DRT111/SFPS Splicing Factor Controls Abscisic Acid Sensitivity during Seed Development and Germination.

RNA splicing is a fundamental mechanism contributing to the definition of the cellular protein population in any given environmental condition. DNA-DAMAGE REPAIR/TOLERATION PROTEIN111 (DRT111)/SPLICING FACTOR FOR PHYTOCHROME SIGNALING is a splicing factor previously shown to interact with phytochrome B and characterized for its role in splicing of pre-mRNAs involved in photomorphogenesis. Here, we show that DRT111 interacts with Arabidopsis (Arabidopsis thaliana) Splicing Factor1, involved in 3' splicing site recognition. Double- and triple-mutant analysis shows that DRT111 controls splicing of ABI3 and acts upstream of the splicing factor SUPPRESSOR OF ABI3-ABI5. DRT111 is highly expressed in seeds and stomata of Arabidopsis and is induced by long-term treatments of polyethylene glycol and abscisic acid (ABA). DRT111 knock-out mutants are defective in ABA-induced stomatal closure and are hypersensitive to ABA during seed germination. Conversely, DRT111 overexpressing plants show ABA-hyposensitive seed germination. RNA-sequencing experiments show that in dry seeds, DRT111 controls expression and splicing of genes involved in osmotic-stress and ABA responses, light signaling, and mRNA splicing, including targets of ABSCISIC ACID INSENSITIVE3 (ABI3) and PHYTOCHROME INTERACTING FACTORs (PIFs). Consistently, expression of the germination inhibitor SOMNUS, induced by ABI3 and PIF1, is upregulated in imbibed seeds of drt111-2 mutants. Together, these results indicate that DRT111 controls sensitivity to ABA during seed development, germination, and stomatal movements, and integrates ABA- and light-regulated pathways to control seed germination.

Alternative splicing in plant abiotic stress responses.

Modifications of the cellular proteome pool upon stress allow plants to tolerate environmental changes. Alternative splicing is the most significant mechanism responsible for the production of multiple protein isoforms from a single gene. The spliceosome, a large ribonucleoprotein complex, together with several associated proteins, controls this pre-mRNA processing, adding an additional level of regulation to gene expression. Deep sequencing of transcriptomes revealed that this co- or post-transcriptional mechanism is highly induced by abiotic stress, and concerns vast numbers of stress-related genes. Confirming the importance of splicing in plant stress adaptation, key players of stress signaling have been shown to encode alternative transcripts, whereas mutants lacking splicing factors or associated components show a modified sensitivity and defective responses to abiotic stress. Here, we examine recent literature on alternative splicing and splicing alterations in response to environmental stresses, focusing on its role in stress adaptation and analyzing the future perspectives and directions for research.

The PP2A-interactor TIP41 modulates ABA responses in Arabidopsis thaliana.

Modulation of growth in response to environmental cues is a fundamental aspect of plant adaptation to abiotic stresses. TIP41 (TAP42 INTERACTING PROTEIN OF 41 kDa) is the Arabidopsis thaliana orthologue of proteins isolated in mammals and yeast that participate in the Target-of-Rapamycin (TOR) pathway, which modifies cell growth in response to nutrient status and environmental conditions. Here, we characterized the function of TIP41 in Arabidopsis. Expression analyses showed that TIP41 is constitutively expressed in vascular tissues, and is induced following long-term exposure to NaCl, polyethylene glycol and abscisic acid (ABA), suggesting a role of TIP41 in adaptation to abiotic stress. Visualization of a fusion protein with yellow fluorescent protein indicated that TIP41 is localized in the cytoplasm and the nucleus. Abolished expression of TIP41 results in smaller plants with a lower number of rosette leaves and lateral roots, and an increased sensitivity to treatments with chemical TOR inhibitors, indicating that TOR signalling is affected in these mutants. In addition, tip41 mutants are hypersensitive to ABA at germination and seedling stage, whereas over-expressing plants show higher tolerance. Several TOR- and ABA-responsive genes are differentially expressed in tip41, including iron homeostasis, senescence and ethylene-associated genes. In yeast and mammals, TIP41 provides a link between the TOR pathway and the protein phosphatase 2A (PP2A), which in plants participates in several ABA-mediated mechanisms. Here, we showed an interaction of TIP41 with the catalytic subunit of PP2A. Taken together, these results offer important insights into the function of Arabidopsis TIP41 in the modulation of plant growth and ABA responses.

