Synergistic effects of carbon cycle metabolism and photosynthesis in Chinese cabbage under salt stress

Chinese cabbage(Brassica rapa ssp. pekinensis) has a long cultivation history and is one of the vegetable crops with the largest cultivation area in China. However, salt stress severely damages photosynthesis and hormone metabolism, nutritional balances, and results in ion toxicity in plants. To better understand the mechanisms of salt-induced growth inhibition in Chinese cabbage, RNA-seq and physiological index determination were conducted to explore the impacts of salt stress on carbon cycle metabolism and photosynthesis in Chinese cabbage. Here, we found that the number of thylakoids and grana lamellae and the content of starch granules and chlorophyll in the leaves of Chinese cabbage under salt stress showed a time-dependent response, first increasing and then decreasing. Chinese cabbage increased the transcript levels of genes related to the photosynthetic apparatus and carbon metabolism under salt stress, probably in an attempt to alleviate damage to the photosynthetic system and enhance CO_(2) fixation and energy metabolism. The transcription of genes related to starch and sucrose synthesis and degradation were also enhanced;this might have been an attempt to maintain intracellular osmotic pressure by increasing soluble sugar concentrations. Soluble sugars could also be used as potential reactive oxygen species(ROS) scavengers, in concert with peroxidase(POD)enzymes, to eliminate ROS that accumulate during metabolic processes. Our study characterizes the synergistic response network of carbon metabolism and photosynthesis under salt stress.

Melatonin Alleviates Abscisic Acid Deficiency Inhibition on Photosynthesis and Antioxidant Systems in Rice under Salt Stress

Melatonin and abscisic acid,as major plant hormones,play important roles in the physiological and biochemical activities of crops,but the interaction between the two under salt stress is not yet clear.This study investigated the endogenous levels of melatonin and abscisic acid in rice by using exogenous melatonin,abscisic acid,and their synthetic inhibitors,and examined their interactions under salt stress.The research results indicate that melatonin and abscisic acid can improve rice salt tolerance.Melatonin alleviated the salt sensitivity caused by abscisic acid deficiency,increased antioxidant enzyme activity and antioxidant content in rice treated with abscisic acid synth-esis inhibitors,and reduced total reactive oxygen species content and thiobarbituric acid reactive substance accu-mulation.Melatonin also increased the activity of key photosynthetic enzymes and the content of photosynthetic pigments,maintaining the parameters of photosynthetic gas exchange and chlorophyllfluorescence.In summary,melatonin alleviated the effects of abscisic acid deficiency on photosynthesis and antioxidant systems in rice and improved salt tolerance.This study is beneficial for expanding the understanding of melatonin regulation of crop salt tolerance.

Genome-Wide Exploration of the Grape GLR Gene Family and Differential Responses of VvGLR3.1 and VvGLR3.2 to Low Temperature and Salt Stress

Grapes,one of the oldest tree species globally,are rich in vitamins.However,environmental conditions such as low temperature and soil salinization significantly affect grape yield and quality.The glutamate receptor(GLR)family,comprising highly conserved ligand-gated ion channels,regulates plant growth and development in response to stress.In this study,11 members of the VvGLR gene family in grapes were identified using whole-genome sequence analysis.Bioinformatic methods were employed to analyze the basic physical and chemical properties,phylogenetic trees,conserved domains,motifs,expression patterns,and evolutionary relationships.Phylogenetic and collinear analyses revealed that the VvGLRs were divided into three subgroups,showing the high conservation of the grape GLR family.These members exhibited 2 glutamate receptor binding regions(GABAb and GluR)and 3-4 transmembrane regions(M1,M2,M3,and M4).Real-time quantitative PCR analysis demonstrated the sensitivity of all VvGLRs to low temperature and salt stress.Subsequent localization studies in Nicotiana tabacum verified that VvGLR3.1 and VvGLR3.2 proteins were located on the cell membrane and cell nucleus.Additionally,yeast transformation experiments confirmed the functionality of VvGLR3.1 and VvGLR3.2 in response to low temperature and salt stress.Thesefindings highlight the significant role of the GLR family,a highly conserved group of ion channels,in enhancing grape stress resistance.This study offers new insights into the grape GLR gene family,providing fundamental knowledge for further functional analysis and breeding of stress-resistant grapevines.

