Transgenic approaches to improve photosynthesis and nitrogen use in wheat

To meet the rapid growth of the global population and the expected demand for food, significant enhancements in yields are needed, together with optimised N fertilisation and environmental issues, particularly in the production of major grain crops, such as wheat and rice. Improving photosynthesis, together with NUE, has been considered an unexploited opportunity in the research on improving crop yields. Therefore, transgenic wheat plants with increased SBPase activity showed an improved photosynthetic leaf rate and total biomass production. The Rubisco protein is a major N investment in crops, but it has also been exhibited that under some environmental conditions, there may be an excess of Rubisco greater than that needed to maintain photosynthesis. This raises the question of whether a small reduction in the amount of the Rubisco enzyme can be used to improve NUE without any negative effects on plant yield. To address the question, wheat plants with decreased Rubisco were produced. Physiological studies were performed on five independent transgenic lines with different levels of Rubisco, and the photosynthetic rates, biomass and grain yields were determined. Rubisco RNAi lines with reductions in the Rubisco protein of more than 40% showed a significant decrease in photosynthesis, growth and grain yield. Interestingly, the plants with the lowest level of Rubisco activity had significantly higher levels of leaf and seed N when compared to WT plants. In contrast, small reductions in the Rubisco protein of between about 10% and 25% did not have an adverse effect on photosynthesis, growth or grain yield in two independent transgenic wheat lines. Furthermore, to search for new promoters to drive good transgene expressions specialised to wheat leaves, two Brachypodium promoters, SBPase and FBPA, were cloned upstream of the GUS fusion gene and transformed into wheat leaves. Consequently, both promoters resulted in detectable GUS expression in wheat leaves at different growth stages and did not show expressions in the roots

Axial-Flexural Behaviour of Reinforced Concrete Masonry Columns Confined by FRP Jackets

Confining existing concrete and masonry columns by Fibre Reinforced Polymers (FRP) is a beneficial method for enhancing the column capacity and ductility. The popularity of using FRP for strengthening and upgrading columns is mainly attributed to the high strength and lightweight characteristics of the FRP materials. Using FRP composites reduces additional dead load associated with traditional strengthening solutions and simplify the application in areas with limited access. The goal of this research is to experimentally quantify the enhancement in strength and strain capacity of Carbon FRP (CFRP) confined concrete masonry columns under concentric and eccentric loading. Research on FRP-strengthened concrete masonry columns under eccentric loads is essential to understand the effect of this retrofitting technique on the performance of columns. The experimental data was then used to propose a simplified methodology that predicts the axial force-moment interaction diagram of fully grouted reinforced concrete masonry column strengthened with FRP jackets. The methodology considers short prismatic reinforced concrete masonry columns failing in a compression controlled manner and complies with equilibrium and strain compatibility principles. To achieve the research goals, 47 scaled fully grouted concrete block masonry columns were tested under concentric, eccentric, and bending loading up to failure. Parameters investigated in this research include the thickness of CFRP jacket, corner radius of cross section and the magnitude of eccentricity. The proposed analytical methodology showed a good correlation with the experimental data. Parametric study was carried out to determine the effect of design variables on the axial-flexural interaction of fully grouted reinforced concrete masonry column strengthened by FRP jackets

Variations in Litterfall Dynamics, C:N:P Stoichiometry and Associated Nutrient Return in Pure and Mixed Stands of Camphor Tree and Masson Pine Forests

Litterfall, directly and indirectly, affects the soil physicochemical properties, microbial activity, and diversity of soil fauna and flora by adding organic matter and nutrients to the soil. This study explores litterfall dynamics such as litterfall production, litter decomposition rate, and associated nutrient return in three forest types, that is, camphor tree forest (CTF), Masson pine forest (MPF), and camphor tree and Masson pine mixed forest (CMF), in subtropical China. Results showed that CMF had the highest mean annual litterfall production (4.30 ± 0.22 t ha−1), which was significantly higher than that of MPF (3.41 ± 0.25 t ha−1) and CTF (3.26 ± 0.17 t ha−1). Leaf represented the major fraction of litterfall, constituting over 71% of the total litterfall mass in the three forest types. The contribution of branch litter was 16.3, 8.9, and 16.9%, and miscellaneous litter was 12.6, 18.9, and 11.1% in CTF, MPF, and CMF, respectively. The concentration of macronutrients ranked as N > Ca > K > Mg > P in all litter fractions. The total annual macronutrient return to the soil from the litterfall was in order as CTF (74.2 kg ha−1‧yr−1) > CMF (70.7 kg ha−1‧yr−1) > MPF (33.6 kg ha−1‧yr−1). The decomposition rate was higher in leaf litter than in branch litter throughout the three forests. Among the forest types, the leaf and branch decomposition rates were in a pattern: CTF > CMF > MPF. The ratio of C/N in both leaf and branch litters was significantly higher in MPF than in CTF and CMF, while no significant differences in N/P ratio were found in these litters among the three forests. The high N:P ratios in leaf litter (23/30) and the branch (24/32) litter indicated the high N returning and low nutrient returning to the soil. Our results suggested that the broadleaved forests have faster litter decomposition and higher macronutrient returns than conifer forests. Moreover, the litter decomposition rate was mainly associated with litterfall quality and chemical composition. The introduction of broadleaved trees into monoculture coniferous stands could increase litter production nutrients return, and thus, it had advantages in soil nutrients restoration and sustainable forest management