High-level production of single chain monellin mutants with enhanced sweetness and stability in tobacco chloroplasts.

MAIN CONCLUSION: Plastid-based MNEI protein mutants retain the structure, stability and sweetness of their bacterial counterparts, confirming the attractiveness of the plastid transformation technology for high-yield production of recombinant proteins. The prevalence of obesity and diabetes has dramatically increased the industrial demand for the development and use of alternatives to sugar and traditional sweeteners. Sweet proteins, such as MNEI, a single chain derivative of monellin, are the most promising candidates for industrial applications. In this work, we describe the use of tobacco chloroplasts as a stable plant expression platform to produce three MNEI protein mutants with improved taste profile and stability. All plant-based proteins were correctly expressed in tobacco chloroplasts, purified and subjected to in-depth chemical and sensory analyses. Recombinant MNEI mutants showed a protein yield ranging from 5% to more than 50% of total soluble proteins, which, to date, represents the highest accumulation level of MNEI mutants in plants. Comparative analyses demonstrated the high similarity, in terms of structure, stability and function, of the proteins produced in plant chloroplasts and bacteria. The high yield and the extreme sweetness perceived for the plant-derived proteins prove that plastid transformation technology is a safe, stable and cost-effective production platform for low-calorie sweeteners, with an estimated production of up to 25-30 mg of pure protein/plant.

Chloroplast proteome response to drought stress and recovery in tomato (Solanum lycopersicum L.).

BACKGROUND: Drought is a major constraint for plant growth and crop productivity that is receiving an increased attention due to global climate changes. Chloroplasts act as environmental sensors, however, only partial information is available on stress-induced mechanisms within plastids. Here, we investigated the chloroplast response to a severe drought treatment and a subsequent recovery cycle in tomato through physiological, metabolite and proteomic analyses. RESULTS: Under stress conditions, tomato plants showed stunted growth, and elevated levels of proline, abscisic acid (ABA) and late embryogenesis abundant gene transcript. Proteomics revealed that water deficit deeply affects chloroplast protein repertoire (31 differentially represented components), mainly involving energy-related functional species. Following the rewatering cycle, physiological parameters and metabolite levels indicated a recovery of tomato plant functions, while proteomics revealed a still ongoing adjustment of the chloroplast protein repertoire, which was even wider than during the drought phase (54 components differentially represented). Changes in gene expression of candidate genes and accumulation of ABA suggested the activation under stress of a specific chloroplast-to-nucleus (retrograde) signaling pathway and interconnection with the ABA-dependent network. CONCLUSIONS: Our results give an original overview on the role of chloroplast as enviromental sensor by both coordinating the expression of nuclear-encoded plastid-localised proteins and mediating plant stress response. Although our data suggest the activation of a specific retrograde signaling pathway and interconnection with ABA signaling network in tomato, the involvement and fine regulation of such pathway need to be further investigated through the development and characterization of ad hoc designed plant mutants.

The Arabidopsis RNA-binding protein AtRGGA regulates tolerance to salt and drought stress.