Different Approaches to Reduce Salinity in Salt-Affected Soils and Enhancing Salt Stress Tolerance in Plants

Salt stress is one of the most harmful environmental stresses in recent times and represents a significant threat to food security. Soil salinization is caused by spontaneous natural processes of mineral dissolution and human activities such as inappropriate irrigation practices. Natural geological progressions like weathering of rocks, arid climate, and higher evaporation, as well as anthropogenic activities, including the use of brackish water for irrigation, and poor tillage operations, are the foremost causes of soil salinization. Typical characteristics of saline soils are salt stress, high pH, and lack of organic carbon, as well as low availability of nutrients. Disruption of precipitation patterns as well as high average annual temperatures due to climate change additionally negatively affects the process of soil salinization. Productivity and ability to support crop growth are reduced on saline soil. Salinity-induced stress reduces plant growth by modulating the antioxidative system and nutrient orchestration. The aim of this work is to show that the mentioned problems can be alleviated in several ways such as the addition of biochar, exogenous application of several elicitors, seed priming, etc. Research has shown that the addition of biochar can significantly improve the recovery of saline soil. The addition of biochar has no significant effect on soil pH, while the cation exchange capacity of the soil increased by 17%, and the electrical conductivity of the saturated paste extract decreased by 13.2% (depends on the initial salinity and the type of biochar raw material). Moreover, biochar enriched with silicon increases the resistance of bananas to salt stress. In addition, exogenous application of several elicitors helps plants to alleviate stress by inducing stress-related physicochemical and molecular changes (selenium, sulfur, silicon, salicylic acid). Finally, seed priming showed positive effects on metabolomics, proteomics and growth of plants subjected to abiotic stress. Priming usually involves immersing the seed in a solution for a period of time to induce physiological and metabolic progression prior to germination.

Adaptive strategy of Nitraria sibirica to transient salt,alkali and osmotic stresses via the alteration of Na+/K+fluxes around root tips

Nitraria sibirica Pall.is an important shrub with a strong salt-alkali tolerance,but the mechanism underlying this tolerance remains obscure.In this study,N.sibirica,with salt-sensitive Vigna radiata(Linn.)Wilczek as the control,was subjected to transient salt stress(100 mM NaCl),alkali stress(50 mM Na_(2)CO_(3)),and osmotic stress(175 mM mannitol).The ionic fluxes of Na^(+)and K^(+)in the root apical region were measured.Results show that,under salt and alkali stress,N.sibirica roots exhibited higher capacities to limit Na+influx and reduce K+efflux,thereby resulting in lower Na^(+)/K^(+)ratios compared with V.radiata roots.Alkali stress induced stronger Na^(+)influx and K+efflux in the root salt stress treatment;Na^(+)influx was mainly observed in the root cap,while K^(+)efflux was mainly observed in the elongation zone.While under osmotic stress,N.sibirica roots showed stronger Na+efflux and weaker K+efflux than V.radiata roots.Na+efflux was mainly observed in the root elongation zone,while K+efflux was in the root cap.These results reveal the ionic strategy of N.sibirica in response to transient salt,alkali,and osmotic stresses through the regulation of Na+/K+flux homeostasis.

Analysis on Maize EST Database under the Co-stress of Drought,Salt and Alkali

[Objective] The research aimed to construct maize cDNA library under the co-stress of drought,salt and alkali,and initially analyze the expression of gene which related to the cellular function.[Method] The total RNA of mixed tissue（leaf,stem and blossom bud） of maize YQ7-96 in the male and female differentiation period（12-leaf age） was extracted.By using SMART technology,cDNA library of pDNR-LIB vector was constructed.BlastX contrast and MIPS classification analysis of EST sequence were carried out by randomly picking the clone.[Result] 3 027 cDNA clones were picked out to sequence.The length of 94.45% EST was bigger than 400 bp,and 1 861 single gene clusters were obtained.The gene which maintained the normal physiological activity occupied 65.36%.The genes which involved in the intracellular transportation,signal transduction,cell defense and cycle,DNA metabolic process were respectively 9.26%,6.58%,2.63% and 3.16%.[Conclusion] Based on the successful construction of maize cDNA library under the co-stress of drought,salt and alkali,EST was sequenced,analyzed and classified.EST which related to the cellular function was screened.It laid the foundation for the following research.

