Potato Organs Research Articles

Effects of cadmium stress on the growth and physiological characteristics of sweet potato

This study evaluated the responses of sweet potatoes to Cadmium (Cd) stress through pot experiments to theoretically substantiate their comprehensive applications in Cd-polluted agricultural land. The experiments included a CK treatment and three Cd stress treatments with 3, 30, and 150 mg/kg concentrations, respectively. We analyzed specified indicators of sweet potato at different growth periods, such as the individual plant growth, photosynthesis, antioxidant capacity, and carbohydrate Cd accumulation distribution. On this basis, the characteristics of the plant carbon metabolism in response to Cd stress throughout the growth cycle were explored. The results showed that T2 and T3 treatments inhibited the vine growth, leaf area expansion, stem diameter elongation, and tuberous root growth of sweet potato; notably, T3 treatment significantly increased the number of sweet potato branches. Under Cd stress, the synthesis of chlorophyll in sweet potato was significantly suppressed, and the Rubisco activity experienced significant reductions. With the increasing Cd concentration, the function of PS II was also affected. The soluble sugar content underwent no significant change in low Cd concentration treatments. In contrast, it decreased significantly under high Cd concentrations. Additionally, the tuberous root starch content decreased significantly with the increase in Cd concentration. Throughout the plant growth, the activity levels of catalase, peroxidase, and superoxide dismutase increased significantly in T2 and T3 treatments. By comparison, the superoxide dismutase activity in T1 treatment was significantly lower than that of CK. With the increasing application of Cd, its accumulation accordingly increased in various sweet potato organs. The the highest bioconcentration factor was detected in absorbing roots, while the tuberous roots had a lower bioconcentration factor and Cd accumulation. Moreover, the transfer factor from stem to petiole was the highest of the potato organs. These results demonstrated that sweet potatoes had a high Cd tolerance and a restoration potential for Cd-contaminated farmland.

Tatlı Patates ve Gölevezin Bazı Biyoaktif Bileşenleri: Bitki Organlarına Dayalı Karşılaştırmalı Bir Çalışma

This study was carried out to evaluate the variability and distribution of bioactive components of different organs of sweet potato and taro plants grown locally in Turkey. Samples extracted from different organs of these two species (tubers and leaves of sweet potato; leaves, petioles, main tubers, and lateral tubers of taro) were evaluated. Total water-soluble protein, total flavonoids, total phenolics, H2O2 scavenging capacity, carotenoids, FRAP antioxidant capacity, CUPRAC antioxidant capacity, and total dry matter parameters of two different species and their organs were measured. The difference between the organ averages for all parameters examined was statistically significant. In general, leaves of both species had the highest content for all parameters except total dry matter and CUPRAC antioxidant capacity. The effectiveness of the parameters in explaining variation in the gene pool was also examined using principal component analysis. All parameters contributed highly to the variation except H2O2 capacity, total dry matter content, and CUPRAC antioxidant capacity. According to the findings, there is a high variation between each species and between the organs. These results will guide future studies on these two species.

EFFECT OF SOIL SALINITY LEVELS ON PHYTOGORMONE BALANCE IN POTATO ADAPTATION

The comprehensive study of changes in the content of cytokinins, indole acetic acid (IAA) and abscisic acid ABA, growth rates, and development of potatoes during soil salinity NaCl. Studies have shown that the hormonal balance of potato organs throughout ontogenesis under the influence of NaCl salinity undergoes significant changes: the content of cytokines and auxins decreases, the level of ABA increases, as a result, the ratio of cytokines +IAA/ABA falls. These changes in the hormonal balance are not only the result of a stress response but also have an adaptive value. The conducted research allowed us to find out the relationship between changes in hormonal balance and physiological processes.

Molecular, in silico and expression studies on lipoxygenases (LOXs) in potato (Solanum tuberosum L.).

