Correction: Hashemi et al. Effects of Abiotic Elicitors on Expression and Accumulation of Three Candidate Benzophenanthridine Alkaloids in Cultured Greater Celandine Cells. Molecules 2021, 26, 1395.

The authors wish to make the following correction to the paper [...].

Limoniastrum guyonianum behavior under seasonal conditions fluctuations of Sabkha Aïn Maïder (Tunisia).

In Sabkha biotope, several environmental factors (i.e., salinity, drought, temperature, etc.) especially during dry season affect halophytes developments. To cope with these harmful conditions, halophytes use multiple mechanisms of adaptations. In this study, we focused on the effect of environmental condition changes over a year in the Sabkha of Aïn Maïder (Medenine - Tunisia) on the physiological and biochemical behavior of Limoniastrum guyonianum using a modeling approach. Our study showed that the model depicted well (R2 > 0.75) the monthly fluctuations of the studied parameters in this habitat. During the dry period (June to September), the salinity of the soil increased remarkably (high level of EC and Na+ content), resulting in high Na+ content in the aerial parts followed by a nutrient deficiency in K+, Ca2+, and Mg2+. As a result of this disruption, L. guyonianum decreased its water potential to more negative values to maintain osmotic potential using inorganic osmolytes (i.e., Na+) and organic osmolytes (i.e., sugars: sucrose, fructose, glucose, and xylitol, and organic acids: citric and malic acids). In addition, CO2 assimilation rate, stomatal conductance, transpiration rate, and photosynthetic pigments decreased significantly with increasing salinity. The phenolic compounds contents and the antioxidant activity increased significantly in the dry period as a result of increased levels of H2O2 and lipid peroxidation. This increase was highly correlated with soil salinity and air temperature. The maintenance of tissue hydration (i.e., moderate decrease of relative water content), the accumulation of sugars and organic acids, the enhancement of phenolic compounds amounts, and the increase of antioxidant activity during the dry period suggest that L. guyonianum possesses an efficient tolerance mechanism that allows the plant to withstand the seasonal fluctuations of climatic conditions in its natural biotope.

Seasonal environmental changes affect differently the physiological and biochemical responses of two Limonium species in Sabkha biotope.

To cope with abiotic stresses, the halophytes use various tolerance mechanisms that are not all known for some species of halophytes. This work aimed to model the responses of two halophytes, Limonium pruinosum and Limonium tunetanum, to changing environmental conditions over a year in Sabkha biotope, Tunisia. Our findings indicated that the model could describe well the seasonal variations of all studied traits over a year in this region (R2  > 0.80). The pH, electrical conductivity (EC), and mineral composition (i.e., Sodium [Na+ ], potassium [K+ ], calcium [Ca2+ ], and magnesium [Mg2+ ] concentrations] in the soil significantly varied during the year (P < 0.01). The highest soil Na+ concentration was found during the dry period (June-August), which matched with a high Na+ content in the aerial parts (i.e., 2455.1 and 3366.0 µmol g-1 SDM in August for L. pruinosum and L. tunetanum, respectively). This accumulation is concomitant with a deficit in nutrients, particularly K+ and Mg2+ and, to a lesser extent, Ca2+ . Following these disturbances, both species decreased their photosynthetic activity, water potential as well as the relative water content to a lesser extent, especially in August. To counteract these harmful effects, these species have accumulated organic substances, but in a different way. Indeed, L. pruinosum accumulated sucrose, fructose, and citrate, while L. tunetanum accumulated sucrose, xylitol, citrate, and malate, indicating a major role of these osmolytes in the stress tolerance mechanisms. In both species, the results also showed that all traits were highly correlated with the edaphic variables (i.e., pH, EC, Na+ , K+ , Ca2+ , and Mg2+ concentrations) and with temperature as the climatic variable.

Effects of Abiotic Elicitors on Expression and Accumulation of Three Candidate Benzophenanthridine Alkaloids in Cultured Greater Celandine Cells.

Efforts to develop the necessary biotechnologies in Greater Celandine (Chelidonium majus L.), a leading plant resource for the development of plant-derived medicines, have been hampered by the lack of knowledge about transcriptome and metabolome regulations of its medicinal components. Therefore, this study aimed to examine the effect of abiotic elicitors, methyl jasmonate (MJ) and salicylic acid (SA), at different time courses (12, 24, 48, and 72 h), on expression and metabolome of key benzophenanthridine alkaloids (BPAs) in an optimized in vitro culture. Gene expression analysis indicated the upregulation of CFS (cheilanthifoline synthase) to 2.62, 4.85, and 7.28 times higher than the control at 12, 24, and 48 h respectively, under MJ elicitation. Besides, MJ upregulated the expression of TNMT (tetrahydroprotoberberine N-methyltransferase) to 2.79, 4.75, and 7.21 times at 12, 24, and 48 h respectively, compared to the control. Investigation of BPAs revealed a significant enhancement in the chelidonine content (9.86 µg/mg) after 72 h of MJ elicitation. Additionally, sanguinarine content increased to its highest level (3.42 µg/mg) after 24 h of MJ elicitation; however, no significant enhancement was detected in its content in shorter elicitation time courses. Generally, higher gene expression and BPAs' level was observed through longer elicitation courses (48 and 72 h). Our findings take part in improving the understanding of transcription and metabolic regulation of BPAs in cultured Greater Celandine cells.

Phosphate solubilization potential and modeling of stress tolerance of rhizobacteria from rice paddy soil in northern Iran.

The purposes of this study were to evaluate the phosphate solubilization activity of bacteria isolated from the rhizosphere of rice paddy soil in northern Iran, and to study the effect of temperature, NaCl and pH on the growth of these isolates by modeling. Three of the most effective strains from a total of 300 isolates were identified and a phylogenetic analysis was carried out by 16S rDNA sequencing. The isolates were identified as Pantoea ananatis (M36), Rahnella aquatilis (M100) and Enterobacter sp. (M183). These isolates showed multiple plant growth-promoting attributes such as phosphate solubilization activity and indole-3-acetic acid (IAA) production. The M36, M100 and M183 isolates were able to solubilize 172, 263 and 254 µg ml(-1) of Ca3(PO4)2 after 5 days of growth at 28 °C and pH 7.5, and to produce 8.0, 2.0 and 3.0 µg ml(-1) of IAA when supplemented with L-tryptophan (1 mg ml(-1)) for 72 h, at 28 °C and pH 7.0, respectively. The solubilization of insoluble phosphate was associated with a drop in the pH of the culture medium and there was an inverse relationship between pH and solubilized P (r = -0.98, P < 0.0952). There were no significant differences among isolates in terms of acidity tolerance based on their confidence limits as assessed by segmented model analysis and all isolates were able to grow at pH 4.3-11 (with optimum at 7.0-7.5). Based on a sigmoidal trend of a three-parameter logistic model, the salt concentration required for 50 % inhibition was 8.15, 6.30 and 8.23 % NaCl for M36, M100 and M183 isolates, respectively. Moreover, the minimum and maximum growth temperatures estimated by the segmented model were 5.0 and 42.75 °C for M36, 12.76 and 40.32 °C for M100, and 10.63 and 43.66 °C for M183. The three selected isolates could be deployed as inoculants to promote plant growth in an agricultural environment.