Soybean is one of the most important economic crops in the world. However, the salinization of soil results in the decrease of soybean yield as it is only a moderately salt-tolerant crop. We treated three soybean cultivars with low and high concentrations of NaCl. The differentially expressed genes between the control group and the salt treatment group were identified by mRNA sequencing and analyzed by gene ontology and Kyoto encyclopedia of genes and genomes annotations. We performed weighted gene co-expression network analysis on all samples and found genes most related to the phenotype. After verifying the results of differentially expressed genes by quantitative PCR, we finally identified Glyma06G01990, Glyma08G22730, Glyma019G05140, and Glyma06G20160 as key genes affecting the soybean growth under salt stress.

The climate change appears to have accelerated in recent years, and more changes are envisaged in the near future. With this in mind, breeders should consider the choices of materials to be used in breeding for the future to potentially mitigate the impacts of changes. In forage grasses, a special attention has to be paid to drought and heat tolerance. Here, in a screening trial of numerous accessions, we investigated drought tolerance and after-drought recovery rates among the species of the Festuca-Lolium complex, including cultivars and breeding materials as well as various ecotypes of wild species. Experimental trials were done using rainout shelters during three successive years 2017 - 2019. The most drought tolerant genotypes belonged to the species F. glaucescens and F. mairei, followed by F. atlantigena, F. arundinacea, and some genotypes of F. pratensis. These genotypes should be considered as suitable candidates for intergeneric hybridization with L. multiflorum and L. perenne. Our test shows that Festulolium krasanii (L. multiflorum × F. arundinacea) is a good candidate to replace pure tall fescue (F. arundinacea) stands. It has the same or similar drought tolerance and drought recovery as tall fescue and at least some cultivars are known for their high feeding value, unlike tall fescue itself. A large variability for drought tolerance and recovery rates in Fl. braunii (the L. multiflorum × F. pratensis hybrid) and Fl. loliaceum (the L. perenne × F. pratensis hybrid) permit selection of genotypes that can outperform the original L. multiflorum and L. perenne.

To further elucidate the molecular mechanism of the germination in common wheat, a differential proteomic analysis was completed between the F₁ hybrid RS5322 and its parental lines (RS53 and SN22) using isobaric tags for relative and absolute quantitation (iTRAQ) based strategy. Rapid grain germination and superior young seedling growth were observed in the F₁ hybrid line. A total of 807 differentially abundant proteins (DAPs) were identified by iTRAQ analysis of grains at 48 h after imbibition in distilled water. Bioinformatics analysis shows that 638 DAPs were annotated in 38 Gene Ontology functional groups, 764 DAPs were classified into 23 clusters of orthologous groups of protein categories, and 538 DAPs were enriched in 65 Kyoto encyclopedia of genes and genomes pathways. Real time quantitative PCR of 12 genes encoding different important proteins showed certain transcriptional and translational expression similarities during grain development. In the F₁ hybrid, the DAPs were particularly those involved in starch and sugar metabolism, protein metabolism, protein modification, and ubiquitin proteasome system (UPS). It was speculated that UPS might be responsible for a high germination ability in the F₁ hybrid by regulating storage substance metabolism. The DAPs identified in this study provide a scope for improving the grain germination trait in agricultural crops.

Festulolium cultivars are widely utilized in Lithuania because they are persistent under abiotic stresses and are high yielding. However, changing climate challenges the existing Festulolium cultivars to adapt to new growing conditions and still maintain the yield. In this study, we aimed at evaluating the yield stability of two Festulolium cultivars in field trials under fluctuating Lithuanian conditions. The mean total dry matter yield (DMY) of both Festulolium cultivars fluctuated greatly between the years and ANOVA analysis showed a significant effect of environment on total DMY as well as DMY of each cut, but the genotype × environment interaction was not significant. There was a high difference between the total DMY of 1^st year and 2^nd year of use of plots in each year of observation. The highest DMYs were harvested in the years 2015 and 2016. Dry matter yield of the 1^st cut was the largest component of the total DMY for most of the years. The plants overwintered the first winter after sowing very well over the whole study period, resulting in excellent spring growth. The winter survival scores of 2^nd year of use of plots were lower than 1^st year of use and strongly correlated with the 1^st cut DMY of 2^nd year of use (r = 0.81). Spring growth of plants at 2^nd year of use was poorer, the correlation between winter survival and spring growth of 2^nd year of use was 0.62. The scores of regrowth after the cuts of 1^st and 2^nd years of use were very similar for most of the experimental years and moderately correlated with the sum of DMYs after cuts (r = 0.55 and r = 0.5, respectively).

