Auxin-binding Protein Research Articles

Breaking ground: ABLs and TMKs as co-receptors to perceive extracellular auxin

Auxin is an important phytohormone that regulates a string of vital rapid responses, and its signaling perception mechanism has been one of the hot spots of research. It has been shown that the ABP1/TMKs module is involved in regulating extracellular auxin signaling, however, the role of ABP1 as an auxin receptor is highly controversial. Therefore, the mechanism of quintessential TMKs sense extracellular auxin remains unresolved. Recently, a study identified two new auxin-binding proteins, ABL1 and ABL2, which directly interact with TMKs to perceive apoplast auxin. This groundbreaking research unravels the mystery surrounding how plants perceive extracellular auxin signals.

Role of calcium signaling in cadmium stress mitigation by indol-3-acetic acid and gibberellin in chickpea seedlings.

Given the adverse impacts of heavy metals on plant development and physiological processes, the present research investigated the protective role of indole-3-acetic acid (IAA) and gibberellic acid (GA3) against cadmium (Cd)-induced injury in chickpea seedlings. Therefore, seeds germinated for 6 days in a medium containing 200 μM Cd alone or combined with 10 μM GA3 or 10 μM IAA. Both GA3 and IAA mitigated Cd-imposed growth delays in roots and shoots (80% and 50% increase in root and shoot length, respectively). This beneficial effect was accompanied by a significant reduction in Cd2+ accumulation in both roots (74% for IAA and 38% for GA3) and shoots (68% and 35%, respectively). Furthermore, these phytohormones restored the cellular redox state by reducing the activity of NADPH oxidase and downregulating the transcription level of RbohF and RbohD genes. Likewise, hydrogen peroxide contents were reduced by GA3 and IAA supply. Additionally, GA3 and IAA countered the Cd-induced reduction in total phenols, flavonoids, and reducing sugars in both roots and shoots. The exogenous effectors enhanced the activities of catalase, ascorbate peroxidase, and thioredoxin, as well as the corresponding gene expressions. Interestingly, adding GA3 and IAA to the Cd-contaminated germination media corrected the level of calcium (Ca2+) ion within seedling tissues. This effect coincided with the upregulation of key genes associated with stress sensing and signal transduction, including auxin-binding protein (ABP19a), mitogen-activated protein kinase (MAPK2), calcium-dependent protein kinase (CDPK1), and calmodulin (CaM). Overall, the current results suggest that GA3 and IAA sustain the Ca2+ signaling pathway, resulting in metal phytotoxicity relief. Amendment of agricultural soils contaminated with heavy metals with GA3 or IAA could represent an effective practice to improve crop yield.

The cellular and molecular basis of the spur development in Impatiens uliginosa.

The nectar spur is an important feature of pollination and ecological adaptation in flowering plants, and it is a key innovation to promote species diversity in certain plant lineages. The development mechanism of spurs varies among different plant taxa. As one of the largest angiosperm genera, we have little understanding of the mechanism of spur development in Impatiens. Here, we investigated the initiation and growth process of spurs of Impatiens uliginosa based on histology and hormone levels, and the roles of AUXIN BINDING PROTEIN (ABP) and extensin (EXT) in spur development were explored. Our results indicate that the spur development of I. uliginosa is composed of cell division and anisotropic cell elongation. Imbalances in spur proximal-distal cell division lead to the formation of curved structures. Endogenous hormones, such as auxin and cytokinins, were enriched at different developmental stages of spurs. IuABP knockdown led to an increase in spur curves and distortion of morphology. IuEXT knockdown resulted in reduced spur length and loss of curve and inner epidermal papillae structures. This study provides new insights into the mechanism of spur development in core eudicots.

