Effects of NaCl addition to the growing medium on plant hydraulics and water relations of tomato

This work reports on experimental evidence for the role of ion-mediated changes of xylem hydraulic conductivity in the functional response of Solanum lycopersicum L. cv. Naomi to moderate salinity levels. Measurements were performed in fully developed 12-week-old plants grown in half-strength Hoagland solution (control, C-plants) or in the same solution added with 35 mM NaCl (NaCl-plants). NaCl-plants produced a significantly less but heavier leaves and fruits but had similar gas-exchange rates as control plants. Moreover, NaCl-plants showed higher vessel multiple fraction (FVM) than control plants. Xylem sap potassium and sodium concentrations were significantly higher in NaCl-plants than in control plants. When stems were perfused with 10 mM NaCl or KCl, the hydraulic conductance of NaCl plants was nearly 1.5 times higher than in control plants. Accordingly, stem hydraulic conductance measured in planta was higher in NaCl- than in control plants. Our data suggest that tomato plants grown under moderate salinity upregulate xylem sap [Na+] and [K+], as well as sensitivity of xylem hydraulics to sap ionic content, thus, increasing water transport capacity.

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ABA-mediated regulation of leaf and root hydraulic conductance in tomato grown at elevated CO2 is associated with altered gene expression of aquaporins

Horticulture Research ◽

10.1038/s41438-019-0187-6 ◽

2019 ◽

Vol 6 (1) ◽

Cited By ~ 4

Author(s):

Liang Fang ◽

Lamis Osama Anwar Abdelhakim ◽

Josefine Nymark Hegelund ◽

Shenglan Li ◽

Jie Liu ◽

...

Keyword(s):

Gene Expression ◽

Stomatal Density ◽

Leaf Gas Exchange ◽

Turgor Pressure ◽

Xylem Sap ◽

Underlying Mechanism ◽

Hydraulic Conductance ◽

Similar Response ◽

Growth Environment ◽

Plant Hydraulics

Abstract Elevated CO2 concentration in the air (e[CO2]) decreases stomatal density (SD) and stomatal conductance (gs) where abscisic acid (ABA) may play a role, yet the underlying mechanism remains largely elusive. We investigated the effects of e[CO2] (800 ppm) on leaf gas exchange and water relations of two tomato (Solanum lycopersicum) genotypes, Ailsa Craig (WT) and its ABA-deficient mutant (flacca). Compared to plants grown at ambient CO2 (400 ppm), e[CO2] stimulated photosynthetic rate in both genotypes, while depressed the gs only in WT. SD showed a similar response to e[CO2] as gs, although the change was not significant. e[CO2] increased leaf and xylem ABA concentrations and xylem sap pH, where the increases were larger in WT than in flacca. Although leaf water potential was unaffected by CO2 growth environment, e[CO2] lowered osmotic potential, hence tended to increase turgor pressure particularly for WT. e[CO2] reduced hydraulic conductance of leaf and root in WT but not in flacca, which was associated with downregulation of gene expression of aquaporins. It is concluded that ABA-mediated regulation of gs, SD, and gene expression of aquaporins coordinates the whole-plant hydraulics of tomato grown at different CO2 environments.

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Impact of Environmental Factors on Stilbene Biosynthesis

Plants ◽

10.3390/plants10010090 ◽

2021 ◽

Vol 10 (1) ◽

pp. 90

Author(s):

Alessio Valletta ◽

Lorenzo Maria Iozia ◽

Francesca Leonelli

Keyword(s):

Environmental Factors ◽

Biosynthetic Pathway ◽

In Planta ◽

Organ Cultures ◽

Related Plant ◽

Valuable Compounds ◽

Stilbene Compounds ◽

Stilbene Biosynthesis ◽

Abiotic Environmental Factors

Stilbenes are a small family of polyphenolic secondary metabolites that can be found in several distantly related plant species. These compounds act as phytoalexins, playing a crucial role in plant defense against phytopathogens, as well as being involved in the adaptation of plants to abiotic environmental factors. Among stilbenes, trans-resveratrol is certainly the most popular and extensively studied for its health properties. In recent years, an increasing number of stilbene compounds were subjected to investigations concerning their bioactivity. This review presents the most updated knowledge of the stilbene biosynthetic pathway, also focusing on the role of several environmental factors in eliciting stilbenes biosynthesis. The effects of ultraviolet radiation, visible light, ultrasonication, mechanical stress, salt stress, drought, temperature, ozone, and biotic stress are reviewed in the context of enhancing stilbene biosynthesis, both in planta and in plant cell and organ cultures. This knowledge may shed some light on stilbene biological roles and represents a useful tool to increase the accumulation of these valuable compounds.

