Development and Evaluation of Codon-modified cry V Constructs in Cultivated Potato (Solanum tuberosum L. ) for Control of Potato Tuber Moth

A cryV gene,specifically toxic to Lepidoptera and Coleoptera,was incorporated into binary vectors with different promoters and the presence or absence of the β-glucuronidase(gus) reporter gene.These constructs were integrated into potato cv.Spunta by Agrobacterium tumefaciens-mediated transformation.Highest expression of cryV gene,determined by mRNA levels and insect mortality,was obtained using the CaMV 35S promoter without the gus gene configuration.Detached leaf and tuber bioassays showed a mortality rate of up to 83% and 100%,respectively,for potato tuber moth(Phthorimaea operculella Zeller) in the transgenic lines.Our results demonstrated that the presence of the gus gene negatively affects the expression level of the cryV gene.Bt expression was also facilitated by using the(ocs)3 mas super promoter,whereas the Bt expression regulated by the patatin promoter(tuber-specific) was too low to have any effect upon the mortality of potato tuber moth.These results represent significant improvement in the level of host plant resistance for the control of potato tuber moth via Bt transgenes.     

Expression of the chemically inducible maize GST-27 promoter in potato

Summary Chemically inducible gene regulation systems provide a mechanism for a temporal control of expression of transgenes. In this study expression from the herbicide safener inducible maize GST-27 promoter was tested in potato, with the aim of using this to provide inducible expression of transgenes implicated in dormancy control. A binary vector comprising 3.8 kb of the GST-27 promoter was fused to the β-glucuronidase (GUS) reporter gene and transformed into potato. Application of the chemical inducer elevated the expression of GUS up to 40 fold in leaf tissue. However in stems, roots and tubers the GST-27 promoter caused high levels of expression of GUS in the absence of safener, demonstrating that in these tissues it acts as a constitutive promoter. A deleted promoter region of the GST-27 promoter displayed a similar expression pattern. Analysis of GUS activity in dormant and sprouting tubers showed that the GST-27 promoter was a strong constitutive promoter throughout the tuber life cycle.     

Expression of afibrobacter succinogenes 1,3-1,4-β-glucanase in Potato (Solanum tuberosum)

The potential development of potato (Solanum tuberosum) as a low-cost eukaryotic system for the production of a commercially valuable enzyme feed supplement was examined. AFibrobacter succinogenes 1,3-1,4-β-glucanase [1,3-1,4-β-D-glucan 4-glucanohydro-lase] gene under the control of the constitutive cauliflower mosaic virus 35S promoter was transferred into the potato cultivar, Desiree. The presence of the β-glucanase cDNA in the plant genome of independent transgenic potato lines was confirmed by PCR and Southern analysis. Northern analysis identified the presence of the β-glucanase mRNA in the leaf tissue of transgenic plants. Furthermore, western analysis showedF. succinogenes β-glucanase accumulations of 0.1% and 0.05% of total soluble protein in the leaves and tubers, respectively. Specific activities of the enzyme in leaves (1693 units mg^-1 β-glucanase) and tubers (2978 units mg^-1 β-glucanase) were comparable to that previously reported for the enzyme produced in bacteria. Lyophilization of leaves had no effect on the specific activity of the β-glucanase, and only marginally influenced the specific activity of the enzyme expressed in tubers. Relative to the control line (cv. Desiree), tuber yields were significantly reduced by 28%-72% in all lines expressing theF. succinogenes β-glucanase, and microscopy showed that expression of the β-glucanase caused changes in cell wall structure. Results of this study demonstrate that a 1,3-1,4-β-glucanase can be expressed in potato tissues, and that potato plants have the potential to be used for the commercial production of heterologous enzymes.     

Transgenic potatoes expressing anErwinia pectate lyase gene — results of a 4-year field experiment

Summary Four potato lines of cv. Désirée that express the pectate lyase (PL) isoenzyme 3 ofErwinia carotovora subsp.atroseptica were examined in a 4-year field experiment with respect to plant development, tuber yield and resistance of tuber tissue toErwinia soft rot. The PL3 degrades plant cell wall pectin into unsaturated oligogalacturonates eliciting plant defence responses. In one line, enzyme expression was controlled by the CaMV 35S promoter (C) and in three lines it was driven by the potato patatin B33 promoter (D). Plant development of the D-lines in field plots was not distinguishable from that of the non-transgenic counterpart. Also tuber yield was not too different. By contrast, plants of the C-line were smaller than those of the nontransformed counterpart and also showed reduced tuber yield. There were no significant differences in dry mass, starch and protein content of tuber tissue between PL transgenic and non-transgenic potatoes. But compared with the latter, field-grown tubers expressing the PL displayed an enhanced resistance toErwinia soft rot. Thus, average rotting caused byEc-bacteria was diminished in tubers of PL-transgenic lines by 34.1%. The resistance of tubers toEc soft rot was significantly correlated with the PPO activity in tuber tissue.     

