Keywords:

Bacterial taxonomy

Functional characterization

Tolerance a salinity

Isolation and characterization of halotolerant bacteria from soils in the municipality of

Remedios, Cuba

Aislamiento y caracterización de bacterias halotolerantes procedentes de suelos del municipio

Remedios, Cuba

Isolamento e caracterização de bactérias halotolerantes provenientes de solos do município Remedios,

Cuba

Marisel Ortega-García

Yoania Ríos-Rocafull

Grisel Tejeda-González

Lily Zelaya-Molina

Ismael Chávez-Díaz

María Nápoles-García

Rev. Fac. Agron. (LUZ). 2026, 43(1): e264318

ISSN 2477-9407

DOI: https://doi.org/10.47280/RevFacAgron(LUZ).v43.n1.XVIII

Crop production

Associate editor: Dra. Evelyn Pérez Pérez

University of Zulia, Faculty of Agronomy

Bolivarian Republic of Venezuela

Instituto de Investigaciones Fundamentales en Agricultura

Tropical “Alejandro de Humboldt” (INIFAT), La Habana,

Cuba.

Centro Nacional de Recursos Genéticos-INIFAP, Tepatitlán

de Morelos, Jalisco, México.

Instituto Nacional de Ciencias Agrícolas, Mayabeque, Cuba.

Received: 03-10-2025

Accepted: 03-02-2026

Published: 05-03-2026

Abstract

The isolation of halotolerant bacteria represents a strategy to

mitigate soil salinization and promote crop adaptation. This study

aimed to identify bacteria from saline soils in Remedios, Cuba, and

evaluate their potential as plant growth-promoting bacteria (PGPB).

Three bacterial strains tolerant to 200 mM NaCl were selected and

identied as Proteus sp. RM 4.2, Lysinibacillus sp. RM 6.2, and

Tenebrionicola sp. RM 4.1. The three strains showed the ability

to x nitrogen and produce siderophores and lytic enzymes. In

tomato plant inoculation assays, Proteus sp. RM 4.2 signicantly

promoted plant growth in the evaluated cultivars, standing out as

the strain with the greatest growth-promoting eect. Overall, the

results indicated that the evaluated strains exhibited functional traits

associated with plant growth promotion and represented a viable

alternative for developing bioinoculants in saline soils.

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2-7 |

Resumen

El aislamiento de bacterias halotolerantes representa una estrategia

para mitigar la salinización del suelo y favorecer la adaptación de

los cultivos. Este estudio tuvo como objetivo identicar bacterias

de suelos salinos en Remedios, Cuba, y evaluar su potencial como

promotoras de crecimiento vegetal (PGPB). Se seleccionaron tres

cepas bacterianas tolerantes a 200 mM de NaCl, identicadas como

Proteus sp. RM 4.2, Lysinibacillus sp. RM 6.2 y Tenebrionicola sp.

RM 4.1. Las tres cepas presentaron capacidad de jar nitrógeno,

producir sideróforos y enzimas líticas. En ensayos de inoculación en

plantas de tomate, Proteus sp. RM 4.2 promovió signicativamente el

crecimiento vegetal en los cultivares evaluados, destacándose como

la cepa con mayor efecto promotor de crecimiento. En conjunto,

los resultados indicaron que las cepas evaluadas presentaron rasgos

funcionales asociados a la promoción del crecimiento vegetal y

representan una alternativa viable para el desarrollo de bioinoculantes

en suelos salinos.

Palabras clave: taxonomía bacteriana, caracterización funcional,

tolerancia, salinidad.

