Browsing by Author "Hdira, Sabrine"

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    Assessment of genetic diversity in Tunisian populations of Medicago polymorpha based on SSR markers
    (Instituto de Investigaciones Agropecuarias, 2021) Haddoudi, Loua; Hdira, Sabrine; Ludidi, Ndiko
    Medicago polymorpha L. is a herbaceous legume that can be a useful pasture crop, especially in Mediterranean climates. This study aimed to analyze the genetic variation in five populations of M. polymorpha collected from different ecogeographic regions in Tunisia using eight SSR markers. The transferability of 112 SSR markers distributed on the eight chromosomes of M. truncatula Gaertn. showed that 50 SSR markers could be amplified in M. polymorpha. Among these 50 SSR markers, eight (8) markers were polymorphous. A high level of polymorphism (126 polymorphic alleles with an average of 5.3 alleles per locus) and a moderate level of genetic diversity were found in all the studied populations, with observed and expected heterozygosities averaging between 0 and 0.69, respectively. Results from analysis of molecular variance (AMOVA) revealed that the most variation was found within populations (76%). Moderate levels of population differentiation (FST = 0.12 to 0.19) accompanied by a high rate of gene flow between populations (Nm = 1.08 to 1.83) were recorded. This molecular differentiation (FST) was not dependent on geographical distances (r = 0.395, p = 0.524), suggesting that studied populations are not geographically isolated. Our results showed that studied populations were clustered into three groups. A first group is formed by the populations of El Kef (TNP7) and Bulla Regia (TNP9), a second group of Enfidha (TNP1) and a third group of Soliman (TNP8) and Mateur (TNP11). Results obtained in our study could be helpful for breeders considering introduction of some lines of this species into M. polymorpha breeding programs.
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    Evaluation of the morpho-physiological, biochemical and molecular responses of contrasting medicago truncatula lines under water deficit stress
    (MPDI, 2021) Haddoudi, Loua; Hdira, Sabrine; Ludidi, Ndiko
    Medicago truncatula is a forage crop of choice for farmers, and it is a model species for molecular research. The growth and development and subsequent yields are limited by water availability mainly in arid and semi-arid regions. Our study aims to evaluate the morpho-physiological, biochemical and molecular responses to water deficit stress in four lines (TN6.18, JA17, TN1.11 and A10) of M. truncatula. The results showed that the treatment factor explained the majority of the variation for the measured traits. It appeared that the line A10 was the most sensitive and therefore adversely affected by water deficit stress, which reduced its growth and yield parameters, whereas the tolerant line TN6.18 exhibited the highest root biomass production, a significantly higher increase in its total protein and soluble sugar contents, and lower levels of lipid peroxidation with greater cell membrane integrity. The expression analysis of the DREB1B gene using RT-qPCR revealed a tissue-differential expression in the four lines under osmotic stress, with a higher induction rate in roots of TN6.18 and JA17 than in A10 roots, suggesting a key role for DREB1B in water deficit tolerance in M. truncatula.
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    Identification of salt-tolerant Tunisian Medicago ciliaris lines during germination and early seedling stages under NaCl stress
    (Springer Nature, 2025) Aloui, Meriem; Ludidi, Ndiko; Hdira, Sabrine
    Germination is a critical determinant of grain yield in Medicago ciliaris, and salinity poses a major stress factor in Tunisian soils. This study aims to evaluate the variability in salt tolerance among four Tunisian populations of M. ciliaris, Enfidha (TNC1), Soliman (TNC8), Rhayet (TNC10), and Mateur (TNC11) during germination under NaCl concentrations of 0, 125, and 175 mM. ANOVA revealed significant differences among populations, lines, treatments, and their interactions for all germination traits. Salt stress led to a marked reduction in germination parameters, with the highest tolerance observed in lines from the Soliman population. Broad-sense heritability (H2) was high, with values ranging from 0.66 to 0.94, reflecting substantial genetic stability across all germination traits under varying salinity levels. Hierarchical clustering categorized the 46 lines into three groups, highlighting the genetic diversity and phenotypic variability in response to salt stress. Four lines demonstrated notable salt tolerance at both 125 and 175 mM NaCl, particularly line TNC8.1, which showed consistent performance across germination and growth stages. These results underscore the potential of the Soliman population (TNC8) as a valuable genetic resource for breeding salt-tolerant M. ciliaris varieties, offering a promising pathway for enhancing crop performance under saline conditions in Tunisia
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    Morpho-physiological, biochemical, and genetic responses to salinity in medicago truncatula
    (MDPI, 2021) Hdira, Sabrine; Haddoudi, Loua; Ludidi, Ndiko
    We used an integrated morpho-physiological, biochemical, and genetic approach to investigate the salt responses of four lines (TN1.11, TN6.18, JA17, and A10) of Medicago truncatula. Results showed that TN1.11 exhibited a high tolerance to salinity, compared with the other lines, recording a salinity induced an increase in soluble sugars and soluble proteins, a slight decrease in malondialdehyde (MDA) accumulation, and less reduction in plant biomass. TN6.18 was the most susceptible to salinity as it showed less plant weight, had elevated levels of MDA, and lower levels of soluble sugars and soluble proteins under salt stress. As transcription factors of the APETALA2/ethylene responsive factor (AP2/ERF) family play important roles in plant growth, development, and responses to biotic and abiotic stresses, we performed a functional characterization of MtERF1 gene. Real-time PCR analysis revealed that MtERF1 is mainly expressed in roots and is inducible by NaCl and low temperature.