Response Of Potato Research Articles

Response of Potato ( L.) Varieties to Different Solanum tuberosumLevels of Nitrogen under Agroclimatic Conditions of Meghalaya

Response of Potato ( L.) Varieties to Different Solanum tuberosumLevels of Nitrogen under Agroclimatic Conditions of Meghalaya

Study of High-Temperature-Induced Morphological and Physiological Changes in Potato Using Nondestructive Plant Phenotyping.

Potato (Solanum tuberosum L.) is vulnerable to high temperatures, which are expected to increase in frequency and duration due to climate change. Nondestructive phenotyping techniques represent a promising technology for helping the adaptation of agriculture to climate change. In this study, three potato cultivars (Agria, Bellarosa and Desiree) were grown under four temperature treatments: 20/15 °C (T1), 25/20 °C (T2), 30/25 °C (T3), and 35/30 °C (T4). Multispectral and chlorophyll fluorescence imaging, 3D multispectral scanning, and gas exchange analysis were used to study the effect of moderate heat stress on potato morphology and physiology and select phenotypic traits most responsive to increased temperatures. The most responsive morphological traits to increased temperatures are related to decreased leaf area, which were detected already at T2. Increased temperatures (already T2) also changed leaf spectral characteristics, indicated by increased red, green, and blue reflectance and decreased far-red reflectance and anthocyanin index (ARI). Regarding chlorophyll fluorescence, increasing temperatures (T2) caused an increase in minimal fluorescence of both dark-adapted (F0) and light-adapted (F0') plants. Stomatal conductance, transpiration rate, photosynthetic rate, instantaneous water use efficiency (WUE), and intrinsic water use efficiency increased from T1 to T3 and decreased again in T4. Using recursive partitioning analysis, the most responsive potato phenotypic traits to increased temperature were leaf area projected (LAP), ARI, F0, and WUE. These traits could be considered marker traits for further studying potato responses to increased temperatures.

Stress response of fresh-cut potatoes to laser irradiation before processing can prevent discoloration and maintain overall quality

Browning is accepted as a main factor affecting quality of fresh cut products. Physical treatments maintaining quality of fresh-cut products have been recently considered by consumer safer than chemical treatments. This study investigated whether preprocess diode laser irradiation can improve the physicochemical quality of fresh-cut potatoes. Laser irradiation at a 450-nm wavelength for 30 min prevented the browning of potato slices during short-term storage at 25 °C. Compared with no treatment, preprocess laser irradiation preserved the appearance and whiteness and inhibited browning and delayed weight loss in potato slices when refrigerated at 4 °C for 96 h. The increases in the total phenol concentration and phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) activities of fresh-cut potatoes were diminished after laser irradiation. Moreover, the laser irradiation also enhanced antioxidant activities in the samples. The expression of PAL, PPO and POD genes was suppressed by the laser treatment. Therefore, the laser irradiation at 450 nm wavelength for 30 min effectively eliminates discolouration and improves quality of sliced potatoes during cold storage.

Nitrogen efficiency indices of potato in response to nitrogen doses estimated by algorithms and applied as top-dressing

The objective of this study was to evaluate the effect of N doses estimated by algorithms and applied as top-dressing on different nitrogen (N) efficiency indices in Asterix potatoes. Two experiments were installed in the field. The experiments were conducted in the randomized block design, in split-plot scheme, with four replicates, whose treatments, in the plots, were determined by five N doses in pre-planting and, in the subplots, by three criteria (algorithms evaluated) of top-dressing N. At 21 DAE (days after an emergency), the fourth fully developed potato leaf was evaluated with the SPAD (Soil Plant Analysis Development) chlorophyll meter. This reading was used as an indicator of the need for top dressing. In harvesting the tubers, the following variables were determined: N content in shoots and tubers, amounts of N absorbed by shoots, tubers and total N, harvest index, N use efficiency, N agronomic efficiency and physiological efficiency of N. The application criteria did not significantly influence the variables related to the content and amount of absorbed N, except for the N content of the tubers in the 2018 experiment. Of N absorbed by shoots, tubers and plants and the agronomic efficiency of N were significantly influenced by the N dose applied pre-planting. The agronomic efficiency was significantly influenced by the N dose estimated by the N cover recommendation criteria. The highest values obtained for the variables related to the content and amount of N absorbed were those under application of 200 to 300 kg ha−1 of N.