Salicylic acid (SA) is an important plant hormone involved in the activation of defense responses against environmental stresses. However, there are still large of unsolved mysteries about how SA pretreatment affects the establishment of plant stress tolerance. In this study, application of SA at different concentrations and different times were conducted to investigate their effects on the response of Arabidopsis seedlings to salt stress. The pretreatment with 10 or 20 μM SA for more than 6 h promoted Arabidopsis seedlings resistance to salt stress. On the other hand, pretreatment with 200 μM SA reduced Arabidopsis resistance to salt stress and aggravated oxidative damage to the seedlings. At all concentrations used, SA pretreatment inhibited the total respiration and promoted reactive oxygen species (ROS) generation. However, the ROS content in 10 or 20 μM SA pretreated seedlings decreased to the basal level within 6 h and high activities of antioxidant enzymes and alternative oxidase were maintained. Notably, the SA-enhanced salt stress resistance was significantly impaired by blocking alternative oxidase (AOX) pathway. Our findings indicate that SA-mediated salt stress response is in a dose- and time-dependent manner and that the effects were related to the induction of AOX capacity and antioxidant system.

To study the biological function of activity of bcl complex (ABC1) proteins in Lepidium apetalum Willd., genes encoding ABC1 family proteins were identified from the seed transcriptome. The sequence most closely related to germination at a low temperature was selected and gene expressions in response to low temperature stress further studied. The results show that 21 ABC1 genes were expressed in seeds germinating at the low temperature: 4 genes were upregulated, 6 were downregulated, and 11 were not significantly different from controls. The results of fluorescence quantification of the low-temperature stress on the seedlings of 7-d-old L. apetalum showed that seven genes were up-regulated, six genes were down-regulated, and eight genes had no significant difference. Real-time quantitative PCR results show that under the low temperature stress, the expression of the LaAbc1-3 gene increased, but its expression decreased after some time. The expression of this gene increased again after removing the low temperature stress. The expression of LaAbc1-21 gene in L. apetalum seedlings showed a trend of decreasing first and then increasing. The LaAbc1-3 gene was insensitive to salt stress. Expression of the LaAbc1-21 gene was significantly up-regulated during the salt stress. Under osmotic stress, the expression of the LaAbc1-3 gene was down-regulated, and the expression was negatively correlated with polyethylene glycol (PEG-6000) concentration. Under the PEG-6000 treatment, the expression of the LaAbc1-21 gene was significantly up-regulated, and the expression was positively correlated with concentration. These results provide a basis for further analysis of the role of the ABC1 genes in the stress resistance of L. apetalum.

Festulolium are grasses formed through interspecific hybridisation of ryegrass (Lolium) and fescue (Festuca) species. The Lolium-Festuca genome complex represents a vast array of heterogeneous and largely outbreeding grass species that have evolved, diverged, and adapted, allowing their world-wide colonisation of temperate grasslands. While strategies for grass improvement have focused primarily on intraspecific breeding and, in particular, on the agronomically desirable species Lolium perenne and Lolium multiflorum, a growing interest has emerged in interspecific hybrids as alternatives. The principal driver has been the increased appreciation of the capability of wide hybridisation to extend phenotypic variation beyond the ranges available within a single species. Lolium and Festuca species share complementary and desirable traits, and the prime aim in Festulolium (Festuca × Lolium) cultivar development has been to combine the agronomic performance of Lolium and the stress resistance of Festuca species. Advances in Festulolium development are timely, and support strategies aimed at delivering a more sustainable future for livestock agriculture, with grass cultivars that are persistent and productive. Festulolium hybrids occur naturally, including examples that demonstrate extreme heterosis with adaptations sufficient to sustain growth in harsh conditions. However, they are largely sterile and their perpetuity depends mainly on vegetative propagation. Synthetic Festulolium hybrids suitable for plant breeding require genome stability and fertility, sufficient for a cost-effective seed production. To this end, suitable amphiploid and introgression-breeding approaches have been developed. Herein, we provide detailed selected highlights in the research and breeding of Festulolium. In addition, recognising the multifunctional properties of grasslands and the development of enabling technologies that permit their study, we review additional benefits likely to accrue from Festulolium that may mitigate climate change effects and provide valuable ecosystem services.

