Summary
There is considerable interest of evolutionary ecologists in the proximate mechanisms that constrain life‐history variation. It is increasingly recognized that oxidative stress may be a prime ...physiological constraint on reproduction, but to the best of our knowledge, this has never been tested experimentally.
To fill in this gap, we examined whether a specific and short‐term experimental increase of pre‐reproductive oxidative stress in females of a songbird (canary, Serinus canaria) would influence reproductive decisions (i.e. when and how many eggs to lay), and reproductive success (hatching and fledging success, number of hatchlings and of fledglings produced by each female), as compared to females whose oxidative stress levels were not manipulated.
Our experimental reduction of glutathione, a key antioxidant, increased oxidative stress and affected reproductive decisions: treated females significantly delayed the start of egg laying and laid significantly smaller clutches. However, both hatching and fledging success and the number of hatchlings and of fledglings produced by each female were similar between control and treated females.
Our results support the hypothesis that oxidative stress may be one proximate mechanism modulating key life‐history traits (such as the timing of laying and clutch size in birds) and therefore may act as a link between prevailing environmental conditions and fitness traits.
Lay Summary
The present study aims to study the effects of biofertilizers potential of Arbuscular Mycorrhizal Fungi (AMF) and Bradyrhizobium japonicum (B. japonicum) strains on yield and growth of drought ...stressed soybean (Giza 111) plants at early pod stage (50 days from sowing, R3) and seed development stage (90 days from sowing, R5).
Highest plant biomass, leaf chlorophyll content, nodulation, and grain yield were observed in the unstressed plants as compared with water stressed-plants at R3 and R5 stages. At soil rhizosphere level, AMF and B. japonicum treatments improved bacterial counts and the activities of the enzymes (dehydrogenase and phosphatase) under well-watered and drought stress conditions. Irrespective of the drought effects, AMF and B. japonicum treatments improved the growth and yield of soybean under both drought (restrained irrigation) and adequately-watered conditions as compared with untreated plants. The current study revealed that AMF and B. japonicum improved catalase (CAT) and peroxidase (POD) in the seeds, and a reverse trend was observed in case of malonaldehyde (MDA) and proline under drought stress. The relative expression of the CAT and POD genes was up-regulated by the application of biofertilizers treatments under drought stress condition. Interestingly a reverse trend was observed in the case of the relative expression of the genes involved in the proline metabolism such as P5CS, P5CR, PDH, and P5CDH under the same conditions. The present study suggests that biofertilizers diminished the inhibitory effect of drought stress on cell development and resulted in a shorter time for DNA accumulation and the cycle of cell division. There were notable changes in the activities of enzymes involved in the secondary metabolism and expression levels of GmSPS1, GmSuSy, and GmC-INV in the plants treated with biofertilizers and exposed to the drought stress at both R3 and R5 stages. These changes in the activities of secondary metabolism and their transcriptional levels caused by biofertilizers may contribute to increasing soybean tolerance to drought stress.
The results of this study suggest that application of biofertilizers to soybean plants is a promising approach to alleviate drought stress effects on growth performance of soybean plants. The integrated application of biofertilizers may help to obtain improved resilience of the agro ecosystems to adverse impacts of climate change and help to improve soil fertility and plant growth under drought stress.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Information on the onset of leaf senescence in temperate deciduous trees and comparisons on its assessment methods are limited, hampering our understanding of autumn dynamics.
We compare five field ...proxies, five remote sensing proxies and two data analysis approaches to assess leaf senescence onset at one main beech stand, two stands of oak and birch, and three ancillary stands of the same species in Belgium during 2017 and 2018.
Across species and sites, onset of leaf senescence was not significantly different for the field proxies based on Chl leaf content and canopy coloration, except for an advanced canopy coloration during the extremely dry and warm 2018. Two remote sensing indices provided results fully consistent with the field data. A significant lag emerged between leaf senescence onset and leaf fall, and when a threshold of 50% change in the seasonal variable under study (e.g. Chl content) was used to derive the leaf senescence onset.
Our results provide unprecedented information on the quality and applicability of different proxies to assess leaf senescence onset in temperate deciduous trees. In addition, a sound base is offered to select the most suited methods for the different disciplines that need this type of data.