Agronomic and Physiological Response of Potato (Solanum tuberosum L.) to Nitrogen Fertilization Rate on a Loess Soil of Northwest China

Agronomic and Physiological Response of Potato (Solanum tuberosum L.) to Nitrogen Fertilization Rate on a Loess Soil of Northwest China

Orange Fleshed Sweet Potato Response to Filter Cake and Macadamia Husk Compost in Two Agroecologies of KwaZulu-Natal Province, South Africa

Field experiments were carried out during the summer/autumn (first trial) and winter/spring (second trial) seasons of 2019 and 2021 in the Dlangubo, Ngwelezane, and Mtubatuba areas of KwaZulu-Natal Province of South Africa to study the drought amelioration effects and impact of two locally available organic wastes (filter cake—a residue derived from sugar cane filtration (FC) and macadamia husk compost (MHC)) on the productivity and physiological responses of four orange-fleshed sweet potato cultivars (Beauregard cv., Impilo, W-119 and 199062.1). The effects of FC and MHC were compared with that of inorganic fertilizer (IF) [2:3:2 (30)], FC + IF, MHC + IF, and the control. The soil amendments were applied in the first trials only. Climatic data such as humidity, temperature, and rainfall were taken via remote sensing. The results of the first trial indicated that filter cake and IF significantly performed better than MHC. The strength of filter cake may be attributable to its rich array of mineral nutrients such as calcium, magnesium, potassium, sodium, zinc, copper, manganese, iron, and phosphorus. The limited performance of MHC may be attributable to its ability to hold water. Furthermore, a positive correction occurred between the yield of the test orange-fleshed sweet potato (OFSP) cultivars, rainfall, and vegetation indices (normalized difference vegetation index, enhanced vegetation index, and normalized difference water index) investigated in the study. In season two, IF treatment did not have any significant effect on the growth and productivity of any of the tested sweet potato cultivars, but, FC, FC + IF, and MHC treatments largely maintained their performances. In conclusion, the use of FC is highly recommended in the production of the test OFSP cultivars. Furthermore, the study indicates that both FC and MHC may not only supply the needed plant nutrients but has the capacity to reduce the impact of drought on the growth of the test cultivars. These findings are of great value to farmers, especially the resource-poor ones.

The sweet potato B-box transcription factor gene IbBBX28 negatively regulates drought tolerance in transgenic Arabidopsis.

B-box (BBX) which are a class of zinc finger transcription factors, play an important role in regulating of photoperiod, photomorphogenesis, and biotic and abiotic stresses in plants. However, there are few studies on the involvement of BBX transcription factors in response to abiotic stresses in sweet potato. In this paper, we cloned the DNA and promoter sequences of IbBBX28. There was one B-box conserved domain in IbBBX28, and the expression of IbBBX28 was induced under drought stress. Under drought stress, compared to wild type Arabidopsis, the protective enzyme activities (SOD, POD, and CAT) were all decreased in IbBBX28-overexpression Arabidopsis but increased in the mutant line bbx28, while the MDA content was increased in the IbBBX28-overexpression Arabidopsis and decreased in the bbx28. Moreover, the expression levels of the resistance-related genes showed the same trend as the protective enzyme activities. These results showed that IbBBX28 negatively regulates drought tolerance in transgenic Arabidopsis. Additionally, the yeast two-hybrid and BiFC assays verified that IbBBX28 interacted with IbHOX11 and IbZMAT2. The above results provide important clues for further studies on the role of IbBBX28 in regulating the stress response in sweet potato.

SWATH-MS based quantitative proteomics analysis reveals novel proteins involved in PAMP triggered immunity against potato late blight pathogen Phytophthora infestans.