Cytosine methylation plays an important role in plant development by regulating gene expressions. However, few studies have investigated methylation changes during the tissue differentiation and development of perennial plants. Here, the fluorescence-labeled methylation-sensitive amplified polymorphism method was used with eight primer combinations to detect methylation in leaves and xylem obtained at the stages of inflorescence emergence (IE), ovary start growth, and fruit maturity (FM) in two pecan (Carya illinoinensis) cvs. Pawnee and Stuart. The results show that the total methylation in the xylem was generally higher than in the leaves at each stage. Substantial methylation variations were observed at the amplified sites in pecan tissues at the various stages. The methylation patterns changed between the leaf and xylem, with frequencies from 44.97 to 67.01 % over the three stages in the two cultivars, among which the variation frequency between the tissues at the FM stage was the highest for each cultivar. The frequencies of methylation variation between the leaf samples at any two stages ranged from 31.86 to 45.88 %, with higher variation frequencies between the xylem samples (40.90 - 59.44 %) for each cultivar, which is consistent with the comparative results of polymorphism rates between the leaf and xylem over the three stages. Cluster analysis and principal coordinate analysis suggest that the xylem at the IE and FM stages had relatively distant epigenetic relationships with other tissue samples as a whole. This study reveals the patterns of methylation variation and methylation relationships among pecan tissues undergoing different developmental processes, implying the important roles of methylation in tissue differentiation and development of trees. These results lay a theoretical foundation for elucidating the regulatory mechanisms of methylation involved in tree development.

Zinc deficiency is a worldwide problem for crops including potato (Solanum tuberosum L.), the fourth most important crop worldwide. The zinc/iron-regulated transporter-like protein (ZIP) transporter family is thought to play key roles in Zn uptake and transport. However, little is known about the potato ZIP family. In this study, 12 genes encoding members of the ZIP family were identified in the potato genome. The 12 StZIP genes were predicted to encode proteins of 220 - 407 amino acids harboring 5 - 9 putative transmembrane domains (TMDs), and 11 of these proteins had a variable region rich in histidine residues between TMDIII and TMDIV. A phylogenetic analysis divided the StZIPs into four groups on the basis of gene structure and conserved motifs. Furthermore, the StZIP expression profiles were determined under Zn-deficiency in both high and low Zn-content genotypes. Four differentially expressed genes, StZIP6, -9, -11, and -12, were identified in tubers of the two genotypes under Zn-deficiency, and StZIP11 and StZIP12 may have a more prominent function in Zn uptake and accumulation in potato tubers owing to their higher expressions. Thus, the results provide useful information for further studying the functions of StZIP genes.

To study the biological function of late embryogenesis abundant (LEA) proteins in Lepidium apetalum Willd., genes encoding LEA family proteins were identified from the seed transcriptome. The sequence most closely related to germination at a low temperature was selected and gene expressions in response to low temperature stress further studied. The results show that 27 LEA genes were expressed in seeds germinating at the low temperature: 3 genes were upregulated, 20 were downregulated, and 4 were not significantly different from controls. The most prominent of the upregulated genes, LaLEA1, contained an open reading frame of 624 bp and encoded 208 amino acids. The protein was rich in hydrophilic amino acids including threonine, alanine, glutamine, and lysine. It is predicted that the secondary structure contains α-helices and irregular curls. Real-time quantitative PCR results show that under low temperature stress, the expression of LaLEA1 was first downregulated and then upregulated rapidly, reaching its highest expression at 12 h, then the expression of LaLEA1 was reduced slightly but maintained higher than that of the non-stress group. As the expression of LaLEA1 was significantly altered in response to low temperature stress, we investigated the expression of LaLEA1 also in response to other abiotic stresses, i.e., salinity and drought. L. apetalum seedlings wilted in the early stage following NaCl or osmotic (polyethylene glycol) stresses, but recovered quickly, showing a strong tolerance. Real-time quantitative PCR results show that LaLEA1 was rapidly upregulated following salt and osmotic stresses, and its expression profile was closely related to NaCl or PEG concentrations. Expression was up to 7.9-fold higher than that of the control after 6 h of salt stress. These results suggest that L. apetalum seedlings responded quickly to salt stress. The response to osmotic stress was slightly slower; expression of LaLEA1 was 6.0-fold higher than that of the control after 12 h. Thus, LaLEA1 played an important role in abiotic stress tolerance. These results provide a basis for further analysis of the role of the LEA genes in the stress resistance of L. apetalum.

