Normal Tubers Research Articles

Ефективність різних способів вирощування посадкового матеріалу батату (Ipomoеa batаtas)

Goal. To determine the effectiveness of different methods of growing sweet potato planting material in terms of growth and development, yield, the biochemical composition of products, and economic parameters in the Left Bank Forest-Steppe of Ukraine. Methods. The research was conducted during 2019–2021 at the Institute of Vegetable and Melon Growing of NAAS (south-eastern agro-soil region of the Left-Bank Forest-Steppe of Ukraine) on podzolic low-humus medium-loam chornozem on loess-like loam. Field research was conducted according to generally accepted methods, taking into account the biometric parameters of plants, yields and biochemical parameters of products. Results. It was found that sweet potato plants of Slobozhansky rubin variety grown from potted seedlings, compared with plants from slips (not rooted shoots) significantly outperformed the latter in biometric parameters (at the end of the growing season the difference decreases), but the yield of marketable tubers did not differ significantly (47 t/ha or 3.3%). There was a certain deterioration in the biochemical composition of tubers for the cultivation of sweet potatoes, which was expressed in a significantly lower content of total sugar (3.04%), starch (10.0%), an increase in nitrate content (from 20 to 57.9 mg/kg of raw weight). Conclusions. When growing sweet potatoes from potted seedlings, the yield of normal (undeformed) tubers is 88.2%, from slips — 90.0%. For growing sweet potatoes through potted seedlings, the yield of seedlings was higher (44 pieces/kg of tubers or 528 pieces/m2 of usable area of the greenhouse), but the cost of such seedlings was 1.39 UAH/piece. For growing sweet potatoes through a single cut of shoots on the slips, the yield of seedlings was 20 pcs/kg of tubers or 240 pcs/m2, while the cost of such seedlings was 0.33 UAH/pc, which indicated the effectiveness of this method of obtaining planting material.

Reproduction of the Spring potato variety with botanical seeds as a method of improving planting material

Since 2003, the State Agrarian University of the Northern Trans-Urals has been conducting research on the cultivation of healthy seed tubers of the Vesna variety from botanical seeds. It was found that under the conditions of the northern forest-steppe of the Tyumen region, the marked variety for many years forms berries on plants. After ripening, the seeds washed from them after one to two years of storage have a high germination capacity. When sown in a greenhouse, they produce minitubers, and the next year, normal tubers. Their further reproduction in isolated areas of the taiga zone and the tundra zone makes it possible to obtain healthy seed tubers in the required volume for sale to amateur gardeners and small farms.

Rapid analysis of GBSS1 and Vinv genes expressed in potato tubers using microtubers produced in liquid culture medium.

This study established a rapid method for the gene expression analysis in potato tubers. The use of microtubers would be useful for primary evaluation of tuber-expressed genes. In the development of transgenic potato or of potato with other genome modifications (e.g., genome editing or RNA-directed DNA methylation (RdDM) and so on) to improve tuber traits, analysis of the target gene is often difficult because of the long cultivation cycle (3-4months), large areas required, numerous materials for plant cultivation, and considerable efforts needed to obtain transgenic tubers. We demonstrate here rapid and convenient analysis of gene expression in potato microtubers. Enough microtubers for expression analysis can be induced over about 4weeks in a simple liquid medium in an Erlenmeyer flask. High-quality RNA and protein can be easily prepared from microtubers and used for northern blot, qRT-PCR, and western blot analyses without further purification. We investigated the expression of two tuber-expressed genes (GBSS1 and Vinv) in microtubers derived from the wild-type and from lines derived from RdDM-mediated transcriptional gene silencing. As expected, the expression of both genes was similar between microtubers and normal tubers. Furthermore, we demonstrated that microtubers can be used in western blot and confocal immunofluorescent microscopy analyses. These results suggest that expression analysis using microtubers is a convenient tool for the analysis of tuber-expressed genes such as GBSS1 and Vinv in potato.