Potato is the most important non-grain food in the world, while late blight caused by Phytophthora infestans seriously threatens the production of potato. Since pathogen-associated molecular patterns (PAMPs) are relatively conserved, PAMP-triggered immunity (PTI) can provide durable resistance to late blight for potato. However, knowledge of the regulatory mechanisms of PTI against oomycete pathogens at protein levels remains limited due to the small number of identified proteins. In the present work, changes in the proteome profile of Nicotiana benthamiana leaves upon P. infestans PAMP induction were examined using the SWATH-MS (sequential windowed acquisition of all theoretical mass spectra) approach, which provides quantification of protein abundances and large-scale identification of PTI-related proteins. A total of 4401 proteins have been identified, of which 1429 proteins were differentially expressed at least at one time point of 8, 12, 24 and 48h after PAMP induction, compared with the expression at 0h when immediately after PAMP induction. They were further analyzed by expression clustering and gene ontology (GO) enrichment analysis. Through functional verification, six novel DEPs of 19 candidates were proved to be involved in PTI responses, including mitochondrial phosphate carrier protein (MPT) 3, vesicle-associated membrane protein (VAMP) 714, lysophospholipase (LysoPL) 2, ascorbate peroxidase (APX) 1, heat shock 70 kDa protein (HSP) 2 and peptidyl-prolyl cis-trans isomerase FKBP (FKBP) 15-1. Taken together, the time course approach and the resulting large-scale proteomic analyses have enlarged our understanding of PTI mechanisms and provided a valuable resource for the discovery of complex protein networks involved in the resistance response of potato to late blight.

Response of artificial potato to phosphorous and potassium levels on available of some nutrients, amount absorbed and their productivity

A field experiment was carried out during autumn season of 2020 at one of the fields of the Al-Hamdhiya Research Station, College of Agriculture, Anbar University, to find out response of artificial potato to phosphorous and potassium levels on available of some nutrients, the amount absorbed and their productivity. The experiment was carried out according to randomized complete block design (RCBD) at three replicates. The experiment included seventeen treatments: T1: 200, 0, 0 (control treatment), T2: 200, 0, 100, T3: 200, 0, 200, T4: 200, 0, 300, T5: 200, 144, 0, T6: 200, 192, 0, T7: 200, 240, 0, T8: 200, 144, 100, T9: 200, 192, 100, T10: 200, 240, 100, T11: 200, 144, 200, T12: 200, 192, 200, T13: 200, 240, 200,T14: 200, 144, 300, T15: 200, 192, 300 and T16: 200, 240, 300 Kg NPK.ha-1 respectively, as well as T17: application of organic matter at level of 20 ton.ha-1. The results indicated that theT15 treatment(200, 192, 300 Kg NPK.ha-1) was significantly superior and gave the highest tuber weight (70.11 g),plant tubers yield (677.5 g.plant-1), tubers yield (57.59 Meq.ha-1) and the highest available of N and K in the soil (48.03 and 240 mg.Kg-1 soil) respectively, whereas the T16 treatment (200, 240, 300 Kg NPK.ha-1) gave the highest available of P in the soil (18.91 mg.Kg-1 soil) and the highest plant content of N, P and K (0.66, 0.09 and 0.78Kg.plant-1) respectively with non-significant difference with T15treatment

Evaluation of Potato Varieties for Yield and Dry Matter Response to Different Fertilizer Levels in Mid Altitude Region in Uganda