Resumo

O isolamento de bactérias halotolerantes representa uma estratégia

para mitigar a salinização do solo e favorecer a adaptação das

culturas. Este estudo teve como objetivo identicar bactérias de solos

salinos en Remedios, Cuba, e avaliar seu potencial como promotoras

de crescimento vegetal (PGPB). Três cepas bacterianas tolerantes a

200 mM de NaCl foram selecionadas e identicadas como Proteus

sp. RM 4.2, Lysinibacillus sp. RM 6.2 e Tenebrionicola sp. RM

4.1. As três cepas apresentaram capacidade de xar nitrogênio e de

produzir sideróforos e enzimas líticas. Em ensaios de inoculação em

plantas de tomate, Proteus sp. RM 4.2 promoveu signicativamente

o crescimento vegetal nos cultivares avaliados, destacando-se como

a cepa com maior efeito promotor. Em conjunto, os resultados

indicam que as cepas avaliadas apresentam características funcionais

associadas à promoção do crescimento vegetal e representam uma

alternativa viável para o desenvolvimento de bioinoculantes em solos

salinos.

Palavras chave: taxonomia bacteriana, caracterização funcional,

tolerância à salinidade

Introduction

The diversity of soil microorganisms worldwide is threatened

by anthropogenic changes, such as land-use intensication,

deforestation, and extreme weather events. These factors alter the

structure and function of microbial communities, directly aecting

soil ecological processes and their stability (Alzate-Zuluaga et al.,

2020). It is estimated that soils are home to approximately a quarter

of the planet’s biodiversity, including plant growth-promoting

microorganisms (PGPB), which are a valuable tool to promote

sustainable and environmentally friendly agriculture (Rosabal et al.,

2021).

Within this diversity, microorganisms that inhabit environments

with high concentrations of salts stand out, particularly halotolerant

bacteria, which are capable of favoring the adaptation of plants to

conditions of salt stress (Guerra-Camacho et al., 2024). In Cuba,

more than one million hectares are aected by salinity, of which

approximately 14 % corresponds to cultivated areas (García-Reyes

et al., 2021). Specically, in the municipality of Remedios, in the

northeast of the Villa Clara province, there are coastal settlements

that are highly vulnerable to sea level rise and anthropogenic

inuence (Pineda-Ruiz et al., 2023). This phenomenon increases soil

salinity and poses a threat to agricultural productivity. Despite this,

information on the diversity and functionality of halotolerant bacteria

in these soils is limited, which highlights the need for local studies to

evaluate their potential as plant growth promoters.

In this context, the study of microorganisms in saline soils should

include rhizobacteria (Velasco-Jiménez et al., 2020). The evaluation

of their phylogenetic and functional diversity in agroecosystems

under salinity conditions allows the identication of strains capable of

mitigating environmental impacts, favoring the recovery of degraded

soils, and improving crop nutrition (Ahluwalia et al., 2021). The

municipality of Remedios, in Cuba, is characterized by the presence

of vertisol soils aected by salinity (Hernández-Jiménez et al., 2023),

which makes it a strategic site for the search for microorganisms with

potential as PGPB. Therefore, the present study aimed to isolate,

identify, and characterize halotolerant bacteria from soils of coastal

settlements in the municipality of Remedios, in order to explore their

potential use as plant growth-promoting bacterial inoculants for crops

exposed to high salt concentrations.

Materials and methods

Between 2024 and 2025, slightly salinized soil samples (2.7-3.5

dS.m⁻¹) (Hernández-Jiménez et al., 2023) were taken from 18 farms

distributed in nine coastal settlements in the municipality of Remedios,

Villa Clara province, Cuba, which corresponded to independent

agricultural agroecosystems and with a non-uniform sampling area.

Five soil subsamples were collected from each farm at a depth of 20

cm using an auger, following a W or zigzag pattern (Villalba-Martínez

and Encina-Rojas, 2024); these were then homogenized to obtain 1 kg

of composite sample per farm. The composite samples were processed

using the serial dilution method for the isolation of bacteria in nutrient

agar culture medium (Rodríguez-Martínez and Zhurbenko, 2018).

From these, the morphotypes present in the 1×10⁻⁵ dilution were

determined; a representative strain of each morphotype was puried

and assigned a code with the abbreviation RM, in reference to the

municipality of Remedios. To evaluate salinity tolerance, the strains

were inoculated in the same medium supplemented with dierent

NaCl concentrations (0, 50, 150, and 200 mM) and incubated at 30

°C for 24 h, selecting only those capable of growing at the maximum

concentration evaluated (200 mM).