Effects of Tembotrione on Potato Crop in a Tropical Soil

ABSTRACTTembotrione is an herbicide with a high persistence in soil, a characteristic that affects the growth and development of susceptible cultures in succession. In this sense, the objective of this research was to evaluate the residual effects of tembotrione on production and quality of potato tubers in a tropical soil. A field experiment (2014/2015) with randomized blocks design with four replications was conducted. The treatments consisted of five doses of tembotrione (0, 8.4, 16.8, 33.6, and 50.4 g a.i. ha−1) incorporated into the soil before planting the potato cultivar Atlantic. At 115 days after herbicide application were evaluated: total solids (%), dry matter content (DMCT %), nitrogen and potassium of the tubers, total yield and classification. The productivity of normal tubers decreased as doses of tembotrione were increased. The percentage of class I tubers was reduced at doses of 33.6 and 50.4 g a.i. ha−1. The increase in the doses increased the percentage of class II tubers and did not influence the percentage of class III and discard. The appearance of cracked tubers increased with increasing herbicide doses. Tembotrione affected the productivity of potato tubers and caused cracks in the tubers, which are dependent on the applied doses.

PhytochromeF plays critical roles in potato photoperiodic tuberization.

The transition to tuberization contributes greatly to the adaptability of potato to a wide range of environments. Phytochromes are important light receptors for the growth and development of plants, but the detailed functions of phytochromes remain unclear in potato. In this study, we first confirmed that phytochromeF (StPHYF) played essential roles in photoperiodic tuberization in potato. By suppressing the StPHYF gene, the strict short-day potato genotype exhibited normal tuber formation under long-day (LD) conditions, together with the degradation of the CONSTANTS protein StCOL1 and modulation of two FLOWERING LOCUST (FT) paralogs, as demonstrated by the repression of StSP5G and by the activation of StSP6A during the light period. The function of StPHYF was further confirmed through grafting the scion of StPHYF-silenced lines, which induced the tuberization of untransformed stock under LDs, suggesting that StPHYF was involved in the production of mobile signals for tuberization in potato. We also identified that StPHYF exhibited substantial interaction with StPHYB both invitro and invivo. Therefore, our results indicate that StPHYF plays a role in potato photoperiodic tuberization, possibly by forming a heterodimer with StPHYB.

Calcium Mitigated Potato Skin Physiological Disorder

Russeting of smooth-skinned potato varieties affect the protective characteristics of the skin against water loss and pathogens invasion. A distinctive russeting disorder, differs from previously reported tuber blemishes, has been observed in the Negev area of Israel and was named ‘Magen russeting’ after one of the repeatedly affected plots. The russeted skin appears as protruding dark-brown patches on the surface of the tubers. Histological studies identified the russet as old skin cells that remain adhered to the newly formed skin layers below them. Phytopathological tests and rDNA pyrosequencing analysis for whole bacterial community suggested that ‘Magen russeting’ is a physiological disorder. Mineral analysis of isolated pure skin samples indicated that russeted skin areas have higher concentrations of Ca and lower concentrations of K than the smooth skin of normal tubers, irrespective of CaCl2 or KCl fertilization of the soil prior to sowing, or of the irrigation regime during the growing season. Nevertheless, application of CaCl2 prior to tuber-seed sowing reduces the rate of affected mature tubers and the severity of the russeting.

Effects of Size of Normal Seed Tubers and Growth Regulator Application on Dormancy, Sprout Behaviour, Growth Vigour and Quality of Normal Seed Tubers of Different Potato Cultivars*

Effects of Size of Normal Seed Tubers and Growth Regulator Application on Dormancy, Sprout Behaviour, Growth Vigour and Quality of Normal Seed Tubers of Different Potato Cultivars*

Production high class of micro tuber potato seeds (Solanum tuberosum L.). by Using tissue culture technique

The aim of this investigation was produced micro tubers of four potato cultivars Premiere, Bintje, Estima and Escort in vitro. Apical meristems (0.2-0.4 mm) of potato cultivars were excised and cultured on nutrient medium and incubated at 24±2 Cº and 1000 lux light intensity for 16 hrs per day. The developing plantlets were examined serological by using ELISA technique to eliminate the viral infected plantlets. The virus-free plantlets were chopped into pieces with single bud and re cultured on fresh medium for mass propagation. For micro tubers formation in test tubes, the cultures were transferred to another medium containing a high percent of sucrose (60g/L) with different concentrations of kinetin; the cultures were incubated under 16±2 Cº and 8 hrs photoperiod. The plantlets formed micro tubers after 8-10 weeks from culturing. The results showed significant differences among cultivar’s in their response to in vitro culture and micro tubers formation. The results also showed that the kinetin concentration had significant effect on micro tubers, and 1mg/l kinetin concentration was the best. The micro tubers were stored for 10 week at 4Cº to break down the dormancy period, and gave 100% germination under nursery condition. Numbers of tubers derived from micro tubers and normal tubers of these cultivars were compared at the end of season.