Development of Marker-Free Transgenic Cry1Ab Rice with Lepidopteran Pest Resistance by Agrobacterium Mixture-Mediated Co-transformation

Cry1Ab gene was transformed into four rice varieties, Zhejing 22, Zhejing 27, Jiahua 1 and Xiushui 63 mediated by Agrobacterium-mixture co-transformation. Rice genotype had an important effect on callus induction and transformation efficiency. Different mixtures of Agrobacterium strains (EHA105 and EHA101) contained Hpt and Cry1Ab genes resulted in different frequencies of resistant calli. There was no correlation between the frequency of transformants with the ratio of the Agrobacterium strain mixture contained Hpt and Cry1Ab genes. A total of 509 transgenic plants were obtained from the four rice varieties, and 272 T₂ progenies were analyzed for Cry1Ab and Hpt genes. PCR analysis revealed that 412 regenerated plants were Hpt positive (80.94%), 62 plants were also Cry1Ab co-transformants (15.05% in total frequency), and 42 plants among the 272 T₂ progenies were Cry1Ab positive but Hpt negative. This suggests that marker-free transgenic plants could be produced by co-transformation mediated by mixed Agrobacterium strains with the selectable marker gene and target gene. Southern blot analysis of five independent marker-free T₂ transgenic lines co-transformed from Zhejing 22 showed that Cry1Ab gene had been inserted into rice genome with a single copy. The transgenic plants showed significantly stronger resistance to lepidopteron than the non-transgenic plants under no application of insecticides against lepidopteron.     

Expression of the chicken lysozyme gene in potato enhances resistance to infection byErwinia carotovora subsp.atroseptica

Infection of potato plants and tubers with the bacteriumErwinia carotovora subsp.atroseptica produces blackleg and soft rot diseases, which cause significant losses to crops and stored potatoes. In order to obtain resistance against this bacterium, the genechly encoding the enzyme lysozyme from chicken was introduced into potato plants (cv. Desirée) viaAgrobacterium- mediated transformation. Sixty-three and 69 transgenic potato clones were evaluated in the greenhouse for resistance to blackleg and soft rot diseases, respectively. Results reported in this paper indicate that 21%-29% of the potato clones showed increased resistance to infection by the bacteriumE. c. subsp.atroseptica T7, as revealed by a reduced severity of blackleg or soft rot symptoms. Nine clones showing different levels of resistance were selected for further molecular analysis. The number of copies of the transgene integrated in the plant genome of these clones was estimated by Southern blot analysis. The level of transgene expression, detected by Northern blot analysis, correlated with the level of resistance detected in these clones.     

Inhibition of potato tuber sprouting: Low levels of cytosolic pyrophosphate lead to non-sprouting tubers harvested from transgenic potato plants

Summary ExpressingE. coli inorganic pyrophosphatase in transgenic plants demonstrated that long distance sucrose transport is dependent on cytosolic pyrophosphate. It was speculated that removal of cytosolic pyrophosphate would impair sucrose utilization during storage of potato tubers and thereby prevent tuber sprouting. To explore this hypothesisSolanum tuberosum var. Désirée plants were transformed with a chimeric PPa gene. FollowingAgrobacterium mediated transformation, metabolite and carbohydrate contents of growing and stored tubers were measured. There was a large accumulation of soluble sugars and a decrease of starch at all developmental stages investigated. The PPase activity in PPaII tubers was parallel with a decrease of PPa, an increase of fructose-2,6-bisphosphate and an increase of UDP-glucose. As expected the amount of hexose-6-phosphates and glycolytic intermediates decreased. As a consequence PPaII tubers did not sprout even after a prolonged storage period of two years. Since the energy status of PPaII tubers is unaltered inhibition of sprouting is most likely due to reduced sucrose export and its subsequent utilization.     