Identication and characterization of bacterial isolates

For the identication and characterization of the selected bacteria,

morphological methods, biochemical tests, and genetic analyses

were combined. Colonies were described based on macroscopic

characteristics (shape, color, margin, elevation, and surface), and cell

shape was determined microscopically, by Gram stain in fresh 24-h

cultures. Additionally, DNase and coagulase tests were performed to

rule out pathogenicity and ensure the safety of the isolates (Madigan

et al., 2019). The identication of the strains was carried out by

phylogenetic analysis of the 16S rRNA gene. Macrogen Inc. (Seoul,

Republic of Korea) performed amplication and sequencing using

the 27f/1493r and 785F/907R universal primers, respectively. The

sequences obtained were edited using BioEdit v.7.0.9.0 (Hall, 1999)

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Ortega-García et al. Rev. Fac. Agron. (LUZ). 2026, 43(1): e264318

3-7 |

and compared with the GenBank library through BLAST searches

to form a database of type strain sequences. The phylogenetic tree

was built with MEGA v.7 with 1,000 bootstrap replicates (Kumar

et al., 2016); the selection of the nucleotide substitution model was

carried out with jModelTest 2 (Darriba et al., 2012), and the identity

percentages were determined with MatGAT v.2.01 (Campanella

et al., 2003). The sequences were deposited in GenBank under the

accession numbers OR902474, OR902479, and PP051518.

Characterization of bacteria as plant growth promoters

The ability of the isolates to promote plant growth was evaluated

in specic culture media; the bacteria were inoculated by stabbing

and incubated at 28 °C for 24 - 48 h. In the media where the strains

showed activity, evidenced by the formation of halos, the diameters

of the colonies (TC) and of the halos (TH) in three directions were

measured, and the activity index (AI) was calculated using the

formula: IA = TH / TC.

Biological nitrogen xation was evaluated qualitatively according

to Elbeltagy et al. (2001), using nitrogen-free Winogradsky medium;

the isolates with growth were reinoculated for four consecutive

passages to rule out residual nitrogen carryover. The solubilization of

phosphates and potassium was evaluated in NBRIP and Alexandrov-

BPB media, respectively, supplemented with 0.001 % bromophenol

blue (Nautiyal, 1999; Sugumaran and Janarthanam, 2007; Zelaya-

Molina et al., 2025). The production of indolic compounds was

determined in TSA with 1 % tryptophan using the Salkowski reagent

(Gordon and Weber, 1951), and that of siderophores in CAS (Louedn

et al., 2011; Nair et al., 2007). Enzyme activity was assessed by

testing for peroxidases, amylases, proteases, lipases, esterases,

cellulases, and peptidases in specic media (Ramos-Garza et al.,

2016; Al-Mohaini et al., 2022).

Eect of strains on tomato cultivars (Solanum lycopersicum L.)

The inoculum of each strain was prepared in nutrient broth and

multiplied in an orbital shaker (EDMUD BUHLER, Germany) at 120

rpm and 30 °C, for 24 h, until a nal concentration of 1×10⁸ CFU.mL

was reached, determined according to the McFarland scale (1907).

Subsequently, a mixture of inoculum with distilled water was applied

to the soil in a proportion of 1:10 (v/v). The tests were carried out

in greenhouses under semi-controlled conditions (temperature and

humidity); tomato cultivars T-60 and FL-5 (determined growth and

fresh consumption) from INIFAT were used. Two seeds per pot were

sown with salinized Vertisol soil (8 dS.m

-1

) (Hernández-Jiménez et

al., 2023). It was irrigated with drinking water (150 mL) to avoid salt

leaching and was veried by registering a nal conductivity similar to

the initial value. Four treatments were established with 25 plants and

three replicates, and the trial was repeated after 30 days. At 60 days

after sowing, the following parameters were evaluated: height, root

length, stem diameter, number of leaves, and dry mass.

