Fahad Al-Qurainy

Role of transgenic plants in agriculture and biopharming

At present, environmental degradation and the consistently growing population are two main problems on the planet earth. Fulfilling the needs of this growing population is quite difficult from the limited arable land available on the globe. Although there are legal, social and political barriers to the utilization of biotechnology, advances in this field have substantially improved agriculture and human life to a great extent. One of the vital tools of biotechnology is genetic engineering (GE) which is used to modify plants, animals and microorganisms according to desired needs. In fact, genetic engineering facilitates the transfer of desired characteristics into other plants which is not possible through conventional plant breeding. A variety of crops have been engineered for enhanced resistance to a multitude of stresses such as herbicides, insecticides, viruses and a combination of biotic and abiotic stresses in different crops including rice, mustard, maize, potato, tomato, etc. Apart from the use of GE in agriculture, it is being extensively employed to modify the plants for enhanced production of vaccines, hormones, etc. Vaccines against certain diseases are certainly available in the market, but most of them are very costly. Developing countries cannot afford the disease control through such cost-intensive vaccines. Alternatively, efforts are being made to produce edible vaccines which are cheap and have many advantages over the commercialized vaccines. Transgenic plants generated for this purpose are capable of expressing recombinant proteins including viral and bacterial antigens and antibodies. Common food plants like banana, tomato, rice, carrot, etc. have been used to produce vaccines against certain diseases like hepatitis B, cholera, HIV, etc. Thus, the up- and down-regulation of desired genes which are used for the modification of plants have a marked role in the improvement of genetic crops. In this review, we have comprehensively discussed the role of genetic engineering in generating transgenic lines/cultivars of different crops with improved nutrient quality, biofuel production, enhanced production of vaccines and antibodies, increased resistance against insects, herbicides, diseases and abiotic stresses as well as the safety measures for their commercialization.

Drought Tolerance: Roles of Organic Osmolytes, Growth Regulators, and Mineral Nutrients

Abstract Drought, the occurrence of a substantial water deficit in the soil or in the atmosphere, is an alarming constraint to crop productivity and yield stability worldwide. It is the leading environmental stress in world agriculture, causing losses in crop yield probably exceeding losses from all other causes combined. Drought stress adversely affects a variety of vital physiological and biochemical processes in plants, leading to reduced growth and final crop yield. Some plant species have evolved mechanisms to cope with the stress, including drought avoidance, dehydration avoidance, or dehydration tolerance. Such adaptive mechanisms are the results of a multitude of morphoanatomical, physiological, biochemical, and molecular changes. Osmoregulation is the most common physiological adaptation, which takes place by reducing cellular water potential via accumulation of a variety of organic and inorganic solutes in the cell. As a consequence, such plants are capable of taking up water from a low water potential medium to sustain normal or near normal physiological processes necessary for growth and development. However, most economically important crop species lack the capability of coping with this type of drought stress, precluding their cultivation under water-limited conditions. Various strategies have been proposed to facilitate crop production under drought conditions, in particular, development of new crop varieties with enhanced drought tolerance. Genetic improvement of crop plants for drought tolerance is a long-term endeavor, which requires, among other things, the availability of genetic sources of tolerance, knowledge of the physiological mechanisms and genetic controls of tolerance traits at different developmental stages, and employment of suitable germplasm screening and breeding protocols. An alternative and quicker strategy to promote plant drought tolerance is exogenous application of various compounds, including organic solutes (organic osmolytes and plant growth regulators) and mineral nutrients. Recently, this strategy has gained considerable attention because of its efficiency, feasibility, and cost- and labor-effectiveness. In this chapter, we review the roles of organic osmolytes, plant growth regulators, and mineral nutrients in plant response to drought stress and discuss their exogenous application in enhancing plant drought tolerance and alleviating the damaging effects of drought stress.

Alleviation of waterlogging stress in upland cotton (Gossypium hirsutum L.) by exogenous application of potassium in soil and as a foliar spray

The effectiveness of exogenous application of K in ameliorating the adverse effects of waterlogging on cotton plants was assessed under greenhouse conditions. Forty-day-old plants were subjected to continuous flooding for 1 week and then K (60 kg ha–1) was applied either as soil application, foliar spray, or in combination. The waterlogging treatment significantly reduced plant height and fresh and dry biomass, photosynthetic pigments, gas exchange parameters and nutrient accumulation (N, K+, Ca2+) in stem, root and leaves of cotton plants, Although Mg2+ content in roots increased significantly due to waterlogging, it was not affected in stem or leaves. In contrast, Mn2+ and Fe2+ contents generally increased under waterlogged conditions. All water relation parameters were also significantly influenced by waterlogging stress. Waterlogged plants supplemented with K showed a significant improvement in growth, photosynthetic pigments and photosynthetic capacity. Potassium supplementation also improved nutrient uptake of waterlogged plants and resulted in significantly higher accumulation of K+, Ca2+, N, Mn2+ and Fe2+ than those plants not supplied with K. Although all modes of K application were effective in mitigating the inhibitory effects of waterlogging, the combined application through soil + foliar spray yielded the best results and the foliar application (alone) being the least effective.

