Search

Nitrogen (N) is an essential nutrient available to the plants in form of nitrate and ammonium. It is a macronutrient important for the plant growth and development, especially in cereal crops, which consume it for the production of amino acids, proteins/enzymes, nucleic acids, cell wall complexes, plant hormones, and vitamins. In rice production, 17 kg N uptake is required to produce 1 ton of rice. Considering this, many techniques have been developed to evaluate leaf greenness or SPAD value for assessing the amount of N application in the rice cultivar to maximize the grain yield. The aim of the present study was to investigate the morpho-physiological characteristics and relative expression level of N assimilation in three different rice genotypes (MT2, RD31, KDML105) under 1.00 × (full N), 0.50 × , 0.25 × (N depletion), and 0.00 × (N deficiency) at seedling stage and the morpho-physiological traits and the grain yield attributes under 1.00 × (full N) and 0.25 × (N depletion) were compared. Leaf chlorosis and growth inhibition in rice seedlings under N deficiency were evidently observed. Shoot height, number of leaves, shoot fresh weight, shoot dry weight, and root fresh weight in KDML105 under N deficiency were decreased by 27.65%, 42.11%, 65.44%, 47.90%, and 54.09% over the control (full N). Likewise, leaf greenness was lowest in KDML105 under N deficiency (78.57% reduction over the full N), leading to low photosynthetic abilities. In addition, expression of nitrogen assimilation-related genes, OsNR1, OsGln1;1, and OsGln2, in KDML105 under N depletion were increased within 3 h and then declined after the long incubation period, whereas those were unchanged in cvs. MT2 and RD31. Similarly, relative expression level of OsNADH-GOGAT, OsFd-GOGAT, and OsAspAt1 in KDML105 was peaked when subjected to 0.50 × N for 6 h and then declined after the long incubation period. Moreover, overall growth characters and physiological changes in cv. RD31 at vegetative stage under 0.25 × N were retained better than those in cvs. KDML105 and MT2, resulting in high yield at the harvesting process. In summary, N assimilated-related genes in rice seedlings under N depletion were rapidly regulated within 3-6 h, especially cv. KDML105 and MT2, then downregulated, resulting in physiological changes, growth inhibition, and yield reduction.

Baby-leaf vegetables are a trade name for leafy vegetables sold as leaves with petioles at the seedling stage. Amaranth (Amaranthus tricolor L.) is a nutritious baby-leaf vegetable containing many bioactive compounds. The effects of short-term ultraviolet B (UV-B) treatments on the growth and quality of baby leaf amaranth were studied, including the conditions of a 24-h recovery period after irradiation, and different irradiation intensities (3.0-9.0 W m

Oryza sativa cv. PTT1 (Pathumthani1) was treated with phenyl-urea-based synthetic cytokinin under drought stress. Soluble sugar contents were examined in rice flag leaves at tillering and grain-filling stages. The same leaf samples were used to analyze the differential abundance intensities of proteins related to metabolism and transport of soluble sugars, and the process of senescence. The results showed drought-induced accumulation of hexose sugars (glucose and fructose) in rice flag leaves, which could be corroborated with enhanced accumulation of MST8 under drought stress. On the other hand, cytokinin-treated plants maintained the normal contents of hexose sugar in their flag leaves under drought stress, alike well-watered plants. In the case of sucrose, cytokinin treatment reduced its accumulation at tillering stage, but the results were reversed at the grain-filling stage, where the cytokinin-treated plants maintained significantly higher contents of sucrose under drought stress. Growth stage dependent variations in sucrose contents corroborated with the accumulation of SPS (SPS1, SPS2, and SPS5) proteins, implicated in sucrose biosynthesis. In our study, among the proteins involved in sucrose transport, SUT1 transporter was induced by drought stress at both the growth stages, whereas SUT2 transporter accumulated equally in all the treatments. However, cytokinin treatment reversed the effect of drought on the accumulation of SUT1. Similarly, SWEET5, and SWEET13 proteins, which were induced by drought stress treatment, were inhibited by cytokinin treatment. However, the accumulation SWEET6, SWEET7, and SWEET15 was not influenced by the treatment of cytokinin in the flag leaves of rice. In addition, cytokinin treatment reduced the leaf wilting, enhanced the fresh weight and grain yield, and curtailed the accumulation of proteins involved in drought-induced senescence. In conclusion, the cytokinin treatment had a positive agro-economic impact on the rice plants and provided better drought adaptability.

Proline rich proteins (PRPs), earlier famous as animal salivary proteins, have now been proven as indispensable plant proteins. They are highly rich in proline amino acid residues at the N-terminus whereas a characteristic eight cysteine motif is located at the C-terminus. The PRPs support a number of developmental processes from germination to plant death. Under normal environmental conditions, PRP genes express customarily in different plant parts depending on the specific function to be carried out. During abiotic stresses, PRP genes exhibit an uneven pattern of transcriptional regulation depending on the time and intensity of stress. Transgenic plants overexpressing PRP genes show an enhanced tolerance to abiotic stresses. This review focuses on contemporary functions of PRPs during stresses and proposes that PRPs are involved in the regulation of free cellular proline content during stress in a well synchronized manner.