Statistical analysis

A completely randomized design was used in the laboratory, and

a randomized block design was employed in the plant trial. The data

were subjected to normality (Kolmogorov-Smirnov) and homogeneity

(Cochran C, Hartley, and Bartlett) tests, one-way analysis of variance

(ANOVA), and Duncan’s test (α = 0.05), using STATGRAPHICS

Plus version 5.0 (Statistical Graphics Corporation, 1994).

Results and discussion

From the soil collection, 15 bacterial morphotypes were obtained,

with densities ranging from 2x10

to 1.5x10

CFU.g

¹ of soil; one

representative isolate of each morphotype was isolated and puried

for subsequent characterization. After evaluating the growth of the 15

strains at three NaCl concentrations, only three grew at 200 mM; this

evidenced their salinity tolerance and supported their selection for

subsequent evaluations.

Morphological characteristics of the strains

In the selected isolates, bacillary forms predominated, forming

white colonies with entire margins and a dry consistency on nutrient

agar medium (Table 1).

The DNase and coagulase tests were negative, which is a favorable

criterion for subsequent evaluation in plant growth promotion trials.

Taxonomic identication of isolates

Phylogenetic analysis based on the sequence of the 16S rRNA

gene allowed the identication of bacterial isolates (Figure 1).

The RM 4.2 strain was grouped in the genus Proteus, with a 100

% identity with the type strain sequence of P. mirabilis, and identity

percentages of 97.3-99.1 % (Table 2) with the type strain sequences

of the closest species, according to the analysis with the MatGAT

program (Campanella et al., 2003).

Table 1. Morphological characteristics of saline soil strains from coastal settlements in the municipality of Remedios in Villa Clara

province, Cuba.

Strains Cell morphology Gram stain Colonie color Morphology of the colonies Image

RM 4.1

Wide bacilli Gram - White

Irregular with entire margins, convex, dry, and with a sunken

center containing granules

RM 4.2

Wide bacilli Gram - White

Circular with irregular margins, convex and dry consistency with

granules

RM 6.2

Short bacilli Gram + White

Circular with entire margins, convex and dry consistency with

granules

RM= code in reference to the municipality of Remedios.

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Figure 1. Phylogenetic tree based on the 16S rRNA gene

sequences, built using the MEGA 7 program, the

maximum likelihood method, and the K2P nucleotide

substitution model. Branch values correspond to

bootstrap percentages obtained from 1,000 replicates.

Table 2. Identity of the 16S rRNA gene sequences of the bacterial

strains obtained from saline soils of Remedios, Cuba,

with respect to the type strain sequences used in the

phylogenetic analysis.

Strain Type strain sequence Identity (%)

Tenebrionicola

sp. RM 4.1

MW680835 Tenebrionicola larvae 93.9

AP019007 Enterobacter oligotrophicus 93.5

CP054212 Paramixta manurensis 93.1

Proteus sp. RM

4.2

MN749808 Proteus mirabilis 100.0

HE978268 Proteus vulgaris 99.1

NR_104767 Proteus hauseri 98.5

NR_146019 Proteus terrae 97.3

Lysinibacillus

sp. RM 6.2

NR_042072 Lysinibacillus fusiformis 99.9

OR096703 Lysinibacillus pinotti 99.2

NR_175531 Lysinibacillus cavernae 98.4

CP067341 Lysinibacillus agricola 98.4

The identity percentages were determined using the MatGAT version 2.01 program. RM= code

in reference to the municipality of Remedios.

The strain RM 4.1 was grouped within the genus Tenebrionicola,

showing proximity to T. larvae, the only species described of the

genus, with 93.9 % identity relative to its type strain sequence.

Likewise, it presented an identity range of 93.1-93.5 % with the type

strain sequence, corresponding to species of the phylogenetically

closest genera, according to the analysis with MatGAT (Campanella

et al., 2003). On the other hand, the RM 6.2 strain was located within

the genus Lysinibacillus, with greater anity to L. fusiformis, with

a 99.9 % identity with the type strain sequence of this species and

a range of 98.4-99.2 % with the type strain sequences of the closest

species, according to the analysis with MatGAT (Campanella et al.,

2003) (Table 2).

