Rice Seedlings In Response Research Articles

Nano-enhanced defense: Titanium-enriched Alginate–Bentonite coating augments Bacillus amyloliquefaciens D203 efficacy against Magnaporthe oryzae in Kenyan rice cultivation

Rice blast disease, caused by Magnaporthe oryzae, poses a significant threat to global rice production, necessitating the development of effective and sustainable management strategies. Biological control using beneficial microbes like Bacillus amyloliquefaciens has emerged as a promising approach due to its ability to enhance plant resistance and reduce disease incidence. Nano-encapsulation of bacteria, which involves embedding beneficial microbes within nanomaterials, offers a novel method to improve the stability, survival, and efficacy of these biocontrol agents. This study evaluated the capacity of encapsulated Bacillus amyloliquefaciens D203, embedded within an alginate-bentonite coating infused with titanium nanoparticles (TNs), to stimulate defense responses in rice seedlings challenged by the Magnaporthe oryzae the causal agent of rice blast disease. Encapsulation was achieved using the extrusion technique, with some modifications. Using a completely randomized design, the experiment was conducted in a greenhouse, with four treatments replicated four times. The experiment used the popular Kenyan rice variety "BASMATI 370”. The study investigated the impact of strain D203 on the incidence, severity, and area under disease progress curves related to M. oryzae, as well as the expression of defense-related enzymes. The results demonstrated that rice plants derived from seeds coated with the D203 encapsulated B. amyloliquefaciens strain exhibited higher levels of defense-related enzyme expression, including peroxidase (POD), phenylalanine ammonia-lyase (PAL), superoxide dismutase (SOD) and catalase (CAT), compared to controls. In addition, the incidence and severity of the disease were markedly lower in plants treated with encapsulated B. amyloliquefaciens compared to controls, sometimes paralleling the efficacy of hexaconazole treatment. These findings suggest that the encapsulation of strain D203 has the potential to enhance resistance against rice blast disease by inducing systemic resistance through the production of antioxidant enzymes.

L-Glutamate Seed Priming Enhances 2-Acetyl-1-pyrroline Formation in Fragrant Rice Seedlings in Response to Arsenite Stress.

2-Acetyl-1-pyrroline (2-AP) is a fragrance compound and flavor in fragrant rice whose precursors are generally glutamate (Glu) and proline (Pro). Our previous study revealed that exogenous Glu enhanced the arsenic (As) tolerance in fragrant rice by improving the ascorbic acid-glutathione cycle and the Pro content in roots. However, less is known about how Glu is involved in 2-AP biosynthesis in fragrant rice under As stress. Herein, a hydroponic experiment of L-Glu seed priming with 0, 100, and 500 μM l-glutamic acid solutions was conducted with two fragrant rice varieties. After that, the 10-day-old seedlings were cultured under 0 and 100 μM arsenite stress for 10 d. Results showed that the 2-AP and Pro contents were increased by 18-30% and 21-78% under As100 μM-Glu100 μM treatment in comparison to the control As100 μM to Glu0 μM, while the activities of pyrroline-5-carboxylate synthetase (P5CS) and proline dehydrogenase (ProDH) were increased by 19-46% and 3-19%, respectively. Furthermore, the 2-AP, Pro contents, and P5CS activity were correlated positively. Correspondingly, a significant abundance of differential expressed metabolites (18) and differential expressed genes (26) was observed in amino acid metabolism and glutathione metabolism pathways. In addition, several essential genes were verified and grouped into the pathways of glutathione metabolism, proline, and arginine metabolism with antioxidant defense system to comodulate 2-AP biosynthesis and stress detoxification. Therefore, the Glu seed priming treatment had a positive impact on the 2-AP biosynthesis of fragrant rice under 100 μM arsenite toxicity.

