Utjecaj NaCl na fermentaciju zrelih zelenih rajčica cv. Ailsa Braig u rasolu

The effect of osmotic strength on gene expression and activity of the major enzymes of fermentative metabolism of mature green tomato fruit (Solanum lycopersicum cv. Ailsa Craig) has been studied by exposing fruit to brine containing 0 (water), 5 and 10 % NaCl. The fruits were surface sterilized prior to treatment to prevent the growth of microbes naturally present on the skin of the fruit. Changes in fruit expression of fermentation genes and the activity of the respective enzymes as well as physicochemical quality characteristics (soluble solid content, titratable acidity, pH and firmness) were studied in both fruit and brine for 0.5, 1, 1.5, 2, 3, 7 and 14 days. Discrepancies in responses that resulted from the different salt concentrations were obtained at molecular and quality levels. The complex kinetics of solutes between the fruit and the surrounding solution due to osmotic potential has led to different responses of the tissue to fermentation. Tomato fruit showed cracking soon after storage in water; water-stored fruit had higher titratable acidity, lower soluble solid content, and higher induction of anaerobic metabolism as indicated by the expression or the activity of the fermentation enzymes compared to fruit stored in brine with 5 or 10 % NaCl. No cracking was observed in fruit stored in 5 (isotonic) or 10 % NaCl (hypertonic) brine, though in the latter, signs of dehydration were observed. The presence of salt in brine reduced the intensity of fermentative metabolism as indicated by the lower gene expression and enzyme activity. However, fruit stored in brine with 5 % NaCl survived longer than with 0 or 10 % NaCl. The presence of 5 % NaCl in brine caused mild changes of both the fermentative metabolism and the physicochemical characteristics and prevented fruit deterioration during storage.U radu je ispitan utjecaj osmoze na ekspresiju gena i aktivnost glavnih enzima koji sudjeluju u fermentaciji zrelih zelenih rajčica (Solanum lycopersicum cv. Ailsa Craig), i to uranjanjem plodova u vodu i rasol što sadržava 5 ili 10 % NaCl. Površina je plodova prije obrade sterilizirana da bi se spriječio rast mikroorganizama na pokožici ploda. Analizirani su plodovi rajčice i rasol tijekom 0,5; 1; 1,5; 2; 3; 7 i 14 dana skladištenja, te ispitani ovi parametri: promjena ekspresije gena i aktivnost enzima koji sudjeluju u fermentaciji, te fizikalno-kemijska svojstva plodova (udio topljivih tvari, titracijska kiselost, pH-vrijednost i čvrstoća). Utvrđene su razlike u dobivenim rezultatima, i to na molekularnoj razini te u kakvoći plodova. Zaključeno je da utjecaj fermentacije na tkivo ploda rajčice ovisi o složenoj kinetici prelaska otopljenih tvari iz plodova u otopinu zbog razlike osmotskih tlakova. Skladištenje u vodi uzrokovalo je pucanje plodova koji su imali veću titracijsku kiselost i manji udio topljivih tvari. Ekspresija gena i aktivnost enzima pokazali su da je došlo do povećanja anaerobnog metabolizma u tim plodovima, u usporedbi s onima skladištenim u rasolu. Skladištenje plodova u izotoničnoj otopini (5 % soli) nije uzrokovalo njihovo pucanje, a u hipertoničnoj (10 % soli) otopini nije došlo do pucanja već do dehidracije plodova. Dodatkom soli smanjen je intenzitet fermentacije, što je dovelo do manje ekspresije gena i aktivnosti enzima. Trajnost plodova skladištenih u izotoničnoj otopini bila je veća od onih skladištenih u vodi ili hipertoničnoj otopini. Manja koncentracija soli u otopini nije bitno utjecala na metabolizam fermentacije te kakvoću plodova, a spriječila je njihovo propadanje tijekom skladištenja

A plant-specific clade of serine/arginine-rich proteins regulates RNA splicing homeostasis and thermotolerance in tomato

Global warming poses a threat for crops, therefore, the identification of thermotolerance mechanisms is a priority. In plants, the core factors that regulate transcription under heat stress (HS) are well described and include several HS transcription factors (HSFs). Despite the relevance of alternative splicing in HS response and thermotolerance, the core regulators of HS-sensitive alternative splicing have not been identified. In tomato, alternative splicing of HSFA2 is important for acclimation to HS. Here, we show that several members of the serine/arginine-rich family of splicing factors (SRSFs) suppress HSFA2 intron splicing. Individual-nucleotide resolution UV cross-linking and immunoprecipitation (iCLIP) combined with RNA-Seq revealed that RS2Z35 and RS2Z36, which make up a plant-specific clade of SR proteins, not only regulate HSFA2 but approximately 50% of RNAs that undergo HS-sensitive alternative splicing, with preferential binding to purine-rich RNA motifs. Single and double CRISPR rs2z mutant lines show a dysregulation of splicing and exhibit lower basal and acquired thermotolerance compared to wild type plants. Our results suggest that RS2Z35 and RS2Z36 have a central role in mitigation of the negative effects of HS on RNA splicing homeostasis, and their emergence might have contributed to the increased capacity of plants to acclimate to high temperatures