Effects of Different Arbuscular Mycorrhizal Fungi on Physiology of Viola prionantha under Salt Stress

Arbuscular mycorrhizal(AM)fungi distribute widely in natural habits and play a variety of ecological functions.In order to test the physiological response to salt stress mediated by different AM fungi,Viola prionantha was selected as the host,the dominant AM fungus in the rhizosphere of V.philippica growing in Songnen saline-alkali grassland,Rhizophagus irregularis,and their mixtures were used as inoculants,and NaCl stress was applied after the roots were colonized.The results showed that V.philippica could be colonized by AM fungi in the field and the colonization rate ranged from 73.33%to 96.67%,and Claroideoglomus etunicatum was identified as the dominant AM fungi species in the rhizosphere of V.philippica by morphology combined with sequencing for AM fungal AML1/AML2 target.Inoculation with both the species resulted in the formation of mycorrhizal symbiosis(the colonization rate was more than 70%)and AM fungi significantly enhanced plants’tolerance to salt stress of varying magnitude.Higher activity of antioxidant enzymes and augmented levels of proline and other osmoregulators were observed in AM plants.The content of MDA in CK was higher than that in the inoculations with the stress of 100,200,and 250 mM.All indices except soluble protein content and MDA content were significantly correlated with AM fungal colonization indices.The analysis for different AM fungal effects showed that the mixtures and R.irregularis worked even better than C.etunicatum.These results will provide theoretical support for the exploration and screening of salt-tolerant AM fungi species and also for the application of AM-ornamental plants in saline-alkali urban greening.

The lectin gene TRpL1 of tetraploid Robinia pseudoacacia L.response to salt stress

Lectins are natural proteins in animals,plants,and microorganisms and can be divided into 12 families.These lectins play important roles in various environmental stresses.Some polyploid plants show tolerance to environmental stresses and to insect pests.However,the mechanism of stress tolerance is unclear.Tetraploid Robinia pseudoacacia(4×)under salt stress showed higher tolerance than diploid R.pseudoacacia(2×).As lectin can improve stress tolerance,it was questioned whether the stress resistance of polyploid plants was related to the lectin protein.In this study,salt resistance of lectin gene TRpL1 was verified by its over-expression in plants.In addition,salt resistance of lectin protein by E.coli strains was detected.The data revealed that the over-expression transgenic plants of TRpL1 showed better salt tolerance than control plants under salt stress,and the TRpL1-expressing strain also grew better in the medium with added NaCl.Therefore,tetraploid plants can resist salt stress through TRpL1 protein regulation.

Analysis of Organic Acids Accumulated in Kochia Scoparia Shoots and Roots by Reverse-phase High Performance Liquid Chromatography Under Salt and Alkali Stress

Several organic acids accumulated in Kochia Scoparia shoots and roots were studied by means of reverse-phase high performance liquid chromatography with a C18 column. Five types of binary organic acids were separated. The organic acid concentrations were determined in K. Scoparia seedlings stressed by saline （NaCI） and alkaline （NaHCO3） at the same Na^＋ concentration. Concentrations of organic acids are stimulated by alkaline because the cells will adjust their pH values through the accumulation of organic acids, when the environment is basic. The concentrations of oxalic acid and succinic acid are higher than those of other organic acids, including tartaric acid and malic acid, and the concentration of citric acid is the lowest. The concentrations of the organic acids in the roots are higher than those in the shoots under salt（NaCI） stress, but the results are opposite while the roots are under alkali （ NaHCO3 ） stress. This indicates that there are different adaptive strategies for K. Scopar/a seedlings in organic acid metabolism under salt and alkali stress.

Effects of salt and alkali stress on Reaumuria soongorica germination

Seed germination and early seedling growth are crucial stages for plant establishment. Two neutral(Na Cl and Na2SO4) and two alkali(Na HCO3 and Na2CO3) salts were selected to investigate their effects on germination and recovery responses in Reaumuria soongorica. Results show that both salt types significantly reduced germination and radicle elongation. The rate of germination and emergence of R. soongorica seeds continuously decreased as salinity increased, and the time to achieve maximum germination rate was delayed. The speed of seed germination dropped rapidly as salt concentration increased.Alkaline salts restricted the germination rate of R. soongorica seeds, and stresses resulting from alkaline salts and high concentrations of neutral salts resulted in many deformed seedlings. The length of the radicle and germ decreased with increasing salt concentration, but certain concentrations of salt and increased p H promoted germ growth. The results of regression analysis show that salt concentration was the dominant factor inhibiting R. soongorica seed germination rate. Salinity, buffering capacity, and p H all affected embryo growth, but salinity had the most pronounced effect. Seed viability under highly saline conditions appears to be a better indicator of adaptation to saline environments than seed germination under saline conditions.