Artificial light has been used to control plant growth and secondary metabolite production. Artemisia annua L. plants were illuminated with three light-emitting diode (LED) spectra to investigate proteomic and biochemical responses. After 7 days, proteomic data revealed different protein numbers in leaves, stems, and roots under particular treatments. Results demonstrated increased accumulation of several proteins, including secondary metabolite-related proteins. The red light (R) (660 nm) highly induced terpenoid proteins. Similar biochemical profiles were observed in white light (W) (445, 544 nm) and blue light (B) (445 nm) conditions, while profiles from R treatment were different. Functional proteins of W and B treatments were involved in the MVA and MEP pathways and sesquiterpene biosynthesis. By contrast, unique proteins in R treatment were mainly expressed in sesquiterpene and tetraterpene biosynthesis. Specific relationships between biosynthetic proteins and sesquiterpenes were observed, suggesting the indispensable role of the light spectrum in regulating terpenoid biosynthesis.

Drought susceptible rice cultivar PTT1 (Pathumthani1) was treated with drought (&minus, 72 kPa) and CPPU (N-2-(chloro-4-pyridyl)-N-phenyl urea) @ 5 mg/L at tillering and grain-filling stages. Plants were tested for the effect of synthetic cytokinin on the parameters influencing the process of photosynthesis. Exogenous spray of CPPU improved the stomatal conductance of rice leaves, which was severely reduced by drought. The abundance intensities of proteins, associated with the stomatal conductance (ZEP, NCED4, PYL9, PYL10, ABI5, SnRK4, Phot1, and Phot2), were also in agreement with the positive impact of CPPU on the stomatal conductance under drought stress. Among the photosynthetic pigments, Chl b contents were significantly reduced by drought stress, whereas CPPU treated plants retained the normal contents of Chl b under drought stress. Subsequently, we examined the abundance intensities of chlorophyll synthase and HCR proteins, implicated in the biosynthesis of chlorophyll pigments and the conversion of Chl b to Chl a, respectively. The results indicated a drought-mediated suppression of chlorophyll synthase. However, CPPU treated plants retained normal levels of chlorophyll synthase under drought stress. In addition, drought stress induced HCR proteins, which might be the cause for reduced Chl b contents in drought stressed plants. Further, CPPU treatment helped the plants sustain photosynthesis at a normal rate under drought stress, which was comparable with well-watered plants. The results were further confirmed by examining the abundance intensities of two key proteins, RAF1 and Rubisco activase, implicated in the assembly and activation of Rubisco, respectively. CPPU treatment reversed the drought mediated suppression of these proteins at both of the growth stages of rice under drought stress. Based on the results, it can be suggested that synthetic cytokinins help the plants sustain photosynthesis at a normal rate under drought stress by positively influencing the determinants of photosynthesis at a molecular level.

Background: Brown rice (BR) and germinated brown rice (GBR) are considered as prime sources of carbohydrate and bioactive compounds for more than half of the populations worldwide. Several studies have reported on the proteomics of BR and GBR; however, the proteomic profiles related to the synthesis of bioactive compounds are less well documented. In the present study, BR and GBR were used in a comparative analysis of the proteomic and bioactive compound profiles for two famous Thai rice varieties: Khao Dawk Mali 105 (KDML) and Mali Daeng (MD).; Results: The proteomes of KDML and MD revealed differences in the expression patterns of proteins after germination. Total phenolic compound content, anthocyanin contents and antioxidant activity of red rice MD was approximately 2.6-, 2.2- and 9.2-fold higher, respectively, compared to that of the white rice KDML. Moreover, GBR of MD showed higher total anthocyanin content and greater antioxidant activity, which is consistent with the increase expression of several proteins involved in the biosynthesis of phenolic compounds and protection against oxidative stress.; Conclusion: Red rice MD exhibits higher nutrient values compared to white rice KDML and the appropriate germination of brown rice could represent a method for improving health-related benefits. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.

“Plant factory with artificial lighting” (PFAL) refers to a plant production facility that can achieve mass production of vegetables year round in a controlled environment. However, the high-density planting pattern in PFALs causes low light conditions in the lower canopy, leading to leaf senescence in the outer leaves and thus to reductions in plant yields. In the present study, the effect of supplemental upward lighting underneath the plants on photosynthetic characteristics and plant yield was examined in lettuce, in comparison with supplemental downward lighting from above the plants at the same light intensity. Supplemental upward lighting increased the curvature factor of the photosynthetic response to light from above the plants. Moreover, supplemental upward lighting significantly enhanced the lettuce yield by retarding the senescence of the outer leaves. Here, we propose a novel cultivation system with a combination of downward lighting and supplemental upward lighting that can effectively increase plant growth and yield in PFALs.