HSP90 regulates temperature-dependent seedling growth in Arabidopsis by stabilizing the auxin co-receptor F-box protein TIR1

Recent studies have revealed that a mild increase in environmental temperature stimulates the growth of Arabidopsis seedlings by promoting biosynthesis of the plant hormone auxin. However, little is known about the role of other factors in this process. In this report we show that increased temperature promotes rapid accumulation of the TIR1 auxin co-receptor, an effect that is dependent on the molecular chaperone HSP90. In addition, we show that HSP90 and the co-chaperone SGT1 each interact with TIR1, confirming that TIR1 is an HSP90 client. Inhibition of HSP90 activity results in degradation of TIR1 and interestingly, defects in a range of auxin-mediated growth processes at lower as well as higher temperatures. Our results indicate that HSP90 and SGT1 integrate temperature and auxin signaling in order to regulate plant growth in a changing environment

An enigma in the genetic responses of plants to salt stresses

Soil salinity is one of the main factors restricting crop production throughout the world. Various salt tolerance traits and the genes controlling these traits are responsible for coping with salinity stress in plants. These coping mechanisms include osmotic tolerance, ion exclusion, and tissue tolerance. Plants exposed to salinity stress sense the stress conditions, convey specific stimuli signals, and initiate responses against stress through the activation of tolerance mechanisms that include multiple genes and pathways. Advances in our understanding of the genetic responses of plants to salinity and their connections with yield improvement are essential for attaining sustainable agriculture. Although a wide range of studies have been conducted that demonstrate genetic variations in response to salinity stress, numerous questions need to be answered to fully understand plant tolerance to salt stress. This chapter provides an overview of previous studies on the genetic control of salinity stress in plants, including signaling, tolerance mechanisms, and the genes, pathways, and epigenetic regulators necessary for plant salinity tolerance

Effects of NaCl on Fermentative Metabolism of Mature Green Tomatoes cv. Ailsa Craig in Brine

The effect of osmotic strength on gene expression and activity of the major enzymes of fermentative metabolism of mature green tomato fruit (Solanum lycopersicum cv. Ailsa Craig) has been studied by exposing fruit to brine containing 0 (water), 5 and 10 % NaCl. The fruits were surface sterilized prior to treatment to prevent the growth of microbes naturally present on the skin of the fruit. Changes in fruit expression of fermentation genes and the activity of the respective enzymes as well as physicochemical quality characteristics (soluble solid content, titratable acidity, pH and firmness) were studied in both fruit and brine for 0.5, 1, 1.5, 2, 3, 7 and 14 days. Discrepancies in responses that resulted from the different salt concentrations were obtained at molecular and quality levels. The complex kinetics of solutes between the fruit and the surrounding solution due to osmotic potential has led to different responses of the tissue to fermentation. Tomato fruit showed cracking soon after storage in water; water-stored fruit had higher titratable acidity, lower soluble solid content, and higher induction of anaerobic metabolism as indicated by the expression or the activity of the fermentation enzymes compared to fruit stored in brine with 5 or 10 % NaCl. No cracking was observed in fruit stored in 5 (isotonic) or 10 % NaCl (hypertonic) brine, though in the latter, signs of dehydration were observed. The presence of salt in brine reduced the intensity of fermentative metabolism as indicated by the lower gene expression and enzyme activity. However, fruit stored in brine with 5 % NaCl survived longer than with 0 or 10 % NaCl. The presence of 5 % NaCl in brine caused mild changes of both the fermentative metabolism and the physicochemical characteristics and prevented fruit deterioration during storage

Perspectives on deciphering mechanisms underlying plant heat stress response and thermotolerance

Contains fulltext : 213847.pdf (publisher's version ) (Open Access

Maternal environmental effects and climate-smart seeds: unlocking epigenetic inheritance for crop innovation in the seed industry

14 p.-2 fig.-1 tab.Seed production is facing a three-fold challenge: ensuring food security, maintaining sustainability, and adapting to climate change. Although most efforts have focused on genetic breeding and crop management, additional levers need to be explored to optimize plant tolerance to the accelerating climate change. A groundbreaking approach will be to capitalize on the ability of plants to naturally adjust their responses to fluctuating environments during the crop cycle and transmit stress-induced information to the next generation(s). This viewpoint aims at highlighting the potential application of maternal stress memory as a priming strategy to produce primed seedlots. This requires identifying the priming conditions among stress memory scenarios, defined according to the starting point of the new generation within the plant, that is, the fertilization. If the contribution of stress-induced epigenetic-associated mechanisms in inheritance patterns to promote germination and early growth development has been evidenced, the whole picture is not fully understood. Further investigations are required to characterize the maternally inherited plant stress imprints leading to higher stress tolerance of seedlots. Detailed characterization of the mechanisms of stress-induced maternally heritable seed traits could provide novel targets for the seed industry and open new avenues to deploy the potential of maternal stress memory for enhancing seed performances.Peer reviewe