Commercial Potato Cultivars Research Articles

Investigating the impact of commercial potato cultivars and fungicides on late blight disease control

Investigating the impact of commercial potato cultivars and fungicides on late blight disease control

Genotyping-by-sequencing and weighted gene co-expression network analysis of genes responsive against Potato virus Y in commercial potato cultivars.

Potato is considered a key component of the global food system and plays a vital role in strengthening world food security. A major constraint to potato production worldwide is the Potato Virus Y (PVY), belonging to the genus Potyvirus in the family of Potyviridae. Selective breeding of potato with resistance to PVY pathogens remains the best method to limit the impact of viral infections. Understanding the genetic diversity and population structure of potato germplasm is important for breeders to improve new cultivars for the sustainable use of genetic materials in potato breeding to PVY pathogens. While, genetic diversity improvement in modern potato breeding is facing increasingly narrow genetic basis and the decline of the genetic diversity. In this research, we performed genotyping-by-sequencing (GBS)-based diversity analysis on 10 commercial potato cultivars and weighted gene co-expression network analysis (WGCNA) to identify candidate genes related to PVY-resistance. WGCNA is a system biology technique that uses the WGCNA R software package to describe the correlation patterns between genes in multiple samples. In terms of consumption, these cultivars are a high rate among Iranian people. Using population structure analysis, the 10 cultivars were clustered into three groups based on the 118343 single nucleotide polymorphisms (SNPs) generated by GBS. Read depth ranged between 5 and 18. The average data size and Q30 of the reads were 145.98 Mb and 93.63%, respectively. Based on the WGCNA and gene expression analysis, the StDUF538, StGTF3C5, and StTMEM161A genes were associated with PVY resistance in the potato genome. Further, these three hub genes were significantly involved in defense mechanism where the StTMEM161A was involved in the regulation of alkalization apoplast, the StDUF538 was activated in the chloroplast degradation program, and the StGTF3C5 regulated the proteins increase related to defense in the PVY infected cells. In addition, in the genetic improvement programs, these hub genes can be used as genetic markers for screening commercial cultivars for PVY resistance. Our survey demonstrated that the combination of GBS-based genetic diversity germplasm analysis and WGCNA can assist breeders to select cultivars resistant to PVY as well as help design proper crossing schemes in potato breeding.

Effects of Abiotic Stress Associated with Climate Change on Potato Yield and Tuber Quality Under a Multi-environment Trial in New Zealand

In the 2018/19 growing season, a multi-environment trial in Opiki, Hastings, and Ohakune located in three different regions of the North Island of New Zealand was conducted to evaluate responses of selected potato cultivars to abiotic stress associated with climate change. Heat and drought stresses were evident with supra-optimal temperatures (> 25 °C) in Opiki and Hastings and sub-optimal rainfall (< 500 mm) in Opiki, which influenced the different morpho-physiological characteristics of the potato crop, ultimately affecting yield and tuber quality. These abiotic stresses also increased the incidence of malformation, growth cracks, and second growth in tubers reducing the total and marketable tuber yields by 43% and 45%, respectively. In addition, the genotype × environment analysis showed that Ohakune had the most favourable environmental conditions for potato production since all cultivars in this site had superior marketable tuber yields. ‘Taurus’ was the most stable and adaptable cultivar across trial sites (wide adaptation), whilst ‘Hermes’ and ‘Snowden’ were more adapted under Opiki and Hastings conditions (specific adaptation), respectively. As established in this study, heat and drought stresses have significant effects on the morpho-physiology, yield, and tuber quality of commercial potato cultivars in New Zealand.