Lipoxygenases (LOXs) namely 9-LOXs and 13-LOXs catalyse the oxygenation of polyunsaturated fatty acids to produce fatty acid hydroperoxides which are crucial in growth, development and stress responses in plants. Here, we isolated and characterized a 2723-bp cDNA encoding a distinct 861-aa 9-LOX form, designated StKCLX-1, using tuber total RNA from an Indian potato cultivar, Kufri Chipsona-1 through RT-PCR. A total of 17 LOX genes distributed in different chromosomes were identified and characterized in the potato genome. Multiple sequence alignment revealed highly conserved amino acids in the crucial domains, motifs and variable N-terminal regions between the LOX classes. A total of 36 LOXs from potato, tomato and Arabidopsis were used in phylogenetic analysis. A 3-D structure of StKCLX-1 was predicted by AlphaFold tool, validated through the predicted local-distance difference test (pLDDT) and Ramachandran Plot. Molecular docking predicted the nature of receptor-ligand interactions. STRING database was used to predict the protein-protein interactions. Expression patterns of the LOXs in the potato organs were examined by Expression Atlas and semi-quantitative RT-PCR. 9-LOX activity was noticed at early stages of tuberization, and significantly increased in the freshly-harvested mature tubers. This report would be useful in gaining insights into the structure-function relationships of the LOXs and corresponding multigene family-prerequisites for understanding tuber development in potato.

Functional analysis on sucrose transporters in sweet potato

Sweet potato is an important food crop that can also be used as an industrial raw material. Sucrose is the main form of long-distance carbohydrate transport in plants, and sucrose transporter (SUT) regulates the transmembrane transport and distribution of sucrose during plant growth and metabolism. Moreover, SUT plays a key role in phloem mediated source-to-sink sucrose transport and physiological activities, supplying sucrose for the sink tissues. In this study, the full-length cDNA sequences of IbSUT62788 and IbSUT81616 were obtained by rapid amplification of cDNA ends (RACE) cloning according to the transcripts of the two SUT coding genes which were differentially expressed in sweet potato storage roots with different starch properties. Phylogenetic analysis was performed to clarify the classification of IbSUT62788 and IbSUT81616. The subcellular localization of IbSUT62788 and IbSUT81616 was determined by transient expression in Nicotiana benthamiana. The function of IbSUT62788 and IbSUT81616 in sucrose and hexose absorption and transport was identified using yeast functional complementarity system. The expression pattern of IbSUT62788 and IbSUT81616 in sweet potato organs were analyzed by real-time fluorescence quantitative PCR (RT-qPCR). Arabidopsis plants heterologous expressing IbSUT62788 and IbSUT81616 genes were obtained using floral dip method. The differences in starch and sugar contents between transgenic and wild-type Arabidopsis were compared. The results showed IbSUT62788 and IbSUT81616 encoded SUT proteins with a length of 505 and 521 amino acids, respectively, and both proteins belonged to the SUT1 subfamily. IbSUT62788 and IbSUT81616 were located in the cell membrane and were able to transport sucrose, glucose and fructose in the yeast system. In addition, IbSUT62788 was also able to transport mannose. The expression of IbSUT62788 was higher in leaves, lateral branches and main stems, and the expression of IbSUT81616 was higher in lateral branches, stems and storage roots. After IbSUT62788 and IbSUT81616 were heterologously expressed in Arabidopsis, the plants grew normally, but the biomass increased. The heterologous expression of IbSUT62788 increased the soluble sugar content, leaf size and 1 000-seed weight of Arabidopsis plants. Heterologous expression of IbSUT81616 increased starch accumulation in leaves and root tips and 1 000-seed weight of seeds, but decreased soluble sugar content. The results obtained in this study showed that IbSUT62788 and IbSUT81616 might be important genes regulating sucrose and sugar content traits in sweet potato. They might carry out physiological functions on cell membrane, such as transmembrane transport of sucrose, sucrose into and out of sink tissue, as well as transport and unloading of sucrose into phloem. The changes in traits result from their heterologous expression in Arabidopsis indicates their potential in improving the yield of other plants or crops. The results obtained in this study provide important information for revealing the functions of IbSUT62788 and IbSUT81616 in starch and glucose metabolism and formation mechanism of important quality traits in sweet potato.