Effects of different doses of low power continuous wave he-ne laser radiation on some seed thermodynamic and germination parameters, and potential enzymes involved in seed germination of sunflower (Helianthus annuus L.).

In this study, water‐soaked seeds of sunflower were exposed to He–Ne laser irradiation of different energies to determine whether or not He–Ne laser irradiation caused changes to seed thermodynamic and germination parameters as well as effects on the activities of germination enzymes. The experiment comprised four energy levels: 0 (control), 100, 300 and 500 mJ of laser energy and each treatment replicated four times arranged in a completely randomized design. The experimentation was performed under the greenhouse conditions in the net‐house of the Department of Botany, University of Agriculture, Faisalabad. The seed thermodynamic parameters were calculated according to seed germination thermograms determined with a calorimeter at 25.8°C for 72 h. Various thermodynamic parameters of seed (ΔH, (ΔS)e, (ΔS)c, (ΔS)e/Δt and (ΔS)c/Δt) were affected significantly due to presowing laser treatment. Significant changes in seed germination parameters and enzyme activities were observed in seeds treated with He–Ne laser. The He–Ne laser seed treatment resulted in increased activities of amylase and protease. These results indicate that the low power continuous wave He–Ne laser light seed treatment has considerable biological effects on seed metabolism. This seed treatment technique can be potentially employed to enhance agricultural productivity.

Alleviation of adverse effects of drought stress on growth and some potential physiological attributes in maize (Zea mays L.) by seed electromagnetic treatment.

Effects of varying preseed magnetic treatments on growth, chlorophyll pigments, photosynthesis, water relation attributes, fluorescence and levels of osmoprotectants in maize plants were tested under normal and drought stress conditions. Seeds of two maize cultivars were treated with different (T0 [0 mT], T1 [100 mT for 5 min], T2 [100 mT for 10 min], T3 [150 mT for 5 min] and T4 [150 mT for 10 min]) electromagnetic treatments. Drought stress considerably suppressed growth, chlorophyll a and b pigments, leaf water potential, photosynthetic rate (A), stomatal conductance (gs) and substomatal CO2 concentration (Ci), while it increased leaf glycinebetaine and proline accumulation in both maize cultivars. However, pretreated seeds with different magnetic treatments significantly alleviated the drought‐induced adverse effects on growth by improving chlorophyll a, A, E, gs, Ci and photochemical quenching and nonphotochemical quenching, while it had no significant effect on other attributes. However, different magnetic treatments negatively affected the gs and Ci particularly in cv. Agaiti‐2002 under drought stress conditions. Of all magnetic treatments, 100 and 150 mT for 10 min were most effective in alleviating the drought‐induced adverse effects. Overall, preseed electromagnetic treatments could be used to minimize the drought‐induced adverse effects on different crop plants.

Biotechnological approaches for conservation and improvement of rare and endangered plants of Saudi Arabia

Genetic variation is believed to be a prerequisite for the short-and long-term survival of the plant species in their natural habitat. It depends on many environmental factors which determine the number of alleles on various loci in the genome. Therefore, it is important to understand the genetic composition and structure of the rare and endangered plant species from their natural habitat to develop successful management strategies for their conservation. However, rare and endangered plant species have low genetic diversity due to which their survival rate is decreasing in the wilds. The evaluation of genetic diversity of such species is very important for their conservation and gene manipulation. However, plant species can be conserved by in situ and in vitro methods and each has advantages and disadvantages. DNA banking can be considered as a means of complimentary method for the conservation of plant species by preserving their genomic DNA at low temperatures. Such approach of preservation of biological information provides opportunity for researchers to search novel genes and its products. Therefore, in this review we are describing some potential biotechnological approaches for the conservation and further manipulation of these rare and endangered plant species to enhance their yield and quality traits.

Relationships between gas-exchange characteristics and stomatal structural modifications in some desert grasses under high salinity

Two populations, one from lesser saline Derawar Fort (DF) and the other from highly saline Ladam Sir (LS) in the Cholistan desert, for each of the five grass species, Aeluropus lagopoides, Cymbopogon jwarancusa, Lasiurus scindicus, Ochthochloa compressa, and Sporobolus ioclados were examined to investigate the influence of salinity on structural and functional characteristics of stomata. Salinity tolerance in A. lagopoides mainly depended on controlled transpiration rate (E) and high water-use efficiency (WUE), which was found to be regulated by fewer and smaller stomata on both leaf surfaces as well as stomatal encryption by epidermal invaginations. C. jwarancusa had sunken stomata on the abaxial surface only, which largely reflected a reduced E, but less affected stomatal conductance (gs) or WUE. L. scindicus had fewer but larger stomata along with hairs/trichomes which may function to avoid water loss through transpiration, and hence, to attain a high WUE. In O. compressa stomata were found only on the abaxial surface and these were completely encrypted by epidermal invaginations as well as a dense covering of microhairs, which was associated with a low E and high WUE under salinity stress. In S. ioclados, the traits of increased stomatal density and decreased stomatal area may be critical for stomatal regulation under salt-prone environments. High stomatal regulation depended largely on stomatal density, area, and degree of encryption under salinity, which is of great ecophysiological significance for plants growing under osmotic stresses.

