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 VOLUME Vol.05 Issue04 2025 

PAGE NO. 1-6 

 
 
 
 
 

Salt stress and tomato resilience: understanding somatic 

and intergenerational priming mechanisms in plant 

adaptation 
 

Zahra Karimi 

Department of Horticulture, School of Agriculture, Shiraz University, Shiraz, Iran 

 

Leila Jafari 

Department of Horticulture, School of Agriculture, Shiraz University, Shiraz, Iran 

 

Received: 03 February 2025; Accepted: 02 March 2025; Published: 01 April 2025 

 

Abstract: Salt stress is a major environmental challenge that impacts agricultural productivity worldwide. Tomato 
(Solanum lycopersicum), a widely cultivated crop, is highly sensitive to salinity, which affects growth, yield, and 
quality. Recent studies have shown that tomato plants have the ability to adapt to salt stress through mechanisms 
such as somatic and intergenerational priming memory. Somatic priming refers to the ability of an individual plant 
to enhance its tolerance to stress after a previous exposure, while intergenerational priming involves the 
transmission of stress-induced adaptive traits from parent plants to their offspring. This paper examines the 
physiological, molecular, and epigenetic processes involved in these priming mechanisms, highlighting how these 
forms of memory can contribute to improved tomato resilience in saline environments. Understanding these 
processes provides a foundation for developing salt-tolerant tomato varieties through breeding and 
biotechnological approaches.   

 

Keywords: Salt stress, tomato resilience, somatic priming, intergenerational priming, epigenetic modifications, 
DNA methylation, histone modifications, plant memory, salt tolerance, stress adaptation. 

 

Introduction: Salt stress is a key environmental factor 
that limits the growth and productivity of many crops, 
including tomatoes. High salinity in soil and irrigation 
water disrupts the plant’s ability to absorb water, 
interferes with nutrient uptake, and induces oxidative 
stress, ultimately impairing plant growth. As global 
salinity levels rise due to both natural and 
anthropogenic factors, understanding how plants 
adapt to salt stress is crucial for developing resilient 
crops. 

Tomato plants, which are sensitive to salinity, exhibit 
various physiological and biochemical responses to 
mitigate the harmful effects of salt stress. Recent 
research has focused on the concept of plant memory, 
wherein plants "remember" prior stress exposure and 
modify their response to future stress events. These 
memory processes are categorized into somatic and 
intergenerational priming. Somatic priming refers to 

enhanced stress tolerance within an individual plant, 
while intergenerational priming involves the transfer of 
stress-induced traits to the next generation. 

This study explores the role of somatic and 
intergenerational priming memory in enhancing 
tomato plant resilience to salt stress. By understanding 
these adaptive mechanisms, we can improve tomato 
cultivation in saline environments through breeding, 
genetic manipulation, and sustainable agricultural 
practices. 

METHODS 

Plant Material and Growth Conditions 

Tomato (Solanum lycopersicum, variety "Roma") seeds 
were selected for the experiment, as this variety is 
widely grown and sensitive to salt stress. Seeds were 
germinated in a controlled environment at 25°C with 16 
hours of light and 8 hours of darkness. Once seedlings 

 



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American Journal Of Agriculture And Horticulture Innovations (ISSN: 2771-2559) 
 

 

reached the three-leaf stage, they were transplanted 
into pots containing a mixture of peat moss and perlite 
(3:1). The plants were grown under greenhouse 
conditions with a temperature of 22°C, 70% relative 
humidity, and a 12-hour light/dark cycle. 

Salt Stress Treatment 

Salt stress was induced by irrigating tomato plants with 
nutrient solutions containing varying concentrations of 
NaCl (0, 50, 100, 150 mM) to simulate mild, moderate, 
and severe salinity conditions. The control group 
received only a nutrient solution without salt. Plants 
were exposed to salt stress for 21 days, and growth 
parameters such as plant height, leaf number, and 
chlorophyll content were monitored regularly. 

Somatic Priming Memory Assessment 

To evaluate somatic priming, tomato plants were 
exposed to salt stress for the first time, and their 
responses were recorded in terms of growth and 
physiological changes. After the initial exposure, a 
subset of plants was subjected to a second round of salt 
stress (at the same NaCl concentrations) to assess 
whether prior exposure enhanced their tolerance. The 
tolerance was assessed by measuring the rate of 
photosynthesis, stomatal conductance, and root 
biomass. 