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Assessment of Morpho-Physiological, Biochemical and Antioxidant Responses of Tomato Landraces to Salinity Stress

Plants ◽

10.3390/plants10040696 ◽

2021 ◽

Vol 10 (4) ◽

pp. 696

Author(s):

Reem H. Alzahib ◽

Hussein M. Migdadi ◽

Abdullah A. Al Ghamdi ◽

Mona S. Alwahibi ◽

Abdullah A. Ibrahim ◽

...

Keyword(s):

Salt Stress ◽

Salinity Stress ◽

Dry Weight ◽

Proline Content ◽

Enzymatic Antioxidants ◽

Sod Activity ◽

Carotene Content ◽

Antioxidants Activity ◽

Solanum Lycopersicum L ◽

Salinity Levels

Understanding salt tolerance in tomato (Solanum lycopersicum L.) landraces will facilitate their use in genetic improvement. The study assessed the morpho-physiological variability of Hail tomato landraces in response to different salinity levels at seedling stages and recommended a tomato salt-tolerant landrace for future breeding programs. Three tomato landraces, Hail 548, Hail 747, and Hail 1072 were tested under three salinity levels: 75, 150, and 300 mM NaCl. Salinity stress reduced shoots’ fresh and dry weight by 71% and 72%, and roots were 86.5% and 78.6%, respectively. There was 22% reduced chlorophyll content, carotene content by 18.6%, and anthocyanin by 41.1%. Proline content increased for stressed treatments. The 300 mM NaCl treatment recorded the most proline content increases (67.37 mg/g fresh weight), with a percent increase in proline reaching 61.67% in Hail 747. Superoxide dismutase (SOD) activity decreased by 65% in Hail 548, while it relatively increased in Hail 747 and Hail 1072 treated with 300 mM NaCl. Catalase (CAT) activity was enhanced by salt stress in Hail 548 and recorded 7.6%, increasing at 75 and 5.1% at 300 mM NaCl. It revealed a reduction in malondialdehyde (MDA) at the 300 mM NaCl concentration in both Hail 548 and Hail 1072 landraces. Increasing salt concentrations showed a reduction in transpiration rate of 70.55%, 7.13% in stomatal conductance, and 72.34% in photosynthetic rate. K+/Na+ ratios decreased from 56% for 75 mM NaCl to 85% for 300 mM NaCl treatments in all genotypes. The response to salt stress in landraces involved some modifications in morphology, physiology, and metabolism. The landrace Hail 548 may have better protection against salt stress and observed protection against reactive oxygen species (ROS) by increasing enzymatic “antioxidants” activity under salt stress.

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The Effect of Fusarium verticillioides Fumonisins on Fatty Acids, Sphingolipids, and Oxylipins in Maize Germlings

International Journal of Molecular Sciences ◽

10.3390/ijms22052435 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2435

Author(s):

Marzia Beccaccioli ◽

Manuel Salustri ◽

Valeria Scala ◽

Matteo Ludovici ◽

Andrea Cacciotti ◽

...

Keyword(s):

Fatty Acids ◽

Fusarium Verticillioides ◽

Fungal Growth ◽

Defense Responses ◽

Ceramide Synthase ◽

Ear Rot ◽

In Planta ◽

Disease Symptoms ◽

The Impact

Fusarium verticillioides causes multiple diseases of Zea mays (maize) including ear and seedling rots, contaminates seeds and seed products worldwide with toxic chemicals called fumonisins. The role of fumonisins in disease is unclear because, although they are not required for ear rot, they are required for seedling diseases. Disease symptoms may be due to the ability of fumonisins to inhibit ceramide synthase activity, the expected cause of lipids (fatty acids, oxylipins, and sphingolipids) alteration in infected plants. In this study, we explored the impact of fumonisins on fatty acid, oxylipin, and sphingolipid levels in planta and how these changes affect F. verticillioides growth in maize. The identity and levels of principal fatty acids, oxylipins, and over 50 sphingolipids were evaluated by chromatography followed by mass spectrometry in maize infected with an F. verticillioides fumonisin-producing wild-type strain and a fumonisin-deficient mutant, after different periods of growth. Plant hormones associated with defense responses, i.e., salicylic and jasmonic acid, were also evaluated. We suggest that fumonisins produced by F. verticillioides alter maize lipid metabolism, which help switch fungal growth from a relatively harmless endophyte to a destructive necrotroph.

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Myco-Suppression Analysis of Soybean (Glycine max) Damping-Off Caused by Pythium aphanidermatum

Plants ◽

10.3390/plants10040788 ◽

2021 ◽

Vol 10 (4) ◽

pp. 788

Author(s):

Shaban R. M. Sayed ◽

Shaimaa A. M. Abdelmohsen ◽

Hani M. A. Abdelzaher ◽

Mohammed A. Elnaghy ◽

Ashraf A. Mostafa ◽

...