Found: The missing discriminators of cell-surface auxin receptors

An Arabidopsis cell-surface auxin receptor that mediates rapid elongation consists of transmembrane kinases (TMKs) and an auxin-binding co-receptor. Auxin-binding protein 1 (ABP1) is one identified TMK co-receptor, but abp1 mutants have no elongation phenotypes. Yu etal. use structural analysis of the ABP1-binding pocket to identify functional ABP1-like (ABL) TMK co-receptors that regulate rapid growth.

ABLs and TMKs are co-receptors for extracellular auxin

Extracellular perception of auxin, an essential phytohormone in plants, has been debated for decades. Auxin-binding protein 1 (ABP1) physically interacts with quintessential transmembrane kinases (TMKs) and was proposed to act as an extracellular auxin receptor, but its role was disputed because abp1 knockout mutants lack obvious morphological phenotypes. Here, we identified two new auxin-binding proteins, ABL1 and ABL2, that are localized to the apoplast and directly interact with the extracellular domain of TMKs in an auxin-dependent manner. Furthermore, functionally redundant ABL1 and ABL2 genetically interact with TMKs and exhibit functions that overlap with those of ABP1 as well as being independent of ABP1. Importantly, the extracellular domain of TMK1 itself binds auxin and synergizes with either ABP1 or ABL1 in auxin binding. Thus, our findings discovered auxin receptors ABL1 and ABL2 having functions overlapping with but distinct from ABP1 and acting together with TMKs as co-receptors for extracellular auxin.

Save your TIRs - more to auxin than meets the eye.

Auxin has long been known as an important regulator of plant growth and development. Classical studies in auxin biology have uncovered a 'canonical' transcriptional auxin-signalling pathway involving the TRANSPORT INHIBITOR RESPONSE1/AUXIN SIGNALING F-BOX (TIR1/AFB) receptors. TIR1/AFB perception of auxin triggers the degradation of repressors and the derepression of auxin-responsive genes. Nevertheless, the canonical pathway cannot account for all aspects of auxin biology, such as physiological responses that are too rapid for transcriptional regulation. This Tansley insight will explore several 'non-canonical' pathways that have been described in recent years mediating fast auxin responses. We focus on the interplay between a nontranscriptional branch of TIR1/AFB signalling and a TRANSMEMBRANE KINASE1 (TMK1)-mediated pathway in root acid growth. Other developmental aspects involving the TMKs and their association with the controversial AUXIN-BINDING PROTEIN 1 (ABP1) will be discussed. Finally, we provide an updated overview of the ETTIN (ETT)-mediated pathway in contexts outside of gynoecium development.

ABP1-TMK auxin perception for global phosphorylation and auxin canalization.

The phytohormone auxin triggers transcriptional reprogramming through a well-characterized perception machinery in the nucleus. By contrast, mechanisms that underlie fast effects of auxin, such as the regulation of ion fluxes, rapid phosphorylation of proteins or auxin feedback on its transport, remain unclear1-3. Whether auxin-binding protein 1 (ABP1) is an auxin receptor has been a source of debate for decades1,4. Here we show that a fraction of Arabidopsis thaliana ABP1 is secreted and binds auxin specifically at an acidic pH that is typical of the apoplast. ABP1 and its plasma-membrane-localized partner, transmembrane kinase 1 (TMK1), are required for the auxin-induced ultrafast global phospho-response and for downstream processes that include the activation of H+-ATPase and accelerated cytoplasmic streaming. abp1 and tmk mutants cannot establish auxin-transporting channels and show defective auxin-induced vasculature formation and regeneration. An ABP1(M2X) variant that lacks the capacity to bind auxin is unable to complement these defects in abp1 mutants. These data indicate that ABP1 is the auxin receptor for TMK1-based cell-surface signalling, which mediates the global phospho-response and auxin canalization.