Salt and drought stress severely reduce plant growth and crop productivity worldwide. The identification of genes underlying stress response and tolerance is the subject of intense research in plant biology. Through microarray analyses, we previously identified in potato (Solanum tuberosum) StRGGA, coding for an Arginine Glycine Glycine (RGG) box-containing RNA-binding protein, whose expression was specifically induced in potato cell cultures gradually exposed to osmotic stress. Here, we show that the Arabidopsis (Arabidopsis thaliana) ortholog, AtRGGA, is a functional RNA-binding protein required for a proper response to osmotic stress. AtRGGA gene expression was up-regulated in seedlings after long-term exposure to abscisic acid (ABA) and polyethylene glycol, while treatments with NaCl resulted in AtRGGA down-regulation. AtRGGA promoter analysis showed activity in several tissues, including stomata, the organs controlling transpiration. Fusion of AtRGGA with yellow fluorescent protein indicated that AtRGGA is localized in the cytoplasm and the cytoplasmic perinuclear region. In addition, the rgga knockout mutant was hypersensitive to ABA in root growth and survival tests and to salt stress during germination and at the vegetative stage. AtRGGA-overexpressing plants showed higher tolerance to ABA and salt stress on plates and in soil, accumulating lower levels of proline when exposed to drought stress. Finally, a global analysis of gene expression revealed extensive alterations in the transcriptome under salt stress, including several genes such as ASCORBATE PEROXIDASE2, GLUTATHIONE S-TRANSFERASE TAU9, and several SMALL AUXIN UPREGULATED RNA-like genes showing opposite expression behavior in transgenic and knockout plants. Taken together, our results reveal an important role of AtRGGA in the mechanisms of plant response and adaptation to stress.

Determination of Differential Alternative Splicing Under Stress Conditions.

Alternative splicing (AS) is an important mechanism contributing to stress-induced regulation of gene expression and proteome diversity. Massive sequencing technologies allow the identification of transcripts generated via stress-responsive AS, potentially important for adaptation to stress conditions. Several bioinformatics tools have been developed to identify differentially expressed alternative splicing events/transcripts from RNA-sequencing results. This chapter describes a detailed protocol for differential alternative splicing analysis using the rMATS tool. In addition, we provide guidelines for validation of the detected splice variants by qRT-PCR based on the obtained output files.

Combined salt and low nitrate stress conditions lead to morphophysiological changes and tissue-specific transcriptome reprogramming in tomato.

Despite intense research towards the understanding of abiotic stress adaptation in tomato, the physiological adjustments and transcriptome modulation induced by combined salt and low nitrate (low N) conditions remain largely unknown. Here, three traditional tomato genotypes were grown under long-term single and combined stresses throughout a complete growth cycle. Physiological, molecular, and growth measurements showed extensive morphophysiological modifications under combined stress compared to the control, and single stress conditions, resulting in the highest penalty in yield and fruit size. The mRNA sequencing performed on both roots and leaves of genotype TRPO0040 indicated that the transcriptomic signature in leaves under combined stress conditions largely overlapped that of the low N treatment, whereas root transcriptomes were highly sensitive to salt stress. Differentially expressed genes were functionally interpreted using GO and KEGG enrichment analysis, which confirmed the stress and the tissue-specific changes. We also disclosed a set of genes underlying the specific response to combined conditions, including ribosome components and nitrate transporters, in leaves, and several genes involved in transport and response to stress in roots. Altogether, our results provide a comprehensive understanding of above- and below-ground physiological and molecular responses of tomato to salt stress and low N treatment, alone or in combination.

Low-Cost Hyperspectral Imaging to Detect Drought Stress in High-Throughput Phenotyping.