Host response of five potato cultivars to Meloidogyne nematodes

Potato (Solanum tuberosum L.) is a well-known food crop that is regarded as an important component in the worldwide battle against hunger and malnutrition. Root-knot nematodes (RKN), Meloidogyne species, are a serious limitation in the potato industry. Potato, being a tuberous crop, yield reduction is mainly due to tuber quality and quantity. In order to evaluate the response of five commercial potato cultivars, viz ‘Buffelspoort 1’, ‘Hertha’, ‘Larnoma’, ‘Mnandi’ and ‘Up-to-date’ to two RKN species, viz M. enterolobii and M. javanica; pot experiments were conducted under net house conditions. Ten separate experiments, each with treatments: 0, 500, 1500, 2500 and 3500 eggs + second-stage juveniles (J2), were arranged in a randomized complete block design (RCBD) with five replicates. Fifty-six days after inoculation, nematode effect on plant yield was evaluated. Potato tubers were assessed for root galls, and nematodes reproductive factor (RF) was computed. There were significant differences amongst treatments on the following potato growth parameters: plant height, stem diameter, chlorophyll content, number of tubers and tuber weight in both M. enterolobii and M. javanica (P ≤ 0.05). The RF was above unity (one) in all potato cultivars for both M. enterolobii and M. javanica; with M. enterolobii showing more aggressiveness compared to M. javanica. Further, cultivars ‘Buffelspoort 1’ and ‘Hertha’ showed the highest susceptibility, whilst cultivar ‘Mnandi’ showed the least susceptibility. Infection of potato cultivars by the nematodes had severe effects on growth parameters of all the cultivars. Results suggested that all five commercial potato cultivars were susceptible to M. enterolobii and M. javanica. Thus, there is an urgent need for RKN management intervention in the aforementioned cultivars.

Estrés hídrico en el crecimiento y rendimiento de cultivares comerciales de papa (&lt;i&gt;Solanum tuberosum&lt;/i&gt; L.) en la región centro del Perú

Potato (Solanum tuberosum L.) is a crop of great importance worldwide due to its high nutritional value and its adaptability to different climatic conditions. In Peru, it is one of the main crops in terms of production and consumption, with Junín being one of the departments with the highest production. The aim of this research was to evaluate the effect of water stress on the growth and yield of commercial potato cultivars. Four irrigation frequencies (field capacity, every 7, 14 and 21 days) and five commercial potato cultivars (Canchán, Yungay, Wankita, Serranita and Shulay) were evaluated, distributed in a completely randomized design with a 5x4 factorial arrangement, with five replications. It was installed under greenhouse conditions and seven variables (plant emergence, plant height, number of stems, number and weight of tubers, transpiration rate and dry matter) were evaluated. The results showed statistical differences in all the variables evaluated. It was found that the Canchán cultivar with irrigation frequency every 21 days was more tolerant to drought with an average rate of 0.69 ml, the maximum permissible irrigation limit in greenhouse is every 14 days. The highest number of tubers was observed in the Wankita cultivar with 29.8 tubers under a drought stress of 14 days. The highest tuber weight was obtained with the Yungay cultivar at field capacity with 0.438 kg per plant. It is concluded that water stress influences potato growth and production.

PRODUCTION OF MICROSHOOT USING THE TEMPORARY IMMERSION SYSTEM (TIS) IN POTATO CULTIVARS

The Temporary Immersion System (TIS) Bioreactor’s performance in cultivation for several commercial potato cultivars became the prevailing study’s review focus. The experiment in a split-plot design had two factors. The first factor comprised the type of culture system (conventional and TIS Bioreactor) treatment used as main plots. The second factor was the four potato cultivars (Atlantic Malang, Dayang Sumbi, Granola L., and Maglia) used as subplots. The TIS Bioreactor culture has the highest average in all studied variables compared with conventional cultures at the multiplication stage. In the TIS Bioreactor, potato cultivar Dayang Sumbi excelled in the number of axillary branching and number of primary roots. At the same time, genotype Granola L. surpassed the height of the plantlets of other cultivars. Meanwhile, the cultivar Atlantic Malang shone in the number of nodes, with Maglia in the number of leaves. Using the TIS Bioreactor produces microshoots with more nodes and can be beneficial as a propagation organ. The Dayang Sumbi cultivar was superior to all other potato cultivars.

The enhancement of photosynthetic performance, water use efficiency and potato yield under elevated CO2 is cultivar dependent.