Floral organ-specific proteome profiling of the floral ornamental orchid (Cymbidium goeringii) reveals candidate proteins related to floral organ development

BackgroundCymbidium goeringii, belonging to the Orchidaceae family, is an important ornamental plant with striking petals and lips. Extremely diversified floral patterns and morphologies make C. goeringii good research material to examine floral development of orchids. However, no floral organ-specific protein has been identified yet. To screen floral development associated proteins, four proteomes from petal (PE), lip (LI), gynostemium (GY), and sepal (SE) were analyzed using Tandem Mass Tag-based proteomic analysis.ResultsA total of 6626 unique peptides encoding 2331 proteins were identified in our study. Proteins in several primary metabolic pathways, including amino acid metabolism, energy metabolism, and lipid metabolism, were identified as differentially expressed proteins. Interestingly, most of the energy metabolism-related proteins highly expressed in SE, indicating that SE is an important photosynthetic organ of C. goeringii flower. Furthermore, a number of phytohormone-related proteins and transcription factors (TFs) were identified in C. goeringii flowers. Expression analysis showed that 1-aminocyclopropane-1-carboxylate oxidase highly expressed in GY, IAA-amino acid hydrolase ILR1-like 4 and gibberellin receptor 1 C greatly expressed in LI, and auxin-binding protein ABP20 significantly expressed in SE, suggesting a significant role of hormones in the regulation of flower morphogenesis and development. For TFs, GY-highly expressed bHLH13, PE-highly expressed WRKY33, and GY-highly expressed VIP1, were identified.ConclusionsMining of floral organ differential expressed enzymes and TFs helps us to excavate candidate proteins related to floral organ development and to accelerate the breeding of Cymbidium plants.

Differences in the Abundance of Auxin Homeostasis Proteins Suggest Their Central Roles for In Vitro Tissue Differentiation in Coffea arabica.

Coffea arabica is one of the most important crops worldwide. In vitro culture is an alternative for achieving Coffea regeneration, propagation, conservation, genetic improvement, and genome editing. The aim of this work was to identify proteins involved in auxin homeostasis by isobaric tandem mass tag (TMT) and the synchronous precursor selection (SPS)-based MS3 technology on the Orbitrap Fusion™ Tribrid mass spectrometer™ in three types of biological materials corresponding to C. arabica: plantlet leaves, calli, and suspension cultures. Proteins included in the β-oxidation of indole butyric acid and in the signaling, transport, and conjugation of indole-3-acetic acid were identified, such as the indole butyric response (IBR), the auxin binding protein (ABP), the ATP-binding cassette transporters (ABC), the Gretchen-Hagen 3 proteins (GH3), and the indole-3-acetic-leucine-resistant proteins (ILR). A more significant accumulation of proteins involved in auxin homeostasis was found in the suspension cultures vs. the plantlet, followed by callus vs. plantlet and suspension culture vs. callus, suggesting important roles of these proteins in the cell differentiation process.

Independent transcriptomic and proteomic networks reveal common differentially expressed chaperone and interactor genes during tomato cv. Micro-Tom fruit ripening

Heat Shock Proteins (HSPs) are a superfamily of chaperones that have been characterized in different organisms. In plants, HSPs contribute to abiotic stress responses and development. The aim of this work was to perform an integrative analysis using bioinformatic and inferential approaches based on protein-protein interactions (PPI) network building, using transcriptomic and proteomic public data from Solanum lycopersicum cultivar (cv.) Micro-Tom during fruit ripening. We were able to identify specific chaperone networks for each maturing stage at both transcriptional and proteomic levels. Also, we noted that the number of induced chaperones was higher at the transcriptomic level than the proteomic one and increased as the fruit matured. Additionally, we identified clusters at both levels during advanced stages of ripening that were over-represented by HSP families (HSP70 and HSP20), chaperones (Proteasome assembly chaperone) and common protein interactors associated with protein folding, protein synthesis and degradation, and response to stress (Glutathione-S-transferase or GST; Endoplasmic reticulum auxin binding protein ER-ABP; tetratricopeptide repeat protein-ripening regulated protein or TRP-RRP). Finally, we found that some of these up-regulated chaperones show the presence of heat shock element (HSE) motifs in their 5′-untranslated regions (5´UTRs). Our combined inferential bioinformatics approach allowed us to integrate RNA, protein expression and co-expression levels of chaperones involved in cv. Micro-Tom fruit ripening. Statement of significance of the studyThe Chaperone network is largely characterized by diverse families including Heat Shock Proteins (HSPs), which participate in the refolding of denatured proteins in physiological processes such as developmental changes and abiotic stress response. In the present work, we performed the integrative analysis of transcriptomic and proteomic publicly available data from Solanum lycopersicum cv. Micro-Tom to describe interactome networks at both primary stages (transcription and translation) of gene expression in tomato fruits. Our strategy based on interactomics allowed us to identify specific networks at both levels for each maturing stage at fruit ripening, discovering new interactions and characterizing chaperones and co-chaperons forming these complex biological protein networks during tomato fruit ripening.