Recent developments in low-cost imaging hyperspectral cameras have opened up new possibilities for high-throughput phenotyping (HTP), allowing for high-resolution spectral data to be obtained in the visible and near-infrared spectral range. This study presents, for the first time, the integration of a low-cost hyperspectral camera Senop HSC-2 into an HTP platform to evaluate the drought stress resistance and physiological response of four tomato genotypes (770P, 990P, Red Setter and Torremaggiore) during two cycles of well-watered and deficit irrigation. Over 120 gigabytes of hyperspectral data were collected, and an innovative segmentation method able to reduce the hyperspectral dataset by 85.5% was developed and applied. A hyperspectral index (H-index) based on the red-edge slope was selected, and its ability to discriminate stress conditions was compared with three optical indices (OIs) obtained by the HTP platform. The analysis of variance (ANOVA) applied to the OIs and H-index revealed the better capacity of the H-index to describe the dynamic of drought stress trend compared to OIs, especially in the first stress and recovery phases. Selected OIs were instead capable of describing structural changes during plant growth. Finally, the OIs and H-index results have revealed a higher susceptibility to drought stress in 770P and 990P than Red Setter and Torremaggiore genotypes.

Transcriptomic landscape of tomato traditional long shelf-life landraces under low water regimes.

'Corbarino' (COR) and 'Lucariello' (LUC) belong to the family of Mediterranean long shelf-life tomato landraces, producing high quality fruits under low water input cultivation regime in their traditional cultivation area. Understanding the morpho-physiological and molecular details of the peculiar drought stress tolerance of these two genotypes may be key to their valorization as breeding material. RNA sequencing of leaf samples of COR and LUC subjected to drought stress by water withholding in a semi-controlled greenhouse identified 3089 and 2135 differentially expressed genes respectively. These included COR- and LUC-specific annotated genes, as well as genes containing single nucleotide polymorphisms as compared to reference genome. Enriched Gene Ontology categories showed that categories such as response to water, oxidoreductase activity, nucleotide salvation and lipid biosynthesis-related processes were enriched among up-regulated DEGs. By contrast, growth and photosynthesis related genes were down-regulated after drought stress, consistent with leaf gas exchange and biomass accumulation measurements. Genes encoding cell wall degrading enzymes of the pectinase family were also down-regulated in drought stress conditions and upregulated in rewatering, indicating that cell wall composition/hardness is important for drought stress responses. Globally our results contribute to understanding the transcriptomic and physiological responses of representative tomato genotypes from Southern Italy, highlighting a promising set of genes to be investigated to improve tomato tolerance to drought.

Transcriptomic and splicing changes underlying tomato responses to combined water and nutrient stress.

Tomato is a horticultural crop of high economic and nutritional value. Suboptimal environmental conditions, such as limited water and nutrient availability, cause severe yield reductions. Thus, selection of genotypes requiring lower inputs is a goal for the tomato breeding sector. We screened 10 tomato varieties exposed to water deficit, low nitrate or a combination of both. Biometric, physiological and molecular analyses revealed different stress responses among genotypes, identifying T270 as severely affected, and T250 as tolerant to the stresses applied. Investigation of transcriptome changes caused by combined stress in roots and leaves of these two genotypes yielded a low number of differentially expressed genes (DEGs) in T250 compared to T270, suggesting that T250 tailors changes in gene expression to efficiently respond to combined stress. By contrast, the susceptible tomato activated approximately one thousand and two thousand genes in leaves and roots respectively, indicating a more generalized stress response in this genotype. In particular, developmental and stress-related genes were differentially expressed, such as hormone responsive factors and transcription factors. Analysis of differential alternative splicing (DAS) events showed that combined stress greatly affects the splicing landscape in both genotypes, highlighting the important role of AS in stress response mechanisms. In particular, several stress and growth-related genes as well as transcription and splicing factors were differentially spliced in both tissues. Taken together, these results reveal important insights into the transcriptional and post-transcriptional mechanisms regulating tomato adaptation to growth under reduced water and nitrogen inputs.

A multi-criteria approach to evaluate the sustainability performances of wines: the Italian red wine case study.