Gibberellin 2-Oxidases in Potato (Solanum tuberosum L.): Cloning, Characterization, In Silico Analysis and Molecular Docking.

Gibberellins (GAs; tetracyclic di-terpenoid carboxylic acids) are endogenous plant growth regulators responsible for stimulating plant growth and development from seed germination to plant maturity. In potato (Solanum tuberosum L.), GA levels are known to be crucial in the complex process of tuberization. Gibberellin 2-oxidases (GA2oxs) inactivate bioactive GAs during stolon swelling and early stages of tuberization as evident from the predominant expression of a member of this gene family namely GA2ox1. We isolated and characterized a 1105-bp cDNA clone encoding a 340-aa GA2ox1 form, designated St-GA2ox1, using total RNA from growing tuber of a potato (Solanum tuberosum L.) cultivar, Kufri Chipsona-1 (KC-1) based on RT-PCR approach. A total of 26 GA2ox sequences were also retrieved from potato genome database and analysed. Multiple sequence alignment revealed sequence relatedness between the GA2oxs. Crucial protein motifs were identified. Phylogenetic analysis revealed the evolutionary relationships between the GA2oxs. Three-dimensional structure of St-GA2ox1 was predicted by using AlphaFold tool, validated by the predicted local-distance difference test and Ramachandran Plot. Structural analysis and molecular docking were carried out to identify domains, binding sites and affinity for the ligand. The STRING database and hydropathy analysis revealed the presence of a putative interaction site for other enzymes. Expression Atlas database and semi-quantitative RT-PCR revealed the expression patterns of various GA2ox forms in different potato organs. This comprehensive report would be useful in providing new insights into possible underlying mechanisms involved in tuber development, and could facilitate the targeted alteration of genes responsible to combat the stress and enhance tuber production.

Genome-Wide Identification, and In-Silico Expression Analysis of YABBY Gene Family in Response to Biotic and Abiotic Stresses in Potato (Solanum tuberosum).

YABBY is among the specific transcription factor (TF) gene family in plants and plays an important role in the development of the leaves and floral organs. Its specific roles include lateral organ development, the establishment of dorsoventral polarity, and response to abiotic stress. Potato is an important crop worldwide and YABBY genes are not still identified and characterized in potato. So, little has been known about YABBY genes in potato until now. This study was carried out to perform genome-wide analysis, which will provide an in-depth analysis about the role of YABBY genes in potato. There have been seven StYAB genes identified, which are found to be located on seven different chromosomes. Through multiple sequence analyses, it has been predicted that the YABBY domain was present in all seven genes while the C2-C2 domain was found to be absent only in StYAB2. With the help of cis-element analysis, the involvement of StYAB genes in light, stress developmental, and hormonal responsiveness has been found. Furthermore, expression analysis from RNA-seq data of different potato organs indicated that all StYAB genes have a role in the vegetative growth of the potato plant. In addition to this, RNA-seq data also identified StYAB3, StYAB5, and StYAB7 genes showing expression during cadmium, and drought stress, while StYAB6 was highly expressed during a viral attack. Moreover, during the attack of Phytophthora infestans on a potato plant StYAB3, StYAB5, StYAB6, and StYAB7 showed high expression. This study provides significant knowledge about the StYAB gene structures and functions, which can later be used for gene cloning, and functional analysis; this information may be utilized by molecular biologists and plant breeders for the development of new potato lines.

A weight optimization-based transfer learning approach for plant disease detection of New Zealand vegetables.