Date palm is an important crop, especially in the hot-arid regions of the world. Date palm fruits have high nutritional and therapeutic value and possess significant antibacterial and antifungal ...properties. In this study, we performed bioactivity analyses and metabolic profiling of date fruits of 12 cultivars from Saudi Arabia to assess their nutritional value. Our results showed that the date extracts from different cultivars have different free radical scavenging and anti-lipid peroxidation activities. Moreover, the cultivars showed significant differences in their chemical composition, e.g., the phenolic content (10.4-22.1 mg/100 g DW), amino acids (37-108 μmol·g-1 FW) and minerals (237-969 mg/100 g DW). Principal component analysis (PCA) showed a clear separation of the cultivars into four different groups. The first group consisted of the Sokary, Nabtit Ali cultivars, the second group of Khlas Al Kharj, Khla Al Qassim, Mabroom, Khlas Al Ahsa, the third group of Khals Elshiokh, Nabot Saif, Khodry, and the fourth group consisted of Ajwa Al Madinah, Saffawy, Rashodia, cultivars. Hierarchical cluster analysis (HCA) revealed clustering of date cultivars into two groups. The first cluster consisted of the Sokary, Rashodia and Nabtit Ali cultivars, and the second cluster contained all the other tested cultivars. These results indicate that date fruits have high nutritive value, and different cultivars have different chemical composition.
Drought is the most important crop yield-limiting factor, and detailed knowledge of its impact on plant growth regulation is crucial. The maize (Zea mays) leaf growth zone offers unique possibilities ...for studying the spatiotemporal regulation of developmental processes by transcriptional analyses and methods that require more material, such as metabolite and enzyme activity measurements. By means of a kinematic analysis, we show that drought inhibits maize leaf growth by inhibiting cell division in the meristem and cell expansion in the elongation zone. Through a microarray study, we observed the downregulation of 32 of the 54 cell cycle genes, providing a basis for the inhibited cell division. We also found evidence for an upregulation of the photosynthetic machinery and the antioxidant and redox systems. This was confirmed by increased chlorophyll content in mature cells and increased activity of antioxidant enzymes and metabolite levels across the growth zone, respectively. We demonstrate the functional significance of the identified transcriptional reprogramming by showing that increasing the antioxidant capacity in the proliferation zone, by overexpression of the Arabidopsis (Arabidopsis thaliana) iron-superoxide dismutase gene, increases leaf growth rate by stimulating cell division. We also show that the increased photosynthetic capacity leads to enhanced photosynthesis upon rewatering, facilitating the often-observed growth compensation.
Drought is a significant global constraint on agricultural production and food security. As a promising approach to improve plant growth and yield under challenging conditions, plant growth-promoting ...actinobacteria has attracted much interest. Further, elevated levels of atmospheric CO
2
(eCO
2
) may promote the plant–actinobacteria interactions which could be effective to improve the plant growth for food production. Herein, we have investigated the impact of actinobacteria and/or CO
2
on biomass production, photosynthesis, macronutrients, levels of organic acids, amino acids, and essential oils as well as antioxidant activities of
Satureja hortensis
under water-deficit conditions. Among different actinobacterial isolates evaluated for development of secondary metabolites and biological activities, Ac9 was highly capable of producing flavonoids, and it also showed high antioxidant and microbial activities. It markedly induced the plant growth, photosynthesis, and global metabolic improvement, under water-deficit conditions. Interestingly, treatment with Ac9 in combination with eCO
2
substantially minimized drought stress–induced biomass and photosynthesis reductions in
Satureja hortensis
. Improved photosynthesis by Ac9 and/or eCO
2
induced the primary and secondary metabolisms in drought-stressed plants. The levels of the majority of the detected organic acids, essential oil, and amino acids were further improved as a result of the synergistic action of Ac9 and eCO
2
, as compared to the individual treatments. Furthermore, Ac9 or eCO
2
significantly improved the antioxidant activities in stressed plants; however, much more positive impact was obtained by their synchronous application. Thus, the current study suggests that actinobacterial treatment induces global metabolic changes in water-stressed
Satureja hortensis
, the effects that have been much more strengthened under eCO
2
.
