7 research outputs found
Expression of antimicrobial peptides in plants
No full textIn an attempt to develop a platform for expression of antimicrobial peptides, as well as to enhance disease resistance in plants, a defensin gene from pig was transferred to 'Nicotiana tabacum' cv. Xanthi in two fusion constructs. The codon-optimized mature peptide of 'pbd-1' was fused with either the 5' end portion of 'po2', a gene from alfalfa, or, with its native signal and pro-peptides, both controlled by the enhanced CaMV35S promoter. Transgenic plants containing both constructs expressed the transformed genes at the mRNA level, but no protein was detected by preliminary Western blots. However, some of the transgenic plants displayed enhanced disease resistance to 'Pseudomonas syringae ' pv. 'tabaci'. For comparison, the coding regions of two plant defensin genes ('ntdef1' and 'ntdef2'), which belong to two different groups of solanaceous defensins, were cloned from 'N. tabacum' cv. Xanthi and were ectopically expressed in 'N. tabacum' cv. Xanthi, again under the control of the enhanced CaMV35S promoter. Only regenerated plants transformed with ' ntdef1' were transgenic, and 'ntdef2' transformed plants were escape plants. 'ntdef1' transformed plants showed a low level of resistance to 'P. syringae' pv. 'tabaci'
Transgenic Plant and Fungal Expression to Assay in vitro and in planta Activity of Sus scrofa beta-Defensin 1 and Nicotiana tabacum Defensin 1
No full textTo explore the use of defensins for transgenic plant disease resistance, expression by agroinfiltration of plants, stable transformation of plants and stable transformation of yeast were tested for porcine β-defensin 1 (pbd-1) and Nicotiana tabacum defensin 1 (Ntdef1). Attempts to screen constructs by agroinfiltration of Nicotiana benthamiana leaves revealed that agroinfiltration alone induced localized resistance against Colletotrichum destructivum. A comparison of Agrobacterium tumefaciens strains showed that the induced resistance required the transfer of type IV effectors into plant cells and was independent of salicylic acid or ethylene signaling. Stable expression of pbd-1 in N. tabacum and Pichia pastoris showed that PBD-1 purified from P. pastoris had varying degrees of antimicrobial activity against a broad range of microbes, including P. syringae pv. tabaci, C. destructivum and C. orbiculare, but in transgenic N. tabacum, the protein could not be detected and resistance increased only slightly to P. syringae pv. tabaci but not to C. destructivum or C. orbiculare. Stable expression of Ntdef1 in P. pastoris yielded a protein with no or little antimicrobial activity, and stable expression in N. tabacum did not result in detectable Ntdef1 or increased resistance to those pathogens. Although PBD-1 had strong antimicrobial activity against plant pathogens, plant disease resistance likely did not increase because of the low level of the protein in the plants, whereas resistance did not increase with Ntdef1 likely because of low antimicrobial activity and low levels of the protein in the plant. This research demonstrates that agroinfiltration is not appropriate for testing genes for antimicrobial activity in planta, while the P. pastoris expression system is useful for producing protein for in vitro tests of a gene prior to its transfer to plants
Effect of Seed Pelleting Application of Plant Growth Promoting Bacteria on Germination and Growth of Lettuce (Lactuca sativa)
No full textPlant growth-promoting bacteria (PGPB) are commonly used to pellet seeds. Different bacterial strains affect germination and plant growth in varying ways. The objective of this experiment was to study the effects of seed pelleting with three strains of bacteria on changes in germination, vigor, seedling growth, and the plant growth of lettuce. The experiment followed a completely randomized design with four repetitions and five treatments: without pelleting (T1), pelleting with CaSO4-zeolite only (T2), pelleting with 1×107 CFU/mL Stenotrophomonas sp. strain sk3 (T3), pelleting with 1×108 CFU/mL Burkholderia sp. strain 3-DB05 (T4), and pelleting with 1×108 CFU/mL Enterobacter sp. strain 4-RB05 (T5). Burkholderia sp. and Enterobacter sp. were more effective in producing indole-3-acetic acid (IAA), and pelleting seeds with these strains resulted in higher germination rates and seedling growth compared to unpelleted seeds when tested in both laboratory and greenhouse conditions. Seed pelleting with 1×108 CFU/mL Enterobacter sp. promoted plant growth and resulted in significantly higher leaf and root weight. Therefore, seed pelleting with 1×108 CFU/mL Enterobacter sp. strain 4-RB05 is recommended to improve the germination and plant growth of Red Oak Leaf lettuce seeds
Efficacy of Economic Mushrooms on the Growth Promotion of Dipterocarpus alatus Seedlings