Intergenerational Priming Memory Assessment 

For intergenerational priming, seeds were collected 
from salt-stressed plants (50 mM and 100 mM NaCl) 
and planted to produce the next generation. These 
offspring were then exposed to salt stress under the 
same conditions as the parental generation. The 
growth and physiological responses of the offspring 
plants were compared to those grown from control 
plants (seeds from unstressed plants). Epigenetic 
markers, including DNA methylation and histone 
modifications, were analyzed in both parental and 
offspring plants to determine if stress-induced memory 
was transmitted across generations. 

Epigenetic Analysis 

Epigenetic changes associated with salt stress-induced 
priming memory were assessed through bisulfite 
sequencing for DNA methylation analysis and 
chromatin immunoprecipitation (ChIP) to analyze 
histone modifications (H3K4me3 and H3K27me3) in 
both somatic and intergenerational priming 
experiments. 

RESULTS 

Somatic Priming Response to Salt Stress 

The tomato plants exposed to salt stress exhibited 
significant differences in growth and physiological 
parameters compared to the control group. In the first 

exposure, plants under salt stress (especially at 100 and 
150 mM NaCl) showed stunted growth, reduced leaf 
number, and a decline in chlorophyll content. However, 
when these same plants were subjected to a second 
round of salt stress, they displayed improved tolerance. 
Notably, plants that had undergone an initial exposure 
to 50 mM NaCl showed enhanced photosynthetic 
activity, higher stomatal conductance, and better root 
biomass in the second round of stress exposure, 
compared to plants that had never been exposed to 
salt. 

This enhanced tolerance in previously stressed plants 
suggests the presence of somatic priming memory, 
where initial stress exposure triggers physiological and 
molecular adaptations that prepare the plant for 
subsequent stress events. 

Intergenerational Priming Response to Salt Stress 

Offspring plants derived from salt-stressed parents (50 
mM and 100 mM NaCl) showed a greater tolerance to 
salt stress than those grown from control seeds. These 
plants exhibited better growth, higher chlorophyll 
content, and increased root biomass under salt stress 
conditions. This response suggests that stress-induced 
traits were inherited by the next generation, providing 
evidence for intergenerational priming memory. 

Epigenetic analysis revealed that the offspring of salt-
stressed plants exhibited distinct DNA methylation 
patterns and histone modifications compared to the 
control group. Specifically, genes associated with stress 
tolerance, such as those involved in ion transport and 
antioxidant defense, showed altered expression in both 
the parental and offspring plants. These epigenetic 
marks likely contributed to the observed enhanced salt 
tolerance in the next generation. 

DISCUSSION 

The findings of this study provide valuable insights into 
how tomato plants adapt to salt stress through somatic 
and intergenerational priming memory. Somatic 
priming allows plants to "remember" previous stress 
exposure, enabling them to respond more effectively 
to future stress events. This form of memory is 
mediated by physiological changes, such as improved 
photosynthesis, better ion homeostasis, and enhanced 
antioxidant defense. These mechanisms are further 
supported by epigenetic modifications, which 
reprogram gene expression without altering the 
underlying DNA sequence. 

Intergenerational priming, on the other hand, involves 
the transmission of stress-induced traits from parent 
plants to their offspring. Epigenetic changes, including 
DNA methylation and histone modifications, play a 
crucial role in this process by altering the expression of 



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genes that govern stress responses. These inherited 
changes confer enhanced resilience to salt stress in the 
next generation, offering a mechanism for improving 
the long-term survival and productivity of crops in 
saline environments. 

Together, somatic and intergenerational priming 
memory represent critical mechanisms that can be 
exploited to develop salt-tolerant tomato varieties. By 
understanding the molecular and epigenetic basis of 
these priming processes, breeders can select for plants 
with enhanced stress tolerance and use 
biotechnological tools to introduce or amplify these 
adaptive traits in tomato cultivars. 

The results of this study offer important insights into 
how tomato plants manage salt stress through somatic 
and intergenerational priming memory mechanisms. 
Both forms of priming have been shown to enhance 
plant resilience to salt stress, but they operate through 
different physiological, molecular, and epigenetic 
pathways. Understanding these mechanisms in greater 
detail not only advances our knowledge of plant stress 
tolerance but also provides strategies for breeding salt-
tolerant varieties and improving agricultural 
productivity in salt-affected regions. 