Potato is an important crop in Uganda that increasing its production and productivity must be emphasized. The yield and quality of potato tubers are partly influenced by the elevation, variety and fertilizers used. However, there is limited information on response of potato varieties to yield and dry matter under different NPK levels. This study therefore, was carried out to determine yield and dry matter response of potato in the mid altitude environment under different NPK (17:17:17) levels. Three potato varieties; Victoria, Rwangume and Kachpot1 were studied for two seasons at BSU Farm under a Randomized Complete Block design with three replications for each season at a fertilizer level of 0Kg/ha, 50Kg/ha and 100Kg/ha. Results showed dry matter was significantly different among the varieties and the overall mean ranged from 17.06% to 23.7%. Across the seasons, Kacpot1 had the highest dry matter content at 22.96% from fertilizer level one, whilst Rwangume had the lowest dry matter content at 18.08% from fertilizer level three. Fertilizer level three produced the highest overall mean of yield (12.19 t/ha) during 2019B and the lowest over all mean (5.3t/ha) from fertilizer level f1 during 2020A. Across the seasons, Katchpot1 yielded the best at 14.78 t/ha, whilst Victoria was the lowest yielder at 7.02 t/ha. The increase in fertilizer levels decreased the dry matter content of potatoes. Fertilizer level f2 is recommended for Katchpot 1, while f3 is recommended for Rwangume and Victoria for optimum yield.

Expression profiling of DUF599 genes revealed their role in regulating abiotic stress response in solanum tuberosum

The proteins containing the domain of unknown functions (DUFs) have significant roles in stress response and the growth of plants. A comprehensive genome-wide analysis and expression profiling of DUF599 was conducted to identify their roles in potato growth and response to stressed conditions. A total of nine DUF599 genes were identified, located on five chromosomes in the potato genome. The phylogenetic analysis divided StDUF599 genes into three groups in accordance with gene conserved motifs and gene structure distribution patterns. The StDUF599 promoters comprised several cis-acting factors responsive to plant hormones and abiotic stresses. The present study revealed that StDUF599 genes also possessed MBS, LTR, ABRE, and anaerobic induction responsive elements, indicating their importance in coping with abiotic stresses. StDUF599 genes were the target of several families of micro-RNAs also identified in this study. Purifying selection pressures lead to the duplication of the StDUF599 genes. Expression analysis of StDUF599-6 and StDUF599-9 in various tissues illustrated their vital role in developmental processes. It was found that StDUF599-7 and StDUF599-9 were highly expressed against heat and salt stresses. Expression profiling revealed that the StDUF599-8 gene has a significant role against GA3 and IAA. Lastly, this article forecasted that the DUF599 genes could enhance plant tolerance against several abiotic stresses.

The IbPYL8-IbbHLH66-IbbHLH118 complex mediates the abscisic acid-dependent drought response in sweet potato.

Drought limits crop development and yields. bHLH (basic helix-loop-helix) transcription factors play critical roles in regulating the drought response in many plants, but their roles in this process in sweet potato are unknown. Here, we report that two bHLH proteins, IbbHLH118 and IbbHLH66, play opposite roles in the ABA-mediated drought response in sweet potato. ABA treatment repressed IbbHLH118 expression but induced IbbHLH66 expression in the drought-tolerant sweet potato line Xushu55-2. Overexpressing IbbHLH118 reduced drought tolerance, whereas overexpressing IbbHLH66 enhanced drought tolerance, in sweet potato. IbbHLH118 directly binds to the E-boxes in the promoters of ABA-insensitive 5 (IbABI5), ABA-responsive element binding factor 2 (IbABF2) and tonoplast intrinsic protein 1 (IbTIP1) to suppress their transcription. IbbHLH118 forms homodimers with itself or heterodimers with IbbHLH66. Both of the IbbHLHs interact with the ABA receptor IbPYL8. ABA accumulates under drought stress, promoting the formation of the IbPYL8-IbbHLH66-IbbHLH118 complex. This complex interferes with IbbHLH118's repression of ABA-responsive genes, thereby activating ABA responses and enhancing drought tolerance. These findings shed light on the role of the IbPYL8-IbbHLH66-IbbHLH118 complex in the ABA-dependent drought response of sweet potato and identify candidate genes for developing elite crop varieties with enhanced drought tolerance.