Gibberellins (GAs) are diterpenoid hormones, control various physiological developments in plants. The role of gibberellins on morphology and secondary metabolite production was examined in Artemisia annua, a medicinal plant that has been acknowledged as a source of artemisinin, an antimalarial compound. Subsequently, the GA20ox gene from Torenia fournieri (TfGA20ox2) was transferred to A. annua by Agrobacterium-mediated transformation. Compared with wild type plants, all nine transgenic plants showed significantly higher plant heights and artemisinin contents. The highest artemisinin content and yield in TfGA20ox2-overexpressing plants was around two-fold higher than wild type. Moreover, transgenic plants had higher numbers of branches (52.4%) and greater branch lengths (60–203%), but smaller leaf size (77.6%). Interestingly, relative to wild type the number and size of glandular trichomes in transgenic leaves was about 30 and 35% higher, respectively. From GC–MS analysis, the proportion of diterpenes in transgenic plant extracts was 1.5-fold lower than those noticed in wild type, while the proportion of sesquiterpenes was increased about 1.6 times when compared to wild type. However, the content proportion of monoterpenes showed a slightly increase, whereas the level of triterpenes showed no variation. In addition, two monoterpenes (eucalyptol and borneol), four sesquiterpenes (α-caryophyllene, β-guaiene, δ-cadinene and β-cubebene) and one triterpenes (isomultiflorenone) were detected only in transgenic extract, whereas d-α-tocopherol, a diterpenoid compound was found only in wild type but not transgenic plant. These results suggested that gibberellins play a significant role in regards to morphology, trichome formation and terpenoid metabolite production in A. annua.

Recalcitrant regeneration is one of the bottlenecks for plant improvement, especially in monocotyledonous species. In this research, plantlet regeneration of a native rice cultivar Oryza sativa ‘Barak Cenana’, high-value local Balinese red rice was successfully demonstrated. Compact nodular calli were induced from excised seed-derived mature embryos of ‘Barak Cenana’ rice. Although 2,4-D was necessary for callus induction, a combination of 2,4-D in regeneration medium caused reduction of green spot and shoot meristemoid differentiation. Root differentiation was firstly regenerated where meristematic shoots were thereafter developed from calli. The highest number of shoot regeneration regenerated from green spots and numbers of plantlet with complete shoot/root development were observed when transferred calli to Murashige and Skoog (MS) medium containing 5 mgL-1. Multiple shoot formation of regenerated plantlets revealed for efficient regeneration system, which was firstly reported in this present study and will potentially serve for plant improvement of this native rice, Barak Cenana.

Hairy root cultures of Mitracarpus hirtus L. were obtained after transforming leaf-disc explants with wild strain Agrobacterium rhizogenes A13. The root cultures of M. hirtus showed high efficiency of shoot formation in both transformed and non-transformed cultures when illuminated with light. However, transformed hairy root proliferation was approximately 3.8–5 times higher than the control in both solidified and liquid plant growth regulator free media. Putatively transformed roots were identified by the presence of the rol gene via PCR. Integration of the rol gene into the plant genome was confirmed via Southern blot analysis after 5 months with no detection in non-transformed roots. In addition, the effect of 2-chloro-4-pyridyl-N-phenylurea (CPPU), a synthetic cytokinin, when applied as an elicitor for hairy root cultures of M. hirtus was investigated. The 24-day-old hairy root cultures of high root proliferation line R107-3, were incubated for 48 h in media supplemented with 0 or 5 mg l−1 CPPU. The methanolic extracts of root tissues were subsequently analyzed for biochemical constituents using Gas Chromatography Mass Spectrometry (GC-MS). The alteration of plant secondary metabolites produced after CPPU treatment was analyzed. Compared to the control (with quality higher than 80 %), six unique compounds were found, five original compounds absent, 11 with increased, and five with decreased contents. Increased contents of two metabolites, chrysophanol and 2-methoxy-4-vinylphenol, showed pharmaceutical potential. CPPU was also found to elicit the alkaloid compound, Eseroline, 7-bromo-, methylcarbamate (ester), which could not be detected in the non-treated sample. The findings of this study demonstrate the establishment of transgenic hairy root of M. hirtus and the application of CPPU as an elicitor to induce variations in plant secondary metabolite that shows its potential to apply for bio-reactor system.

Artemisia annua L. is a commercial source of artemisinin. Nevertheless, artemisinin content within the plant is relatively low and varies depending on genotype and environment. To broaden the genetic variability, the mutation effect of 12C-ion beam irradiation on A. annua was examined. Irradiation at 2.5 Gy had a slight lethal effect to nodal segments while a noticeable lethal effect was observed at 5 and 10 Gy. Furthermore, at higher doses (20 and 50 Gy), a severe lethal effect was observed. Mutations at the DNA level of axillary bud-derived shoots were performed by RAPD. The mutation frequency at 10 Gy was about 1.7 and 2.1 times higher than that at 2.5 and 5 Gy, respectively. After growth and artemisinin production observation of 72 irradiated mutants, around 14 and 7 % of them showed higher artemisinin content and artemisinin yield compared to the controls, respectively. The highest artemisinin content in a mutant was 1.43 % DW, which was 3.2-fold higher than the original wild type. Additionally, the highest artemisinin yield in mutants was 3.68 mg/plant, which was around 1.4-fold higher than in the wild type. Moreover, irradiated mutants exhibited antibacterial activity against S. aureus, but the wild types did not. This study presents an effective application of heavy ion beam irradiation to create variations and improve artemisinin production in A. annua.