The wine industry has faced two significant environmental problems in recent years: productivity is challenged by environmental trends such as global warming, and buyers are becoming more environmentally conscious. From an environmental standpoint, the food industry is one of the most impacting sectors and wine results as one of the most studied agri-food products in the scientific literature. In general, comprehensive studies that consider an application of set of indicators to evaluate the overall sustainability of wine sector are lacking in literature. This paper aims to carry out a sustainable assessment using different indicators for fifteen Italian red wines: Water Footprint (WF), Carbon Footprint (CF), Vineyard Indicator (VI), and Territory Indicator (TI). VI is an indicator of the vineyard's agronomic management's sustainability at plot level with values ranging from 0 (fully sustainable) to 1 (fully not sustainable), while TI covers the socio-economical aspects of sustainability. Considering system boundaries from cradle to grave, at 90% confidence interval, CF results ranged between 0.97 kg CO2 eq./functional unit and 1.97 kg CO2 eq./functional unit, with an average estimated at 1.47 kg CO2 eq./functional unit, while the WF of a 0.75 L bottle of wine from cradle to gate is 666.7 L/functional unit on average, out of which 86.75% is green, 1.92% is blue and 11.34% is grey water. Concerning the VI, at 90% confidence interval VI results were between 0.117 and 0.498 with an average estimated at 0.307. The results of the correlation analyses confirmed that each indicator is not statistically correlated with each other. Concerning the sub-indicators, a positive correlation has been found between the total CF and the sum of blue and grey WF. The application of a multi-criteria analysis for sustainability performances evaluation of the wine sector presented in this study can be used by wine companies' experts to better assess sustainability performances.

Benchmarking of carbon footprint data from the Italian wine sector: A comprehensive and extended analysis.

The interest in sustainability, within the wine sector, is growing simultaneously with the awareness of the environmental impacts on climate change generated by the sector itself. In this context, environmental methodologies need to be applied: Carbon Footprint of a Product (CFP) is a quantitative expression of Greenhouse Gases (GHGs) emissions that plays an influent role in emission management and evaluation of mitigation measures over the full life cycle of a product. Moreover, CFP application in the agri-food sector remains scarce due to complex, expensive, and difficult data collection. This paper aims to determine the main factors that contribute to the CFP of 33 Italian wines from 16 wineries and compare and evaluate the results obtained using all the inventory data or results obtained using a simplified model with fewer inputs. The results per Function Unit (0.75/ L of wine) have been obtained using a unique methodology. Considering system boundaries from cradle to grave, at 90% confidence interval, CFP results ranged between 0.899 kg CO2 eq./FU and 1.882 kg CO2 eq./FU. The study underlines that most of the impacts can be related to few inventory data, in fact the main contributors of GHGs emissions are: glass bottle (29%), electricity used in the winery stage (14%), transport and distribution of the final product (13%), heat used in the winery phase (9%) and fossil fuels used in vineyard (8%). The results can be helpful to support the development of a simplified CFP and to obtain a benchmark for the CFP of the Italian wine sector. Furthermore, the present study can help businesses, policy makers and consumers in making decisions that lead to a better environmental outcome.

Developmental and heat stress-regulated expression of HsfA2 and small heat shock proteins in tomato anthers.

The high sensitivity of male reproductive cells to high temperatures may be due to an inadequate heat stress response. The results of a comprehensive expression analysis of HsfA2 and Hsp17-CII, two important members of the heat stress system, in the developing anthers of a heat-tolerant tomato genotype are reported here. A transcriptional analysis at different developmental anther/pollen stages was performed using semi-quantitative and real-time PCR. The messengers were localized using in situ RNA hybridization, and protein accumulation was monitored using immunoblot analysis. Based on the analysis of the gene and protein expression profiles, HsfA2 and Hsp17-CII are finely regulated during anther development and are further induced under both short and prolonged heat stress conditions. These data suggest that HsfA2 may be directly involved in the activation of protection mechanisms in the tomato anther during heat stress and, thereby, may contribute to tomato fruit set under adverse temperatures.

Physiological Basis of Salt Stress Tolerance in a Landrace and a Commercial Variety of Sweet Pepper (Capsicum annuum L.).