Relationship Between Tuber Storage Proteins and Tuber Powdery Scab Resistance in Potato

The potato genotypes (Solanum tuberosum L.) with russet tuber skin are generally resistant to powdery scab (Spongospora subterranea f.sp. subterranea or Sss). Lipoxygenase (LOX; EC 1.13.11.12) and patatin are two key storage proteins that are known to offer resistance to several diseases and insects. The objective of this study was to find out the relationship of these proteins in stored tubers with potato tuber powdery scab resistance, especially in russet skinned potatoes. An evaluation of potato germplasm with different tuber characteristics in a greenhouse environment over several years (2006–’11) suggests that russet skinned tuber genotypes (Mesa Russet, Centennial Russet and Russet Nugget) with negligible tuber disease severity index (DSI) and 100 % marketability were resistant to powdery scab. Higher physiological levels of LOX protein (on a dry weight basis) were negatively correlated with tuber DSI and positively correlated with tuber russet skin. Tuber total protein and patatin-lipase levels did not have a significant relationship with tuber powdery scab resistance. The proposed role of LOX protein in suberin- and/or non-suberin-mediated mechanisms of powdery scab resistance in russet skinned tubers are discussed here. The physiological levels of LOX protein can be considered as a useful marker for powdery scab resistance in potato breeding programs.     

Overexpression of a Maize SPS Gene Improves Yield Characters of Potato under Field Conditions

Abstract

We analyzed the yield characters of field-grown transgenic potato plants (Solanum tuberosum) carrying a maize gene for sucrose-phosphate synthase (SPS), the key enzyme in sucrose synthesis. The SPS activity in the leaves of transgenic plants (line Ag1203) was 2 times that of the control (cv. May Queen). There was no difference in the photosynthetic CO₂ uptake rates between Ag1203 and May Queen plants, and the leaf starch content of Ag1203 was lower. These observations indicate that the introduction of a foreign SPS gene improved the supply of photosynthate from source (leaves) to sink (tubers). Additionally, leaf senescence of the transgenic potato plants was delayed relative to that of May Queen. The average tuber weight and total yield of Ag1203 plants were at least 20% higher, and the tuber sucrose content, which is related to eating quality, was also higher. Increased translocation of photosynthate and longer period of photosynthetic activity in the leaves may have increased the yield of Ag1203. These results suggest that introduction of the SPS gene improved the yield characters and quality of potato tubers under field conditions.     

Validation of tuber blight (Phytophthora infestans) prediction model

Potato tuber blight caused by Phytophthora infestans accounts for significant losses of tubers in storage. Despite research on infection and management of tuber blight, there is paucity of information on the prediction of the occurrence tuber blight or modelling of tuber infection by P. infestans under field conditions. A tuber blight prediction model was developed in New York in experiments conducted using cultivars Allegany, NY101, and Katahdin in 1998 and 1999. This model was validated using data collected from the potato cultivar Snowden in field experiments in Laingsburg, Michigan from 2000 to 2009. In both New York and Michigan experiments, disease was initiated by artificial inoculation of cultivars with a US-8 isolate of P. infestans. Mean leaf area affected ranged from 0 to 94% at New York, and 0 to 93% at Michigan. At New York and Michigan, mean tuber blight incidences ranged from 1 to 40% and 0 to 15%, respectively. In the validation of the model using data collected at Laingsburg, Michigan, the model correctly predicted tuber blight incidence in 7 out of 9 years. Comparison of observed with predicted values indicated that slopes of the regression line between observed and predicted germination and infection data were not significantly different (P > 0.3547). Correlation coefficient between observed and predicted values was high (r² > 0.65) and the coefficient of variation of the residuals of error was about 12%. Although inoculum availability is assumed in the model, incorporation of relationships of inoculum density, propagule survival in soil, and tuber blight incidence would greatly improve the prediction of tuber blight under field conditions.     

Effects of drip irrigation regimes on potato tuber yield and quality under plastic mulch in arid Northwestern China

Field experiments were conducted to study the effects of drip irrigation regimes on potato (Solanum tuberosum L.) growth, tuber yield and quality, and water use efficiency (WUE) when grown under plastic mulch in an arid area of Northwestern China in 2008, 2009 and 2010. The 2008 experiment consisted of a drip irrigation check without plastic mulch and four different drip irrigation frequency treatments with plastic mulch: once every day, once every 2 days, once every 4 days, and once every 8 days. In 2009 and 2010 the drip check treatment without mulch was irrigated at −25 kPa soil matric potential (SMP) during three potato development stages and four different SMP drip irrigation strategies were compared during the potato development stages (using plastic mulch): S1 (−25 kPa SMP during the three development stages), S2 (−25 kPa SMP during tuber initiation and bulking and −35 kPa SMP during maturation), S3 (−25 kPa SMP during tuber initiation and maturation and −35 kPa SMP during bulking), S4 (−35 kPa SMP during the three development stages). Plastic mulch negatively affected tuber yield, WUE, and tuber quality. In the presence of plastic mulch, tuber yield, specific gravity, starch content, and vitamin C content seemed to be enhanced as the irrigation frequency increased, although the differences were not statistically significant. Irrigation frequency did not affect WUE for potato grown under plastic mulch. Analysis of plant height, tuber yield and WUE showed that a drip irrigation threshold of −35 kPa SMP led to obvious water stress for potato growth in this arid area. Under plastic mulch in 2010, S2 was the optimum drip irrigation regime because of the significantly higher yield than S3 and S4, the highest WUE and significantly firmer tubers than any of the other irrigation regimes tested.     