Tuber development phenotypes in adapted and acclimated, drought-stressed Solanum tuberosum ssp. andigena have distinct expression profiles of genes associated with carbon metabolism

A drought screen identified accessions of Solanum tuberosum ssp. andigena that showed varying degrees of physiological acclimation or adaptation to repeated drought stress. The accessions also showed variable tuber phenotypes from small tubers that failed to develop in an accession that showed photosynthetic adaptation to normal tubers in an accession with a phenotype showing some degree of photosynthetic adaptation and acclimation. Using microarray data, we correlated the expression of genes associated with carbon metabolism with the tuber development phenotypes under drought. Genes associated with sucrose and starch metabolism showed responses consistent with starch deficiency in the adapted accession and normal starch deposition in the intermediate accession. Starch phosphorylase and glycogen bound starch synthase were induced in the adapted accession, which had abnormal tuber development. Genes associated with trehalose were induced in the intermediate accession with normal tuber development. Genes associated with respiration were also induced in the intermediate accession, and a pattern compatible with the existence of a 3PGA recovery pathway was revealed. Expression of thioredoxin genes also correlated with tuber development phenotypes under drought stress. The data suggest differential regulation of starch deposition in accessions of Andigena with different abilities to respond to drought stress.

StGA2ox1 is induced prior to stolon swelling and controls GA levels during potato tuber development

The formation and growth of a potato (Solanum tuberosum) tuber is a complex process regulated by different environmental signals and plant hormones. In particular, the action of gibberellins (GAs) has been implicated in different aspects of potato tuber formation. Here we report on the isolation and functional analysis of a potato GA 2-oxidase gene (StGA2ox1) and its role in tuber formation. StGA2ox1 is upregulated during the early stages of potato tuber development prior to visible swelling and is predominantly expressed in the subapical region of the stolon and growing tuber. 35S-over-expression transformants exhibit a dwarf phenotype, reduced stolon growth and earlier in vitro tuberization. Transgenic plants with reduced expression levels of StGA2ox1 showed normal plant growth, an altered stolon swelling phenotype and delayed in vitro tuberization. Tubers of the StGA2ox1 suppression clones contain increased levels of GA20, indicating altered GA metabolism. We propose a role for StGA2ox1 in early tuber initiation by modifying GA levels in the subapical stolon region at the onset of tuberization, thereby facilitating normal tuber development and growth.

Synchytrium endobioticum

<i>Synchytrium endobioticum</i>

Starch granule initiation is controlled by a heteromultimeric isoamylase in potato tubers.

Starch granule initiation is not understood, but recent evidence implicates a starch debranching enzyme, isoamylase, in the control of this process. Potato tubers contain isoamylase activity attributable to a heteromultimeric protein containing Stisa1 and Stisa2, the products of two of the three isoamylase genes of potato. To discover whether this enzyme is involved in starch granule initiation, activity was reduced by expression of antisense RNA for Stisa1 or Stisa2. Transgenic tubers accumulated a small amount of a soluble glucan, similar in structure to the phytoglycogen of cereal, Arabidopsis, and Chlamydomonas mutants lacking isoamylase. The major effect, however, was on the number of starch granules. Transgenic tubers accumulated large numbers of tiny granules not seen in normal tubers. These data indicate that the heteromultimeric isoamylase functions during starch synthesis to suppress the initiation of glucan molecules in the plastid stroma that would otherwise crystallize to nucleate new starch granules.

Mycoflora of tuber surface of white yam (Dioscorea rotundata Poir) and postharvest control of pathogens with Bacillus subtilis.

Bacillus subtilis (Enrenberg) Cohn was investigated for its antagonistic properties against surface mycoflora of yam (Dioscorea rotundata Poir) tubers in storage. Yam tubers inoculated with a spore suspension of B. subtilis in potato dextrose broth using a knapsack sprayer showed a drastic reduction in the range and number of mycoflora, including pathogens of the tuber surface in contrast to the control tubers, during the five-month storage period in a traditional yam barn. However, B. subtilis maintained a high frequency of occurrence during the same period. Botryodiploidia theobromae Pat, Fusarium moniliforme Wollen and Reink., Penicillium sclerotigenum Yamamoto, and Rhizoctonia sp. were displaced completely on the treated tubers. The antagonism of B. subtilis was so effective that the normal tuber surface mycoflora was greatly reduced throughout the storage period of five months by a simple initial application of the antagonist.