As a fourth major food crop, potato could fulfill the nutritional demand of the growing population. Understanding how potato plants respond to predicted increase in atmospheric CO2 at the physiological, biochemical and molecular level is therefore important to improve potato productivity. Thus, the main objectives of the present study are to investigate the effects of elevated CO2 on the photosynthetic performance, water use efficiency and tuber yield of various commercial potato cultivars combined with biochemical and molecular analyses. We grew five potato cultivars (AC Novachip, Atlantic, Kennebec, Russet Burbank and Shepody) at either ambient CO2 (400 μmol CO2 mol-1) or elevated (750 μmol CO2 mol-1) CO2. Compared to ambient CO2-grown counterparts, elevated CO2-grown Russet Burbank and Shepody exhibited a significant increase in tuber yield of 107% and 49% respectively, whereas AC Novachip, Atlantic and Kennebec exhibited a 16%, 6% and 44% increment respectively. These differences in CO2-enhancement of tuber yield across the cultivars were mainly associated with the differences in CO2-stimulation of rates of photosynthesis. For instance, elevated CO2 significantly stimulated the rates of gross photosynthesis for AC Novachip (30%), Russet Burbank (41%) and Shepody (28%) but had minimal effects for Atlantic and Kennebec when measured at growth light. Elevated CO2 significantly increased the total tuber number for Atlantic (40%) and Shepody (83%) but had insignificant effects for other cultivars. Average tuber size increased for AC Novachip (16%), Kennebec (30%) and Russet Burbank (80%), but decreased for Atlantic (25%) and Shepody (19%) under elevated versus ambient CO2 conditions. Although elevated CO2 minimally decreased stomatal conductance (6-22%) and transpiration rates (2-36%), instantaneous water use efficiency increased by up to 79% in all cultivars suggesting that enhanced water use efficiency was mainly associated with increased photosynthesis at elevated CO2. The effects of elevated CO2 on electron transport rates, non-photochemical quenching, excitation pressure, and leaf chlorophyll and protein content varied across the cultivars. We did not observe any significant differences in plant growth and morphology in elevated versus ambient CO2-grown plants. Taken all together, we conclude that the CO2-stimulation of photosynthetic performance, water use efficiency and tuber yield of potatoes is cultivar dependent.

Variation in Leaf Volatile Emissions in Potato (Solanum tuberosum) Cultivars with Different Late Blight Resistance.

Volatile organic compounds (VOCs) play key roles in plant abiotic and biotic stress resistance, but even for widespread crops, there is limited information on variations in the magnitude and composition of constitutive VOC emissions among cultivars with varying stress resistance. The foliage VOC emissions from nine local and commercial potato cultivars (Alouette, Sarme, Kuras, Ando, Anti, Jõgeva Kollane, Teele, 1681-11, and Reet) with medium to late maturities and varying Phytophthora infestans (the causative agent of late blight disease) resistance backgrounds were analyzed to gain an insight into the genetic diversity of constitutive VOC emissions and to test the hypothesis that cultivars more resistant to Phytophthora infestans have greater VOC emissions and different VOC fingerprints. Forty-six VOCs were identified in the emission blends of potato leaves. The majority of the VOCs were sesquiterpenes (50% of the total number of compounds and 0.5-36.9% of the total emissions) and monoterpenes (30.4% of the total number of compounds and 57.8-92.5% of the total VOC emissions). Qualitative differences in leaf volatiles, mainly in sesquiterpenes, were related to the potato genotype background. Among the volatile groups, the monoterpenes α-pinene, β-pinene, Δ3-carene, limonene, and p-cymene, the sesquiterpenes (E)-β-caryophyllene and α-copaene, and green leaf volatile hexanal were the major volatiles in all cultivars. A higher share of VOCs known to have antimicrobial activities was observed. Interestingly, the cultivars were grouped into high and low resistance categories based on the VOC profiles, and the total terpenoid and total constitutive VOC emission scale positively with resistance. To support and expedite advances in breeding for resistance to diseases such as late blight disease, the plant research community must develop a fast and precise approach to measure disease resistance. We conclude that the blend of emitted volatiles is a fast, non-invasive, and promising indicator to identify cultivars resistant to potato late blight disease.

Assembly and Analysis of Plastomes for 15 Potato Cultivars Grown in Russia

Chloroplasts are important organelles in a plant cell, having their own DNA (cpDNA), transmitted only through the female line, and performing the function of photosynthesis. The determination of chloroplast DNA is of interest in the study of the genetic diversity and phylogeny of potatoes, and of cytoplasmic sterility, as well as for applications in biotechnology and genetic engineering. Here, we reconstructed the complete plastomes of 15 S. tuberosum potato cultivars grown in Russia. Our analysis allowed us to determine the composition and location of genes for these plastid DNAs. It was shown that the plastid genome contains both highly and low-variable regions. The region at position 63,001–68,000 nt has the highest variability. We determined the types of cpDNA based on in silico approaches: 10 cultivars have cpDNA of the W-type and 5 cultivars have cpDNA of the T-type. The genetic diversity of the plastid DNA for these potato cultivars was analyzed alongside the previously reconstructed plastomes of South American accessions, European/North American commercial cultivars and potato cultivars bred in the Ural region. The results show that plastid DNAs of the same type form clusters by sequence similarity, in agreement with previous studies.