Growth, nutrient uptake and transcriptome profiling of rice seedlings in response to mixed provision of ammonium- and nitrate-nitrogen

Nitrogen (N) is a principal macronutrient and plays a paramount role in mineral nutrition of rice plants. Mixed provision of ammonium- and nitrate-nitrogen (MPAN) at a moderate level could enhance N uptake and translocation and promote growth of rice, but current understanding of their molecular mechanisms is still insufficient. Two rice lines of W6827 and GH751, with contrasting ability of N uptake, were subjected to four levels of MPAN (NH4+/NO3− = 100:0, 75:25, 50:50, 25:75) in hydroponic experiments. In terms of plant height, growth rate and shoot biomass, growth of GH751 tended to increase firstly and then decrease with enhancement in NO3−-N ratio. It attained maximal level under 75:25 MPAN, with an 8.3% increase in shoot biomass. In general, W6827 was comparatively less responsive to MPAN. For GH751, the uptake rate of N, phosphor (P) and potassium (K) under 75:25 MPAN was enhanced by 21.1%, 20.8% and 16.1% in comparison with that of control (100:0 MPAN). Meanwhile, the translocation coefficient and content in shoots of N, P and K were all increased significantly. In contrast to transcriptomic profile under control, 288 differentially expressed genes (DEGs) were detected to be up-regulated and 179 DEGs down-regulated in transcription under 75:25 MPAN. Gene Ontology analysis revealed that some DEGs were up-regulated under 75:25 MPAN and they code for proteins mainly located in membrane and integral component of membrane and involved in metal ion binding, oxidoreductase activity and other biological processes. KEGG pathway enrichment analysis indicated that DEGs related to nitrogen metabolism, carbon fixation in photosynthetic organisms, photosynthesis, starch and sucrose metabolism, and zeatin biosynthesis were up- or down-regulated in transcription under 75:25 MPAN, and they are responsible for improved nutrient uptake and translocation and enhanced growth of seedlings.

The Expanded and Diversified Calmodulin-Binding Protein 60 (CBP60) Family in Rice (Oryza sativa L.) Is Conserved in Defense Responses against Pathogens

Plant disease management is key to sustainable production of staple food crops. Calcium (Ca2+) signal and phytohormones play critical roles in regulating plant defense responses against pathogens. The Ca2+ signals are sensed, decoded and transduced by calmodulin and other Ca2+ -binding proteins, followed by interaction with and modulation of activities of target proteins such as calmodulin-binding proteins (CBPs). Members of the Arabidopsis CBP60 gene family, AtCBP60g and AtSARD1, have emerged as major regulators of immune responses. In this study, we identified a 15 member CBP60 gene family in rice (Oryza sativa) of which OsCBP60g-3, OsCBP60g-4, OsCBP60a and OsSARD-like1 genes were consistently upregulated in rice seedlings in response to infection with both fungal (Magnaporthe oryzae) and bacterial (Xanthomonas oryzae) pathogens as well as by salicylic acid (SA). OsCBP60g-4 and OsCBP60g-3 were induced maximally by SA and brassinosteroid (BR), respectively, and OsCBP60g-4 was expressed at 3-fold higher levels in the M. oryzae resistant rice genotype (IC-346004) as compared to the susceptible rice genotype (Rajendra Kasturi). The considerable expansion of the immunity clade and the up-regulation of several OsCBP60 genes in response to pathogens and defense hormones supports the importance of further investigating OsCBP60 genes as targets for increasing disease resistance in rice.

Transcriptional and physiological data revealed cold tolerance in a photo-thermo sensitive genic male sterile line Yu17S