Long-term subculture affects rooting competence via changes in the hormones and protein profiles in Cedrela fissilis Vell. (Meliaceae) shoots

Long-term subculture plays an essential role in the large-scale multiplication and production of somatic plantlets. We investigated the effects of long-term subculture on in vitro shoot development and ex vitro rooting associated with changes in the hormones and protein profiles in Cedrela fissilis. The number of subcultures of shoots induced a decrease in the ex vitro rooting response. The reduction in adventitious root (AR) formation was associated with decreases in the contents of indole-3-acetic acid (IAA), abscisic acid (ABA), 12-oxo-phytodienoic acid (OPDA), putrescine (Put), and spermine and increases in jasmonic acid (JA), jasmonoyl-isoleucine, trans-cinnamic acid, and salicylic acid contents in shoots at the fourth subculture compared to the first. The ornithine decarboxylase enzyme preferentially functions in the Put biosynthesis pathway, and it was related to the highest AR formation in shoots at the first subculture. Down-accumulation of the auxin-binding protein ABP19a in shoots from the fourth subculture compared to the first subculture was related to a decrease in both the IAA content and AR formation. In addition, down-accumulation of glucose-6-phosphate isomerase; glutamine synthetase leaf isozyme, chloroplastic; 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase; l-ascorbate peroxidase, cytosolic; monodehydroascorbate reductase; and 2-Cys peroxiredoxin BAS1-like, chloroplastic and up-accumulation of caffeoyl-CoA O-methyltransferase 1 and isoforms of peroxidase 4 proteins in shoots from the fourth relative to the first subculture were associated with a reduction in AR formation. These results showed that the understanding of hormonal and molecular mechanisms related to the potential of AR formation in shoots under successive subcultures is relevant to improving large-scale plantlet production in C. fissilis.

In silico promoter and expression analyses of rice Auxin Binding Protein 57 (ABP57)

Auxin Binding Protein 57 (ABP57) is one of the molecular components involved in rice response to abiotic stress. The ABP57 gene encodes an auxin receptor which functions in activating the plasma membrane H+-ATPase. Biochemical properties of ABP57 have been characterized; however, the function of ABP57, particularly on stress and hormone responses is still limited. This study was conducted to understand the regulation of ABP57 expression under abiotic stress. Thus, in silico identification of cis-acting regulatory elements (CAREs) in the promoter region of ABP57 was performed. Several motifs and transcription factor binding site (TFBS) that are involved in abiotic stress such as ABRE, DRE, AP2/EREBP, WRKY and NAC were identified. Next, expression analysis of ABP57 under drought, salt, auxin (IAA) and abscisic acid (ABA) was conducted by reverse transcription-PCR (RT-PCR) to verify the effect of these treatments on ABP57 transcript level. ABP57 was expressed at different levels in the shoot and root under drought conditions, and its expression was increased under IAA and ABA treatments. Moreover, our results showed that ABP57 expression in the root was more responsive to drought, auxin and ABA treatments compared to its transcript in the shoot. This finding suggests that ABP57 is a drought-responsive gene and possibly regulated by IAA and ABA.