The study aimed to observe the flowering of macadamia grown under different locations in northern Thailand. It is hoped that the success of macadamia growing would be an opium substitute crop as well as a reforestation tree in northern Thailand. Although introduced cultivars have adapted well and are grown widely from sea level to the top of mountains, the yield is still low compared to those reported in other countries. The role of microclimate as a factor influencing annual growth cycle should be clearly understood to further develop appropriate cultural practices. Fifteen uniform mature macadamia trees were selected from three sites with two types of microclimate characteristics; mountain ridge and valley at commercial plantations of Doi Tung Development Project in Chiang Rai, northern Thailand. Floral biology, fruiting and vegetative flushing characters were observed from limb at 1.5-2 m above ground level. Air temperature and light intensity, as microclimate parameters were recorded during 2007-2008. Mostly racemes and fruits set on two-year-old shoots. The fruiting shoots of trees located at mountain ridge had significantly shorter length than at the valley site. Seasonal new vegetative shoots at three sites flushed on the same period. Racemes of trees at mountain ridge bloomed earlier in late November; however, it was one month later for trees at valley site. Interestingly, the flower phenology at the valley site showed better performances with a shorter bloom period and higher floret numbers resulting in higher fruiting rate. Daily light intensity, minimum and average temperature of two microclimate types or three altitudes showed similar pattern. Nevertheless, maximum temperature during flowering at the valley site was lower. Thus, the amount of daily temperature interval occurring at lower level might cause the differences in flowering and yield performances. In addition, the flowering and fruit setting of rain-fed and irrigated sites were observed on ten mature trees at the ridge. It was found that trees in rain-fed site had two periods of flowering; the first in-season bloom was in January after annual nut harvesting started and the second bloom, a so-called off-season, was found later in October. The off-season bloom of macadamia trees grown in northern Thailand reflected their adaptability to Thai environment. Thus, it might be a good potential that is of benefit to further develop off-season macadamia nut production.

Tetraploid plants were successfully induced for the first time in Mitracarpus hirtus L., by overnight immersion of shoot meristems in 0.1 % colchicine solution, followed by in vitro culture leading to plant regeneration. Examination of ploidy level by flow cytometric analysis and counting chromosome number at metaphase confirmed that original diploid plant (WT1) contained chromosome number as 2n = 2x = 28, whereas 2n = 4x = 56 was observed in the tetraploids induced with colchicine treatment (CC102 and CC110). Thicker root formation, larger stomata (1.3–2 times), and lower density of stomata (1.7–4 times) were observed in these tetraploid plants. After transplantation to the pot, tetraploid plant (CC110) showed higher fresh weights of aerial part and leaves (1.5 and 1.4 times respectively) than diploid. However, the methanolic extracts from leaves of tetraploid line CC102 showed inhibition against human pathogenic bacterium, S. aureus while WT1 and CC110 showed no activity. GC–MS revealed 40 unique compounds present in CC102, but absent in WT1 and CC110. Through hierarchical clustering analysis the 40 unique compounds in CC102 formed a cluster group found to correlate with anti-S. aurens activity. These results suggested that tetraploid M. hirtus CC102 created in this study provides a novel source of compounds useful in fighting infectious disease.

Plants respond to abiotic stresses by activating a specific genetic program that supports survival by developing robust adaptive mechanisms. This leads to accelerated senescence and reduced growth, resulting in negative agro-economic impacts on crop productivity. Cytokinins (CKs) customarily regulate various biological processes in plants, including growth and development. In recent years, cytokinins have been implicated in adaptations to osmotic stresses with improved plant growth and yield. Endogenous CK content under osmotic stresses can be enhanced either by transforming plants with a bacterial isopentenyl transferase (IPT) gene under the control of a stress inducible promoter or by exogenous application of synthetic CKs. CKs counteract osmotic stress-induced premature senescence by redistributing soluble sugars and inhibiting the expression of senescence-associated genes. Elevated CK contents under osmotic stress antagonize abscisic acid (ABA) signaling and ABA mediated responses, delay leaf senescence, reduce reactive oxygen species (ROS) damage and lipid peroxidation, improve plant growth, and ameliorate osmotic stress adaptability in plants.

Gibberellins (GAs) are the plant hormones that control many aspects of plant growth and development, including stem elongation. Genes encoding enzymes related to the GA biosynthetic and metabolic pathway have been isolated and characterized in many plant species. Gibberellin 2-oxidase (GA2ox) catalyzes bioactive GAs or their immediate precursors to inactive forms; therefore, playing a direct role in determining the levels of bioactive GAs. In the present study, we produced transgenic plants of the liliaceous monocotyledon Tricyrtis sp. overexpressing the GA2ox gene from the linderniaceous dicotyledon Torenia fournieri (TfGA2ox2). All six transgenic plants exhibited dwarf phenotypes, and they could be classified into two classes according to the degree of dwarfism: three plants were moderately dwarf and three were severely dwarf. All of the transgenic plants had small or no flowers, and smaller, rounder and darker green leaves. Quantitative real-time reverse transcription-polymerase chain reaction (PCR) analysis showed that the TfGA2ox2 expression level generally correlated with the degree of dwarfism. The endogenous levels of bioactive GAs, GA1 and GA4, largely decreased in transgenic plants as shown by liquid chromatography-mass spectrometry (LC-MS) analysis, and the level also correlated with the degree of dwarfism. Exogenous treatment of transgenic plants with gibberellic acid (GA3) resulted in an increased shoot length, indicating that the GA signaling pathway might normally function in transgenic plants. Thus, morphological changes in transgenic plants may result from a decrease in the endogenous levels of bioactive GAs. Finally, a possibility of molecular breeding for plant form alteration in liliaceous ornamental plants by genetically engineering the GA metabolic pathway is discussed.