BackgroundRice is highly sensitive to chilling stress during the seedling stage. However, the adaptable photo-thermo sensitive genic male sterile (PTGMS) rice line, Yu17S, exhibits tolerance to low temperatures. Currently, the molecular characteristics of Yu17S are unclear.ResultsTo evaluate the molecular mechanisms behind cold responses in rice seedlings, a comparative transcriptome analysis was performed in Yu17S during seedling development under normal temperature and low temperature conditions. In total, 9317 differentially expressed genes were detected. Gene ontology and pathway analyses revealed that these genes were involved mostly in photosynthesis, carotenoid biosynthesis, carbohydrate metabolism and plant hormone signal transduction. An integrated analysis of specific pathways combined with physiological data indicated that rice seedlings improved the performance of photosystem II when exposed to cold conditions. Genes involved in starch degradation and sucrose metabolism were activated in rice plants exposed to cold stress treatments, which was accompanied by the accumulation of soluble sugar, trehalose, raffinose and galactinol. Furthermore, chilling stress induced the expression of phytoene desaturase, 15-cis-ζ-carotene isomerase, ζ-carotene desaturase, carotenoid isomerase and β-carotene hydroxylase; this was coupled with the activation of carotenoid synthase activity and increases in abscisic acid (ABA) levels in rice seedlings.ConclusionsOur results suggest that Yu17S exhibited better tolerance to cold stress with the activation of carotenoid synthase activity and increasing of ABA levels, and as well as the expression of photosynthesis-related genes under cold condition in rice seedlings.

Membrane stability and antioxidant enzyme activity of rice seedlings in response to short-term high temperature treatments

The impact of temperature on plants varies depending on the temperature level and the time of exposure. The aim of this study was evaluating different short-term temperatures to stimulate rice (Oryza sativa L.) seedling growth indicated by some physiological functions. Thus, oxidative stress, membrane stability and antioxidant activity in ‘Dular’, ‘IR64’ and ‘KDML105’ rice seedlings were evaluated in response to 25, 35 and 45 °C for 30 min. At 25 °C, ‘IR64’ showed higher electrolyte leakage (EL) percentages, protein contents and peroxidase (POX) activity but lower hydrogen peroxide (H2O2) content. At 35 °C, the highest H2O2 content was found in ‘KDML105’ followed by ‘IR64’ and ‘Dular’. In all rice seedlings the lowest EL was after 35 °C exposure and activities of catalase (CAT) in ‘IR64’ and ‘KDML105’, ascorbate peroxidase (APX) in ‘Dular’, ‘IR64’ and ‘KDML105’ and glutathione reductase (GR) in ‘Dular’, ‘IR64’ and ‘KDML105’, and superoxide dismutase (SOD) in ‘Dular’ and ‘KDML105’ were stimulated by higher H2O2 production. At 45 °C, all rice seedlings showed pronounced EL increase but reduced H2O2 production, protein content and all antioxidant enzyme activities. These results suggested that short-term temperature at 35 °C was an optimum condition for all rice seedlings as indicated by the least membrane damage (EL ≈ 45.04%) and induction of most antioxidant enzymes (CAT, APX, GR and SOD ≈ 48.29 nmol min-1 μg-1 protein, 247.49 ng ascorbic acid min-1 μg-1 protein, 0.16 μM min-1 μg-1 protein and 0.078 unit min-1 μg-1 protein, respectively). This temperature induced higher H2O2 production which plays a significant role in signaling molecules to stimulate protein function and antioxidant enzyme activities. While short-term 45 °C proved to be damaging temperature for all rice seedlings because of membrane damage and decreased reactive oxygen species defense mechanism.

Linkage analysis, GWAS, transcriptome analysis to identify candidate genes for rice seedlings in response to high temperature stress

BackgroundRice plants suffer from the rising temperature which is becoming more and more prominent. Mining heat-resistant genes and applying them to rice breeding is a feasible and effective way to solve the problem.ResultThree main biomass traits, including shoot length, dry weight, and fresh weight, changed after abnormally high-temperature treatment in the rice seedling stage of a recombinant inbred lines and the natural indica germplasm population. Based on a comparison of the results of linkage analysis and genome-wide association analysis, two loci with lengths of 57 kb and 69 kb in qDW7 and qFW6, respectively, were associated with the rice response to abnormally high temperatures at the seedling stage. Meanwhile, based on integrated transcriptome analysis, some genes are considered as important candidate genes. Combining with known genes and analysis of homologous genes, it was found that there are eight genes in candidate intervals that need to be focused on in subsequent research.ConclusionsThe results indicated several relevant loci, which would help researchers to further discover beneficial heat-resistant genes that can be applied to rice heat-resistant breeding.