Effects of salt-alkali stress on active oxygen metabolism in roots of Spiraea × bumalda 'Gold Mound' and Spiraea × bumalda 'Gold Flame'

Under artificially-simulated complex salt-alkali stress, the levels of active oxygen metabolism in roots were studied using three-year-old cutting seedlings of Spiraea × bumalda ‘Gold Mound＇ and Spiraea × bumalda ‘Gold Flame＇. The present study aimed at exploring the antioxidant capacity in roots of spiraeas and revealing their adaptability to salt-alkali stress. Results indicate that the oxygen free radicals contents, electrolyte leakage rates and MDA contents in roots of Spiraea × bumalda ＇Gold Mound＇ and Spiraea × bumalda ＇Gold Flame＇ show an increasing tendency with the increases of the salinity and pH value, whereas the activities of superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） all increased firstly and then decreased. With the increase in intensity of salt-alkali stress, the CAT activity in roots of Spiraea × bumalda ‘Gold Flame＇ is higher and the increasing extents in the oxygen free radicals contents, electrolyte leakage rates as well as MDA contents are lower compared with Spiraea × bumalda ‘Gold Mound＇, indicating that Spiraea × bumalda ‘Gold Flame＇ has a stronger antioxidant capacity.

Genome-wide analysis of soybean DnaJA-family genes and functional characterization of GmDnaJA6 responses to saline and alkaline stress

Plant Dna JA proteins act as molecular chaperones in response to environmental stressors.The purpose of this study was to characterize the function and regulatory mechanisms of Dna JA genes in soybean.Gene expression profiles in various soybean tissues at various stages of development indicated that Gm Dna JAs function in the coordination of stress and plant hormone responses.Gm Dna JA6 was identified as a candidate regulator of saline and alkaline stress resistance and Gm Dna JA6 overexpression lines showed increased soybean saline and alkaline tolerance.Dna J interacted with Hsp70,and Gm Hsp70 increased the saline and alkaline tolerance of plants with chimeric soybean hairy roots.

Transcriptome Profiling of the Salt-Stress Response in Paper Mulberry

Paper mulberry is a high-quality woody feed resource plant with high crude protein content.It is widely distributed in China and has excellent characteristics of salt and alkali tolerance.Paper mulberry has ecological and economic importance.Salt stress has become a critical factor with the increasing degree of soil salinity that restricts plant growth.In the saline-alkali environments,transcriptome expression is altered leading to phenotypic defects in most plants.However,the regulatory mechanism related to paper mulberry’s salt-stress(SS)response is not clearly understood.In the present study de novo transcriptomic assembly was performed,and gene expression levels were measured between different SS and natural conditions(25℃)as a control for paper mulberry plants.According to the results of our study,under NaCl stress conditions,the differential gene expression was observed in the leaves of paper mulberry compared with the control.A total of 2126 differentially expressed unigenes were observed.Among these unigenes the expression of 812 DEGs was up-regulated and the expression of 1,314 DEGs was down-regulated.Additionally,The GO and KEGG analyses regarding differentially expressed unigenes(DEUs)revealed that the observed critical transcriptomic alterations under salt stress(SS)conditions were associated with primary and secondary metabolism,photosynthesis,and plant hormone signaling pathways.Further investigations such as gene function studies regarding the unigenes depicting altered expression under salt stress conditions in paper mulberry will help understand the mechanism of salt tolerance,and this information can be utilized in paper mulberry breeding and improvement programs.

GhSCL4 Acts as a Positive Regulator in Both Transgenic Arabidopsis and Cotton during Salt Stress

GRAS transcription factors play important roles in plant abiotic stress response,but their characteristics and functions in cotton have not been fully investigated.A cotton SCL4/7 subgroup gene in the GRAS family,GhSCL4,was found to be induced by NaCl treatments.Nuclear localization and transactivation activity of GhSCL4 indicate its potential role in transcriptional regulation.Transgenic Arabidopsis thaliana over-expressing GhSCL4 showed enhanced resistance to salt and osmotic stress.What’s more,the transcript levels of salt stress-induced genes(AtNHX1 and AtSOS1)and oxidation-related genes(AtAPX3 and AtCSD2)were more highly induced in the GhSCL4 over-expression lines than in wild type after salt treatment.Furthermore,silencing of GhSCL4 resulted in reduced salt tolerance in cotton caused by reactive oxygen species(ROS)enrichment under salt treatment,and antioxidant enzyme activities were accordingly significantly reduced in GhSLC4-silenced lines.These results indicated that GhSCL4 enhances salt tolerance of cotton by detoxifying ROS.In addition,the transient expression assay confirmed an interactive relationship between GhSCL4 and GhCaM7,which indicated that salt tolerance conferred by GhSCL4 might be associated with salt-induced Ca^(2+)/CaM7-mediated signaling.Taken together,GhSCL4 acts as a positive regulator in cotton during salt stress that is potentially useful for engineering salt-tolerant cotton.