A novel hypersensitive resistance response against potato virus A in cultivar ’Shepody’

The potato cultivar ’Shepody’ is susceptible to a number of potato viruses including potato virus Y (PVY, potyvirus) but was found to possess extreme resistance to another potyvirus, potato virus A (PVA). ’Shepody’ plants were resistant to PVA infection in manual and graft inoculations. PVA replication was not detected in any of the inoculated plants by ELISA, an infectivity assay and RT-PCR. However, ’Shepody’ plants grafted with shoots containing PVA developed a novel symptomology which resembled a virus infection in appearance and in rate of translocation to the entire plant. Efforts to transmit the symptom-inducing agent manually failed. Graft-inoculation to potato virus indicator plants and PVA-susceptible potato plants showed that the symptom inducer was PVA at an extremely low concentration, detected using RT-PCR followed by Southern blot assay. Tubers from grafted but resistant ’Shepody’ plants had necrotic surfaces and internal spots. PVA was detected from necrotic areas but not from the non-necrotic ones. However, plants resulting from necrotic tubers were free from aerial leaf symptoms observed in grafted plants and produced non-necrotic normal tubers. A trace-back of the parental lineage of ’Shepody’ indicated that the resistance had been introgressed from the cultivar ’Bake King’. Analysis of progeny of a cross of resistant ’Shepody’ to the susceptible ’Goldrus’ indicated that this resistance is controlled by two independent dominant complementary genes in contrast to monogenic resistance reported for other potato viruses.

Compositional and enzymatic changes associated with the sugar-end defect in Russet Burbank potatoes

This study was initiated to determine the starchsugar composition and the activities of relevant enzymes of carbohydrate metabolism in Russet Burbank (cv.) potatoes exhibiting the sugar-end defect. The frequency of sugar-end tubers was increased by applying a single, transient, moisture-deficit stress period following tuberization. The following properties were unique to sugar-end tubers compared to normal tuber tissue. (1) Starch and total solids decreased markedly while glucose content increased 15-fold, (2) The concentration of Suc was markedly lower, (3) Pi was slightly but significantly increased, (4) The activities of UGPase and Susy decreased nearly 3 and 2-fold, respectively, (5) The activity of AGPase decreased 50%, (6) The ratio of STPLase to AGPase shifted over 3-fold in favor of starch mobilization, (7) Basal AcInv activity (assayed in the presence of inhibitor) increased 7-fold during storage, (8) Tuber Glc concentration showed a better correlation to basal Aclnv activity than to total Aclnv activity (inhibitor destroyed), (9) Kinetic analysis suggested that the level and/or effectiveness of the Aclnv inhibitor was decreased in the sugar-end tuber tissue. These results are discussed in relation to metabolic changes which occur in converting a starch storing tuber to one primarily involved with starch mobilization.

Antisense repression of the mitochondrial NADH-binding subunit of complex I in transgenic potato plants affects male fertility

Mitochondrial respiratory chain complex I is a large multi-subunit enzyme composed of both organellar and nuclear encoded proteins. To investigate the role of the nuclear encoded components, expression of the gene for the 55 kDa NADH-binding subunit of complex I was disturbed by antisense repression in transgenic potato plants. The antisense construct driven by the CaMV 35S promoter decreases the steady-state mRNA levels of transcripts for the 55 kDa subunit to 33% of the wild type levels. Quantities of the 55 kDa protein in mitochondrial protein extracts are lowered to about 50% in these plants. Transgenic plants show normal vegetative growth and tuber formation, but pollen maturation is found to be disturbed. The reduced male fertility of the transgenic 55 kDa antisense plants may be caused by an insufficient mitochondrial respiratory chain, impaired by the decreased expression of the NADH-binding component of mitochondrial complex I.