The Story of Auxin-Binding Protein 1 (ABP1).

The auxin-binding protein 1 (ABP1) has endured a history of undulating prominence as a candidate receptor for this important phytohormone. Its capacity for binding auxin has not been in doubt, a feature adequately explained by its crystal structure, but any relevance of this to auxin signaling and plant development has been far more demanding to define. Over its research lifetime, it has been associated with many auxin-induced activities, including ion fluxes across the plasma membrane, rearrangement of the cytoskeleton and cell shape, and the abundance of PIN proteins at the plasma membrane via control of endocytosis, all of which required its presence in the apoplast. Yet, ABP1 has a KDEL sequence that targets it to the endoplasmic reticulum, where most of it remains. This mismatch has been more than adequately compensated for by the need for an auxin receptor to account for responses far too rapid to be executed through transcription and translation and the TIR1/AuxIAA coreceptor system. However, discoveries showing that abp1-null mutants are not compromised for auxin signaling or development, that TIR1 or AFB1 are necessarily involved with very rapid responses at the plasma membrane, and that these rapid responses are mediated with intracellular auxin all suggest that ABP1's auxin-binding capacity is not physiologically relevant. Nevertheless, ABP1 is ubiquitous in higher plants and throughout plant tissues. We need to complete its history by defining its function inside plant cells.

Developmental roles of Auxin Binding Protein 1 in Arabidopsis thaliana

Auxin is a major plant growth regulator, but current models on auxin perception and signaling cannot explain the whole plethora of auxin effects, in particular those associated with rapid responses. A possible candidate for a component of additional auxin perception mechanisms is the AUXIN BINDING PROTEIN 1 (ABP1), whose function in planta remains unclear.Here we combined expression analysis with gain- and loss-of-function approaches to analyze the role of ABP1 in plant development. ABP1 shows a broad expression largely overlapping with, but not regulated by, transcriptional auxin response activity. Furthermore, ABP1 activity is not essential for the transcriptional auxin signaling. Genetic in planta analysis revealed that abp1 loss-of-function mutants show largely normal development with minor defects in bolting. On the other hand, ABP1 gain-of-function alleles show a broad range of growth and developmental defects, including root and hypocotyl growth and bending, lateral root and leaf development, bolting, as well as response to heat stress. At the cellular level, ABP1 gain-of-function leads to impaired auxin effect on PIN polar distribution and affects BFA-sensitive PIN intracellular aggregation.The gain-of-function analysis suggests a broad, but still mechanistically unclear involvement of ABP1 in plant development, possibly masked in abp1 loss-of-function mutants by a functional redundancy.

Morpho-Physiology and Antioxidant Enzyme Activities of Transgenic Rice Plant Overexpressing ABP57 under Reproductive Stage Drought Condition

MR219 transgenic rice line which overexpressed an auxin-binding protein (ABP57) and its wild-type cultivar, MR219, were screened under well-watered (WW) and drought stress (DS) conditions at the early reproductive stage. This study was conducted with the standard planting distance and under a normal environment to assess the yield advantages based on the field conditions. The aim of this study was to understand the response of these rice genotypes towards DS at morpho-physiological, biochemical, and agronomical levels. It was found that the DS had affected all these levels of the genotypes studied; however, the transgenic plant showed a higher number of tillers, flag leaf area, biomass, relative water content, total chlorophyll content, and antioxidative defense mechanism than the MR219 under DS. Compared to its wild-type, the transgenic plant showed an increased leaf photosynthetic rate by 7% under WW and 11% under DS. The transgenic plant also showed higher yields than MR219 under the WW (10%) and DS (59%). The results propose that drought tolerance is significantly improved in the MR219 transgenic rice line. It may develop a new opportunity for the drought-tolerant rice breeding programme via overexpression of ABP57.

Fruit Development in Ficus carica L.: Morphological and Genetic Approaches to Fig Buds for an Evolution From Monoecy Toward Dioecy.