γ-Aminobutyric acid (GABA) regulates plant tolerance to abiotic stresses; however, a transcriptomic change and key stress-related genes induced by GABA have not been investigated in plants during a prolonged period of salt stress. Roots of creeping bentgrass (Agrostis stolonifera) cv. Penncross were pretreated with or without 0.5 mM GABA solution for 2 days and then subjected to salt stress for 20 days (150 mM NaCl solution for 3 d, 200 mM NaCl for another 3 d, and 250 mM NaCl for 14 d) in controlled growth chambers. The application of GABA significantly increased GABA content in roots and alleviated a salt-stress induced decrease in GABA content in leaves. This was associated with a significant increase in salt tolerance as demonstrated by a significantly higher leaf relative water content, photochemical efficiency, performance index on absorption basis, and lower electrolyte leakage in GABA-pretreated plants as compared to untreated plants under salt stress. Transcriptomic analysis found that GABA-induced salt tolerance was closely associated with saccharide, amino acid, and lipid metabolism. The GABA upregulated key differentially expressed genes including cytochrome P450 (CYP450), zinc transporter 29 (ZTP29), alpha-amylase 3 (AMY3), 3-ketoacyl-CoA synthase 6 (KCS6), aldehyde oxidase (AO), acetyl-CoA carboxylase 1 (ACC1), and magnesium-chelatase (Mg-CHT) involved in zinc homeostasis, starch degradation, and the biosynthesis of wax, fatty acid, chlorophyll, and abscisic acid, which could contribute to GABA-regulated salt tolerance. Current findings prove that GABA application is an efficient approach to enhance salt tolerance of creeping bentgrass during a prolonged period of salt stress and also provide valuable information to better understand key candidate genes and regulatory pathways of GABA-induced salt tolerance in plants.

Leaf venation and coupled physiological function of wild plants co-evolve during the natural selection. How artificial selection affects leaf vein traits and coordinated physiological functions of main crops are largely unknown. This study examined the changes of leaf vein traits and their correlation with gas exchange of flag leaves and yield in eight wheat genotypes of differing ploidy under the same growing conditions. The results indicate that flag leaf vein density (VLA), major-vein density (VLA_major), and minor-vein density (VLA_minor) decreased whereas the proportion of minor-vein length and interveinal distance between small longitudinal veins (IVD) increased during the polyploidization process, and the major advance occurred from the period from diploids to tetraploids. The VLA, VLA_major, and VLA_minor were closely coordinated with maximum net photosynthetic rate (P_N) and photosynthetic N use efficiency (PNUE), but not with stomatal conductance. The proportion of minor-vein length and IVD were negatively related with P_N and PNUE but positively related with N content per area (N_area) during wheat evolution. A higher proportion of minor-vein length and IVD, and a lower VLA_major in flag leaves along with a larger N_area were largely responsible for the increased yield in modern cultivars. The decreased redundancy of leaf vein density and increased minor-vein proportion in modern cultivars can confer a yield advantage during wheat evolution.

Plants are severely affected by many biotic stresses, which cause a reduction in crop quality and quantity. One of the strategies to manage biotic stresses is the generation of transgenic plant lines that can be used as biosensors. These biosensor plants can trigger an early warning upon any pathogen infection. Two promoters with β-glucuronidase reporter gene fusions were constructed. The first contained the flagellin sensing 2 gene promoter, whereas the second contained synthetic promoter containing four repeats of cis-acting elements from the pathogen-related protein 1 gene and two transcription enhancers from the 35S promoter. Transformed leaves were treated with a phytohormone salicylic acid to mimic the occurrence of biotic stress. Validation of reporter gene expression induced from both constructs in transformed potato leaves displayed an increase upon salicylic acid treatment. The results reflect that both constructs could serve in the production of potato biotic stress biosensors.

Festulolium are hybrids between species within the Lolium and Festuca genera. They are attractive candidates for hybridisation due to their complementary characteristics in the context of forage production and environmental challenges, with Lolium exhibiting greater digestibility and Festuca possessing superior resilience to abiotic stress. To establish the extent of the representation of these characteristics in different Festulolium hybrids, a five-year field experiment was undertaken in a mild Atlantic climate. Four alternative species combinations and six pure species (controls) were evaluated for dry matter yield and persistency from 2014 to 2018, and various nutritional parameters in the first silage cut were measured from 2015 to 2017. Festulolium hybrids derived from L. multiflorum were found to group with both Lolium and Festuca pure species for a mean ground score to evaluate persistency (P < 0.05). Hybrid types of the L. perenne lineage were found to have ground score values more alike to their Lolium component and distinct from the F. pratensis pure species. In terms of dry matter yield, the majority of L. multiflorum hybrids observed formed a higher yielding group with the tetraploid L. multiflorum pure species and distinct from diploid F. pratensis pure species, whereas all other hybrid types and controls shared groups in common. For the nutrient content parameters including dry matter digestibility, water soluble sugars, and buffering capacity, Lolium pure species exhibited more favourable values, whereas hybrids were largely found to display intermediate to low values. Festuca pure species consistently exhibited poorer values with the exception of crude protein content where F. pratensis displayed the highest values and also the 2017 measurement of buffering capacity. In conclusion, the Festulolium hybrids shared characteristics with both parental types, but they often showed a greater likeness to the Lolium component.