Influence of allelic polymorphism in the 3’ untranslated region of the &lt;i&gt;StTCP23&lt;/i&gt; gene on the tolerance of potato cultivars to the potato spindle tuber viroid

Background. It is known that the pathological phenotype of potato plants can be mediated by complementary interactions between the genomic RNA of PSTVd and mRNA of some regulatory genes, which consequently lead to RNA interference, the synthesis of small interfering RNAs (vd-sRNA PSTVd), and impaired morphogenesis. At the same time, symptoms caused by the viroid may vary in different potato cultivars. Here we predict the interactions between the 3’ UTRs of various alleles of the StTCP23 transcription factor gene and the complementary regions in PSTVd genomic RNA.Materials and methods. We selected eight commercial potato cultivars with different symptoms of viroid infection and disease. For each cultivar, six clones of each cDNA amplicon of StTCP23 with a 3’ UTR were identified, and the allelic compositions of the target regions within their 3’ UTRs were characterized.Results. In total, 11 types of alleles of the 3’ UTR StTCP23 segment complementary to the vd-sRNA PSTVd were identified. Cultivars with the A allele (‘Gala’, ‘Colomba’, ‘Favorit’, and ‘Fioletovy’) identical to the reference genome or a high dose of the C allele with a deletion of four nucleotides (cv. ‘Impala’) were characterized by high susceptibility already at the primary (firstyear) infection with the PSTVd. Cvs. ‘Krepysh’, ‘Labadia’ and ‘Riviera’, classified as tolerant during primary inoculation, on the contrary, were characterized by the absence of the A allele and the presence of cultivar-specific mutant alleles.Conclusion. A high degree of polymorphism in the target site (3’ UTR region) of StTCP23 indicates a possible selection pressure on this locus. It can be assumed that cultivars with shorter alleles, which have fewer bases complementary to vd-sRNA in hypothetical duplexes and therefore less likely to induce target gene silencing, are more tolerant to the PSTVd upon primary viroid infection.

Screening of endophytic bacteria from potato tubers and their antagonistic activity against soil-borne potato pathogens

In order to appraise the bacterial endophyte communities that help resist disease in potato tuber, the separation, the population density, biodiversity and the antagonistic activity of endophytic bacteria, from the tuber peel of potato cultivars (Fontan90, Agria, Sante’a and Jeli89), were examined in the Fars province in Iran. In this study, the bacterial endophyte Colony Forming Units (CFU) were counted based on the most suitable dilution in petri dishes and expressed per g of wet weight of tuber tissue. The presence of bacteria was found mostly in the outer layer. A wide variety of endophyte species biodiversity was in Agria cultivar. To estimate the antagonistic effect of potato associated endophytic bacteria, 115 bacterial isolates were evaluated by dual culture method against main soil-borne potato pathogens Fusarium oxysporum, Rhizoctonia solani, Verticillium dahliae, Streptomyces scabies and Ralstonia solanacearum. Endophyte strains were identified based on physiological, morphological and chemical characteristics and the 16S rRNA gene sequence analysis. The highest degree of the inhibitory activity in all layers of potato cultivars was related to Bacillus subtilis, Bacillus mojavensis and Klebsiella variicola. Antagonistic activity of endophytic bacteria against the pathogens was significantly higher (p&lt;0.01) in the examined strains from the outermost layer of tuber peel and decreased progressively toward the center of the tuber. In this research, Klebsiella variicola was reported as endophyte bacteria in the four commercial potato cultivars mentioned above, for the first time.