Recent temperature increases have elicited strong phenological shifts in temperate tree species, with subsequent effects on photosynthesis. Here, we assess the impact of advanced leaf flushing in a ...winter warming experiment on the current year’s senescence and next year’s leaf flushing dates in two common tree species: Quercus robur L. and Fagus sylvatica L. Results suggest that earlier leaf flushing translated into earlier senescence, thereby partially offsetting the lengthening of the growing season. Moreover, saplings that were warmed in winter–spring 2009–2010 still exhibited earlier leaf flushing in 2011, even though the saplings had been exposed to similar ambient conditions for almost 1 y. Interestingly, for both species similar trends were found in mature trees using a long-term series of phenological records gathered from various locations in Europe. We hypothesize that this long-term legacy effect is related to an advancement of the endormancy phase (chilling phase) in response to the earlier autumnal senescence. Given the importance of phenology in plant and ecosystem functioning, and the prediction of more frequent extremely warm winters, our observations and postulated underlying mechanisms should be tested in other species.
Elevated CO2 (eCO2) reduces the impact of drought, but the mechanisms underlying this effect remain unclear. Therefore, we used a multidisciplinary approach to investigate the interaction of drought ...and eCO2 in Arabidopsis thaliana leaves. Transcriptome and subsequent metabolite analyses identified a strong induction of the aliphatic glucosinolate (GL) biosynthesis as a main effect of eCO2 in drought‐stressed leaves. Transcriptome results highlighted the upregulation of ABI5 and downregulation of WRKY63 transcription factors (TF), known to enhance and inhibit the expression of genes regulating aliphatic GL biosynthesis (e.g., MYB28 and 29 TFs), respectively. In addition, eCO2 positively regulated aliphatic GL biosynthesis by MYB28/29 and increasing the accumulation of GL precursors. To test the role of GLs in the stress‐mitigating effect of eCO2, we investigated the effect of genetic perturbations of the GL biosynthesis. Overexpression of MYB28, 29 and 76 improved drought tolerance by inducing stomatal closure and maintaining plant turgor, whereas loss of cyp79f genes reduced the stress‐mitigating effect of eCO2 and decreased drought tolerance. Overall, the crucial role of GL metabolism in drought stress mitigation by eCO2 could be a beneficial trait to overcome future climate challenges.
Summary Statement
Elevated CO2 can mitigate drought stress, but the underlying mechanisms remain largely unclear. This study identifies the genetic regulation of aliphatic glucosinolate by eCO2 and its role in inducing drought tolerance by improving water relations through their role in stomatal regulation.
Ocean acidification is impacting marine life all over the world. Understanding how species can cope with the changes in seawater carbonate chemistry represents a challenging issue. We addressed this ...topic using underwater CO2 vents that naturally acidify some marine areas off the island of Ischia. In the most acidified area of the vents, having a mean pH value of 6.7, comparable to far‐future predicted acidification scenarios (by 2300), the biomass is dominated by the brown alga Sargassum vulgare. The novelty of the present study is the characterization of the S. vulgare proteome together with metabolite analyses to identify the key proteins, metabolites, and pathways affected by ocean acidification. A total of 367 and 387 proteins were identified in populations grown at pH that approximates the current global average (8.1) and acidified sites, respectively. Analysis of their relative abundance revealed that 304 proteins are present in samples from both sites: 111 proteins are either higher or exclusively present under acidified conditions, whereas 120 proteins are either lower or present only under control conditions. Functionally, under acidification, a decrease in proteins related to translation and post‐translational processes and an increase of proteins involved in photosynthesis, glycolysis, oxidation–reduction processes, and protein folding were observed. In addition, small‐molecule metabolism was affected, leading to a decrease of some fatty acids and antioxidant compounds under acidification. Overall, the results obtained by proteins and metabolites analyses, integrated with previous transcriptomic, physiological, and biochemical studies, allowed us to delineate the molecular strategies adopted by S. vulgare to grow in future acidified environments, including an increase of proteins involved in energetic metabolism, oxidation–reduction processes, and protein folding at the expense of proteins involved in translation and post‐translational processes.
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