Flood in rice fields at the time of seed sowing and early seedling establishment causes extensive crop loss due to the inability of the seeds to tolerate and overcome submergence. In the present study, rice genotypes from Assam, India tolerant to hypoxia during germination were identified through systematic screening of deep-water rice genotype collection from flood-prone ecosystem of Brahmaputra river valley. The difference in tolerance to hypoxia during germination within the species provides scope for identification of novel hypoxia-responsive factors involved in tolerance as mechanism of tolerance may not be conserved across tolerant germplasms. Tolerant genotypes were further subjected to physiological and molecular characterization. Growth rate kinetics in tolerant genotypes new Rangdhakekua bao (RKB) and cultivar Khao Hlan On (KHO) from International Rice Research Institute (IRRI) used as positive control exhibited stronger escape strategy under hypoxic condition compared to sensitive genotype IR-64 (negative control). Activities of α-amylase and pyruvate decarboxylase were significantly higher in RKB and KHO than in IR-64, while no significant difference was observed in the alcohol dehydrogenase activity. Reverse transcription quantitative PCR confirmed increased amounts of transcripts of sucrose nonfermenting 1 related protein kinase, myeloblastosis-related protein S1, rice amylase 3D, and trehalose phosphate phosphatase 7 genes, which are known to be involved in hypoxia signaling cascade. Besides, transcription factors (TFs) like ethylene responce factors 71 and 63, ethylene insensitive 3-like 1a and proteins like expansins A7 and A2, which are involved in cell elongation had also significantly higher amounts in RKB compared to IR-64. Additional factors that include TFs like ERF71 and ERF63 that shows perturbation at transcription even within tolerant genotypes might constitute the genotype-specific regulation, evolved as a part of its adaptive mechanism to survive under submerged conditions.

The calcineurin B-like protein (CBL)-interacting protein kinase (CIPK) complex is an essential calcium sensor and contributes to biotic and abiotic stress responses. However, citrus CBL and CIPK gene family members and their underlying roles during drought and arbuscular mycorrhizal fungi (AMF) colonization remain relatively unknown. In the present study, CBLs and CIPKs were characterized in Citrus sinensis by analyzing the presence of specific domains such as the elongation factor (EF)-hand motif in CBLs, and a protein kinase and an Asn-Ala-Phe domain in CIPKs. After mining the C. sinensis genome, we identified 8 CsCBLs and 17 CsCIPKs. Among these genes, three CsCBLs and nine CsCIPKs showed syntenic relationships with the Arabidopsis thaliana homologs AtCBLs and AtCIPKs, respectively. According to gene expression and cis-acting element analysis, all 8 CsCBLs and 16 CsCIPKs were expressed in the roots, where the regulation of expression was not consistent with their promoter cis-elements. Drought treatment remarkably downregulated the expression of CsCBL8 and upregulated CsCBL7, CsCIPK4, and CsCIPK7 expressions. The AMF colonization induced CsCBL4, 5, 6, and 7 as well as CsCIPK2, 4, 10, 11, 13, 14, and 16 expressions and repressed CsCBL1, 2, 3, and 8 and CsCIPK1, 3, 6, 8, 9, and 12 expressions. Based on the expression data and co-expression analysis, CsCBL1-CsCIPK1, CsCBL1-CsCIPK3, CsCBL1-CsCIPK6, and CsCBL1-CsCIPK9 showed the significant positive correlations to drought and AMF responses.

Sugars are important molecules that function not only as primary metabolites, but also as nutrients and signal molecules in plants. The sugar transport protein genes family SWEET has been recently identified. The availability of the Dendrobium officinale and Phalaenopsis equestris genome sequences offered the opportunity to study the SWEET gene family in this two orchid species. We identified 22 and 16 putative SWEET genes, respectively, in the genomes of D. officinale and P. equestris using comprehensive bioinformatics analysis. Based on phylogenetic comparisons with SWEET proteins from Arabidopsis and rice, the DoSWEET and PeSWEET proteins could be divided into four clades; among these, clade II specifically lacked PeSWEETs and clade IV specifically lacked DoSWEETs, and there were orthologs present between D. officinale and P. equestris. Protein sequence alignments suggest that there is a predicted serine phosphorylation site in each of the highly conserved MtN3/saliva domain regions. Gene expression analysis in four tissues showed that three PeSWEET genes were most highly expressed in the flower, leaf, stem, and root, suggesting that these genes might play important roles in growth and development in P. equestris. Analysis of gene expression in different floral organs showed that five PeSWEET genes were highly expressed in the column (gynostemium), implying their possible involvement in reproductive development in this species. The expression patterns of seven PeSWEETs in response to different abiotic stresses showed that three genes were upregulated significantly in response to high temperature and two genes were differently expressed at low temperature. The results of this study lay the foundation for further functional analysis of SWEET genes in orchids.