Transcriptome analysis of sweet potato responses to potassium deficiency

BackgroundAs one of three essential nutrients, potassium is regarded as a main limiting factor for growth and development in plant. Sweet potato (Ipomoea batatas L.) is one of seven major food crops grown worldwide, and is both a nutrient-rich food and a bioenergy crop. It is a typical ‘K-favoring’ crop, and the level of potassium ion (K+) supplementation directly influences its production. However, little is known about the transcriptional changes in sweet potato genes under low-K+ conditions. Here, we analyzed the transcriptomic profiles of sweet potato roots in response to K+ deficiency to determine the effect of low-K+ stress on this economically important crop.ResultsThe roots of sweet potato seedlings with or without K+ treatment were harvested and used for transcriptome analyses. The results showed 559 differently expressed genes (DEGs) in low and high K+ groups. Among the DEGs, 336 were upregulated and 223 were downregulated. These DEGs were involved in transcriptional regulation, calcium binding, redox-signaling, biosynthesis, transport, and metabolic process. Further analysis revealed previously unknow genes involved in low-K+ stress, which could be investigated further to improve low K+ tolerance in plants. Confirmation of RNA-sequencing results using qRT-PCR displayed a high level of consistency between the two experiments. Analysis showed that many auxin-, ethylene- and jasmonic acid-related genes respond to K+ deficiency, suggesting that these hormones have important roles in K+ nutrient signaling in sweet potato.ConclusionsAccording to the transcriptome data of sweet potato, various DEGs showed transcriptional changes in response to low-K+ stress. However, the expression level of some kinases, transporters, transcription factors (TFs), hormone-related genes, and plant defense-related genes changed significantly, suggesting that they have important roles during K+ deficiency. Thus, this study identifies potential genes for genetic improvement of responses to low-K+ stress and provides valuable insight into the molecular mechanisms regulating low K+ tolerance in sweet potato. Further research is required to clarify the function of these DEGs under low-K+ stress.

The MYB33, MYB65, and MYB101 transcription factors affect Arabidopsis and potato responses to drought by regulating the ABA signaling pathway.

Drought is one of the main climate threats limiting crop production. Potato is one of the four most important food crop species worldwide and is sensitive to water shortage. The CBP80 gene was shown to affect Arabidopsis and potato responses to drought by regulating the level of microRNA159 and, consequently, the levels of the MYB33 and MYB101 transcription factors (TFs). Here, we show that three MYB TFs, MYB33, MYB65, and MYB101, are involved in plant responses to water shortage. Their downregulation in Arabidopsis causes stomatal hyposensitivity to abscisic acid (ABA), leading to reduced tolerance to drought. Transgenic Arabidopsis and potato plants overexpressing these genes, with a mutated recognition site in miR159, show hypersensitivity to ABA and relatively high tolerance to drought conditions. Thus, the MYB33, MYB65, and MYB101 genes may be potential targets for innovative breeding to obtain crops with relatively high tolerance to drought.

Response of potato (Solanum tuberosum L.) to the combined application of organic and inorganic fertilizers at Chena district, South Western Ethiopia

Low level or no use of organic and inorganic fertilizers and serious imbalances soil nutrients, depressed potato yields and pose accelerated mining of native soil nutrients. Present on-farm studies was undertaken to observe the combined effects of FYM and compost along with inorganic fertilizers, particularly NPSB on potato production. The experiment comprised of seven treatments: No fertilizer, recommended NP (115 kg N and 92 kg ha-1 P2O5), NPSB (115 kg N and 92 kg P2O5, 6.5 kg S. and 0.71 kg B ha-1), 10 tone FYM ha-1, 10 tone compost ha-1, 5 tone FYM + 50% NPSB (57.5 kg N and 92 kg P2O5 ha-1), and 5 tone compost + 50% NPSB ha-1 were arranged in RCBD with three replications. The yield and yield components were collected and subjected to mean separation and economic analysis. The analysis of variance indicated that either applied organic and inorganic fertilizers combined or alone significantly (p ≤ 0.05) improved potato yield at Chena. Full dose of each FYM and compost, recommended NP rate and NPSB gave similar potato yield. The highest average marketable and total fresh potato tuber yield (27.44, 27.92 t ha-1, respectively) were recorded by combined application of 5 t FYM ha-1 with 50% NPSB (115 kg N and 92 kg P2O5, 6.5 kg S. and 0.71 kg B ha-1) which is economically acceptable with MRR (1239.7%), whereas the lowest tuber yield (14.45 t ha-1) was obtained from unfertilized plot. Hence, combined application of 50% FYM and 50% NPSB proved best potato yield in the study area. Int. J. Agril. Res. Innov. Tech. 12(1): 18-22, June 2022