Fusarium solani, P1, a new endophytic podophyllotoxin-producing fungus from roots of Podophyllum hexandrum

Podophyllotoxin, a well-known naturally occurring aryl tetralin lignan produced by few plant species is used as precursor for the chemical synthesis of the anticancer drugs like etoposide, teniposide and etopophos phosphate. The availability of this lignan is limited due to the scarce occurrence of its natural sources. Further, synthetic approaches for its production are still commercially unacceptable. This paper reports the synthesis of podophyllotoxin by an endophytic fungus Fusarium solani isolated from the roots of Podophyllum hexandrum. The presence of podophyllotoxin in fungal biomass was confirmed and quantified by HPLC and mass spectrometry. The fungus is able to produce 29.0 µg/g podophyllotoxin on dry weight basis.

Salt‐induced modulation in inorganic nutrients, antioxidant enzymes, proline content and seed oil composition in safflower (Carthamus tinctorius L.)

BACKGROUND Safflower (Carthamus tinctorius L.) has gained considerable ground as a potential oil-seed crop. However, its yield and oil production are adversely affected under saline conditions. The present study was conducted to appraise the influence of salt (NaCl) stress on yield, accumulation of different inorganic elements, free proline and activities of some key antioxidant enzymes in plant tissues as well as seed oil components in safflower. Two safflower accessions differing in salt tolerance (Safflower-33 (salt sensitive) and Safflower-39 (salt tolerant)) were grown under saline (150 mmol L(-1) ) conditions and salt-induced changes in the earlier-mentioned physiological attributes were determined. RESULTS Salt stress enhanced leaf and root Na(+) , Cl(-) and proline accumulation and activities of leaf superoxide dismutase, catalase and peroxidase, while it decreased K(+) , Ca(2+) and K(+) /Ca(2+) and Ca(2+) /Na(+) ratios and seed yield, 100-seed weight, number of seeds, as well as capitula, seed oil contents and oil palmitic acid. No significant effect of salt stress was observed on seed oil α-tocopherols, stearic acid, oleic acid or linoleic acid contents. Of the two safflower lines, salt-sensitive Safflower-33 was higher in leaf and root Na(+) and Cl(-) , while Safflower-39 was higher in leaf and root K(+) , K(+) /Ca(2+) and Ca(2+) /Na(+) and seed yield, 100-seed weight, catalase activity, seed oil contents, seed oil α-tocopherol and palmitic acid. Other attributes remained almost unaffected in both accessions. CONCLUSION Overall, high salt tolerance of Safflower-39 could be attributed to Na(+) and Cl(-) exclusion, high accumulation of K(+) and free proline, enhanced CAT activity, seed oil α-tocopherols and palmitic acid contents.

Assessment of genetic diversity in the endangered populations of Breonadia salicina (Rubiaceae) growing in The Kingdom of Saudi Arabia using inter-simple sequence repeat markers

BackgroundBreonadia salicina (Rubiaceae) is a critically endangered plant at the local scale native to southwestern Saudi Arabia. To understand the levels and partitioning of genetic variation across populations and geographical regions of this species, we assessed its genetic diversity using inter-simple sequence repeat (ISSR) markers.ResultsFourteen ISSR primers selected from 43 primers gave rise to 211 amplified loci, of which 68 were polymorphic. The percentage of polymorphic loci (PPL) at the population level ranged from 17.1 to 23.7%, with an average of 21.3%. Nei’s gene diversity (h) and Shannon’s information index (I) were 0.086 and 0.125, respectively. At the species level, PPL was 32.2%, while h and I were 0.116 and 0.172, respectively. A hierarchical analysis of molecular variance revealed a high level of genetic differentiation among populations (17% of total variance, P = 0.001), consistent with the gene differentiation coefficient (GST = 0.256). Nevertheless, the evaluated genetic diversity was very low within populations; while relatively high among populations, levels were insufficient for long-term survival. Saudi Arabian accessions were also compared to accessions of a population from Yemen, where the species is more widespread. The Yemeni population also showed low genetic diversity but clustered separately.ConclusionsBreonadia salicina in Saudi Arabia is characterized by low within-population genetic diversity and high among-population genetic differentiation. Based on our findings, this locally endangered species is on the verge of local extinction. The species’ survival depends on successful implementation of suggested strategies for its long-term conservation.