Soluble carbohydrates play a key role as osmolytes and significantly contribute in salt defence mechanism, especially in halophyte species. The objective of this study is to investigate the transcriptional expression of starch-related genes, sugar profile and physiological performances of two contrasting rice genotypes, Pokkali (salt tolerant) and IR29 (salt sensitive), in response to salt stress. Total soluble sugars, glucose and fructose levels in the flag leaf of salt-stressed Pokkali rice were enhanced relative to soluble starch accumulation in plants exposed to EC = 13.25 dS m(-1) (salt stress) for 3 days. In Pokkali, the net photosynthetic rate and starch metabolism may play a key role as energy resources under salt stress. In contrast, photosynthetic performance, indicated by photosynthetic pigment levels and chlorophyll fluorescence parameters, in salt-stressed IR29 was significantly reduced, leading to delayed starch biosynthesis. The reduction in photosynthetic ability and lack of defence mechanisms in IR29 caused growth inhibition and yield loss. Soluble starch and soluble sugar enrichment in Pokkali rice may function alternatively as osmotic adjustment in salt defence mechanism and strengthen carbon energy reserves, greater survival prospects under salt stress and enhanced productivity.

Cytokinins are phytohormones that play multiple roles to control plant growth and development. In this study, leaf biomass and the production of andrographolide compounds in a medicinal plant Andrographis paniculata were significantly increased after exogenously treating with the synthetic cytokinin cytokinin-1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU) at 0 (water), 5, or 10 mg L−1 and observed the results for 24 h, 48 h, and 7 days of treatment. It was found that CPPU could significantly enhance new axillary bud formation and further promote branching 4.6–5.6-fold higher, resulting in higher fresh weight (FW) and dry weight (DW) than the control. Application of CPPU at 5 mg L−1 significantly promoted the highest contents of total reducing sugar at 2.5-fold in leaves and at 1.5-fold in roots. Although treatments of CPPU significantly affected the increasing contents of chlorophyll and carotenoid (1.2–1.6-fold), CPPU at 10 mg L−1 slightly caused leaf stress and chlorophyll reduction. Interestingly, 5 mg L−1 CPPU could enhance andrographolide content, an active anti-infectious compound in Andrographis paniculata (2.2-fold higher than the control) that reached the highest content at 24 h after treatment. This study suggested that CPPU should be suitable for field application to promote leaf yields and induce the production of useful pharmaceutical compounds in Andrographis paniculata.

Surplus absorption of elements that contribute little to crop productivity and quality can be avoided, and fertilizer consumption costs minimized, by applying elements quantitatively to the nutrient solution fed to the plants. The aim of this study was to determine the minimum macronutrient requirements of spinach (Spinacia oleracea L.) with a desired plant size, so that fertilizer management in plant factories can be maximized. Spinach plants were grown in a plant factory (20°C/17°C day/night temperature, photosynthetic photon flux (PPF) of 350 μmol·m-2·s-1 for 12 hours per day using cool-white fluorescent lamps, 1,000 μmol·mol-1 CO2). Spinach grew and developed rapidly, and reached its desired marketable size in only 12–15 days after being transplanted to the study conditions. At day 15 of cultivation under the treatment conditions, the required quantities of macronutrients per plant (90 grams in fresh weight) were determined as follows: 191 mg N, 31 mg P, 345 mg K, 34 mg Ca, 38 mg Mg, and 13 mg S. In conclusion, a quantitative nutrient managing method with low nutrient concentrations is feasible and resource-saving for hydroponic vegetable production in plant factories.

To understand the molecular responses of Thai jasmine rice (Oryza sativa L. ssp. indica cv. KDML105) under drought, proteomes of KDML105 cultivars and two check cultivars, namely NSG19 (tolerant) and IR20 (sensitive) were investigated. The effect of PEG6000 and mannitol for creating osmotic stress (−0.1 MPa to − 2.1 MPa) was tested in KDML105 before applied to the three cultivars. The leaf proteomes were analyzed by GeLC-MS/MS shotgun proteomics. Among 623 proteins identified, 53 proteins showed significant difference in protein expressions, which could be hierarchically classified into three clusters of proteins up-regulated in IR20, NSG19, or in KDML105. Coronatine-insensitive 1 protein that thought to be involved in stomatal closing was prominently observed in NSG19, regarding to its physiology of rapid stomatal closing and highest stability of photosystem II. WD-40 repeat protein which involves in cell death was induced in IR20. On the other hand, H-protein promoter binding factor-2a remarkably increa...

Water shortage is a major abiotic stress for crop production worldwide, limiting the productivity of crop species, especially in dry-land agricultural areas. This investigation aimed to classify the water-deficit tolerance in mutant rice (Oryza sativa L. spp. indica) genotypes during the reproductive stage. Proline content in the flag leaf of mutant lines increased when plants were subjected to water deficit. Relative water content (RWC) in the flag leaf of different mutant lines dropped in relation to water deficit stress. A decrease RWC was positively related to chlorophyll a degradation. Chlorophyll a , chlorophyll b , total chlorophyll , total carotenoids , maximum quantum yield of PSII , stomatal conductance , transpiration rate and water use efficiency in mutant lines grown under water deficit conditions declined in comparison to the well-watered, leading to a reduction in net-photosynthetic rate. In addition, when exposed to water deficit, panicle traits, including panicle length and fertile grains were dropped. The biochemical and physiological data were subjected to classify the water deficit tolerance. NSG19 (positive control) and DD14 were identified as water deficit tolerant, and AA11, AA12, AA16, BB13, BB16, CC12, CC15, EE12, FF15, FF17, G11 and IR20 (negative control) as water deficit sensitive, using Ward's method.