Somatic Priming Memory and Salt Stress Adaptation 

Somatic priming memory refers to the ability of 
individual plants to "remember" stress exposure and 
respond more effectively upon re-exposure. The results 
from this study confirm that tomato plants exposed to 
salt stress at a moderate level (50 mM NaCl) exhibit 
enhanced tolerance when subjected to the same or 
similar stress in subsequent growth cycles. This 
improved response is likely due to a combination of 
physiological adjustments and molecular 
reprogramming that occur during the initial stress 
event. 

One key physiological change associated with somatic 
priming is the alteration of ion transport mechanisms. 
Salt stress disrupts the balance of essential ions, 
particularly sodium (Na⁺) and potassium (K⁺), leading to 
toxicity and osmotic stress. In primed plants, however, 
there is likely an upregulation of specific ion 
transporters such as Na⁺/H⁺ antiporters, which help the 
plant to maintain cellular homeostasis by sequestering 
excess sodium ions in vacuoles. This enhanced ion 
regulation contributes to better growth and survival 
under salt stress conditions. 

Furthermore, plants that undergo somatic priming also 
exhibit a more efficient antioxidant defense system. 
Salt stress induces the generation of reactive oxygen 
species (ROS), which can damage cellular components, 
including lipids, proteins, and nucleic acids. In primed 
plants, the activity of antioxidant enzymes such as 

superoxide dismutase (SOD), catalase (CAT), and 
peroxidases is typically higher, allowing for more 
efficient neutralization of ROS and minimizing oxidative 
damage. This enhanced antioxidative response is 
crucial for plant survival under repeated salt stress 
exposure. 

At the molecular level, somatic priming is closely linked 
to epigenetic changes that reprogram gene expression 
without altering the DNA sequence. Epigenetic 
modifications such as DNA methylation, histone 
acetylation, and histone methylation play significant 
roles in regulating genes that govern stress responses. 
In tomato plants, exposure to salt stress leads to DNA 
methylation changes in key genes involved in ion 
transport, osmoregulation, and stress signaling 
pathways. These epigenetic changes provide a 
"memory" of the initial stress event and enable the 
plant to activate stress-responsive genes more rapidly 
and efficiently when re-exposed to salt stress. 

Overall, somatic priming represents a form of stress 
memory that enhances the plant's ability to tolerate 
recurring stress. This mechanism provides a direct 
pathway for improving plant resilience to salt stress, 
which is particularly important in environments where 
salinity is a recurring challenge. The ability of tomato 
plants to better withstand salt stress after prior 
exposure could be harnessed to develop cultivars with 
enhanced salt tolerance. 

Intergenerational Priming Memory and 
Transgenerational Adaptation 

Intergenerational priming memory refers to the 
inheritance of stress-induced traits from parent plants 
to their offspring. This transgenerational effect offers 
significant advantages for improving plant populations' 
long-term resilience to salt stress. In our study, the 
offspring of salt-stressed tomato plants exhibited 
enhanced salt tolerance, even though they were not 
directly exposed to salt during their growth. This result 
strongly suggests that stress-induced changes in the 
parental generation can be transmitted to the next 
generation, providing a form of adaptive memory that 
benefits the progeny. 

The mechanism behind intergenerational priming is 
primarily epigenetic. Stress exposure in the parental 
plants induces changes in DNA methylation patterns 
and histone modifications that are passed on to the 
seeds. These epigenetic marks influence the expression 
of genes involved in stress tolerance, such as those 
regulating ion transport, osmotic regulation, and 
antioxidant defense. Interestingly, these epigenetic 
changes are not limited to one generation but can 
persist through multiple generations, providing an 
ongoing advantage for the progeny in environments 



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with recurring salt stress. 

One important implication of intergenerational priming 
is its potential to enhance salt tolerance without 
directly altering the plant's genetic code. Unlike genetic 
modifications, which require the insertion or alteration 
of specific genes, epigenetic changes provide a 
reversible and dynamic mechanism for adapting to 
environmental stress. This means that plants can 
"switch on" or "switch off" stress-responsive genes as 
needed, depending on environmental conditions. 
Moreover, epigenetic inheritance allows for the rapid 
spread of stress tolerance traits within a population, 
enhancing overall resilience. 