Phosphorus-solubilizing bacteria isolated from the rhizosphere of wild potato Solanum bulbocastanum enhance growth of modern potato varieties

BackgroundWild potato species harbor a distinctive rhizosphere microbiome relative to their modern counterparts, thus providing a competitive advantage for acquiring phosphorus (P) in their native habitats. Despite this, the effects of transferring phosphorus-solubilizing bacteria (PSB), recruited from wild potatoes rhizosphere, on modern potato varieties’ performance has not been investigated. Here, it was hypothesized that PSB isolated from wild potatoes could enhance plant growth and solubilization of various P forms when co-inoculated with commercial potatoes (Solanum tuberosum).ResultsTo test this hypothesis, three bacteria Enterobacter cloacae, Bacillus thuringiensis, and Pseudomonas pseudoalcaligenes were isolated from the rhizosphere of the wild potato Solanum bulbocastanum grown under greenhouse conditions and characterized for their P-solubilizing activities. It was found that both individual bacterial species and the consortium of the three bacteria, dissolved organic (i.e., phytin) and inorganic P (i.e., calcium phosphate) in vitro. The bacterial consortium increased dissolved P by 36-fold for calcium phosphate and sixfold for phytin compared to a sterile control and surpassed the effect of each individual PSB strain. To further evaluate the effect of the PSB consortium on plant growth and P use efficiency, the bacteria were co-inoculated on a commercial potato cultivar and amended separately with phytin, calcium phosphate, commercial P fertilizer, or a combination of the three P sources. The results showed an overall increase in total dry biomass and shoot P content in treatments co-inoculated with PSB.ConclusionsOur findings indicate that PSB isolated from wild potatoes and inoculated with modern potato varieties have the potential to enhance yield and nutrient uptake.

Comprehensive Genome-Wide Analysis of the Catalase Enzyme Toolbox in Potato (Solanum tuberosum L.)

As antioxidant enzymes, catalase (CAT) defends organisms from oxidative stress caused by excessive production of reactive oxygen species (ROS). These enzymes play important roles in miscellaneous biological processes. However, little is known about the CAT genes in S. tuberosum (StCAT) despite its essential economical rank in the world. So far, abiotic and biotic stresses severely hinder plant growth and development which affects the crop production and quality. To identify the possible roles of CAT genes especially under salt stress, a genome-wide analysis of CAT gene family has been performed in the potato plant. In this study, the StCAT gene’s structure, secondary and 3D protein structure, physicochemical properties, synteny analysis, phylogenetic tree and also expression profiling under various developmental and environmental cues were predicted using bioinformatics tools. The expression analysis by RT-PCR was performed upon a commercial potato cultivar. Three genes encoding StCAT that code for three proteins each of size 492 aa, interrupted by seven introns, have been identified in potatoes. StCAT proteins were found to be localized in the peroxisome which is judged as the main H2O2 cell production site during different processes. Many regulating cis-elements related to stress responses and plant hormones signaling were found in the promoter sequence of each gene. The analysis of motifs and phylogenetic trees showed that StCAT are closer to their homologous in S. lycopersicum and share a 41–95% identity with other plants’ CATs. Expression profiling revealed that StCAT1 is the constitutively expressive member; while StCAT2 and StCAT3 are the stress-responsive members.

Genome architecture and tetrasomic inheritance of autotetraploid potato

Potato (Solanum tuberosum) is the most consumed non-cereal food crop. Most commercial potato cultivars are autotetraploids with highly heterozygous genomes, severely hampering genetic analyses and improvement. By leveraging the state-of-the-art sequencing technologies and polyploid graph binning, we achieved a chromosome-scale, haplotype-resolved genome assembly of a cultivated potato, Cooperation-88 (C88). Intra-haplotype comparative analyses revealed extensive sequence and expression differences in this tetraploid genome. We identified haplotype-specific pericentromeres on chromosomes, suggesting a distinct evolutionary trajectory of potato homologous centromeres. Furthermore, we detected double reduction events that are unevenly distributed on haplotypes in 1021 of 1034 selfing progeny, a feature of autopolyploid inheritance. By distinguishing maternal and paternal haplotype sets in C88, we simulated the origin of heterosis in cultivated tetraploid with a survey of 3110 tetra-allelic loci with deleterious mutations, which were masked in the heterozygous condition by two parents. This study provides insights into the genomic architecture of autopolyploids and will guide their breeding.