Resistencia de tuberculos a las fusaria que afectan papa en el Peru

Fungi of the genusFusarium Link isolated in Perú from potatoes (Solanum tuberosum L. subsp.andigena Juz. & Buk.) affected by: i) wilt, ii) dry rot of stored tubers, iii) secondary rot in tubers affected by “cork” disease (potato mop-top virus?), caused dry rot when inoculated to tubers of Renaacimiento variety. The identification of some of theseFusaria suggests thatFusarium solani Snyder & Hansen is associated with wilt and dry rot, andFusarium oxysporum Snyder & Hansen with rot secondary to cork disease. Tubers of eight potato varieties inoculated with fourFusaria representative of those isolated showed a great range in levels of susceptibility to colonization by theseFusaria, Sapa being the most susceptible variety, and Mantaro appearing to be the most resistant. These results suggest that useful levels of resistance toFusarium tuber rot are available in the Peruvian germ-plasm.     

Expression of a pea disease resistance response gene in the potato cultivar Shepody

The coding sequence from the pea disease resistance response gene 49 (DRR49 gene), was transferred into the potato (Solanum tuberosum L.) cultivar Shepody viaAgrobacterium co-cultivation. Potato leaf explants were co-cultivated withAgrobacterium tumefaciens harboring a binary vector containing the coding sequence from the DRR49 gene under the control of the 35S promoter from cauliflower mosaic virus (CaMV). Transformed potato plants were selected by their resistance to kanamycin. The insertion of foreign DNAs was detected by polymerase chain reaction (PCR) and Southern blot analysis. The expression of DRR49 coding sequence was confirmed via the detection of the corresponding mRNA in northern blot analysis. Field pathogenicity tests indicated that transgenic plants expressing the pea DRR49 mRNA have higher tuber yields than the control plants when grown in PED (potato early dying) infested soil.     

Furrow vs hill planting of sprinkler-irrigated russet burbank potatoes on coarse-textured soils

Surface water runoff from the hill, where potatoes are planted, to the furrow may exacerbate potato drought sensitivity. Planting into furrows and constructing midrow ridges may improve water use efficiency and relieve water stress on potato by directing water toward, not away from, the plants. A 3-year field study was conducted to compare yields and tuber size distributions of furrow- and hill-planted potato (Solanum tuberosum L., ‘Russet Burbank’) on coarse-textured, well-drained soils under sprinkler irrigation. A split-plot experimental design with main plots of row orientation (N-S vs E-W) and subplots of planting method (hill and furrow) combined with two planting depths was used at two central North Dakota sites. Except for planting method and limiting the post-emergence cultivation in the furrow treatments, all cultural practices (fertilizer, irrigation, etc.) were identical and corresponded with conventional practices for hill planted potato. Row orientation did not affect yield for any tuber size category. Averaged over 3 years, furrow-planted potato produced 24% larger tubers (188 vs 151 g), 31% smaller yield for tubers <113 g (4.99 vs 7.21 Mg ha^?1), 28% smaller yield for tubers 113 to 170 g (8.14 vs 11.3 Mg ha^?1), 8% larger yields for tubers 170 to 283 g (18.0 vs 16.6 Mg ha^?1), 103% larger yields for tubers 283 to 454 g (10.9 vs 5.36 Mg ha^?1), 341% larger yields for tubers >454 g (2.65 vs 0.60 Mg ha^?1), and 10% larger total yields (46.2 vs 41.9 Mg ha^?1) compared with hill-planted potato. There were no differences in tuber specific gravity. Preliminary soil water measurements indicated an inter-row water-harvesting effect for furrow planting compared with hill planting. The furrow-planting method may offer significant potential for ameliorating the drought sensitivity of potato.     