Deep learning (DL) is an effective approach to identifying plant diseases. Among several DL-based techniques, transfer learning (TL) produces significant results in terms of improved accuracy. However, the usefulness of TL has not yet been explored using weights optimized from agricultural datasets. Furthermore, the detection of plant diseases in different organs of various vegetables has not yet been performed using a trained/optimized DL model. Moreover, the presence/detection of multiple diseases in vegetable organs has not yet been investigated. To address these research gaps, a new dataset named NZDLPlantDisease-v2 has been collected for New Zealand vegetables. The dataset includes 28 healthy and defective organs of beans, broccoli, cabbage, cauliflower, kumara, peas, potato, and tomato. This paper presents a transfer learning method that optimizes weights obtained through agricultural datasets for better outcomes in plant disease identification. First, several DL architectures are compared to obtain the best-suited model, and then, data augmentation techniques are applied. The Faster Region-based Convolutional Neural Network (RCNN) Inception ResNet-v2 attained the highest mean average precision (mAP) compared to the other DL models including different versions of Faster RCNN, Single-Shot Multibox Detector (SSD), Region-based Fully Convolutional Networks (RFCN), RetinaNet, and EfficientDet. Next, weight optimization is performed on datasets including PlantVillage, NZDLPlantDisease-v1, and DeepWeeds using image resizers, interpolators, initializers, batch normalization, and DL optimizers. Updated/optimized weights are then used to retrain the Faster RCNN Inception ResNet-v2 model on the proposed dataset. Finally, the results are compared with the model trained/optimized using a large dataset, such as Common Objects in Context (COCO). The final mAP improves by 9.25% and is found to be 91.33%. Moreover, the robustness of the methodology is demonstrated by testing the final model on an external dataset and using the stratified k-fold cross-validation method.

In silico promoter analysis and expression of the BIG BROTHER gene in different organs of potato

The ubiquitin E3 ligase BIG BROTHER/ENHANCER OF DA1 (BB) gene encoding a RING finger protein was identified as a central growth regulator in Arabidopsis thaliana. It was found that BB restricts cell proliferation and promotes leaf senescence. Besides of Arabidopsis, however, the role and regulation of BB in other plant species is only sparsely known. Supposing that the BB gene, like in Arabidopsis, has an important role in the development of potato we aimed to analyse a 3.0-kb promoter sequence of the potato BB gene, StBB, in silico and study the level of StBB expression by quantitative reverse transcription PCR in different organs. A total of 48 binding sites for 15 transcription factor (TF) families were predicted. Most of them were located in the -1.5-kb promoter region. The dominating family of TFs was DOF. It was found that 20 out of the 24 TFs with known functions are involved in developmental processes such as for example, the flower-, leaf-, stem- and root development or cell cycle regulation. In line with this finding, the StBB mRNA was detected in each organ tested with the largest amounts in petal and stamen. These results suggest a similar function of StBB in potato than that is of BB in Arabidopsis, i.e., restriction of organ overgrowth during development and limitation of the plant growth.

Molecular cloning, expression and in silico analyses of calcium-dependent protein kinase 2 (CDPK2) in potato (Solanum tuberosum L.)

In plants, calcium-dependent protein kinases (CDPKs) play crucial role in the regulation of growth and development in response to various stresses. They act as sensor-transducers in decoding the calcium (Ca2+) ions associated with multiple signal transduction pathways. The plant CDPK isoforms are encoded by the nuclear multigene families. Some CDPK isoforms were reported earlier in potato; but their three-dimensional (3-D) structures were not predicted. Based on the RT-PCR approach using tuber total RNA, a 1560-bp cDNA clone encoding 515-aa CDPK2 isoform (designated StCDPK2) was isolated and characterized from the potato cultivar Kufri Chipsona-1(KC-1). A thorough sequence analysis revealed both sequence identities and crucial motifs in the potato CDPKs. Semi-quantitative RT-PCR approach was adopted to show the expression patterns of StCDPK2 in different potato organs grown under field condition. The three-dimensional (3-D) structures of potato CDPK1−3 were predicted by a composite approach using ab initio modeling, and further validated and assessed by Ramachandran plot analyses. In addition, a number of the CDPK isoforms were retrieved from the potato genome sequence database; their probable biochemical properties and functional aspects were predicted based on both bioinformatics tools and published reports.