The mechanism behind the bud evolution towards breba or main crop in Ficus carica L. is uncertain. Anatomical and genetic studies may put a light on the possible similarities/differences between the two types of fruits. For this reason, we collected complimentary data from anatomical, X-ray imaging, and genetic techniques. The RNA seq together with structural genome annotation allowed the prediction of 34,629 known genes and 938 novel protein-coding genes. Transcriptome analysis of genes during bud differentiation revealed differentially expressed genes in two fig varieties (Dottato and Petrelli) and in breba and main crop. We chose Dottato and Petrelli because the first variety does not require pollination to set main crop and the latter does; moreover, Petrelli yields many brebas whereas Dottato few. Of the 1,615 and 1,904 loci expressed in Dottato and Petrelli, specifically in breba or main crop, respectively, only 256 genes appeared to be transcripts in both varieties. The buds of the two fig varieties were observed under optical microscope and using 3D X-ray tomography, highlighting differences mainly related to the stage of development. The X-ray images of buds showed a great structural similarity between breba and main crop during the initial stages of development. Analysis at the microscope indicated that inflorescence differentiation of breba was split in two seasons whereas that of main crop started at the end of winter of season 2 and was completed within 2 to 3 months. The higher expression of floral homeotic protein AGAMOUS in breba with respect to main crop, since this protein is required for normal development of stamens and carpels in the flower, may indicate an original role of these fruits for staminate flowers production for pollination of the main crop, as profichi in the caprifig. Several genes related to auxin (auxin efflux carrier, auxin response factor, auxin binding protein, auxin responsive protein) and to GA synthesis (GA20ox) were highly expressed in brebas with respect to main crop for the development of this parthenocarpic fruit.

Proteomic responses to progressive dehydration stress in leaves of chickpea seedlings

BackgroundChickpea is an important food legume crop with high protein levels that is widely grown in rainfed areas prone to drought stress. Using an integrated approach, we describe the relative changes in some physiological parameters and the proteome of a drought-tolerant (MCC537, T) and drought-sensitive (MCC806, S) chickpea genotype.ResultsUnder progressive dehydration stress, the T genotype relied on a higher relative leaf water content after 3 and 5 d (69.7 and 49.3%) than the S genotype (59.7 and 40.3%) to maintain photosynthetic activities and improve endurance under stress. This may have been facilitated by greater proline accumulation in the T genotype than the S genotype (14.3 and 11.1 μmol g− 1 FW at 5 d, respectively). Moreover, the T genotype had less electrolyte leakage and lower malondialdehyde contents than the S genotype under dehydration stress, indicating greater membrane stability and thus greater dehydration tolerance. The proteomic analysis further confirmed that, in response to dehydration, the T genotype activated more proteins related to photosynthesis, stress response, protein synthesis and degradation, and gene transcription and signaling than the S genotype. Of the time-point dependent proteins, the largest difference in protein abundance occurred at 5 d, with 29 spots increasing in the T genotype and 30 spots decreasing in the S genotype. Some of the identified proteins—including RuBisCo, ATP synthase, carbonic anhydrase, psbP domain-containing protein, L-ascorbate peroxidase, 6-phosphogluconate dehydrogenase, elongation factor Tu, zinc metalloprotease FTSH 2, ribonucleoproteins and auxin-binding protein—may play a functional role in drought tolerance in chickpea.ConclusionsThis study highlights the significance of genotype- and time-specific proteins associated with dehydration stress and identifies potential resources for molecular drought tolerance improvement in chickpea.