Effects of the repression of GIGANTEA gene StGI.04 on the potato leaf transcriptome and the anthocyanin content of tuber skin

BackgroundGIGANTEA (GI) is a plant-specific, circadian clock-regulated, nuclear protein with pleiotropic functions found in many plant species. This protein is involved in flowering, circadian clock control, chloroplast biogenesis, carbohydrate metabolism, stress responses, and volatile compound synthesis. In potato (Solanum tuberosum L.), its only role appears to be tuber initiation; however, based on findings in other plant species, we hypothesised that the function of GI in potatoes is not restricted only to tuberisation.ResultsTo test this hypothesis, the expression of a GI gene in the commercial potato cultivar ‘Désirée’ was repressed, and the effects of repression at morphological and transcriptome level were investigated. Previously, two copies of GI genes in potato were found. A construct to reduce the mRNA levels of one of these genes (StGI.04) was assembled, and the effects of antisense repression were studied in greenhouse-grown plants. The highest level of repression reached around 50%. However, this level did not influence tuber formation and yield but did cause a reduction in tuber colour. Using high-performance liquid chromatography (HPLC), significant reductions in cyanidin 3,5-di-O-glucoside and pelargonidin 3,5-di-O-glucoside contents of tuber peels were detected. Anthocyanins are synthesized through a branch of the phenylpropanoid pathway. The transcriptome analysis indicated down-regulation in the expression of PHENYLALANINE AMMONIA LYASE (PAL), the LEUCOANTHOCYANIDIN OXIDISING enzyme gene LDOX, and the MYB-RELATED PROTEIN Hv1 (MYB-Hv1), a transcription factor coding gene, which is presumably involved in the regulation of flavonoid biosynthesis, in the leaves of a selected StGI.04-repressed line. Furthermore, alterations in expression of genes affecting the circadian clock, flowering, starch synthesis, and stress responses were detected in the leaves of the selected StGI.04-repressed line.ConclusionsWe tested the effects of antisense repression of StGI.04 expression in potatoes and found that as with GI in other plant species, it influences the expression of the key genes of the circadian clock, flowering, starch synthesis, and stress responses. Furthermore, we detected a novel function of a GI gene in influencing the anthocyanin synthesis and potato tuber skin colour.

Commercial Potato Cultivars Exhibit Distinct Susceptibility to the Root Lesion Nematode Pratylenchus penetrans

The root lesion nematode Pratylenchus penetrans is an important plant-parasitic nematode of potato. In this study, the susceptibility of commercial potato cultivars to P. penetrans was assessed. Nematode penetration was evaluated in cultivars Agria, Camel, Kennebec, Laura, Royata, and Stemster at 1, 3, 7, and 15 days after inoculation (DAI) with 750 nematodes/plant, and an egression assay at 3 DAI with 1000 nematodes/plant. Reproduction assays of cultivars Agata, Agria, Camel, Désirée, Dirosso, Kennebec, Laura, Picasso, Royata, and Stemster were performed in 2 L pots inoculated with four P. penetrans/g soil and quantified at 60 DAI. Tenue or moderate root cell browning to advanced necrotic areas were observed after nematode penetration, and the number of nematodes/g of root gradually increased with time of infection. A lower number of deposited eggs and nematodes were observed within the roots of cultivar Laura in all assays comparatively to other cultivars. The susceptibility index (SI) was significantly lower in cultivar Laura (0.4–0.6), followed by cultivars Camel and Picasso (0.8–0.9). All remaining cultivars showed SI values above 1. Although the potato susceptibility to the nematode varied among cultivars, no differences on the average number or weight of tubers produced by each plant of inoculated versus non-inoculated plants were detected. Our data reveals that these cultivars have a distinct ability to support the reproduction of P. penetrans.