It should be noted that the identied species are not frequent in

studies of plant growth-promoting bacteria, especially P. mirabilis, L.

fusiformis, and particularly Tenebrionicola sp., whose presence has

been little documented in this type of environment.

Characterization of plant growth-promoting strains

All three strains showed growth in nitrogen-free Winogradsky

medium, suggesting their ability to x atmospheric nitrogen. The RM

4.1 strain presented signicant dierences with respect to the others

(Table 3).

Table 3. Plant growth promotion characteristics (PGP) of bacteria

from saline soils in Remedios, Cuba.

Tests

Bacterial strains

RM 4.1 RM 4.2 RM 6.2 ESx

Biological nitrogen xation

(diameter of colonies in cm)

Winodrasky medium 1.86 a 1 c 1.56 b 0.0158

Nutrient solubilization index

Phosphate (Calcium) 1.52 a 1.44 b 0 0.0050

Phosphate (Aluminum) 0 0 2.00 a 0.0171

Potassium 0 0 0

Iron and siderophore

production index

Iron 1.25 c 1.30 b 3.18 a 0.0043

Production of indolic

compounds

Indolic compounds + - +

Equal letters do not dier signicantly between rows (Duncan’s Multiple Range Test, α =

0.05, n = 10). ESx= standard error. RM= code in reference to the municipality of Remedios.

Regarding phosphate solubilization capacity, dierences were

observed among the three strains. RM 4.1 and RM 4.2 solubilized

calcium phosphate, with a predominance of RM 4.1, while only RM 6.2

solubilized aluminum phosphate (Table 3). None of the strains showed

the ability to solubilize potassium. Similarly, all of them produced

siderophores, with RM 6.2 standing out with signicant dierences

compared to the others. In the production of indolic compounds, RM

4.1 and RM 6.2 were exclusively positive (Table 3).

In relation to enzyme production, the results showed a remarkable

versatility among the strains evaluated (Table 4). The RM 4.2 strain

distinguished itself from the rest by producing ve lytic enzymes,

highlighting its potential compared to the other two. Regarding amylase

activity, RM 4.1 and RM 6.2 stood out, the latter being the one with the

highest capacity. Only RM 4.2 showed protease and esterase activity,

while both RM 4.1 and RM 4.2 produced lipases, with a predominance

of MR 4.2. All three strains showed cellulase activity, with RM 6.2

standing out. Regarding peroxidase, all strains were positive.

Table 4. Production of enzymes by bacteria isolated from saline

soils in Remedios, Cuba.

Enzymes

Bacterial strains

RM 4.1 RM 4.2 RM 6.2 ESx

Peroxidases

+ + +

Enzyme activity indices

Amylases

1.25 b 0 3.55 a 0.0153

Proteases

0 1.44 0

Lipases

1.67 b 2.43 a 0 0.0041

Esterases

0 2.95 0

Cellulases

1.35 c 1.47 b 3.02 a 0.0035

Peptidases

0 0 0

Equal letters do not dier signicantly between rows (Duncan’s Multiple Range Test, α =

0.05, n = 10). ESx= standard error. RM= code in reference to the municipality of Remedios.

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5-7 |

Similar studies on microorganisms from saline soils have

revealed how they activate tolerance and resistance mechanisms that

allow them to mitigate these adverse eects through plant growth

promotion, not only in the presence of salts but also of potentially

toxic metals (Ahluwalia et al., 2021). These manifestations described

in the literature support the functionality and adaptations observed

in the new strains, which reveal that they can not only survive in

saline environments, but can also have positive eects in agricultural

environments aected by this type of stress.

In general terms, plant growth-promoting bacteria (PGPB) have a

set of attributes that support plant development, including atmospheric

nitrogen xation through nitrogenase production (Masood et al.,

2020), the stimulation of antioxidant enzymes such as oxidoreductase,

peroxidase, ascorbate peroxidase, superoxide dismutase, catalase,

glutathione reductase and adenosine triphosphatase (Liu et al., 2021),

as well as the synthesis of 1-aminocyclopropane-1-carboxylate

(ACC) deaminase that contributes to reducing ethylene levels in plant

tissues.