Functional Analysis of SBPase Gene Promoter in Transgenic Wheat under Abiotic Stresses

Background and Objective: This study focused on evaluation of SBPase promoter in driving transgenes under drought, high light intensity and salinity as major abiotic stresses limiting plant growth and production in various areas of the world. Wheat production has remained constant despite the rapidly growing population around the world. Materials and Methods: This had made it necessary to develop other varieties with higher yield in order to satisfy the future demand. When elite wheat varieties’ photosynthesis is genetically manipulated, it gives a high possibility for yield increase. Lack of a properly defined molecular tool-box promoter for driving gene expression for manipulation of photosynthesis, hinders the progression of this field. Gus histochemical staining and quantitative PCR were used to examine the function of Brachypodium distachyon sedoheptulose-1, 7-bisphosphatase (SBPase) promoter to drive the expression of GUS in the stably transformed wheat plants under various stresses conditions. Results: Results revealed that B. distachyon SBPase promoter fully drive the GUS expression in the stable wheat transformants (cv. Cadenza) in the leaf tissues under normal and high light conditions. It also drove GUS gene expression under drought and salinity stress conditions. In addition, the promoter responds to light/dark/light alternation as light responsive genes. Conclusion: The Bd SBPase promoter provides innovative molecular tool to drive genes in wheat leaves under natural, drought, high light intensity and salinity conditions as well as to allow for multigene photosynthetic manipulation for yield increase under various abiotic conditions

Increased SBPase activity improves photosynthesis and grain yield in wheat grown in greenhouse conditions

To meet the growing demand for food, substantial improvements in yields are needed. This is particularly the case for wheat, where global yield has stagnated in recent years. Increasing photosynthesis has been identified as a primary target to achieve yield improvements. To increase leaf photosynthesis in wheat, the level of the Calvin-Benson cycle enzyme sedoheptulose-1,7-biphosphatase (SBPase) has been increased through transformation and expression of a Brachypodium dystachion SBPase gene construct. Transgenic lines with increased SBPase protein levels and activity were grown under greenhouse conditions and showed enhanced leaf photosynthesis and increased total biomass and dry seed yield. This showed the potential of improving yield potential by increasing leaf photosynthesis in a crop species such as wheat. The results are discussed with regards to future strategies for further improvement of photosynthesis in wheat.publishersversionPeer reviewe

Rice Straw Vermicompost Enriched With Cellulolytic Microbes Ameliorate the Negative Effect of Drought in Wheat Through Modulating the Morpho-Physiological Attributes

Wheat growth and productivity are unfavorably pretentious by a lack of sufficient water (drought or water deficit) worldwide. Drought stress significantly affects all the morpho-physiological and biochemical characteristics and the agronomical yield of wheat. Different management approaches have been adopted to cope with the negative effects of water deficit. Soil-applied vermicompost is helpful in improving the growth and developmental processes of wheat under water deficit conditions. Therefore, a trial was carried out to optimize the best amount of vermicompost and to assess its role in ameliorating the negative effects of drought for sustainable crop production. The treatments consisted of 1) two contrasting wheat cultivars Faisalabad-08 (drought-tolerant) and Galaxy-13 (drought-sensitive), 2) drought with three levels [D0 = 70% of field capacity (no drought), D1 = 45% of field capacity (mild drought), and D2 = 30% of field capacity (severe drought)] and 3) cellulolytic microbe-enriched vermicompost prepared from rice straw with four levels (VT0 = Control, VT1 = 4 t ha−1, VT2 = 6 t ha−1 , and VT3 = 8 t ha−1). Data on various morphological, physiological, and biochemical parameters were recorded from sowing to crop harvesting. In this study, it was demonstrated that all these parameters were negatively affected by moisture deficit conditions. The application of vermi-fertilizer significantly increased (p < 0.05) the aforementioned parameters of wheat in both the absence and presence of drought. Under severe drought, VT2 treatment increased the seedling length by 14.02–26.14%, fresh weight by 15.16–22.91%, and dry weight by 0.37–28.20% in both cultivars compared with control. In addition, VT2 treatment reduced the leaf water potential by 6.36 and 3.36%, leaf osmotic potential by 1.74 and 1.68%, and increased the turgor potential by 4.83 and 3.36%, and photosynthetic rate by 18.59 and 26.42% in Faislabad-08 and Galaxy-13, respectively, over control. We concluded that the application of vermicompost is a valuable approach to alleviate the adverse impacts of water stress on wheat

Molecular markers-based DNA fingerprinting coupled with morphological diversity analysis for prediction of heterotic grouping in sunflower (Helianthus annuus L.)