ADPglucose Pyrophosphorylase: Basic Science and Applications in Biotechnology

The enzymatic reactions of bacterial glycogen and plant starch synthesis are similar and some of the properties of the biosynthetic enzymes are compared. Regulation occurs at the synthesis of ADPglucose and in almost all cases, ADPglucose pyrophosphorylase, is allosterically activated about 10- to over 40-fold by glycolytic intermediates and inhibited by AMP, ADP or Pi. The activator specificity of the ADPglucose pyrophosphorylase varies with respect to the source of enzyme and can be correlated to the major assimilation pathway occurring in the organism. For example, ADPglucose pyrophosphorylases from plants and other oxygenic photosynthetic organisms are activated by 3-phosphoglycerate. Organisms using glycolysis for carbon assimilation have ADPglucose pyrophosphorylases with fructose-1,6-bis-phosphate as the major activator. Chemical modification and site-directed mutagenesis studies that have determined the activator binding sites for some enzymes are described. The structural genes of Escherichia coli ADPglucose pyrophosphorylase allosteric mutants which no longer require activator for activity have been isolated. Transformation of plant systems with an allosteric bacterial mutant gene (but not with the wild-type gene) increases their starch content. Transformed potato tubers can have 25-60% more starch than the normal tuber indicating the importance of allosteric regulation of ADPglucose synthesis. The increase of a normal plant product by transformation of the plant with a gene encoding the rate-limiting enzyme in starch synthesis is an important biotechnological advance and suggests the possibilities of changing starch composition (extent of branching and chain sizes) via transformation with the starch synthase and branching enzyme genes.

Microtuber and minituber production and field performance compared with normal tubers

Microtuber and minitubers of cv. Monalisa were produced in the laboratory and compared with normal seed tubers in a field experiment. These tubers were planted at similar plant densities (13.6 sprouts per m2) with two distances between rows (60 and 90 cm). Final ground cover was almost complete only in the plots derived from normal tubers and decreased with the size of the mother tubers. Normal seed, mini- and microtubers yielded respectively 50.8, 31.7, and 17.0 t/ha (means of two spacings). At close and wide spacing between rows, microtubers yielded respectively 27.3 and 6.7 t/ha, and minitubers 38.9 to 24.4 t/ha. Row spacing did not influence the yields from normal seed tubers. Total number of tubers per m2 was also affected and, as means of the two spacings, ranged from 107.8 with microtubers, 122.1 with minitubers, to 142.9 with normal tubers. Mother tuber type also affected the yield distribution in three tuber grades (<36, 36–55, and 55–80 mm) and micro and minitubers produced many small tubers. Multiplication rates and the possible use of different propagation sources are discussed.

Reduction of the chloroplastic fructose‐1,6‐bisphosphatase in transgenic potato plants impairs photosynthesis and plant growth

SummaryTransgenic potato plants expressing reduced levels of the chloroplastic isoform of fructose‐1,6‐bisphosphatase (cp‐FBPase) were created via the antisense RNA technique. Transformants with different levels of FBPase activity were selected and analysed with respect to photosynthesis, carbon metabolism, and growth. FBPase activity of less than 15% of wild‐type levels led to reduced growth rates, probably due to the reduction of photosynthetic activity. A significant decrease in tuber yield is observed in plants with a FBPase activity below 15% of wild‐type levels, whereas plants with 36% of wild‐type enzyme activity still give normal tuber yields, even though they demonstrate a lowered photosynthetic capacity. Decreased photosynthesis also results in a reduction of total carbohydrate contents in leaves. Interestingly, increased carbohydrate partitioning towards soluble sugars is observed in plants displaying less than 15% of the wild‐type FBPase activity. When excised leaf discs are placed on sucrose‐containing media in darkness, discs derived from plants with a reduced FBPase activity accumulate higher amounts of starch. Possible implications are discussed.

Detection of immunologically related Kunitz and Bowman-Birk proteinase inhibitors expressed during potato tuber development

Antiserum against a potato Kunitz-type proteinase inhibitor (PKPI) expressed in Escherichia coli was produced. In immunoblotting assays of proteins from potato tubers cultured in vitro, three proteins reacted to the antiserum, two of 20 kDa and one of 10 kDa. Their N-termini were sequenced. While the 20 kDa proteins showed 59 and 90% identity to PKPI, the 10 kDa one had 65% identity to soybean C-II proteinase inhibitor. Characterization of the temporal expression of these proteins showed that both could be detected from 10 days after induction of tuberization (DAI) in vitro, but the times when maximum amounts of PKPI and 10 kDa protein could be detected were different, corresponding to 22 and 32 DAI, respectively. The amounts of these proteins decreased in the following stages, and no positive reaction of the antiserum with mature tuber proteins could be found. The 20 kDa proteins were also detected in early stages of development of potato tubers grown in the field, indicating that these proteins are expressed during normal tuber development, and differ from the PKPIs reported previously.