Isolation and Characterization of a Rice Mitochondrial Small Heat Shock Protein Gene

To understand the role of small heat shock protein (sHSPs) in rice plant response to various stresses such as the heat and oxidative stresses, a cDNA encoding a 24.1 kDa mitochondrial small HSP (Oshsp24.1) was isolated from rice by rapid amplification of cDNA ends (RACE) PCR. The deduced amino acid sequence shows very high similarity with other plant small HSPs. DNA gel blot analysis suggests that the rice genome contains more than one copy of Oshsp24.1. High level of expression of Oshsp24.1 transcript was observed in rice seedlings in response to heat, methyl viologen, hydrogen peroxide, ozone, salt and heavy metal stresses. Recombinant OsHSP24.1 protein was produced in E. coli cells for biochemical assay. The protein formed oligomeric complex when incubated with Sulfo-EGS (ethylene glycol bis (succinimidyl succinate)). Our results shows that Oshsp24.1 has an important role in abiotic stress response and have potential for developing stress-tolerant plants.

Effect of seedling age on growth and yield of fine rice cultivars under alternate wetting and drying system

Use of older age seedlings of rice often decreased the yield in transplanted rice systems. However, the response of rice seedlings at different ages in transplanting system under alternate wetting and drying (AWD) is not well documented. Therefore, this study was endeavored to identify the suitable seedling age of fine rice cultivars in transplanted rice systems under AWD. Four seedling age treatments (20, 25, 30, and 35 days), and three fine rice cultivars (Chenab, Punjab, Kissan basmati) were arranged under randomized complete block design (RCBD). Two years (2017–2018) of studies demonstrated that overall younger seedlings (20 days old) increased rice growth phase (days taken to reach physiological maturity) after transplantation with less mortality rate, and quantified with higher water productivity. Younger seedlings (20 days old) produced 14.69% and 13.36% longer panicle, 19.36% and 18% more filled grains panicle−1 in both years (2017 and 2018) respectively as compared to the older seedlings (35 days old). Moreover, younger seedling (20 days) produced 22% and 22.92% kg ha−1 more yield in comparison to (35 days) older seedling in both years, respectively. However, cultivars also had significant differences in growth and yield production, and Chenab basmati showed vigorous growth and produced higher yield than Punjab and Kissan basmati. Furthermore, agronomic traits such as, productive tillers, panicle length, number of branches, and filled grains in panicle significantly contributed for grain yield formation. Overall, our results revealed that younger seedlings of fine rice could be a better option to obtain optimum fine rice yield under AWD.

Prohydrojasmon prevents spindly growth and induces the expression of an abiotic and biotic stress marker gene, PBZ1p::sGFP, in rice

ABSTRACT Prohydrojasmon (PDJ) is a synthetic derivative of the plant hormone jasmonic acid (JA), which is used in apples, grapes, and mandarin oranges as a plant growth regulator. Here, we show that irrigation of PDJ could prevent spindly growth of rice seedlings in both indica and japonica cultivars. PDJ also inhibited root elongation in hydroponically growing seedlings in various cultivars. The higher dry root weight following PDJ application than the controls was observed in two japonica cultivars. Furthermore, its reduction was slight in comparison with the inhibition of root elongation. Starch degradation in the endosperm of seedlings grown in PDJ solution was slower than those grown in the control. The inhibition of root elongation could be mediated by the combined application of PDJ and appropriate concentrations of a synthetic auxin, NAA (1-Naphthaleneacetic acid). Additionally, we generated transgenic rice carrying sGFP driven by the PBZ1 promoter, a marker gene for abiotic and biotic stress responses. The expression of PBZ1p::sGFP was induced by PDJ treatment in the roots and seeds. PDJ could be used as a plant growth regulator to prevent spindly growth and to induce stress responses in rice seedlings.