Physiological response, yield and quality of G0 potato (Solanum tuberosum) seed yield to various concentrations and time of application of prohexadione-ca bioregulator

Potato cultivation on the surface of the media faces obstacles in the form of high temperatures which cause the biosynthesis of gibberellins to increase and disrupt the tuberization process of potatoes. The use of hormonal engineering that can be done to increase the quantity and quality of G0 potato seeds is the use of retardant or anti-gibberellin Prohexadione-Ca with the right concentration and time of application. The experiment was carried out from June 2021 to February 2022 at Screen House, Ciparanje Jatinangor Experimental Garden, and Hortiklutura Laboratory, Faculty of Agriculture, Padjadjaran University. This experiment factorial randomized block design consisting of two factors., concentration of Prohexadione-Ca which includes three levels (50, 100, and 150 ppm) application time of Prohexadione-Ca (30, 40, and 50 days after planting). The experimental results showed that there was an independent effect between the dose and time of application of Prohexadione-Ca on the physiological components, yield, and quality of results. The dose of Prohexadione-Ca 50 ppm independently gave the best effect on the chlorophyll content index and stomatal conductance. The time of application of Prohexadione-Ca 40 days after planting independently gave the best effect on the number of potatoes per plant, potato weight per plant, and shoot length.

Physiological response, yield and quality of G0 potato (Solanum tuberosum) seed yield to various concentrations and time of application of prohexadione-ca bioregulator

Potato cultivation on the surface of the media faces obstacles in the form of high temperatures which cause the biosynthesis of gibberellins to increase and disrupt the tuberization process of potatoes. The use of hormonal engineering that can be done to increase the quantity and quality of G0 potato seeds is the use of retardant or anti-gibberellin Prohexadione-Ca with the right concentration and time of application. The experiment was carried out from June 2021 to February 2022 at Screen House, Ciparanje Jatinangor Experimental Garden, and Hortiklutura Laboratory, Faculty of Agriculture, Padjadjaran University. This experiment factorial randomized block design consisting of two factors., concentration of Prohexadione-Ca which includes three levels (50, 100, and 150 ppm) application time of Prohexadione-Ca (30, 40, and 50 days after planting). The experimental results showed that there was an independent effect between the dose and time of application of Prohexadione-Ca on the physiological components, yield, and quality of results. The dose of Prohexadione-Ca 50 ppm independently gave the best effect on the chlorophyll content index and stomatal conductance. The time of application of Prohexadione-Ca 40 days after planting independently gave the best effect on the number of potatoes per plant, potato weight per plant, and shoot length.

Construction of drought stress regulation networks in potato based on SMRT and RNA sequencing data

BackgroundPotato (Solanum tuberosum) is the fourth most important food crop in the world and plays an important role in food security. Drought stress has a significantly negative impact on potato growth and production. There are several publications involved drought stress in potato, this research contributes to enrich the knowledge.ResultsIn this study, next-generation sequencing (NGS) and single-molecule real-time (SMRT) sequencing technology were used to study the transcription profiles in potato in response to 20%PEG6000 simulates drought stress. The leaves of the variety “Désirée” from in vitro plantlets after drought stress at six time points from 0 to 48 hours were used to perform NGS and SMRT sequencing. According to the sequencing data, a total of 12,798 differentially expressed genes (DEGs) were identified in six time points. The real-time (RT)-PCR results are significantly correlated with the sequencing data, confirming the accuracy of the sequencing data. Gene ontology and KEGG analysis show that these DEGs participate in response to drought stress through galactose metabolism, fatty acid metabolism, plant-pathogen interaction, glutathione metabolism and other pathways. Through the analysis of alternative splicing of 66,888 transcripts, the functional pathways of these transcripts were enriched, and 51,098 transcripts were newly discovered from alternative splicing events and 47,994 transcripts were functionally annotated. Moreover, 3445 lncRNAs were predicted and enrichment analysis of corresponding target genes was also performed. Additionally, Alternative polyadenylation was analyzed by TADIS, and 26,153 poly (A) sites from 13,010 genes were detected in the Iso-Seq data.ConclusionOur research greatly enhanced potato drought-induced gene annotations and provides transcriptome-wide insights into the molecular basis of potato drought resistance.