Genome-wide identification of PEBP gene family members in potato, their phylogenetic relationships, and expression patterns under heat stress

The phosphatidylethanolamine-binding protein (PEBP) gene family is involved in regulating many plant traits. Genome-wide identification of PEPB members and knowledge of their responses to heat stress may assist genetic improvement of potato (Solanum tuberosum). We identified PEBP gene familymembers from both the recently-updated, long-reads-based reference genome (DM v6.1) and the previous short-reads-based annotation (PGSC DM v3.4) of the potato reference genome and characterized their heat-induced gene expression using RT-PCR and RNA-Seq. Fifteen PEBP familygenes were identified from DM v6.1 and named as StPEBP1 to StPEBP15 based on their locations on 6 chromosomes and were classified into FT, TFL, MFT, and PEBP-like subfamilies. Most of the StPEBP genes were found to have conserved motifs 1 to 5. Tandem or segmental duplications were found between StPEBP genes in seven pairs. Heat stress induced opposite expression patterns of certain FT and TFL members but involving different members in leaves, roots and tubers. The long-reads-based genome assembly and annotation provides a better genomic resource for identification of PEBP familygenes. Heat stress tends to decrease FT gene activities but increases TFL gene activities, but this opposite expression involves different FT/TFL pairs in leaves, roots, and tubers. This tissue-specific expression pattern of PEBP members may partly explain why different potato organs differ in their sensitivities to heat stress. Our study provides candidate PEBP familygenes and relevant information for genetic improvement of heat tolerance in potato and may help understand heat-induced responses in other plants.

Does Elemental Sulfur Act as an Effective Measure to Control the Seasonal Growth Dynamics of Potato Tubers (Solanum tuberosum L.)?

The in-season dynamics of potato tuber biomass (TTB) growth requires effective nitrogen (N) control. This hypothesis was tested in 2006 and 2007. The two-factorial experiment with two rates of N (60, 120 kg ha−1) and sulfur (S; 0, 50 kg ha−1) was carried out in the split-plot design. The third factor was the sampling of plants at 10-day intervals. The collected plant material was divided into leaves, stems, stolons + roots, and tubers. The seasonal trend of TTB was linear, while the biomass of leaves, stems, and stolons + roots was consistent with polynomial regression models. TTB was controlled by (i) the date of potato growth after emergence, when the TTB exceeded the leaf biomass (DAEcrit); (ii) the stem growth rate; and iii) the share of stems in the total potato biomass. TTB growth was reduced when DAEcrit preceded the DAEop for leaf biomass, determining its maximum. This phenomenon appeared in 2007 on plots fertilized only with N. The absolute growth rate of the stem biomass, exceeding ¼ of that of the tuber biomass in the descending phase, resulted in an increased and prolonged share of stems in the total potato biomass, which ultimately led to a decrease in tuber yield. The use of sulfur to balance the N, applied effectively, controlled the growth rate of potato organs competing with tubers.

Variation in Cadmium Accumulation among Potato Cultivars Grown on Different Agricultural Sites: A Potential Tool for Reducing Cadmium in Tubers

Potato (Solanum tuberosum L.) is an important crop in Egypt with great trade value for the export market. The addition of agrochemicals with possibly containing heavy metals, such as cadmium (Cd), decreases the quality of the final product. Generally, little is known about the factors that influence Cd content in this crop. The current study estimated the Cd levels in different organs of three potato cultivars grown in four commercial regions across Egypt. Further, we investigated the soil properties that affected Cd uptake during two growing seasons. With the exception of the Cd content of the soils, no relationships were detected between the tested soil properties (i.e., pH, conductivity, organic matter, and clay content) and Cd content in potato organs, because the soil from different regions showed comparable levels for these parameters. The average Cd content in the peeled tubers among different cultivars (0.145 mg Kg−1 DW) was below the maximum limit (0.5 mg Kg−1 DW). The patterns of Cd accumulation in potato organs were constant among cultivars, with the highest levels detected in leaves (~82%), followed by stems (~16.5%), and the lowest content observed in tubers (~1.5%). The study showed that the tested potato cultivars exhibited diversity in the accumulation levels of Cd in the tubers (~2.6-fold). The cultivar Suntana displayed the lowest Cd levels among different field sites for the two growing seasons, suggesting the potential involvement of genetic factors.