In addition, these bacteria reinforce the activity of soil enzymes,

such as alkaline and acid phosphatases, urease, and β-glucosidase

(Kumar et al., 2021), and produce siderophores that facilitate plant

access to iron (Jalal et al., 2023). In this context, the strains obtained in

the present study show characteristics that position them as promising

candidates for PGPB, with emphasis on saline environments.

Studies on strains of Proteus mirabilis describe them as human

pathogens (Mekibib et al., 2015). However, some authors have

reported that they are also PGPB, with the ability to solubilize

phosphate and potassium (Saheed and Ikhajiagbe, 2024), in

addition to producing indole-3-acetic acid (Sushma et al., 2021) and

siderophores (Amaresan et al., 2021). These strains show tolerance to

dierent stress conditions, such as salinity (Akintokun et al., 2019),

reduce proline accumulation against zinc toxicity (Suganya et al.,

2020), and activate antioxidant enzymes such as catalase, peroxidase,

and superoxide dismutase in the presence of other metals (Sushma et

al., 2021).

In the case of Lysinibacillus fusiformis, it is known as a plant

growth-promoting species (Ahsan and Shimizu, 2021) due to the

production of phytohormones such as indole-3-acetic acid and abscisic

acid, involved in the elongation and regulation of plant growth. It

also has the ability to solubilize phosphates through the production of

organic acids (fumaric, lactic, malic, citric, succinic, propionic, and

acetic) and inorganic phosphorus (Passera et al., 2021). In addition,

its potential to synthesize antimicrobial compounds as siderophores

has been described (Passera et al., 2021) and enzymes with antifungal

action against pathogens such as Aspergillus niger, Botrytis cinerea,

Phomopsis viticola, and Rhizoctonia solani (Passera et al., 2021).

It also produces urease (Jibrin et al., 2020) and participates in

bioremediation processes for heavy metals such as cadmium and

copper (Mathivanan et al., 2016).

As for the genus Tenebrionicola, T. larvae is the rst species

described within this genus and was isolated from larvae of Tenebrio

molitor L. (Dong et al., 2022); however, there are no reports of strains

of this species or possible strains related to this genus as plant growth

promoters, since studies have been based mainly on their taxonomic

value, rather than in their possible uses or specic biotechnological

applications. The evidence found in the present study opens new lines

of research that indicate that this bacterium could be applied and be

of benet to sustainable agriculture.

Together, the three strains analyzed in this study x atmospheric

nitrogen, two solubilize calcium phosphate and aluminum phosphates;

all promote the production of siderophores and, in two cases, produce

indolic compounds. Similarly, all three strains generate lytic enzymes,

reinforcing their potential as plant growth-promoting bacteria.

Inoculation of the strains in tomato cultivars (Solanum

lycopersicum L.)

When evaluating the eect of the application of the three strains on

tomato cultivars T-60 and FL-5, established in a salinized Vertisol soil, the

strain Proteus sp. RM 4.2 stood out, showing higher values in all growth

and development indicators, with signicant dierences compared to

the rest of the treatments in both cultivars (Table 5). In contrast to the

studies of Islam et al. (2016) and Suganya et al. (2020), these results

demonstrate that the strain Proteus sp. RM 4.2 was also eective in

signicantly stimulating both tomato cultivars, which is consistent with

several studies describing the role of Proteus sp. as PGPB.

Table 5. Eect of bacterial strains isolated from saline soils in

the municipality of Remedios, Cuba, on the growth and

development of tomato cultivars T-60 and FL-5, in a

salinized Vertisol soil during two trials.

Treatments

Plant

height

(cm)

Root

length

(cm)

Stem

diameter

(cm)

Number

of leaves

(u)

Dry

plant

mass

(g)

Cultivar T-60

Tenebrionicola sp.

RM 4.1

6.49 b 1.38 b 0.07 b 3.81 0.26 b

Proteus sp.