Synthesis, phytotoxic evaluation and in silico studies for the development of novel natural products-inspired herbicides

Abstract Natural products are viable sources for the design of new chemical entities that may have their activities improved by fast/inexpensive synthetic modifications of their substituents. Herein we report the synthesis of six analogs of 2,4,5-trimethoxybenzaldehyde (1), a phenolic derivate isolated from Duguetia furfuracea, their corresponding phytotoxic activities and the predicted affinities concerning the inhibition of the auxin-binding protein (ABP-1). The synthesized compound 4b, methyl 2-(2,4,5-trimethoxyphenoxy)propanoate, showed the same growth-inhibition effect compared to the natural product 1 on the hypocotyl of the dicotyledon model, while 4c and 5a, (2-(2,4,5-trimethoxyphenoxy) acetic acid and 2-(2,4,5-trimethoxyphenoxy propanoic acid, respectively), demonstrated epinastic activities. The potential of interacting with the auxin-binding protein (ABP-1) was investigated by molecular docking and has shown that all the synthesized compounds were able to bind to the ABP-1 active site by similar patters of binding of the reference compound, 1-naphthalene acetic acid by hydrogen bond interactions and hydrophobic contributions. The compounds presented in this study could be highlighted as potential herbicide agents with anti-ABP-1, as well as 2,4,5-trimethoxybenzaldehyde as a good prototype to the development of new herbicides agents to the agrochemical industry.

Chilli leaf curl virus infection downregulates the expression of the genes encoding chloroplast proteins and stress-related proteins.

Virus infection alters the expression of several host genes involved in various cellular and biological processes in plants. Most of the studies performed till now have mainly focused on genes which are up-regulated and later projected them as probable stress tolerant/susceptible genes. Nevertheless, genes which are down-regulated during plant-virus interaction could also play a critical role on disease development as well as in combating the virus infection. Hence, to identify such down-regulated genes and pathway, we performed reverse suppression subtractive hybridization in Capsicum annuum var. Punjab Lal following Chilli leaf curl virus (ChiLCV) infection. The screening and further processing suggested that majority of the genes (approximately 35% ESTs) showed homology with the genes encoding chloroplast proteins and 16% genes involved in the biotic and abiotic stress response. Additionally, we identified several genes, functionally known to be involved in metabolic processes, protein synthesis and degradation, ribosomal proteins, energy production, DNA replication and transcription, and transporters. We also found 3% transcripts which did not show homology with any known genes. The redundancy analysis revealed the maximum percentage of chlorophyll a-b binding protein (15/96) and auxin-binding proteins (13/96). We developed a protein interactome network to characterise the relationships between proteins and pathway involved during the ChiLCV infection. We identified that the most of the interaction occurs either among the chloroplast proteins (Arabidopsis proteins interactive map) or biotic and abiotic stress responsive proteins (Solanum lycopersicum interactome). Taken together, our study provides the first transcriptome and protein interactome of the down-regulated genes during C. annuum-ChiLCV interaction. These resources could be exploited in deciphering the steps involved in the process of virus infection.

OsRGLP2 promoter derived GUS expression in transgenic tobacco in response to salicylic acid, H2O2, PEG, NaCl and auxins

Plants germin-like proteins (GLPs) and auxin binding proteins are involved in response to various phytohormones including auxin, pathogen infestations and abiotic stresses. Rice GLPs are involved in sheathing against blast pathogens. Keeping in view the role of GLPs in plant defence, the present study was conducted to investigate the expression analysis of rice OsRGLP2 (Oryza sativa root germin-like protein 2) promoter in response to drought, salt stress, auxins, H2O2 and salicylic acid (SA) in transgenic tobacco. A decrease in GUS expression was observed with an increase in PEG-6000 concentration while OsRGLP2 expression was strongly induced in response to SA. The maximum promoter-derived GUS expression of OsRGLP2 was noted with 300 mM NaCl after 2 h of application and lower activity in the following hours. OsRGLP2 promoter activity was observed in response to all given concentrations of H2O2 with the maximum expression at 1 and 5 mM of H2O2 after 6 h and decreased activity was observed after 9 h of application. The OsRGLP2 promoter also contains cis-acting elements, which are responsive to drought, SA, NaCl, H2O2 and auxin. Analysis of this stress inducible promoter can be useful in studying its potential use in developing stress tolerance in plants.