In this study, a rooting protocol was developed for macadamia plantlets with healthy roots and enhanced growth performance, along with enhanced photosynthetic capability. In vitro-grown shoots rooted in vented vessels containing vermiculite as the supporting material exhibited 100% frequency of root induction, whereas when shoots were grown in non-vented vessels containing a solidified Murashige and Skoog (MS) medium, the frequency of root induction was less than 30%. The formation of root with callus, hyperhydricity, and leaf necrosis was observed in this photomixotrophic closed system. The modification of the vented photoautotrophic system with different concentrations of CO2 and sucrose were investigated using vermiculite as the supporter. The number of roots, root length, root surface area, fresh weight, and dry weight were significantly higher in plantlets grown in CO2-enriched (1,000 μmol CO2 mol−1) photoautotrophic conditions. The water content in both root and shoot tissues of plantlets cultured under photoautotrophic conditions was maximized. In addition, shoot and leaf performances were enhanced in plantlets cultured under CO2-enriched photoautotrophic conditions. The supplementation of sucrose (29–88 mM) to culture media in both ambient and elevated CO2 conditions affected a reduction in the shoot and root performance of in vitro plantlets. Chlorophyll a, chlorophyll b, and total carotenoids in the leaf tissues of plantlets acclimatized in CO2-enriched photoautotrophic conditions were enriched, leading to increasing photosynthetic abilities, including chlorophyll fluorescence and net photosynthetic rate. From this investigation, a root induction protocol was established and the production of healthy macadamia plantlets was successfully implemented using CO2-enriched photoautotrophic conditions.

Betaine aldehyde dehydrogenase (BADH) is a major oxidative enzyme that converts betaine aldehyde to glycine betaine (GB), an osmoprotectant compound in plants. Japonica rice (salt-sensitive) was genetically engineered to enhance salt tolerance by introducing the OsBADH1 gene from Indica rice (salt-tolerant), which is a GB accumulator. We produced transgenic rice plants overexpressing the modified OsBADH1 gene under the control of the maize ubiquitin promoter. The transgenic rice showed increased OsBADH1 gene expression and OsBADH1 enzyme production, resulting in the accumulation of GB. It also exhibited enhanced salt tolerance in immature and mature transgenic rice seedlings. The adverse effect of salt stress on seed germination, the growth of immature and mature seedlings, water status, and photosynthetic pigments was alleviated in transgenic seedlings.

Artemisinin is a promising and potent antimalarial drug naturally produced by the plant Artemisia annua L. but in very low yield. Its artemisinin content is known to be greatly affected by both genotype and environmental factors. In this study, the production of artemisinin and leaf biomass in Artemisia annua L. was significantly increased by exogenous GA3 treatment. The effect of GA3 application on expression of proposed key enzymes involved in artemisinin yield was examined in both wild type (007) and FPS-overexpression (253-2) lines of A. annua. In the wild type (007) at 6 h post GA3 application there was an abrupt rise in FPS, ADS and CYP71AV1 expression and at 24 h a temporary and significant peak in artemisinin (1.45-fold higher than the control). After GA3 application in line 253-2, there was a dramatic rise in expression of FPS at 3 h, CYP71AV1 at 9 h and ADS at 72 h and accumulation of artemisinin after 7 days, which was a delay when compared with the wild type plant. Thus, increased artemisinin content from exogenous GA3 treatment was associated with increased expression of key enzymes in the artemisinin biosynthesis pathway. Interestingly, exogenous GA3 continuously enhanced artemisinin content from the vegetative stage to flower initiation in both plant lines and gave significantly higher leaf biomass than in control plants. Consequently, the artemisinin yield in GA3-treated plants was much higher than in control plants. Although the maximum artemisinin content was found at the full blooming stage [2.1% dry weight (DW) in 007 and 2.4% DW in 253-2], the highest artemisinin yield in GA3-treated plants was obtained during the flower initiation stage (2.4 mg/plant in 007 and 2.3 mg/plant in 235-2). This was 26.3 and 27.8% higher, respectively, than in non-treated plants 007 and 253-2. This study showed that exogenous GA3 treatment enhanced artemisinin production in pot experiments and should be suitable for field application.

Transgenic plants of Artemisia annua L., a medicinal plant that produces the compound artemisinin which has an anti-malarial activity, were developed following Agrobacterium tumefaciens-mediated transformation of leaf explants. A. tumefaciens strain EHA105 carrying either pCAMBIA1301 or pCAMBIAFPS was used. Both plasmids harbored the hygromycin phosphotransferase II (hptII) gene as a selectable gene, but the latter plasmid also harbored the gene encoding for farnesyl pyrophosphate synthase (FPS), a key enzyme for artemisinin biosynthesis. Shoot regeneration was observed either directly from leaf sections or via intervening callus when explants were incubated on solidified Murashige and Skoog (MS) (1962) medium containing 0.1 mg l−1 α-naphthaleneacetic acid (NAA), 1 mg l−1 N6-benzyladenine (BA), 30 mg l−1 meropenem and 10 mg l−1 hygromycin. Applying vacuum infiltration dramatically increased transformation efficiency up to 7.3 and 19.7% when plasmids with and without FPS gene were used, respectively. All putative transgenic regenerants showed positive bands of hptII gene following Southern blot analysis. Expression of FPS was observed in all transgenic lines, and FPS over-expressed lines exhibited higher artemisinin content and yield, of 2.5- and 3.6-fold, respectively, than that detected in wild-type plants. A relatively high correlation (R 2 = 0.78) was observed between level of expression of FPS and artemisinin content. However, gene silencing was detected in some transgenic lines, especially for those lines containing two copies of the FPS transgene, and with some lines exhibiting reduced growth.