Excess radiation is one of frequent natural environmental stresses that plants have to cope with on a daily basis. Therefore, plants have evolved many short- and long-term mechanisms to acclimate to high irradiance and tolerate it. Ureides, generated from purine degradation, have been proposed as compounds involved in environmental stress responses, including altered irradiance. In the present study, high irradiance was used to investigate ureide content and gene expression in Arabidopsis thaliana. Arabidopsis plants shifted to high irradiance showed high content of a specific ureide compound, allantoin. The accumulation of allantoin was associated with increased expression of uricase, an enzyme involved in its production. When an Arabidopsis mutant (aln-3), which constitutively accumulates elevated amounts of allantoin, was exposed to high irradiance, mutant plants demonstrated enhanced tolerance to the stress conditions compared to the wild-type plants. Our results provide evidence that accumulation of the allantoin might contribute in plants response to increased growth irradiance.

DNA methylation is one of the epigenetic mechanisms regulating gene expression in plants in response to environmental conditions. In this study, analysis of methylation patterns was carried out in order to assess the effect of water stress in two contrasting wheat genotypes using methylation-sensitive amplified polymorphism (MSAP). The results revealed that demethylation was higher in drought-tolerant genotype (C306) as compared to drought-sensitive genotype (HUW468) after experiencing drought stress. Comparisons of different MSAP patterns showed a high percentage of polymorphic bands between tolerant and susceptible wheat genotypes (from 74.79 % at anthesis to 88.89 % at tillering). Furthermore, differential DNA methylation in roots and leaves also revealed tissue-specific methylation of genomic DNA. Interestingly, 54 developmental stage-specific bands and 23 bands that were found contrasting between these two wheat genotypes were detected. Furthermore, a few sites with stable DNA methylation differences were identified between drought-tolerant and drought-sensitive cultivars, thus providing genotype-specific epigenetic markers. These results not only provide data on differences in DNA methylation changes but also contribute to dissection of molecular mechanisms of drought response and tolerance in wheat.

Sulfur dioxide is a widespread air pollutant and it also acts as a signaling molecule in various processes in mammals. However, the role of SO₂ in programmed cell death (PCD) in plants is unclear. Here we studied the role of SO₂ in gibberellin (GA)-treated wheat aleurone layers. The results showed that 100 μM SO₂ donor (NaHSO₃/Na₂SO₃) could effectively delay PCD and inhibit the coalescence of small protein storage vacuoles (PSVs) in aleurone cells treated with GA. Also, SO₂ could reduce the accumulation of hydrogen peroxide and superoxide anion in GA-treated aleurone layers. In this process, SO₂ could sustain higher activities of catalase, guaiacol peroxidase, ascorbate peroxidase, and superoxide dismutase and lower activities of lipoxygenase and polyphenol oxidase by comparing with GA alone. In addition, an induction of endogenous H₂S and NO was observed in SO₂-treated aleurone layers. The application of NO scavenger cPTIO could accelerate PCD in SO₂ or H₂S treated aleurone cells, suggesting that NO alleviated PCD by acting downstream of SO₂ and H₂S. In conclusion, these results imply that SO₂ could delay PCD in GA-treated wheat aleurone layers by enhancing cellular antioxidative capacity and H₂S/NO signals act downstream of SO₂.

The aim of this study was to find a correlation between the freezing tolerance of three chickpea (Cicer arietinum L.) cultivars (İnci, Işik-05, and Sari-98) and their wild relative C. echinospermum and physiological responses. Chickpea plants (15-d-old) were subjected to cold acclimation (CA) (10 °C for 7 d), freezing (-3 or -5 °C for 2 h), and subsequent rewarming (25 °C for 7 d). In two separate experiments with three replications, we determined growth, water status, photosystem 2 photochemical activity, photosynthetic pigments, H₂O₂, malondialdehyde, and proline content, relative leakage ratio, antioxidant enzyme activities, and gene expressions in cultivars different in freezing tolerance. Freezing temperatures adversely affected all the physiological parameters of all cultivars. Rewarming did not lead to complete recovery. The cultivar İnci was more tolerant to the freezing temperatures than others.

Heterotrimeric guanine-nucleotide-binding proteins (G-proteins) play important roles in signal transduction and regulate responses to various stresses. Although G-protein signaling pathways have been extensively identified and characterized in model plants, there is little knowledge in non-model and especially in woody plants. Mulberry is an economically and ecologically important perennial tree, which is adaptable to many environmental stresses. In this study, we identified and cloned six G-protein genes including one Gα, one Gβ, two Gγ, one RGS (regulator of G-protein signaling protein) and one RACK1 (receptor for activated C kinase 1) involved in G-protein signaling. Sequence and phylogenetic analysis revealed that Morus G-proteins are evolutionarily conserved compared with those of other plants. A real-time quantitative reverse transcription polymerase chain reaction analysis showed that Morus G-protein signaling genes were ubiquitously but differentially expressed in various tissues. The expression of all of these genes was affected by abiotic stresses and signal molecules, which indicated that Morus G-protein signaling may be involved in environmental stress and defense responses.