Effects and mechanisms of foliar application of silicon and selenium composite sols on diminishing cadmium and lead translocation and affiliated physiological and biochemical responses in hybrid rice (Oryza sativa L.) exposed to cadmium and lead

Currently, exploring effective measures to reduce multiple toxic metals accumulation in rice grains is an urgent issue to be tackled. Pot experiments were thus conducted to explore the effects and mechanisms of foliar spraying with composite sols of silicon (Si) and selenium (Se) during tillering to booting stage on diminishing cadmium (Cd) and lead (Pb) translocation to rice grains and affiliated physiological and biochemical responses in rice seedlings grown in Cd + Pb-polluted soils (positive control). Results showed that Cd and Pb contents in leaves or grains were distinctly below the positive control by the sols. Compared to the positive control, transcriptions of Cd transporter-related genes including OsLCT1, OsCCX2, OsHMA2 and OsPCR1 genes in leaves, and OsLCT1, OsCCX2, TaCNR2 and OSPCR1 in peduncles were downregulated by the increasing sols. Meanwhile, Se-binding protein 1 was evidently upregulated, together to retard Cd and Pb translocation to rice grains. The sols not only upregulated transcriptions of Lhcb1, RbcL, and OsBTF3 genes and production of psbA, Lhcb1 and RbcL proteins, but also increased the chlorophylls contents and RuBP carboxylase activities in the leaves, improving photosynthesis. The sols restrained ROS production from NADPH oxidases, but activated glutathione peroxidase, alleviating oxidative stress and damage. Additionally, Se was significantly enriched and was existed as selenomethionine in the rice grains. However, Pb transporter-related genes remain to be specified. Thus, the composite sols have potential to reduce Cd and Pb accumulation, mitigate oxidative damage, and promote photosynthesis and organic Se enrichment in rice plants under Cd and Pb combined pollution.

Integrated analyses of miRNAome and transcriptome reveal zinc deficiency responses in rice seedlings

BackgroundZinc (Zn) deficiency is one of the most widespread soil constraints affecting rice productivity, but the molecular mechanisms underlying the regulation of Zn deficiency response is still limited. Here, we aim to understand the molecular mechanisms of Zn deficiency response by integrating the analyses of the global miRNA and mRNA expression profiles under Zn deficiency and resupply in rice seedlings by integrating Illumina’s high-throughput small RNA sequencing and transcriptome sequencing.ResultsThe transcriptome sequencing identified 360 genes that were differentially expressed in the shoots and roots of Zn-deficient rice seedlings, and 97 of them were recovered after Zn resupply. A total of 68 miRNAs were identified to be differentially expressed under Zn deficiency and/or Zn resupply. The integrated analyses of miRNAome and transcriptome data showed that 12 differentially expressed genes are the potential target genes of 10 Zn-responsive miRNAs such as miR171g-5p, miR397b-5p, miR398a-5p and miR528-5p. Some miRNA genes and differentially expressed genes were selected for validation by quantitative RT-PCR, and their expressions were similar to that of the sequencing results.ConclusionThese results provide insights into miRNA-mediated regulatory pathways in Zn deficiency response, and provide candidate genes for genetic improvement of Zn deficiency tolerance in rice.

Biochemical responses of rice roots to cold stress

BackgroundCold stress is the main factor that reduces rice yield in subtropical areas, especially at the seedling stage. Most of the current studies on cold stress focus the responses of rice shoots to cold stress. Limited studies are available on that of rice roots to cold stress. This study aimed to illustrate the biochemical responses of rice root under cold treatment, and subject to the establishment of cold stress-related biochemical traits for rice breeding or cropping-adjustment.ResultsOur results showed that the growth of rice seedling diminished under cold stress with difference extents among eight rice cultivars of most productive in Taiwan. Under cold treatments, the tested cultivars with higher growth rate had a higher level of hydrogen peroxide (H2O2) in the shoots but had a lower level in the roots. In contrast, the tested cultivates with low growth rate had higher levels of H2O2 in the roots but a lower level in the shoots. Meanwhile, higher MDA contents and higher cell-damage related electrolyte leakage were also found in the roots not in the shoots, suggesting that cold stress might induce oxidative stress in the roots, not in the shoots. Furthermore, the activity analysis of four antioxidant enzymes, namely superoxide dismutase (SOD), catalase (CAT), ascorbic peroxidase (APX), and glutathione reductase (GR), revealed that cold stress could increase SOD and CAT activities in the roots.ConclusionsIn summary, low H2O2 and low MDA contents along with lower SOD and CAT activities in rice root could be the biochemical traits of cold responses in rice seedlings. The results are hoping to have a contribution to the rice breeding or cropping-adjustment on cold tolerance.