In Silico Characterization and Expression Analysis of GIGANTEA Genes in Potato

GIGANTEA (GI) genes are ubiquitous in the plant kingdom and are involved in diverse processes from flowering during stress responses to tuberization; the latter occurs in potato (Solanum tuberosum L.). GI genes have a diurnal cycle of expression; however, no details on the regulation of GI gene expression in potato have been reported thus far. The aim of our work was the analysis of the GI promoter sequence and studying GI expression in different organs and under abiotic stress conditions in potato. Two GI genes homologous to Arabidopsis GI located on chromosomes 4 and 12 (StGI.04 and StGI.12) were identified in the genome-sequenced potato S. phureja. The GI promoter regions of the commercial potato cultivar ‘Désirée’ were cloned and found to be almost identical to the S. phureja GI promoter sequence. More than ten TF families binding to the GI promoters were predicted. EVENING ELEMENT and ABSCISIC ACID RESPONSE ELEMENT LIKE elements related to circadian regulation and a binding site for POTATO HOMEOBOX 20 presumably involved in tuber initiation were detected in both GI promoters. However, the locations of these elements and several other cis-acting regulatory elements as well as the organ-specific expression and responses of the genes to abiotic stresses and abscisic acid were different. Thus, we presume that the function of StGI.04 and StGI.12 are at least partially different. This study lays foundation for further investigation of the roles of GI genes in potato.

Comparative analyses of the starch quality isolated from a local red potato and a commercial non-pigmented potato cultivar

Comparative analyses of the starch quality isolated from a local red potato and a commercial non-pigmented potato cultivar

Difference in Foliar Fatty Acid Composition in Potato Cultivars over a Growing Season May Influence the Host Location Preference of Leptinotarsa Decemlineata

The production of commercial potatoes (Solanum tuberosum) for different market classes is of vital agricultural importance in the United States. For the production of chips, fresh-market or processing potatoes, potato producers rely upon different potato cultivars to meet market and consumer demands. Many cultivars possess distinctive traits which make them more or less susceptible to disease and insect pressure. One important and understudied trait that may confer host location preference and population performance include leaf fatty acid composition(s). It is known that leaf fatty acid composition can influence growth, taste, and even insect defense mechanisms. In the current investigation we examined the fatty acid composition of leaf tissue obtained from 8 commercial potato cultivars representing different market classes grown in a controlled field study. We examined colonization preference of Leptinotarsa decemlineata among the 8 different potato cultivars over a 45 day period representing the first full generation in Wisconsin. Results of these experiments suggest, i) that fatty acid compositions in leaf tissue vary between potato cultivars and among sample dates throughout the experiment, ii) that Leptinotarsa decemlineata may preferentially colonize particular potato cultivars, and iii) that there was a significant correlation between omega-3 fatty acid composition in leaf tissue and Leptinotarsa decemlineata cultivar preference.

Response of potato (Solanum tuberosum L.) cultivars to drought stress under in vitro and field conditions

BackgroundPotato (Solanum tuberosum L.), the world’s third most important crop, is frequently thought to be sensitive to moderately sensitive to drought, and yield has fallen considerably over consecutive stress periods. Drought produces a wide range of responses in potato, from physiological alterations to variations in growth rates and yield. Knowledge about these responses is essential for getting a full understanding of drought-tolerance mechanism in potato plants which will help in the identification of drought-tolerant cultivars.ResultsA set of 21 commercial potato cultivars representing the genetic diversity in the Middle East countries market were screened for drought tolerance by measuring morpho-physiological traits and tuber production under in vitro and field trials. Cultivars were exposed to drought stress ranging from no drought to 0.1, 0.2 and 0.3 mol L−1 sorbitol in in vitro-based screening and 60, 40 and 20% soil moisture content in field-based screening. Drought stress adversely affected plant growth, yield and cultivars differed for their responses. Shoots and roots fresh weights, root length, surface area of root, no. of roots, no. of leaves, leaf area, plant water content %, K+ content, under in vitro drought treatments and shoots fresh and dry weights, no. of tubers and tuber yield under field drought treatments were examined and all decreased due to drought. The stress tolerance index decreased with increasing drought in examined cultivars; nevertheless, it revealed a degree of tolerance in some of them. Grouping cultivars by cluster analysis for response to drought resulted in: (i) a tolerant group of five cultivars, (ii) a moderately tolerant group of 11 cultivars, and (iii) a sensitive group of five cultivars. Furthermore, stress-related genes, i.e., DRO, ERECTA, ERF, DREB and StMYB were up-regulated in the five cultivars of the tolerant group. Likewise, the stomatal conductance and transpiration explained high correlation with the tuber yield in this group of cultivars.ConclusionThe diversity in germplasm indicated that potato cultivars can be developed for production under certain degrees of drought. Some cultivars are good candidates to be included in drought-tolerant breeding programs and recommended for cultivation in drought-stricken regions.Graphical