Biofortification of Potato and Carrot With Iodine by Applying Different Soils and Irrigation With Iodine-Containing Water

Accumulation of iodine by potato (Solanum tuberosum L.) and carrot (Daucus carota L. var. sativus) plants cultivated on different soils (sand, sandy silt, and silt) using irrigation water containing iodine at concentrations of 0.1 and 0.5 mg/L was investigated. In the edible organs of potato and carrot control plants grown on sand, sandy silt, and silt soils, the iodine concentrations were 0.15, 0.17, and 0.20 mg/kg (potato) and 0.012, 0.012, and 0.013 mg/kg (carrot); after the treatment by applying 0.5 mg/L iodine dosage, the iodine concentrations were 0.21, 0.19, 0.27 mg/kg (potato) and 3.5, 3.7, 3.0 mg/kg (carrot), respectively. Although the iodine treatment had no significant effect on the biomass production of these plants, in potato tubers, it resulted in higher Fe and lower Mg and P concentrations, whereas no similar trend was observable in carrot roots. The accumulation of Mn, Cu, Zn, and B in the edible part of both plants was not influenced by the iodine treatment. The soil properties did not have a significant impact on biomass production under the same environmental conditions. The concentration and the distribution of iodine in both plants were slightly modified by the growing medium; however, the photosynthetic efficiency and the chlorophyll content index of potato plants cultivated in silt soil increased significantly. Potato plant was not suitable for biofortification with iodine, while considering the iodine concentration and the moisture content of carrot roots, it can be calculated that consuming 100 g fresh carrot would cover about 38% of the daily iodine intake requirement for an average adult person.

Allelopathic effects of water extracts from sweet potato on the growth of invasive alien species Alternanthera philoxeroides

It is an effective approach to control invasive plants based on the allelopathic effect of native plants with higher economic values, from the perspective of allelopathy. The aim of this study was to test the allelopathic effect of a local crop, sweet potato (Ipomoea batatas), on the invasive plant Alternanthera philoxeroides. Water extracts from different organs of sweet potato (roots, stems, leaves) with three concentrations (0.025, 0.05, 0.1 g·mL-1) were used in the study. To test the effect of sweet potato on rhizome growth of A. philoxeroides, the morphological index (ramet number, node number, leaf number, leaf area, plant height, total dry weight and root number of new ramets), allelopathic response index, trait values (succulent degree, root-shoot ratio, specific leaf area, leaf mass ratio, stem mass ratio, root mass ratio), CAT, POD, MDA and SOD in young leaves were measured. The results showed that 1) Water extracts from different organs of sweet potato with different concentrations differed in their effects on the growth of A. philoxeroides. Water extract from root with 0.1 g·mL-1 significantly inhibited all morphological indices. Except total dry weight and root number, other morphological indices decreased significantly with increasing concentration of water extract from all organs. 2) The synthetic allelopathic response index (RI) was negative under all treatments, indicating that water extract of sweet potato had negative effects on all indices of A. philoxeroides and thus inhibited their growth. Among all the treatments, water extract from root with a concentration of 0.1 g·mL-1 had the strongest allelopathic inhibition (RI=-0.73), followed by that from stem with a concentration of 0.1 g·mL-1(RI=-0.44) and from root with a concentration of 0.05 g·mL-1(RI=-0.44). 3) Water extract of sweet potato had significant inhibitory effects on the degree of succulence, root-shoot ratio, specific leaf area, and leaf mass ratio, but did not affect stem mass ratio and root mass ratio. 4) Water extract of sweet potato significantly increased the contents of MDA and SOD in the fresh leaves of A. philoxeroides, while had no effect on the contents of CAT and POD. All these results indicates that water extract of sweet potato significantly suppress the ramet growth of A. philoxeroides.