Editing of the OsACS locus alters phosphate deficiency-induced adaptive responses in rice seedlings.

Phosphate (Pi) deficiency severely influences the growth and reproduction of plants. To cope with Pi deficiency, plants initiate morphological and biochemical adaptive responses upon sensing low Pi in the soil, and the plant hormone ethylene plays a crucial role during this process. However, how regulation of ethylene biosynthesis influences the Pi-induced adaptive responses remains unclear. Here, we determine the roles of rice 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS), the rate-limiting enzymes in ethylene biosynthesis, in response to Pi deficiency. Through analysis of tissue-specific expression of OsACS in response to Pi deficiency and OsACS mutants generated by CRISPR/Cas9 [clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9] genome editing, we found that two members of the OsACS family, i.e. OsACS1 and OsACS2, are involved but differed in their importance in controlling the remodeling of root system architecture, transcriptional regulation of Pi starvation-induced genes, and cellular phosphorus homeostasis. Interestingly, in contrast to the known inhibitory role of ethylene on root elongation, both OsACS mutants, especially OsACS1, almost fail to promote lateral root growth in response to Pi deficiency, demonstrating a stimulatory role for ethylene in lateral root development under Pi-deficient conditions. Together, this study provides new insights into the roles of ethylene in Pi deficiency response in rice seedlings and the isoform-specific function of OsACS genes in this process.

Nitrogen supply influences arsenic accumulation and stress responses of rice (Oryza sativa L.) seedlings.

In the present study, the effects of nitrogen supply (low nitrogen: LN and high nitrogen: HN) on As stress (25 μM) responses of rice seedlings were monitored for 7 d. The mean length of primary, adventitious and lateral roots and number of adventitious and lateral roots were significantly improved in LN+As, while further reduced in HN+As, as compared to As alone treatment at 7 d. The LN+As treatment resulted in significant decline in As (848 μg g-1 DW) than that in As alone treatment (1434 μg g-1 DW) in roots but no significant effect was seen in shoot. In contrast, HN+As treatment showed significant increase in shoot As (6.86 μg g-1 DW) as compared to As alone treatment (3.43 μg g-1 DW). The level of nitrate was increased in roots but declined in shoots in As alone treatment. Surprisingly, no improvement in nitrate level was seen in HN+As as compared to that in As alone treatment in both root and shoot. The expression analysis of nitrate transporters (NRT2;1, NRT2;3a, NRT2;4) showed significant differences in expression patterns in As, LN+As and HN+As treatments. In conclusion, nitrogen supply had profound influences on responses of rice plants to As.

NAC transcription factor family members are differentially expressed in rice seedlings in response to Rice Tungro Spherical Virus

NAC transcription factor family members are differentially expressed in rice seedlings in response to Rice Tungro Spherical Virus

Changes in physiological and antioxidant activity of indica rice seedlings in response to mannitol-induced osmotic stress

Changes in physiological and antioxidant activity of indica rice seedlings in response to mannitol-induced osmotic stress

A comparative study of effects of increasing concentrations of phosphate and phosphite on rice seedlings