Salt stress is one of the most impactful abiotic stresses that plants must cope with. Plants' ability to tolerate salt stress relies on multiple mechanisms, which are associated with biomass and yield reductions. Sweet pepper is a salt-sensitive crop that in Mediterranean regions can be exposed to salt build-up in the root zone due to irrigation. Understanding the physiological mechanisms that plants activate to adapt to soil salinization is essential to develop breeding programs and agricultural practices that counteract this phenomenon and ultimately minimize yield reductions. With this aim, the physiological and productive performances of Quadrato D'Asti, a common commercial sweet pepper cultivar in Italy, and Cazzone Giallo, a landrace of the Campania region (Italy), were compared under different salt stress treatments. Quadrato D'Asti had higher tolerance to salt stress when compared to Cazzone Giallo in terms of yield, which was associated with higher leaf biomass vs. fruit ratio in the former. Ion accumulation and profiling between the two genoptypes revealed that Quadrato D'Asti was more efficient at excluding chloride from green tissues, allowing the maintenance of photosystem functionality under stress. In contrast, Cazzone Giallo seemed to compartmentalize most sodium in the stem. While sodium accumulation in the stems has been shown to protect shoots from sodium toxicity, in pepper and/or in the specific experimental conditions imposed, this strategy was less efficient than chloride exclusion for salt stress tolerance.

Biochemical Characterization of Traditional Varieties of Sweet Pepper (Capsicum annuum L.) of the Campania Region, Southern Italy.

Bioactive compounds of different Campania native sweet pepper varieties were evaluated. Polyphenols ranged between 1.37 mmol g-1 and 3.42 mmol g-1, ß-carotene was abundant in the red variety "Cazzone" (7.05 µg g-1). Yellow and red varieties showed a content of ascorbic acid not inferior to 0.82 mg g-1, while in some green varieties the presence of ascorbic acid was almost inconsistent. Interrelationships between the parameters analyzed and the varieties showed that ascorbic acid could represent the factor mostly influencing the antioxidant activity. Polyphenol profile was different among the varieties, with a general prevalence of acidic phenols in yellow varieties and of flavonoids in red varieties. Principal Component Analysis, applied to ascorbic acid, total polyphenols and ß-carotene, revealed that two of the green varieties ("Friariello napoletano" and "Friariello Sigaretta") were well clustered and that the yellow variety "Corno di capra" showed similarity with the green varieties, in particular with "Friariello Nocerese". This was confirmed by the interrelationships applied to polyphenol composition, which let us to light on a clustering of several red and yellow varieties, and that mainly the yellow "Corno di capra" was closer to the green varieties of "Friariello".

High-level expression of the HIV-1 Pr55gag polyprotein in transgenic tobacco chloroplasts.

Plants have been recognized as a promising production platform for recombinant pharmaceutical proteins. The human immunodeficiency virus Gag (Pr55(gag)) structural polyprotein precursor is a prime candidate for developing a HIV-1 vaccine, but, so far, has been expressed at very low level in plants. The aim of this study was to investigate factors potentially involved in Pr55(gag) expression and increase protein yield in plant cells. In transient expression experiments in various subcellular compartments, the native Pr55(gag) sequence could be expressed only in the chloroplast. Experiments with truncated subunits suggested a negative role of the 5'-end on the expression of the full gene in the cytosol. Stable transgenic plants were produced in tobacco by Agrobacterium-mediated nuclear transformation with protein targeted to plastids, and biolistic-mediated plastid transformation. Compared to the nuclear genome, the integration and expression of the gag transgene in the plastome resulted in significantly higher protein accumulation levels (up to 7-8% TSP, equivalent to 312-363 mg/kg FW). In transplastomic plants, a 25-fold higher protein accumulation was obtained by translationally fusing the Pr55(gag) polyprotein to the N-terminus of the plastid photosynthetic RbcL protein. In chloroplasts, the Pr55(gag) polyprotein was processed in a pattern similar to that achieved by the viral protease, the processing being more extended in older leaves of mature plants. The Gag proteins produced in transgenic plastids were able to assemble into particles resembling VLPs produced in baculovirus/insect cells and E. coli systems. These results indicate that plastid transformation is a promising tool for HIV antigen manufacturing in plant cells.