The cation/H⁺ exchange is a basic process in transmembrane transport. The acquisition of genome sequences has now established that plants possess genes encoding a large number of cation/proton antiporter 1 (CPA1) proteins, few of which have been characterized with respect to their contribution to ion homeostasis. The CPA1s comprise plasma membrane, vacuolar, and endosomal forms, and they have been identified as important for a salinity tolerance. They are, however, also involved in both the control of cellular pH and K⁺ homeostasis, and regulate processes over a wide range of physiological events, from vesicle trafficking to development.

We compared C₃ and CAM (crassulacean acid metabolism) states in Mesembryanthemum crystallinum, a facultative CAM species, with respect to the involvement of phosphoenolpyruvate carboxylase (PEPC) and nitrogen metabolismrelated enzymes in plant response to Botrytis cinerea infection. The enzyme activities were monitored both in pathogeninoculated 2^nd leaf pair and non-inoculated 3^rd leaf pair. The control activities of most studied enzymes were dependent on the mode of photosynthesis. Compared to C₃ plants, those performing CAM exhibited higher PEPC, nitrate reductase (NR), and deaminating glutamate dehydrogenase (NAD-GDH) activities but lower glutamine synthetase (GS) and alanine aminotransferase (ALT) activities. Regardless of the mode of photosynthetic carbon assimilation, the plants responded to infection with enhancement of PEPC and inhibition of NR activities in the inoculated leaves. Whereas the activity of GS remained unaffected, those of all glutamate-yielding enzymes, namely ferredoxin-dependent glutamate synthase (Fd-GOGAT), aspartate aminotransferase (AST), ALT, and aminating glutamate dehydrogenase (NADHGDH) were altered after infection. However, the time-course and extent of the observed changes differed in C₃ and CAM plants. In general, CAM plants responded to infection with an earlier increase in PEPC and Fd-GOGAT activities as well as later inhibition of NR activity. Contrary to C₃ plants, in those performing CAM the activities of PEPC, Fd-GOGAT, NADH-GDH, and AST in the non-inoculated 3^rd leaf pair were similarly influenced by infection as in leaves directly inoculated with the pathogen. This implies that the local infection induced an alteration of carbon/nitrogen status in healthy upper leaves. This reprogramming resulting from changes in PEPC and nitrogen metabolism-related enzymes was C₃- and CAM-specific.

Protein phosphorylation/dephosphorylation is a major signalling event induced by abiotic stresses in plants. Sucrose nonfermenting 1-related protein kinase 2 (SnRK2) plays important roles in response to osmotic stress. In the present study, four SnRK2s, TpSnRK2.1/3/7/8, were cloned and characterized from Triticum polonicum L. (dwarf Polish wheat, DPW, AABB). All of these were individually located on 2AL, 1AL, 2AL, and 5BL. Two spliced isoforms of TpSnRK2.8 (TpSnRK2.8a and TpSnRK2.8b) were observed. TpSnRK2.1 and TpSnRK2.3 were classified into the group II; TpSnRK2.7 was classified into the group I; and TpSnRK2.8a/b were classified into the group III. Expression patterns revealed that TpSnRK2.1 responded to cold, NaCl, polyethylene glycol (PEG), and abscisic acid (ABA) in both roots and leaves; TpSnRK2.3 was strongly regulated by cold, NaCl, and ABA in both roots and leaves, and by PEG in roots; TpSnRK2.7 was induced by NaCl and PEG in roots, but was not activated by ABA; and TpSnRK2.8s were significantly activated by cold, NaCl, PEG, and ABA in both roots and leaves. From the above results, we inferred that TpSnRK2.1/3/8 may participate in the responses to environmental stresses in ABA-dependent signal transduction pathway but TpSnRK2.7 is possibly involved in responses to environmental stresses in a non-ABA-dependent manner. They play important roles in specific tissues under different stresses.

Reverse transcription of RNA followed by real-time quantitative PCR (qPCR) is to date the most reliable method for gene expression studies. However, to control the errors introduced along the numerous experimental procedures, it requires a normalization using internal reference genes with stable expression. To address this issue, nine candidate reference genes were investigated in Ilex paraguariensis leaves subjected to water stress. To facilitate the selection, we analysed the real-time qPCR data with three different software programs. The obtained results support the conclusion that RNA polymerase associated protein rtf1 homolog (RTF) combined with any of the following pairs is the most suitable triad of genes to compute a normalization factor: elongation factor 1-alpha + tubulin alpha chain (EF1a + α-Tub), actin + cyclophilin 38 (ACT + CYP38), or cyclophilin 38 + vacuolar protein sorting-associated protein 18 homologs (CYP38 + VPS). Our analysis constitutes the first in-depth study to identify the appropriate reference genes for the quantification of transcription in Ilex paraguariensis leaves during drought and provides essential information for further gene expression studies in this tree species.