Keyword(s):

Glycine Max ◽

Biocontrol Agent ◽

Lateral Roots ◽

Dry Weight ◽

Pythium Aphanidermatum ◽

Damping Off ◽

Pythium Oligandrum ◽

Rdna Its ◽

Half Strength

The role of Pythium oligandrum as a biocontrol agent against Pythium aphanidermatum was investigated to avoid the harmful impacts of fungicides. Three isolates of P. oligandrum (MS15, MS19, and MS31) were assessed facing the plant pathogenic P. aphanidermatum the causal agent of Glycine max damping-off. The tested Pythium species were recognized according to their cultural and microscopic characterizations. The identification was confirmed through sequencing of rDNA-ITS regions including the 5.8 S rDNA. The biocontrol agent, P. oligandrum, isolates decreased the mycelial growth of the pathogenic P. aphanidermatum with 71.3%, 67.1%, and 68.7% through mycoparasitism on CMA plates. While the half-strength millipore sterilized filtrates of P. oligandrum isolates degrade the pathogenic mycelial linear growth by 34.1%, 32.5%, and 31.7%, and reduce the mycelial dry weight of the pathogenic P. aphanidermatum by 40.1%, 37.4%, and 36.8%, respectively. Scanning electron microscopy (SEM) of the most effective antagonistic P. oligandrum isolate (MS15) interaction showed coiling, haustorial parts of P. oligandrum to P. aphanidermatum hyphae. Furthermore, P. oligandrum isolates were proven to enhance the germination of Glycine max seedling to 93.3% in damping-off infection using agar pots and promote germination of up to 80% during soil pot assay. On the other hand, P. oligandrum isolates increase the shoot, root lengths, and the number of lateral roots.

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Ralstonia solanacearum Needs Motility for Invasive Virulence on Tomato

Journal of Bacteriology ◽

10.1128/jb.183.12.3597-3605.2001 ◽

2001 ◽

Vol 183 (12) ◽

pp. 3597-3605 ◽

Cited By ~ 201

Author(s):

Julie Tans-Kersten ◽

Huayu Huang ◽

Caitilyn Allen

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Soft Agar ◽

Cell Protein ◽

In Planta ◽

Tomato Plants ◽

Bacterial Wilt Disease ◽

Virulence Assay ◽

Flagellar Filament

ABSTRACT Ralstonia solanacearum, a widely distributed and economically important plant pathogen, invades the roots of diverse plant hosts from the soil and aggressively colonizes the xylem vessels, causing a lethal wilting known as bacterial wilt disease. By examining bacteria from the xylem vessels of infected plants, we found thatR. solanacearum is essentially nonmotile in planta, although it can be highly motile in culture. To determine the role of pathogen motility in this disease, we cloned, characterized, and mutated two genes in the R. solanacearum flagellar biosynthetic pathway. The genes for flagellin, the subunit of the flagellar filament (fliC), and for the flagellar motor switch protein (fliM) were isolated based on their resemblance to these proteins in other bacteria. As is typical for flagellins, the predicted FliC protein had well-conserved N- and C-terminal regions, separated by a divergent central domain. The predicted R. solanacearum FliM closely resembled motor switch proteins from other proteobacteria. Chromosomal mutants lackingfliC or fliM were created by replacing the genes with marked interrupted constructs. Since fliM is embedded in the fliLMNOPQR operon, the aphAcassette was used to make a nonpolar fliM mutation. Both mutants were completely nonmotile on soft agar plates, in minimal broth, and in tomato plants. The fliC mutant lacked flagella altogether; moreover, sheared-cell protein preparations from the fliC mutant lacked a 30-kDa band corresponding to flagellin. The fliM mutant was usually aflagellate, but about 10% of cells had abnormal truncated flagella. In a biologically representative soil-soak inoculation virulence assay, both nonmotile mutants were significantly reduced in the ability to cause disease on tomato plants. However, the fliC mutant had wild-type virulence when it was inoculated directly onto cut tomato petioles, an inoculation method that did not require bacteria to enter the intact host from the soil. These results suggest that swimming motility makes its most important contribution to bacterial wilt virulence in the early stages of host plant invasion and colonization.

