones had the highest total phenol (82.66 mgGAE/100 g FW). Based on DPPH test, the most free radicals scavenging potential was seen for the leaves collected from the habitat and the callus of terminal bud explants on B5 medium with concentration of 0.5 mg L-1 2, 4-D. Investigation on total antioxidant capacity also revealed that callus of terminal bud on MS medium, 2 mg L-1 2,4-D, leaves and stems of plants collected from habitats showed more activities. These conditions can provide the suggestion for the use of these media to produce more secondary metabolites with antioxidant properties

Impact of an arbuscular mycorrhizal fungal inoculum and exogenous MeJA on fenugreek secondary metabolite production under water deficit

Trigonella foenum-graecum (fenugreek) is a leguminous plant that produces secondary metabolites frequently used in medicinal and food preparation. Here, the role of an arbuscular mycorrhizal (AM) fungal inoculum, alone or in combination with methyl jasmonate (MeJA) chemical treatment, was evaluated on the production of trigonelline and diosgenin in fenugreek plants grown under mild water limitation. After inoculation, fenugreek plants were subjected to several combined treatments, i.e. well-watered (NS) and water-stressed (WS), both treated with different MeJA concentrations (0, 50, 100, 200 mL/L). At the end of the experiment, in addition to trigonelline and diosgenin content, an array of plant growth parameters (i.e. fruit, stem and root dry weights, fruit number) and biochemical stress markers (i.e. proline, nitric oxide, hydrogen peroxide, MDA) were examined. Results mainly showed a significant increase in production of the considered secondary metabolites, although they are differentially influenced by the individual factors (Stress, SYM, MeJA) and their interactions. SYM treatment was more effective on the production of trigonelline, independently from growth conditions, while diosgenin biosynthesis was influenced by the presence of root symbioses only in combination with MeJA treatment. A differential impact, depending on the applied treatment (inoculum, MeJA treatments, water deficit), on plant growth and on production of the considered bioactive molecules was revealed, providing new information on the effect of biological and chemical priming treatments

Beneficial worm allies warn plants of parasite attack below‐ground and reduce above‐ground herbivore preference and performance

Antagonistic interactions among different functional guilds of nematodes have been recognized for quite some time, but the underlying explanatory mechanisms are unclear. We investigated responses of tomato (Solanum lycopersicum) to two functional guilds of nematodes-plant parasite (Meloidogyne javanica) and entomopathogens (Heterorhabditis bacteriophora, Steinernema feltiae below-ground, and S. carpocapsae)-as well as a leaf mining insect (Tuta absoluta) above-ground. Our results indicate that entomopathogenic nematodes (EPNs): (1) reduced root knot nematode (RKN) infestation below-ground, (2) reduced herbivore (T. absoluta) host preference and performance above-ground, and (3) induced overlapping plant defence responses by rapidly activating polyphenol oxidase and guaiacol peroxidase activity in roots, but simultaneously suppressing this activity in above-ground tissues. Concurrently, we investigated potential plant signalling mechanisms underlying these interactions using transcriptome analyses. We found that both entomopathogens and plant parasites triggered immune responses in plant roots with shared gene expression. Secondary metabolite transcripts induced in response to the two nematode functional guilds were generally overlapping and showed an analogous profile of regulation. Likewise, we show that EPNs modulate plant defence against RKN invasion, in part, by suppressing active expression of antioxidant enzymes. Inoculations of roots with EPN triggered an immune response in tomato via upregulated phenylpropanoid metabolism and synthesis of protease inhibitors in plant tissues, which may explain decreased egg laying and developmental performance exhibited by herbivores on EPN-inoculated plants. Furthermore, changes induced in the volatile organic compound-related transcriptome indicated that M. javanica and/or S. carpocapsae inoculation of plants triggered both direct and indirect defences. Our results support the hypothesis that plants "mistake" subterranean EPNs for parasites, and these otherwise beneficial worms activate a battery of plant defences associated with systemic acquired resistance and/or induced systemic resistance with concomitant antagonistic effects on temporally co-occurring subterranean plant pathogenic nematodes and terrestrial herbivores