Salinity and ABA Seed Responses in Pepper: Expression and Interaction of ABA Core Signaling Components.

Abscisic acid (ABA) plays an important role in various aspects of plant growth and development, including adaptation to stresses, fruit development and ripening. In seeds, ABA participates through its core signaling components in dormancy instauration, longevity determination, and inhibition of germination in unfavorable environmental conditions such as high soil salinity. Here, we show that seed germination in pepper was delayed but only marginally reduced by ABA or NaCl with respect to control treatments. Through a similarity search, pepper orthologs of ABA core signaling components PYL (PYRABACTIN RESISTANCE1-LIKE), PP2C (PROTEIN PHOSPHATASE2C), and SnRK2 (SUCROSE NONFERMENTING1 (SNF1)-RELATED PROTEIN KINASE2) genes were identified. Gene expression analyses of selected members showed a low abundance of PYL and SnRK2 transcripts in dry seeds compared to other tissues, and an up-regulation at high concentrations of ABA and/or NaCl for both positive and negative regulators of ABA signaling. As expected, in hydroponically-grown seedlings exposed to NaCl, only PP2C encoding genes were up-regulated. Yeast two hybrid assays performed among putative pepper core components and with Arabidopsis thaliana orthologs confirmed the ability of the identified proteins to function in ABA signaling cascade, with the exception of a CaABI isoform cloned from seeds. BiFC assay in planta confirmed some of the interactions obtained in yeast. Altogether, our results indicate that a low expression of perception and signaling components in pepper seeds might contribute to explain the observed high percentages of seed germination in the presence of ABA. These results might have direct implications on the improvement of seed longevity and vigor, a bottleneck in pepper breeding.

TIP41 network analysis and mutant phenotypes predict interactions between the TOR and ABA pathways.

Environmental conditions inform the rate of plant growth and development. The target of rapamycin (TOR) signalling pathway is a central regulator of plant growth in response to nutrients and energy, while abscisic acid (ABA) is a main mediator of abiotic stress responses. We recently characterized Arabidopsis TIP41, a predicted TOR pathway component involved in the ABA-mediated response to abiotic stress. Here, we report the ABA sensitivity of tip41 mutants, supporting the relation between TIP41 and the hormone pathway. The analysis of predicted TIP41 functional network identified several protein phosphatases. In particular, candidate protein interactors included catalytic subunits of type 2A protein phosphatases and protein phosphatases 6, which regulate different developmental processes and responses to environmental stimuli. These results provide important information on the role of TIP41 in the cross talk between TOR and ABA pathways.

Response mechanisms induced by exposure to high temperature in anthers from thermo-tolerant and thermo-sensitive tomato plants: A proteomic perspective.

Constant global warming is one of the most detrimental environmental factors for agriculture causing significant losses in productivity as heat stress (HS) conditions damage plant growth and reproduction. In flowering plants such as tomato, HS has drastic repercussions on development and functionality of male reproductive organs and pollen. Response mechanisms to HS in tomato anthers and pollen have been widely investigated by transcriptomics; on the contrary, exhaustive proteomic evidences are still lacking. In this context, a differential proteomic study was performed on tomato anthers collected from two genotypes (thermo-tolerant and thermo-sensitive) to explore stress response mechanisms and identify proteins possibly associated to thermo-tolerance. Results showed that HS mainly affected energy and amino acid metabolism and nitrogen assimilation and modulated the expression of proteins involved in assuring protein quality and ROS detoxification. Moreover, proteins potentially associated to thermo-tolerant features, such as glutamine synthetase, S-adenosylmethionine synthase and polyphenol oxidase, were identified.