Proteome-wide identification of S-sulfenylated cysteines response to salt stress in Brassica napus root

Reactive oxygen species(ROS)play a key role in a variety of biological processes,such as the perception of abiotic stress,the integration of different environmental signals,and the activation of stress response networks.Salt stress could induce an increased ROS accumulation in plants,disrupting intracellular redox homeostasis,leading to posttranslational modifications(PTMs)of specific proteins,and eventually causing adaptive changes in metabolism.Here,we performed an iodoTMT-based proteomic approach to identify the sulfenylated proteins in B.napus root responsing to salt stress.Totally,1348 sulfenylated sites in 751 proteins were identified and these proteins were widely existed in different cell compartments and processes.Our study revealed that proteins with changed abundance and sulfenylation level in B.napus root under salt stress were mainly enriched in the biological processes of ion binding,glycolysis,ATP binding,and oxidative stress response.This study displays a landscape of sulfenylated proteins response to salt stress in B.napus root and provides some theoretical support for further understanding of the molecular mechanisms of redox regulation under salt stress in plants.

Identification of novel salt stress-responsive microRNAs through sequencing and bioinformatic analysis in a unique halophilic Dunaliella salina strain

Dunaliella salina is a classic halophilic alga.However,its molecular mechanisms in response to high salinity at the post transcriptional level remain unknown.A unique halophilic alga strain,DS-CN1,was screened from four D.salina strains via cell biological,physiological,and biochemical methods.High-throughput sequencing of small RNAs(sRNAs)of DS-CN1 in culture medium containing 3.42-mol/L NaCl(SS group)or 0.05-mol/L NaCl(CO group)was performed on the BGISEQ-500 platform.The annotation and sequences of D.salina sRNAs were profiled.Altogether,44 novel salt stress-responsive microRNAs(miRNAs)with a relatively high C content,with the majority of them being 24 nt in length,were identified and characterized in DS-CN1.Twenty-one differentially expressed miRNAs(DEMs)in SS and CO were screened via bioinformatic analysis.A total of 319 putative salt stress-related genes targeted(104 overlapping genes)by novel miRNAs in this alga were screened based on our previous transcriptome sequencing research.Furthermore,these target genes were classified and enriched by GO and KEGG pathway analysis.Moreover,5 novel DEMs(dsa-mir3,dsa-mir16,dsa-mir17,and dsa-mir26 were significantly upregulated,and dsa-mir40 was significantly downregulated)and their corresponding 10 target genes involved in the 6 significantly enriched metabolic pathways were verified by quantitative real-time PCR.Next,their regulatory relationships were comprehensively analyzed.Lastly,a unique salt stress response metabolic network was constructed based on the novel DEM-target gene pairs.Taken together,our results suggest that 44 novel salt stress-responsive microRNAs were identified,and 4 of them might play important roles in D.salina upon salinity stress and contribute to clarify its distinctive halophilic feature.Our study will shed light on the regulatory mechanisms of salt stress responses.

Chlorophyll Fluorescence Response of Persimmon Plants under Salt Stress

[Objectives]To study the photosynthetic response mechanism of persimmon seedlings to salt stress.[Methods]The chlorophyll fluorescence parameters of Diospyros virginiana and Diospyros lotus seedlings under 4%salt stress were studied by pot culture salt control method,including the minimal fluorescence(F_(0)),maximum fluorescence(F_(m)),potential activity of PS II(F_(v)/F_(0)),maximum photochemical efficiency of PS II(F_(v)/F_(m)),electron transport rate(ETR),actual photochemical efficiency of PS II(Y II),and photochemical quenching coefficient(q_(p)).[Results]Under 4%salt stress,the maximum fluorescence(F_(m)),maximum photochemical efficiency of PS II(F v/F m),and photochemical quenching coefficient(q_(p))of two persimmon plants decreased with time.The potential activity of PS II(F_(v)/F_(0)),actual photochemical efficiency of PS II(Y_(II)),and electron transport rate(ETR)decreased under salt stress.[Conclusions]This study indicates that the PS II reaction center in the persimmon leaves was damaged and the electron transport at the acceptor side was damaged under salt stress.It is expected to lay a foundation for the analysis of salt-tolerance mechanism of persimmon plants.