RM 4.2

7.31 a 2.02 a 0.13 a 4.11 0.46 a

Lysinibacillus sp.

RM 6.2

6.56 b 1.40 b 0.09 b 3.80 0.31 b

Control 6.35 c 1.01 c 0.03 c 3.42 0.12 c

ESx 0.0408 0.0484 0.0066 0.3755 n.s 0.0383

Cultivar FL-5

Tenebrionicola sp.

RM 4.1

6.71 b 1.18 c 0.06 b 4.19 0.25 b

Proteus sp.

RM 4.2

7.56 a 1.92 a 0.16 a 4.40 0.42 a

Lysinibacillus sp.

RM 6.2

6.82 b 1.25 b 0.07 b 4.21 0.29 b

Control 5.72 c 0.86 d 0.03 c 4.09 0.10 c

ESx 0.0261 0.0281 0.0074 0.2378 n.s 0.0309

Equal letters in the same column do not dier signicantly from each other, according to

Duncan’s Multiple Range test α = 0.05 n=25. ns: not signicant. ESx= Standard error. RM=

code in reference to the municipality of Remedios.

P. mirabilis has been reported to stimulate the growth of corn (Zea

mays L.) in saline soils (Akintokun et al., 2019) and improve nutrient

uptake under high concentrations of Zn, which has a favorable impact

on grain yield and quality (Suganya et al., 2020). Likewise, its ability

to increase soil nutrients and chelate iron in rice cultivars (Oryza

sativa L.) has been described (Saheed and Ikhajiagbe, 2024).

The results of the present study conrm the capacity of the strain

Proteus sp. RM 4.2 to promote plant growth, as it has the ability to

x nitrogen, solubilize phosphate, as well as produce siderophores,

indolic compounds, and hydrolytic enzymes (peroxidases, proteases,

lipases, esterases, and cellulases). The combination of these functional

traits was associated with the highest promoting eects observed in

the bioassays in tomato plants (S. lycopersicum), compared to the

other strains evaluated (Table 5), which is in accordance with the

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Rev. Fac. Agron. (LUZ). 2026, 43(1): e264318 January-March ISSN 2477-9409.

6-7 |

attributes previously indicated for this species (Amaresan et al., 2021;

Saheed and Ikhajiagbe, 2024; Suganya et al., 2020; Sushma et al.,

2021). However, its agricultural use requires additional studies to rule

out phytopathological risks.

In the case of L. fusiformis, several studies have documented its

ability to improve the uptake of N, P, and K, as well as the yield in corn

and the development of seedlings of dierent crops under greenhouse

conditions (Passera et al., 2021). Similarly, positive eects on tomato

yield and nutritional quality have been reported (Jyolsna et al., 2021).

The results obtained in this study conrm that the strain Lysinibacillus

sp. RM 6.2 presents functional traits comparable to those previously

described, and its inoculation promotes plant growth under salt stress

conditions (Table 5).

For its part, the strain Tenebrionicola sp. RM 4.1 showed positive

eects on plant growth promotion in the bioassays conducted, which

are relevant given that there are no previous reports on its potential

as a plant growth-promoting bacterium. This study constitutes the

rst record of this genus in Cuban saline soils and its rst functional

evaluation as a PGPB, expanding knowledge about the microbial

diversity associated with saline agroecosystems. Together, these

results provide relevant information for the selection of native

bacteria with potential application in crop management in salinized

soils in the municipality of Remedios, in Cuba.

Conclusions

The three strains isolated from saline soils in the municipality of

Remedios showed functional attributes associated with plant growth

promotion. Among them, the strain Proteus sp. RM 4.2, related to

P. mirabilis, stood out signicantly in stimulating the growth of

tomato cultivars. These results indicated that the studied strains have

potential for the development of bioinoculants aimed at improving

crop growth in saline soils. However, additional studies under eld

conditions are required, as well as biosecurity evaluations, especially

in the case of Proteus sp. RM 4.2, to rule out phytopathological risks

and ensure safe use in agriculture.

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