While phosphate (Pi) serves as an essential and indispensible plant nutrient, phosphite (Phi) acts as a potent herbicide. Despite their differential influence on plants, both the ions can attenuate phosphate starvation responses (PSRs). We analyzed and compared Pi and Phi uptake and accumulation, attenuation of PSRs and the morphological and physiological responses of the rice seedlings in response to the increasing concentrations of Pi and Phi. Our study revealed that increasing levels of Phi led to pronounced reduction in shoot and root mass in rice seedlings in comparison to similar Pi treatments. Phi inhibited root hair and root formation at 5 and 30 mM Phi concentrations, respectively. Whereas, higher Pi concentrations (40 and 50 mM) affected only root hair elongation. Increasing Phi dose led to drastic reduction in chlorophyll content which was not so in case of Pi. There was inverse relationship between external Pi/Phi level and anthocyanin content of the leaves. In comparison to 20 mM Pi treatment, similar dose of Phi led to significant downregulation of Pi transporters in both leaves and roots. Rice seedlings were found to accumulate mmol and µmol levels of Pi and Phi, respectively. Comparison of various PSR parameters revealed that in comparison to Pi, Phi exhibited greater degree of attenuation of PSRs. Lesser Phi accumulation and greater attenuation of PSRs by Phi indicate plant’s adaption to restrict entry of this toxic ion inside cells.

Gene expression profiling of rice seedlings in response to glutamine treatment

Glutamine, the most abundant free amino acid in humans (Curi et al., 2007 [1]), has many functions. In addition to protein, amino acid, and nucleic acid biosynthesis, glutamine also regulates the expression of genes related to metabolism, cell defense, and signal transduction in humans (Curi et al., 2007 [1]; Brasse-Lagnel et al., 2009 [2]). Glutamine is also one of the major forms of nitrogen in rice (Fukumorita and Chino, 1982 [3]). In addition to metabolic and nutritional effects, glutamine may function as a signaling molecule to regulate gene expression in plants. To this end, we used microarray analysis to identify genes that are rapidly induced by 2.5 mM glutamine in rice roots. The results revealed that glutamine induced the expression of at least 35 genes involved in metabolism, transport, signal transduction, and stress responses within 30 min (Kan et al., 2015 [4]). Here, we provide the details of the experimental procedure associated with our microarray data deposited in NCBI's Gene Expression Omnibus (GEO ID: GSE56770).

Quantitative proteomics study on Lsi1 in regulation of rice (Oryza sativa L.) cold resistance

Low temperature is one of the major abiotic stresses which severely affects the productivity and the geographical distribution of rice (Oryza sativa). Silicon is considered a broad spectrum alleviator to combat stress in rice plant. Rice root absorbs silicon by a silicon transporter, Low silicon gene 1 (Lsi1). To gain a better understanding of cold stress responses triggered by overexpression of Lsi1 in rice (Oryza sativa L.), we carried out physiological and molecular studies between Lsi1-overexpression Dular (Lsi1-D) and its wild type (WD). Two leaf stage rice seedlings of above mentioned both lines were treated at 15 °C/12 °C (day/night) for 7 days. WD seedling leaves were turned comparatively yellow as compared to Lsi1-D seedlings. Microscopic studies showed significantly more deposition of silicon bodies in epidermal cells of Lsi1-D leaf seedlings in comparison with WD leaves. Lsi1-D leaves comparatively, depicted more SOD, POD and CAT activity, chlorophyll a, b contents in consistency with more silicon concentration. Protein extraction was carried out from whole seedling of both lines and further analyzed by tandem mass tag quantitative proteomics approach with double replicates. Among 393 reproducible proteins, 63 were up-regulated and 39 proteins were down-regulated. The total cold responsive differential proteins were involved in several processes, i.e. photosynthesis, signal transduction, redox homeostasis, hormone metabolism, carbohydrate metabolism, cell wall organization, N-assimilation, protein processing and secondary metabolism. We confirmed up-regulation of key proteins involved in cold-responsive pathway at mRNA level through qPCR such as chlorophyll a–b binding protein 1, peroxidase 2, signaling G-proteins RIC1, aquaporin PIP1.2, 1, 4-alpha-glucan branching enzyme, germin-like protein subfamily 2 member 4 and germin-like protein subfamily 8 member 2. In conclusion, our study provides new insights into cold stress responses in rice seedlings triggered by Lsi1-overexpression defense pathway.