Comparison of catalase activity in different organs of the potato (Solanum tuberosum L.) cultivars grown under field condition and purification by three-phase partitioning

Catalase (CAT) (H2O2: H2O2 oxidoreductase; EC 1.11.1.6) is capable of directly dismutating moderately reactive H2O2 into H2O and O2, and is regarded as one of the major enzymatic antioxidants in plants. The CAT isozymes are known to be differentially expressed and regulated. In this study, micropropagated potato plantlets of seven cultivars were grown under field condition with uniform agricultural practices. CAT activities were measured in the crude extracts from different potato organs namely tubers, leaves and stems at different stages of their growth. Relatively higher CAT activity was noticed in the very small actively growing tubers as compared to the other tissues. Cultivar-dependent differences were noticed in terms of the CAT activities which clearly indicated variation with regard to their antioxidative capacities. pH profile, thermostability and storage stability of CAT were examined. A simple and rapid three-phase partitioning (TPP) method worked effectively with regard to purification of CAT from the crude extracts. Both denaturing and non-denaturing PAGE analyses suggested that both the tuber-type and leaf-type CAT are tetrameric in nature and varied in size, possibly referred to the distinct isoforms in potato.

The Opposite Effect of Low Temperature on the Pho1a Starch Phosphorylase Gene Expression in Solanum tuberosum L. Tubers and Petota Species Leaves

Starch turnover is important for plant response to abiotic stresses and plastidic starch phosphorylase Pho1a is a key enzyme regulating starch metabolism. In this study, we identified Pho1a coding sequences in seven wild tuber-bearing potato species. In Solanum tuberosum cv. Nadezhda grown at normal conditions, Pho1a transcription was low; it was detected in stems, leaves, flowers, and roots. After harvest, Pho1a expression in tubers of 16 S. tuberosum cultivars was either absent or low but progressively increased during storage at +4 °C, which corresponded to an increase in the content of reducing sugars. In the leaves of both cultivated and wild potato species, exposure to short-term cold stress downregulated Pho1a expression, especially at night, and stimulated starch degradation, but there was no uniform diurnal pattern in Pho1a expression dynamics. These findings indicate that Pho1a may have different functions in storage and photosynthetic organs of potato.

The in-season variability in the calcium concentration in potato organs and its relationship with the tuber yield

The in-season variability in the calcium concentration in potato organs and its relationship with the tuber yield

Eicosapolyenoic fatty acids alter oxylipin gene expression and fatty acid hydroperoxide profiles in tomato and pepper roots

Eicosapolyenoic fatty acids (EP), such as arachidonic acid (AA), are abundant in oomycetes and can serve as microbe-associated molecular patterns (MAMPs) to elicit host defense responses. Solanaceous plants have multiple enzymes that convert EP into biologically active oxylipins. We evaluated expression of genes involved in oxylipin production in tomato and pepper seedlings with roots treated with AA and in tomato seedlings inoculated with Phytophthora capsici. AA treatment of tomato and pepper roots significantly increased expression of 9-lipoxygenase (9-LOX), 9-divinyl ether synthase (9-DES), α-dioxygenase (α-DOX), 13-lipoxygenase (13-LOX), and 13-allene oxide synthase (13-AOS), with 9-DES and α-DOX having the largest increases in expression. A similar pattern of expression was observed for 9-LOX, 9-DES, and α-DOX in tomato roots inoculated with P. capsici. Expression of 13-LOX and 13-AOS in tomato roots inoculated with P. capsici did not consistently follow the pattern observed in AA-treated tomato and pepper roots. AA treatment of tomato roots increased production of 9-LOX products of LA and AA, with no change in 13-LOX products of LA. These results implicate the 9-oxylipin and α-dioxygenase pathways in EP signal-response coupling, and establish that the EP response in tomato and pepper roots, generally the primary site of attack by soil-borne oomycetes, parallels that in other vegetative organs of potato and tomato.

Trends in phosphorus concentrations in potato organs during the growing season

Trends in phosphorus concentrations in potato organs during the growing season