LIDAR-Based Phenotyping for Drought Response and Drought Tolerance in Potato

AbstractAs climate changes, maintenance of yield stability requires efficient selection for drought tolerance. Drought-tolerant cultivars have been successfully but slowly bred by yield-based selection in arid environments. Marker-assisted selection accelerates breeding but is less effective for polygenic traits. Therefore, we investigated a selection based on phenotypic markers derived from automatic phenotyping systems. Our trial comprised 64 potato genotypes previously characterised for drought tolerance in ten trials representing Central European drought stress scenarios. In two trials, an automobile LIDAR system continuously monitored shoot development under optimal (C) and reduced (S) water supply. Six 3D images per day provided time courses of plant height (PH), leaf area (A3D), projected leaf area (A2D) and leaf angle (LA). The evaluation workflow employed logistic regression to estimate initial slope (k), inflection point (Tm) and maximum (Mx) for the growth curves of PH and A2D. Genotype × environment interaction affected all parameters significantly. Tm(A2D)s and Mx(A2D)s correlated significantly positive with drought tolerance, and Mx(PH)s correlated negatively. Drought tolerance was not associated with LAc, but correlated significantly with the LAs during late night and at dawn. Drought-tolerant genotypes had a lower LAs than drought-sensitive genotypes, thus resembling unstressed plants. The decision tree model selected Tm(A2D)s and Mx(PH)c as the most important parameters for tolerance class prediction. The model predicted sensitive genotypes more reliably than tolerant genotype and may thus complement the previously published model based on leaf metabolites/transcripts.

Comparative Transcriptome and Interaction Protein Analysis Reveals the Mechanism of IbMPK3-Overexpressing Transgenic Sweet Potato Response to Low-Temperature Stress.

The sweet potato is very sensitive to low temperature. Our previous study revealed that IbMPK3-overexpressing transgenic sweet potato (M3) plants showed stronger low-temperature stress tolerance than wild-type plants (WT). However, the mechanism of M3 plants in response to low-temperature stress is unclear. To further analyze how IbMPK3 mediates low-temperature stress in sweet potato, WT and M3 plants were exposed to low-temperature stress for 2 h and 12 h for RNA-seq analysis, whereas normal conditions were used as a control (CK). In total, 3436 and 8718 differentially expressed genes (DEGs) were identified in WT at 2 h (vs. CK) and 12 h (vs. CK) under low-temperature stress, respectively, whereas 1450 and 9291 DEGs were detected in M3 plants, respectively. Many common and unique DEGs were analyzed in WT and M3 plants. DEGs related to low temperature were involved in Ca2+ signaling, MAPK cascades, the reactive oxygen species (ROS) signaling pathway, hormone transduction pathway, encoding transcription factor families (bHLH, NAC, and WRKY), and downstream stress-related genes. Additionally, more upregulated genes were associated with the MAPK pathway in M3 plants during short-term low-temperature stress (CK vs. 2 h), and more upregulated genes were involved in secondary metabolic synthesis in M3 plants than in the WT during the long-time low-temperature stress treatment (CK vs. 12 h), such as fatty acid biosynthesis and elongation, glutathione metabolism, flavonoid biosynthesis, carotenoid biosynthesis, and zeatin biosynthesis. Moreover, the interaction proteins of IbMPK3 related to photosynthesis, or encoding CaM, NAC, and ribosomal proteins, were identified using yeast two-hybrid (Y2H). This study may provide a valuable resource for elucidating the sweet potato low-temperature stress resistance mechanism, as well as data to support molecular-assisted breeding with the IbMPK3 gene.