Objective: To explore the effect of gibberellic acid (GA3) and its inhibitor paclobutrazol (PBZ) on chemical composition and their pharmacological effects on Andrographis paniculata (Burm. f.) Wall. ex Nees, and to clarify action mode of andrographolide. Methods: The chemical composition was extracted by sequential extraction with hexane, dichloromethane, ethyl acetate and methanol, respectively. Andrographolide and its derivatives were evaluated by HPLC. Moreover, the metabolic profiling was analyzed by GC-MS. Inhibitory effect of crude extracts was tested against Staphylococcus aureus using agar well diffusion method. Mode of action was tested against mutant yeast by spotting assay. Andrographolide were tested for their mode of action against eukaryotes. Results: Among different solvents, dichloromethane gave the highest yield of crude (3.58% DW), with the highest andrographolide content (8.3 mg/g DW). The effect of plant hormone (10 mg/L GA3 or PBZ) on phytochemical variations and bioactivity of Andrographis paniculata was demonstrated. It was found that PBZ promoted sesquiterpene compounds about 3.5 times over than GA3 treatment. But inhibitory effect of extracts against Staphylococcus aureus was highest in GA3 treated plants; andrographolide and 14-deoxy-11,12-didehydroandrographolide contents were significantly higher than those of water or PBZ. It was found that there were 11 strains involving in ergosterol biosynthesis, V-ATPase activity and homeostasis, and superoxide detoxification process. In this regard, andrographolide might cause the damage on the lipid bilayer of yeast cell and plasma membrane by interfering ergosterol biosynthesis. Conclusions: It is found that GA3 promotes andrographolide and 14-deoxy-11,12-didehydroandrographolide content while PBZ promotes sesquiterpene content. Andrographolide might cause the damage on the lipid bilayer of yeast cell and plasma membrane by interfering ergosterol biosynthesis. It might also affect mitochondria electron transport chain, leading to the occurrence of ROS, which can further harm cell organelles. However, the library screening is the first step to investigate mode of action of andrographolide.

Tetraploid plants of Artemisia annua L. exhibiting high-artemisinin-yield were successfully induced by treating excised leaves of in vitro plant with 0.1% colchicine. The chromosome number of original diploid plant was confirmed to be 2n=2x=18 whereas that of the tetraploid plant was 2n=4x=36. Morphological and anatomical characteristics of tetraploid plants were obviously different from the diploid counterpart. The tetraploid plants had larger sizes of root system, stomata and glandular secretory trichomes than diploid plant, whereas leaf size in tetraploid was smaller but thicker than diploid. The highest amount of artemisinin content was produced at flower blooming stage in both diploid (2.4% dry weight) and tetraploid (3.8% dry weight) lines. Based on the maximum yield of artemisinin, the optimum harvest time for the diploid lines was flower initiation stage but it was at full blooming stage for tetraploid lines. The highest artemisinin yield in tetraploid plants up to 3.0 mg plant−1 was detected at this stage which was 1.5 times greater than diploid plants. This is a first report that clearly showed the potential of chromosome doubling strategy to produce high-yield line of A. annua plant for artemisinin production.

Glycine betaine has been reported as an osmoprotectant compound conferring tolerance to salinity and osmotic stresses in plants. We previously found that the expression of betaine aldehyde dehydrogenase 1 gene (OsBADH1), encoding a key enzyme for glycine betaine biosynthesis pathway, showed close correlation with salt tolerance of rice. In this study, the expression of the OsBADH1 gene in transgenic tobacco was investigated in response to salt stress using a transgenic approach. Transgenic tobacco plants expressing the OsBADH1 gene were generated under the control of a promoter from the maize ubiquitin gene. Three homozygous lines of T2 progenies with single transgene insert were chosen for gene expression analysis. RT-PCR and western blot analysis results indicated that the OsBADH1 gene was effectively expressed in transgenic tobacco leading to the accumulation of glycine betaine. Transgenic lines demonstrated normal seed germination and morphology, and normal growth rates of seedlings under salt stress conditions. These results suggest that the OsBADH1 gene could be an excellent candidate for producing plants with osmotic stress tolerance.

Establishment of the efficient method for isolating the female germ unit (FGU; egg, synergid and central cell) is useful for the studies on the characterization of each FGU as well as in vitro fertilization and gametosomatic hybridization. In this study, an easy one-step enzymatic procedure was successfully developed to isolate FGU from ovules of Petunia hybrida without releasing the somatic protoplasts from ovular tissues, which could not be achieved in the previous studies. Each FGU was separately liberated after treating the ovules, which were collected from ovaries of flowers one day after anthesis, with an appropriate enzyme solution comprised of 10 g l−1 Cellulase Onozuka R-10, 10 g l−1 Macerozyme R-10, 0.6 M mannitol, 5 mM 2-morpholinoethane-sulfonic acid and 5 g l−1 potassium dextran sulfate, pH 5.8 with 50-rpm shaking for 2 h at room temperature. Isolated FGUs were distinguished by their specific size and characteristics. Fluorescent staining with 4′, 6-diamidino-2-phenylindole could identify the polar nuclei of central cell and the nuclear polarity of egg apparatus cells. After transfer into washing solution supplemented with 0.6 M mannitol using a micropump-connected microcapillary, about 80% of the isolated FGUs were viable for up to 8 h after the isolation, as determining by fluorescein diacetate staining.