No full textDipterocarpus alatus is an economically important tree species currently in demand within the wood product industry. However, D. alatus has a slow growth rate and will take 20-30 years before timber can be cut to harvest. Implementing the use of ectomycorrhizal fungi in its seedling production has potential to improve D. alatus growth. Therefore, effects of two species of ectomycorrhizal fungi, Amanita vaginata and Astraeus odoratus, and one species of saprotraphic fungus, Phlebopus portentosus, on growth of D. alatus were evaluated by inoculating 6-month old seedlings with each fungus and monitored growth monthly for 6 months. The results showed that applications of ectomycorrhizal fungi significantly (95% confidence) increased root collar diameter and total height of D. alatus. After 6 months, D. alatus seedlings treated with A. vaginata had the highest root collar diameter of 73.6±3.3 mm followed by those treated with P. portentosus, A. odoratus and without fungal treatment at 70.5±2.5, 68.2±3.1 and 66.6±2.0 mm, respectively. In terms of total height, D. alatus seedlings treated with P. portentosus had the highest total height at 41.89±0.75 cm followed by A. odoratus, A. vaginata and without fungal treatment at 40.95±1.66, 40.37±1.10, 36.54±0.37 cm, respectively. Laboratory analysis for root colonization by ectomycorrhizal fungi indicated that the 3 fungi colonized D. alatus seedlings at the tips of new roots. Inoculation with A. vaginata and P. portentosus resulted in 10 and 30 % colonization in the epidermis indicated compatibility between the fungi and D. alatus
Plant community structure of Melientha suavis bearing deciduous dipterocarp forest at the Banpong royal-initiated development project, Maejo University, Chiang Mai Province
No full textThis study was conducted to evaluate a structure of the deciduous dipterocarp forest where Melientha suavis Pierre was found and to elucidate some aspects of M. suavis ecology. A 200 x 200 m permanent plot was set up to measure diameter at breast height (DBH) of all plants with DBH of at least 1 cm. Locations of all trees within a plot was recorded as well as diameter at root collar of M. suavis. The study found that there were 2,291 trees found per hectare, from 40 species, 36 genera, and 22 families. Species with the highest DBH was Shorea obtusa with the value of 54.71 cm. S. obtusa, S. siamensis, Dipterocarpus obtusifolius, Gluta usitata, and D. tuberculatus were the top five species with the highest Importance Value Index (IVI) of 66.46, 56.87, 51.56, 33.84, and 33.64, respectively. The areas Shannon-Wiener Index was 2.08. Distribution of trees within each DBH class was found to be in a negative exponential form, with most trees occupied a 5.0-7.5 DBH class indicating that the forest under study was in a reestablishment stage. Relationship between DBH and height in form of hyperbolic equation yielded the coefficient of a and Hmax of 1.338 and Hmax of 23.15 m. In terms of M. suavis ecology, it was found that there were 794 M. suavis stands in the area under investigation with the density of 202 stands/ha. The maximum diameter at root collar of M. suavis was 3.75 cm. Most M. suavis was found to fall in the 0.25-0.5 cm. diameter at root collar range. Analysis of Variance within a 20 x 20 subplots indicated that average diameter at root collar, number of trees, number of Dipterocarpaceous trees, and number of S. siamensis were found to be significantly different along different elevations
A protein coding for a pollen-specific gene in alfalfa (Medicago sativa L.) is localized mainly in the intine of the pollen wall
No full textStructure and composition of tree species in deciduous dipterocarp forest where Calamus acanthophyllus was found within Ban Lad Somboon Mai, Huai Yang Sub-district, Mueang Sakon Nakorn District, Sakon Nakorn Province.
No full textThis study was conducted to evaluate structure and composition of tree species in the deciduous dipterocarp forest where Calamus acanthophyllus was found. Three studied areas with different degrees of disturbance was selected, including, protected fire area (plot 1), reestablished area from farming activity (plot 2), and non protected fire area (plot 3). The permanent plot, 50 x 100 m, was set up in each area. In each plot, all trees with diameter at breast height (DBH) over than 1 cm were identified and measured of DBH and height of randomly selected trees, including the position of all trees were also recorded. In addition, diameter at root collar and height of C. acanthophyllus were measured. It was found that tree density and total basal area of plot 1, 2 and 3 were 1,284, 1,196 1,842 stands/ha, 6.96, 7.93, 8.01 m2/ha, respectively. Plants with the highest Importance Value Index (IVI) for plot 1, 2 and 3 were Tectona grandis Linn.f., Dipterocarpus tuberculatus Roxb. and D. tuberculatus Roxb., with the IVI of 86.23, 188.88 and 112.86 %, respectively while numbers of plant species and diversity index (Shannon-Wiener index) were 19, 17, 23 species and 1.59, 1.16, 1.485, respectively. Distribution of trees among different DBH classes for plot 3 was found to be in a negative exponential form indicating that the forest in this plot was in a reestablishment stage. Relationship between DBH and height in form of hyperbolic equation yielded the highest Hmax in plot 1 at 18.44 m. In terms of C. acanthophyllus ecology, it found that the average diameter at root collar, average height, and maximum height in all plots were statistically different. It maybe concluded that area management and/or degree of disturbance from both from human activities and fire could have an impact on number and growth of C. Acanthophyllus