Potato growth with and without plastic mulch in two typical regions of Northern China

Plastic film mulching is an important agricultural practice to save water and improve crop productivity in Northern China. Three field experiments were conducted to examine the effect of plastic mulch on soil temperature, potato (Solanum tuberosum L.) growth and evapotranspiration under drip irrigation in two typical regions of Northern China in 2001 and 2006. Results suggest that daily mean soil temperature under mulch was 2–9 °C higher than without mulch, especially during the early growth. Potato growth was restrained under mulching conditions in the North China Plain mainly due to the higher air temperature in this region and thus the higher soil temperature. The negative effects of mulching included a lower emergence and fewer marketable tubers per plant. Evapotranspiration and potato tuber yield were both reduced by mulch, especially in the North China Plain. In northwest China, mulch favorably increased the weight of jumbo tubers (W ≥ 300 g) per plant. Mulching duration had little effect on potato evapotranspiration in northwest China. However, both tuber yield and water use efficiency (WUE) decreased with increases in mulch duration, which suggests the plastic mulch should be removed early.     

Effects of partial root-zone drying on yield,tuber size and water use efficiency in potato under field conditions

Water resources are limited for irrigation worldwide; therefore, there is a need for water-saving irrigation practices to be explored. Partial root-zone drying (PRD) is a new water-saving irrigation strategy being tested in many crop species. Experiments were conducted in potato (Solanum tuberosum L. cv. Folva) under open field conditions in 2004 and under a mobile rainout shelter in 2005. Two subsurface irrigation treatments were studied: full irrigation (FI) receiving 100% of evaporative demands, 50.1 and 201 mm of irrigation water in the 2 years, to keep it close to field capacity; and PRD, which received 21.7 and 140 mm of irrigation in 2004 and 2005 respectively. Due to rain in 2004, the PRD treatment was imposed over a short period only during the late tuber filling and maturing stages. In 2005, the PRD treatment was imposed during the whole period of tuber filling and tuber maturation. The PRD treatment was shifted from one side to the other side of potato plants every 5–10 days. Especially in 2005 it was apparent that stomatal conductance was generally lower in the PRD than in the FI plants, whereas leaf water potential tended to be lower in only a few instances. During the treatment period, plants were harvested five times, and no significant difference was found between the treatments in leaf area index, top dry mass and tuber yield. At final harvest, tubers were graded based on size into four classes C₁–C₄, of which the yield of the important marketable class (C₂) was significantly higher (20%) in the PRD than in the FI treatment. Compared with FI, the PRD treatment saved 30% of irrigation water while maintaining tuber yield, leading to a 61% increase of irrigation water use efficiency. The limited data of 2004 support these results. In summary, PRD is a promising water-saving irrigation strategy for potato production in areas with limited water resources.     

Change in Some Glycoalkaloids of Potato under Different Storage Regimes

The potato (Solanum tuberosum L.) is an important food crop worldwide. Potato tubers can be stored to provide continuity of supply between production seasons, but it is important that they be stored under appropriate conditions as incorrect storage will result in deterioration in end user quality and may increase glycoalkaloid levels. We have investigated the effects of types of household storage on potato glycoalkaloid content (total glycoalkaloids [TGA]; α-solanine; α-chaconine) in Turkey. Tubers of potato cultivars (cvs.) Agria and Bettina were stored under four types of storage conditions (indirect sunlight for 10 h per day and dark storage for the remaining 14 h per day; storage under continuous fluorescent light; storage in constant darkness; storage in the dark in a refrigerator) for 56 days. Samples of tubers were taken at the beginning of the storage period and after 14, 28 and 56 days of storage for tuber glycoalkaloid measurement. Tubers stored in the three light environments showed an increase in glycoalkaloid levels; however, none of the cv. Agria tubers reached the critical level of 200 mg/kg tuber. On day 56 the TGA level of cv. Bettina tubers stored under fluorescent light reached 234.31 mg/kg.     

Chipping performance of three processing potato cultivars during long-term storage at two temperature regimes

Three potato cultivars (Russet Burbank, Norchip, and Gemchip) grown with nitrogen applied at three rates were stored at two temperature regimes (Treatment 1: 13 months at 10 CTreatment 2: 1 month at 10 C; followed by a 1 C decrease per week until tubers were 4 C; followed by 6 months at 4 C; followed by a 1 C increase per week until tubers were 10 C; followed by 3 months at 10 C). Tuber chemical components and potato chip appearance were measured at harvest and after 3, 6, 9, 11, 12, and 13 months; these measurements were performed within 24 hours of the time potatoes were removed from storage. Sugar responses (tuber glucose, fructose, sucrose) and potato chip appearance were affected by cultivar over time in both years and storage temperatures. Russet Burbank tubers displayed a significantly higher glucose forming potential and produced darker appearing chips, regardless of storage temperature or time in storage, compared to Norchip and Gemchip. Potatoes receiving a cold-storage treatment contained less sugar and produced lighter appearing chips after 12 months storage compared to tubers stored at a constant 10 C for 12 months. The linear association between tuber chemical components and potato chip appearance varied with storage temperature.