1 Corresponding author Abstract Somaclonal variation that possibly occurs during the process of plant tissue culture is considered to provide a source of new germplasm. Polyploidy is one of the most frequent incidents among the somaclonal variations. In the present study, we performed cytological and morphological characterization of tetraploid plants that were obtained from long-term subcultured callus culture of Lilium longiflorum. Friable green calli of L. longiflorum were induced from in vitro leaves on solidified MS medium supplemented with 30 g L -1 sucrose and 1 mg L -1 picloram and maintained for 3 years by subculturing routinely on the same medium at 30-day intervals. High regeneration ability was observed after transferring the calli to half-strength MS medium without plant growth regulator, and approximately 6.7% of the regenerated plantlets tested were tetraploid (2n=4x=48). Karyotypic analysis of the control plant (a bulblet-derived plant) showed diploid chromosome number (2n=2x=24) with 4-large submetacentric, 12-medium acrocentric, 4-medium telocentric, 2-small acrocentric and 2-small telocentric chromosomes (L4 sm + M12 a + M4 t + S2 a + S2 t ). Whereas karyotypic pattern of a tetraploid (code no. V18) revealed the completely duplicated set of chromosomes with 8-large submetacentric, 24-medium acrocentric, 8-medium telocentric, 4-small acrocentric and 4-small telocentric chromosomes (L8 sm + M24 a + M8 t + S4 a + S4 t ). The average number of stomata in leaves of somaclonal tetraploids was less than in control plants, but thicker leaves with greenish color and the alteration of the shape of guard cells were detected in these tetraploids.

In this study, the interference of T-DNA insertion upon Agrobacterium-mediated transformation on the biochemical expression of the host genome is discussed. Plant extracts of transgenic Artemisia annua L. with or without an overexpressed farnesyl pyrophosphate synthase gene have been investigated for their bioactivity and metabolic profile in comparison with wild type A. annua. The highest antimicrobial activity against Staphylococcus aureus, Bacillus subtilis and Candida albicans was observed in the T253 transgenic lines. Moreover, the crude extract from T253 showed higher antimalarial activity against the Plasmodium faciparum K1 strain than those of the others. The terpenoid constituents and antimicrobial properties of the plant samples were grouped by hierarchical clustering analysis. The clustering showed that squalene is a putative compound that might be involved in increasing the bioactivity of the transgenic line. In addition, T253 had a triterpene content that was about twice as great as that of the T253-2 line, which had a higher content of sesquiterpenes. However, both lines were transformed by the same FPS gene. These results suggested that the different bioactive properties observed in each transgenic line may be caused by variations in their terpenoid composition, which is affected by T-DNA insertion at different positions in the host plant.

A system for producing transgenic plants was developed for the Liliaceous ornamental Agapanthus praecox ssp. orientalis (Leighton) Leighton via Agrobacterium -mediated genetic transformation. Leaf-derived embryogenic calli were inoculated with A . tumefaciens strain EHA101/pIG121Hm or LBA4404/pTOK233, both of which harbored the binary vector carrying the neomycin phosphotransferase II (NPTII), hygromycin phosphotransferase (HPT) and intron-containing β-glucuronidase (GUS-intron) genes in the T-DNA region. Following co-cultivation, the calli were transferred to a medium containing 1 mg l −1 picloram (PIC), 50 mg l −1 hygromycin and 500 mg l −1 cefotaxime, on which several hygromycin-resistant (Hyg r ) cell clusters were obtained 5–6 weeks after transfer. Agrobacterium strain, co-cultivation period and acetosyringone (AS) treatment during co-cultivation affected the number of Hyg r callus lines produced: the best result was obtained when embryogenic calli were co-cultivated with LBA4404/pTOK233 for 7 days in the presence of 20 mg l −1 AS. Hyg r calli were transferred to the same medium, but lacking PIC, for inducing somatic embryos. Somatic embryos thus obtained developed into complete plantlets following their transfer to a medium without PIC and antibiotics. All of them were verified to be stable transformants by GUS histochemical assay, PCR and Southern blot analyses.

Meristematic nodular calli (NOD) were successfully induced from various plant parts such as seeds, flower organs, shoot apices, stem segments and bulb scales of Lilium spp. on media containing 1mg/l picloram alone or in combination with 1mg/l cytokinin. In L. longiflorum, green friable callus (FC) was also induced from bulb scales. Suspension cultures established from both NOD and FC showed high proliferation rate. NOD retained high regeneration ability as well as stable ploidy level during the culture for more than 4 years, while the suspension culture of FC became tetraploid. Protoplasts were efficiently isolated from NOD in some species and cultivars after long term subculture in suspension cultures and the plants were successfully regenerated from the protoplasts of L. x formolongi.