Effect of Exogenous Gibberellin on Wheat Seed Germination under Salt Stress

[Objectives]In this experiment,wheat seeds were treated with different concentrations of gibberellin and different concentrations of salt solution to study the change of germination index of wheat seeds.[Methods]The germination rate,germination potential and germination index of wheat seeds were measured by routine methods,and the effect of exogenous gibberellin on germination of wheat seeds under salt stress was observed.[Results]The germination rate,germination potential and germination index of wheat seeds under salt stress were significantly increased after exogenous treatment of 0.25 and 0.50 g/L gibberellin within the range of salt concentration gradient.However,when the concentration of gibberellin was too high,it would inhibit the germination of seeds.[Conclusions]Appropriate concentration of gibberellin can effectively alleviate the stress caused by salt on wheat seed germination.In this experiment,the best concentration of gibberellin to alleviate salt stress was 0.25 g/L.

Overexpression of vacuolar proton pump ATPase(V-H^+-ATPase) subunits B, C and H confers tolerance to salt and saline-alkali stresses in transgenic alfalfa(Medicago sativa L.)

The vacuolar proton pump ATPase（V-H^＋-ATPase）, which is a multi-subunit membrane protein complex, plays a major role in the activation of ion and nutrient transport and has been suggested to be involved in several physiological processes, such as cell expansion and salt tolerance. In this study, three genes encoding V-H^＋-ATPase subunits B（Sc VHA-B, Gen Bank： JF826506）, C（Sc VHA-C, Gen Bank： JF826507） and H（Sc VHA-H, Gen Bank： JF826508） were isolated from the halophyte Suaeda corniculata. The transcript levels of Sc VHA-B, Sc VHA-C and Sc VHA-H were increased by salt, drought and saline-alkali treatments. V-H^＋-ATPase activity was also examined under salt, drought and saline-alkali stresses. The results showed that V-H^＋-ATPase activity was correlated with salt, drought and saline-alkali stress. Furthermore, V-H^＋-ATPase subunits B, C and H（Sc VHA-B, Sc VHA-C and Sc VHA-H） from S. corniculata were introduced separately into the alfalfa genome. The transgenic alfalfa was verified by Southern and Northern blot analysis. During salt and saline-alkali stresses, transgenic lines carrying the B, C and H subunits had higher germination rates than the wild type（WT）. More free proline, higher superoxide dismutase（SOD） activity and lower malondialdehyde（MDA） levels were detected in the transgenic plants under salt and saline-alkali treatments. Moreover, the Sc VHA-B transgenic lines showed greater tolerance to salt and saline-alkali stresses than the WT. These results suggest that overexpression of Sc VHA-B, Sc VHA-C and Sc VHA-H improves tolerance to salt and saline-alkali stresses in transgenic alfalfa.

AcWRKY28 mediated activation of AcCPK genes confers salt tolerance in pineapple(Ananas comosus)

Unfavorable environmental cues severely affect crop productivity resulting in significant economic losses to farmers. In plants, multiple regulatory genes, such as the WRKY transcription factor (TF) family, modulate the expression of defense genes. However, the role of the pineapple WRKY genes is poorly understood. Here, we studied the pineapple WRKY gene, AcWRKY28, by generating AcWRKY28 over-expressing transgenic pineapple plants. Overexpression of AcWRKY28 enhanced the salt stress resistance in transgenic pineapple lines. Comparative transcriptome analysis of transgenic and wild-type pineapple plants showed that “plant-pathogen interaction” pathway genes, including 9calcium-dependent protein kinases (CPKs), were up-regulated in AcWRKY28 over-expressing plants. Furthermore, chromatin immunoprecipitation and yeast one-hybrid assays revealed AcCPK12, AcCPK3, AcCPK8, AcCPK1, and AcCPK15 as direct targets of AcWRKY28. Consistently, the study of AcCPK12 over-expressing Arabidopsis lines showed that AcCPK12 enhances salt, drought, and disease resistance. This study shows that AcWRKY28 plays a crucial role in promoting salt stress resistance by activating the expression of AcCPK genes.