Pseudoroegneria libanotica is an important herbage diploid species possessing the St genome. The St genome participates in the formation of nine perennial genera in Triticeae (Poaceae). The whole chloroplast (cp) genome of P. libanotica is 135 026 bp in length. The typical quadripartite structure consists of one large single copy of 80 634 bp, one small single copy of 12 766 bp and a pair of inverted regions (20 813 bp each). The cp genome contains 76 coding genes, four ribosomal RNA and 30 transfer RNA genes. Comparative sequence analysis suggested that: 1) the 737 bp deletion in the cp of P. libanotica was specific in Triticeae species and might transfer into its nuclear genome; 2) hot-spot regions, indels in intergenic regions and protein coding sequences mainly led to the length variation in Triticeae; 3) highly divergence regions combined with negative selection in rpl2, rps12, ccsA, rps8, ndhH, petD, ndhK, psbM, rps3, rps18, and ndhA were identified as effective molecular markers and could be considered in future phylogenetic studies of Triticeae species; and 4) ycf3 gene with rich cpSSRs was suitable for phylogeny analysis or could be used for DNA barcoding at low taxonomic levels. The cpSSRs distribution in the coding regions of diploid Triticeae species was shown for the first time and provided a valuable source for developing primers to study specific simple sequence repeat loci.

Cadmium (Cd) is a major abiotic stressor that affects plant growth and reduces the productivity of field crops. Here, we examined the ultrastructural, physiological, and molecular changes in three wheat cultivars [Sumai 3, Jingdong 8 (JD 8), and Nannong 9918 (9918)] in response to different concentrations of Cd (0, 10, 50, and 100 μM) in 1/4 Hoagland nutrient solution. The results showed that JD 8 contained the lowest shoot Cd content and the highest root Cd content among the three cultivars at higher Cd concentrations and so JD 8 was proposed to be a relatively Cd-tolerant cultivar. Next, the stress responses of JD 8 and 9918 were compared. Cadmium reduced root growth and size and number of the leaves, inhibited root hair development, and promoted leaf cell death. The result of trypan blue staining showed that the dead leaf cells induced by Cd stress gradually emerged in the xylem, supporting the hypothesis that cell death could restrict Cd transport. The Cd-induced deterioration of the leaf ultrastructure led to the complete disorganization of the chloroplasts, which had lower amounts of transitory starch and an increased number of osmiophilic granules compared to those in the untreated controls. Autophagy-related genes and autophagy in the leaves were induced by Cd stress. At the same concentration and Cd treatment time, the Cd-tolerant genotype JD 8 exhibited less toxic symptoms compared to the Cd-sensitive genotype 9918. The results of this study provide insights into the ultrastructural and physiological damages induced by Cd stress, which may help in selecting Cd-tolerant wheat cultivars.

Heat causes stress in blueberry; therefore, the present study aimed to investigate whether exogenous ferulic acid (FA) might protect plants against heat stress and to analyze possible mechanisms underlying such protection. Blueberry (Vaccinium corymbosum) seedlings were pretreated with 0.6 mM FA for 1 d and then kept at normal (25/20 °C) or elevated (39/30 °C) temperatures for 3 d. One day of FA pretreatment increased transcriptions of genes encoding iron superoxide dismutase, cytoplasmic copper/zinc superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase and elevated content of proline and soluble sugars in leaves. When the FA-pretreated blueberries were exposed to heat, transcriptions of these genes and content of proline and soluble sugars were higher than after heat treatment alone. Under heat, FA pretreatment also enhanced transcriptions of genes encoding chloroplast copper/zinc superoxide dismutase, catalase, glutathione peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase. This corresponds with increased activities of superoxide dismutase and glutathione peroxidase and is consistent with elevated content of ascorbate and glutathione in the FA-pretreated and heat-stressed blueberries. Compared with heat treatment alone, the combination of FA pretreatment and heat enhanced content of endogenous FA, decreased production of superoxide anion, and content of hydrogen peroxide and malondialdehyde, and also increased relative water content and osmotic potential in the leaves. Thus, pretreatment with FA mitigated the heat stress in the blueberries by elevating endogenous FA content, reducing accumulation of reactive oxygen species, and increasing proline and soluble sugar content.