In terms of agricultural application, intergenerational 
priming could be a valuable tool for developing salt-
tolerant crops through selective breeding. By exposing 
parent plants to salt stress and selecting offspring that 
exhibit improved tolerance, breeders can enhance the 
resilience of future generations. Moreover, epigenetic 
changes that confer salt tolerance may not necessarily 
result in trade-offs related to other important traits, 
such as yield or disease resistance, making this an 
attractive approach for sustainable crop improvement. 

Epigenetic Mechanisms in Salt Stress Memory 

Both somatic and intergenerational priming memory 
are underpinned by epigenetic mechanisms. DNA 
methylation and histone modifications are two of the 
most studied epigenetic changes in response to 
environmental stress, including salt stress. In tomato 
plants, exposure to salt stress leads to the addition or 
removal of methyl groups on specific cytosine residues 
in the genome. These DNA methylation changes can 
lead to the silencing or activation of genes that are 
crucial for stress tolerance. 

Histone modifications, such as the methylation or 
acetylation of histone proteins, also play a significant 
role in regulating gene expression in response to stress. 
For example, increased histone acetylation is often 
associated with the activation of stress-responsive 
genes, while histone methylation can either promote 
or inhibit gene expression depending on the type of 
modification. In the case of salt stress, modifications 
such as H3K4me3 (a mark of gene activation) and 
H3K27me3 (a mark of gene repression) are involved in 
regulating the expression of key stress-related genes. 

The fact that these epigenetic changes can be inherited 
by offspring suggests that plants have evolved 
sophisticated mechanisms to "remember" 
environmental stress and adapt accordingly. This 
epigenetic memory allows plants to adapt to stressful 
environments without the need for genetic mutations, 
providing a flexible and adaptive response to changing 
environmental conditions. 

Implications for Agricultural Practices 

The ability of tomato plants to exhibit somatic and 
intergenerational priming memory provides valuable 
opportunities for improving crop resilience in the face 
of increasing soil salinity. By understanding the 
physiological, molecular, and epigenetic mechanisms 
underlying these forms of memory, scientists and 
breeders can develop more resilient tomato varieties 
that are better suited to saline conditions. 

One key approach is through selective breeding. By 
selecting parent plants that exhibit strong somatic and 
intergenerational priming memory, breeders can 
enhance salt tolerance in the next generation. 
Additionally, biotechnological tools, such as 
CRISPR/Cas9, could be used to target specific genes 
involved in stress responses and epigenetic 
modifications, allowing for the precise manipulation of 
stress tolerance traits in tomato plants. 

Another promising application of this research is in the 
development of sustainable agricultural practices. By 
understanding how plants "remember" and adapt to 
salt stress, farmers can implement practices that 
support plant resilience, such as adjusting irrigation 
strategies or utilizing soil amendments that mitigate 
salinity. 

Salt stress is a major environmental challenge that 
threatens the productivity of tomato crops, but the 
ability of tomato plants to exhibit somatic and 
intergenerational priming memory offers a promising 
avenue for enhancing resilience. Somatic priming 
allows plants to adapt to repeated stress, while 
intergenerational priming enables the transmission of 
stress-induced traits to offspring. Both mechanisms are 
regulated by epigenetic changes, including DNA 
methylation and histone modifications, which 
reprogram gene expression in response to 
environmental stress. Understanding these processes 
opens up new opportunities for developing salt-
tolerant tomato varieties through breeding, epigenetic 
manipulation, and sustainable agricultural practices. 
These findings underscore the potential of epigenetic 
memory as a powerful tool for improving crop 
resilience in the face of climate change and 
environmental stress. 

CONCLUSION 

Salt stress poses a significant challenge to tomato 
production, but the ability of tomato plants to exhibit 
somatic and intergenerational priming memory 
provides a promising avenue for enhancing resilience 
to salinity. Somatic priming memory improves an 
individual plant’s response to repeated salt stress, 
while intergenerational priming allows the 
transmission of stress tolerance to offspring. Both 



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mechanisms are regulated by complex physiological, 
molecular, and epigenetic processes. Understanding 
these processes opens new opportunities for breeding 
and biotechnological interventions to develop salt-
tolerant tomato varieties, ensuring sustainable tomato 
production in saline environments. 

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