Agronomical, Physiological and Biochemical Characterization of In Vitro Selected Eggplant Somaclonal Variants under NaCl Stress

• Published in: Plants (Basel) 2021-11, Vol.10 (11), p.2544
• Main Authors: Hannachi, Sami, Werbrouck, Stefaan, Bahrini, Insaf, Abdelgadir, Abdelmuhsin, Affan Siddiqui, Hira
• Format: Article
• Language: English
• Subjects: Abiotic stress; Accumulation; Agronomy; Ascorbic acid; Calcium ions; Carbohydrates; Catalase; Chlorophyll; Chloroplasts; Crops; eggplant; Enzymatic activity; Evaluation; Explants; Fluorescence; Germination; growth; Guaiacol; L-Ascorbate peroxidase; Leaves; Magnesium; Malondialdehyde; MDA carbohydrates; Mutants; Osmotic potential; Oxidative stress; Parameters; Peroxidase; Photochemicals; Photosynthesis; Photosystem II; Physiology; Plant growth; Plants; Progeny; Proline; Proteins; Quenching; Regeneration; Roots; Salinity; Salinity effects; Salinity tolerance; Salt; Salt tolerance; Scavenging; Seedlings; Sodium chloride; Solanum melongena; somaclonal variants; Stability; Water potential
• ISSN: 2223-7747; 2223-7747
• DOI: 10.3390/plants10112544

Previously, an efficient regeneration protocol was established and applied to regenerate plants from calli lines that could grow on eggplant leaf explants after a stepwise in vitro selection for tolerance to salt stress. Plants were regenerated from calli lines that could tolerate up to 120 mM NaCl. For further in vitro and in vivo evaluation, four plants with a higher number of leaves and longer roots were selected from the 32 plants tested in vitro. The aim of this study was to confirm the stability of salt tolerance in the progeny of these four mutants ('R18', 'R19', 'R23' and 'R30'). After three years of in vivo culture, we evaluated the impact of NaCl stress on agronomic, physiological and biochemical parameters compared to the parental control ('P'). The regenerated and control plants were assessed under in vitro and in vivo conditions and were subjected to 0, 40, 80 and 160 mM of NaCl. Our results show significant variation in salinity tolerance among regenerated and control plants, indicating the superiority of four regenerants ('R18', 'R19', 'R23' and 'R30') when compared to the parental line ('P'). In vitro germination kinetics and young seedling growth divided the lines into a sensitive and a tolerant group. 'P' tolerate only moderate salt stress, up to 40 mM NaCl, while the tolerance level of 'R18', 'R19', 'R23' and 'R30' was up to 80 mM NaCl. The quantum yield of PSII (Φ ) declined significantly in 'P' under salt stress. The photochemical quenching was reduced while nonphotochemical quenching rose in 'P' under salt stress. Interestingly, the regenerants ('R18', 'R19', 'R23' and 'R30') exhibited high apparent salt tolerance by maintaining quite stable Chl fluorescence parameters. Rising NaCl concentration led to a substantial increase in foliar proline, malondialdehyde and soluble carbohydrates accumulation in 'P'. On the contrary, 'R18', 'R19', 'R23' and 'R30' exhibited a decline in soluble carbohydrates and a significant enhancement in starch under salinity conditions. The water status reflected by midday leaf water potential (ψl) and leaf osmotic potential (ψπ) was significantly affected in 'P' and was maintained a stable level in 'R18', 'R19', 'R23' and 'R30' under salt stress. The increase in foliar Na and Cl content was more accentuated in parental plants than in regenerated plants. The leaf K , Ca and Mg content reduction was more aggravated under salt stress in 'P'. Under increased salt concentration, 'R18', 'R19', 'R23' and 'R30' assoc