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Chemical Phenotypes of the hmg1 and hmg2 Mutants of Arabidopsis Demonstrate the In-planta Role of HMG-CoA Reductase in Triterpene Biosynthesis

Chemical and Pharmaceutical Bulletin ◽

10.1248/cpb.55.1518 ◽

2007 ◽

Vol 55 (10) ◽

pp. 1518-1521 ◽

Cited By ~ 45

Author(s):

Kiyoshi Ohyama ◽

Masashi Suzuki ◽

Kazuo Masuda ◽

Shigeo Yoshida ◽

Toshiya Muranaka

Keyword(s):

In Planta ◽

Hmg Coa Reductase ◽

Coa Reductase ◽

Triterpene Biosynthesis

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An investigation of the role of solutes in the xylem sap and in the xylem parenchyma as the source of root pressure

PROTOPLASMA ◽

10.1007/bf01304486 ◽

2000 ◽

Vol 211 (3-4) ◽

pp. 183-197 ◽

Cited By ~ 21

Author(s):

L. C. Enns ◽

M. J. Canny ◽

M. E. McCully

Keyword(s):

Xylem Sap ◽

Xylem Parenchyma ◽

Root Pressure

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Differential Responses of Two Broccoli (Brassica oleraceaL. var Italica) Cultivars to Salinity and Nutritional Quality Improvement

The Scientific World JOURNAL ◽

10.1100/2012/291435 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12 ◽

Cited By ~ 18

Author(s):

Chokri Zaghdoud ◽

Carlos Alcaraz-López ◽

César Mota-Cadenas ◽

María del Carmen Martínez-Ballesta ◽

Diego A. Moreno ◽

...

Keyword(s):

Nutritional Quality ◽

Genetic Background ◽

Nutritional Value ◽

Soluble Sugars ◽

Root Hydraulic Conductance ◽

Nutritional Properties ◽

Specific Strategy ◽

Nutritional Characteristics ◽

Salinity Levels

The comparative responses of two broccoli cultivars (Brassica oleraceavar. Italica, cv. Parthenon and cv. Naxos) to a 15 d exposure to different NaCl levels were investigated. Salinity led to increased concentrations of Na+and Cl−ions in both cultivars, a disruption of the endogenous minerals levels in the shoots and roots—that varied with the cultivar and salt concentration—and decreases in the osmotic potential (Ψπ), root hydraulic conductance (L0), and stomatal conductance (Gs). The reduced biomass of Naxos at moderate NaCl indicates greater sensitivity to salinity, compared with Parthenon. Parthenon accumulated more soluble sugars, for osmotic adjustment, whereas Naxos accumulated proline, which gave the two cultivars differing nutritional characteristics. The total glucosinolates (GSLs) content was not affected by salinity in Parthenon while it decreased significantly in Naxos as a consequence of the decrease in the indole GSL. However, Naxos accumulated more aliphatic GSLs under salt stress than Parthenon, which confers on this cultivar a greater nutritional value when cultivated under salinity.These results suggest that, at distinct salinity levels, each broccoli cultivar adopts a specific strategy, indicating the crucial role of the genetic background on the organoleptic and nutritional properties that each cultivar acquires.

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Testing for ion-mediated enhancement of the hydraulic conductance of the leaf xylem in diverse angiosperms

Journal of Plant Hydraulics ◽

10.20870/jph.2017.e004 ◽

2017 ◽

Vol 4 ◽

pp. e004 ◽

Cited By ~ 2

Author(s):

Christine Scoffoni ◽

Grace John ◽

Herve Cochard ◽

Lawren Sack

Keyword(s):

Water Solution ◽

Pure Water ◽

Xylem Sap ◽

Hydraulic Conductance ◽

Membrane Pores ◽

Whole Plant ◽

Pit Membrane ◽

Major Bottleneck ◽

The Difference ◽

Xylem Conduits

Replacing ultra-pure water solution with ion solution closer to the composition of natural xylem sap increases stem hydraulic conductance by up to 58%, likely due to changes in electroviscosity in the pit membrane pores. This effect has been proposed to contribute to the control of plant hydraulic and stomatal conductance and potentially to influence on carbon balance during dehydration. However, this effect has never been directly tested for leaf xylem, which constitutes a major bottleneck in the whole plant. We tested for an ion-mediated increase in the hydraulic conductance of the leaf xylem (Kx) for seven species diverse in phylogeny and drought tolerance. Across species, no significant changes in Kx were observed between 0 and 15 mM KCl. We further tested for an effect of ion solution during measurements of Kx vulnerability to dehydration in Quercus agrifolia and found no significant impact. These results for leaf xylem contrast with the often strong ion effect reported for stems, and we suggest several hypotheses to account for the difference, relating to the structure of xylem conduits across vein orders, and the ultrastructure of leaf xylem pores. A negligible ion response in leaves would weaken xylem sap ion-mediated control of plant hydraulic conductance, facilitating modeling of whole plant hydraulic behavior and its influence on productivity.

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