Cultivated sunflower holds a very narrow genetic base and the efficient utilization of available genetic diversity is very important for a successful breeding program. In the present study, 109 sunflower genotypes were assessed for diversity paneling through a combined approach of morphological and molecular markers analysis. Morphological parameters including days to flower initiation, days to flower completion, plant height, stem curvature, number of leaves per plant, leaf area, head diameter, hundred seed weight, and seed yield per plant were studied. Simple sequence repeats (40 DNA markers) were deployed for diversity profiling. Data were analyzed by both univariate and multivariate statistics. SD and coefficient of variation confirm the presence of significant amounts of genetic variation for all the morphological parameters. Cluster Analysis and Principal Component Analysis further confirm the presence of distinct grouping patterns in the studied material. Cluster analysis of both morphological and molecular analysis revealed that restorer lines tend to group separately from A, B, and open-pollinated lines. Further grouping, at the sub-cluster level, revealed six distinct sub-clusters in each of the two major clusters. In total, 12 genotypes, 6 CMS lines (CMS-HAP-12, CMS-HAP-54, CMS-HAP-56, CMS-HAP-99, CMS-HAP-111, and CMS-HAP-112) and 6 restorer lines (RHP-38, RHP-41, RHP-53, RHP-68, RHP-69, and RHP-71) could be used as potential parents for hybrid development. As genotypes of similar genetic backgrounds tend to group closer, it is deduced that one genotype with the highest seed yield per plant could be used for further hybrid breeding programs in sunflowers

The impact of different biochars on Stemphylium leaf blight SLB suppression and productivity of onion Allium cepa L.

Objectives: Onion is a highly consumed vegetable crop in many countries, being a vital component of every dish. Recent studies indicated that different plant residues’ and animal manure-based biochars have strong impacts on the growth and development of plants. However, the impact of these biochars on disease suppression remains elusive. Therefore, this two-year study assessed the impact of animal and plant residues-based biochars on the suppression of Stemphylium leaf blight (SLB) of onion and productivity of the crop. Methods: Three pyrolyzed biochars cotton sticks, wheat straw and poultry litter) were used in the study. Biochars were prepared in the laboratory and applied to soil prior to crop sowing in same concentration during both years of study. Results: Poultry litter biochar had the highest impact on allometric traits and productivity of onion, and successfully reduced SLB severity. The control treatment had the lowest productivity and the highest disease severity during both years of the study. The remaining biochars (cotton sticks and wheat straw) hadmoderate influence on growth and development of onion plants. The disease severity was higher compared to poultry litter; however, it was lower in both biochars than control treatment. It is concluded that different animal and plant residues-based biochars could be used to improve plant health. Nonetheless, the response of these biochars will be crop-specific. Conclusion: Poultry litter biochar can be successfully used to suppress SLB in onion and productivity of the crop. Nevertheless, the actual mechanisms involved in disease suppression warrant further investigation

Control Potentials of Three Entomopathogenic Bacterial Isolates for the Carob Moth, Ectomyelois ceratoniae (Lepidoptera: Pyralidae) in Pomegranates

Ectomyelois ceratoniae (Lepidoptera: Pyralidae) is the primary pest of pomegranates in Saudi Arabia and is mostly controlled using broad-spectrum pesticides. Providing environmentally sound choices to limit reliance on chemical management is a major challenge in the control of E. ceratoniae and, as a consequence, in the protection of pomegranate crops from its invasion. Entomopathogenic bacteria (EPB) symbiotically associated with entomopathogenic nematodes (EPNs) are well-known biocontrol agents of soil-dwelling or aerial pests. The bacterium symbiont (EPB) is the real insect-killing biocontrol agent, while the nematode (EPN) serves as a vector. We wondered whether the EPB vector, which is extremely vulnerable to adverse environmental conditions, like drought, high temperatures, and repellent soil microorganisms, could be omitted. We intended to evaluate the biocontrol potential of directly applied EPB cells and cell-free culture media (CFCM) on the larval instar E. ceratoniae. Xenorhabdus budapestensis DSM 16342 (EMA), X. szentirmaii DSM 16338 (EMC), and Photorhabdus luminescens ssp. laumondi (TT01) strains were used. After three days of exposure, the cells of EMA, EMC, and TT01 strains resulted in 100%, 88%, and 79.3% larval mortality rates, respectively. The applied EMA CFCM resulted in 53.7% larval mortality, indicating the presences of (at least) one extremely strong component produced by EMA. We concluded that the direct application of either the EPB cells or the CFCM must be a prospective alternative biocontrol of E. ceratoniae, especially to protect the important fruit (pomegranate, Punica granatum) cultivars. Especially, newly identified local EPB isolates could be applied as bio-pesticides for integrated management practices or organic pomegranate production