Drought and salt stress are two major abiotic factors significantly impacting crop growth and yield. Climate change leads to increasing drought and soil salinization issues, rising significant challenges to agricultural production. Amylases play a crucial role in enhancing the tolerance of crops to these stresses by regulating physiological and enzymatic activities. Previous study identified MeAMY1 and MeBAM3 as key genes involved in cassava starch metabolism under drought stress. To investigate their functions under drought and salt stress, MeAMY1 and MeBAM3 genes were cloned and over-expressed in Arabidopsis thaliana in the current study. Overexpression of MeAMY1 in Arabidopsis enhances amylase activities, promotes starch hydrolysis, releases soluble sugar and thus enhances osmotic balance in transgenic Arabidopsis. In the mean while, expression of BAM1 and SEX1 were depressed by MeAMY1 to maintain the protects cells closed under stress and preserved starch for adapting the stressful environments. Overexpression of the MeBAM3 in Arabidopsis can increase the expression levels of AMY3 and RVE1, promotes starch hydrolysis, releases soluble sugar from the chloroplasts to the cytoplasm and thus enhances osmoregulatory substance content, reducing stress-induced damage to antioxidant enzymes and cell membranes and improving stress tolerance. The principal component analysis further indicated that MeAMY1 and MeBAM3 overexpression lines responded similarly to drought stress, while MeBAM3 overexpression provided greater resilience to salt stress.
Amylase has numerous applications in the processing food sector, including brewing, animal feed, baking, fruit juice manufacturing, starch syrups, and starch liquefaction. Practical applications have been the primary focus of recent research on novel properties of bacterial alpha-amylases. Many amylolytic-active bacterial isolates were obtained from samples of organic-rich, salinity-rich soil. Morphological and 16S rRNA gene sequence studies clearly revealed that the organism belongs to Bacillus sp. and was named Bacillus cereus strain GL2 (PP463909.1 (When pH 6.0, 45 degrees C, and 12 hours of incubation were met the optimal growth conditions for the strain produced the highest amount of alpha-amylase activity. B. cereus strain GL2 alpha-amylase isoenzyme was purified to homogeneity using Sephacryl (TM) S-200 chromatography and ammonium sulfate precipitation. The electrophoretic molecular weight of B. cereus alpha-amylase was 58 kDa. The optimal pH and temperature for measuring alpha-amylase activity were 50 degrees C and 6.0, respectively. alpha-Amylase did not change at 50 degrees C. The purified enzyme improves bread texture by reducing stiffness while improving cohesiveness and flexibility. Purified alpha-amylase was added to the flour, which improved the rheological properties and overall bread quality. As a result, the alpha-amylase from B. cereus strain GL2 can be used to promote bread-making.
The aim of this study is to evaluate the seasonal changes in leachate compositions, and their impact on germination tests and alpha-amylase activity. Throughout the four seasons of the year 2022, leachate samples were collected in autumn, winter, spring, and summer directly from the collection conduit of the untreated leachate pond at Mediouna landfill (Casablanca, Morocco). The parameters analyzed in the leachate samples included pH, electrical conductivity (EC), chemical oxygen demand (COD), 5-day biochemical oxygen demand (BOD5), nitrate (NO3-), ammonium (NH4+), and orthophosphate (PO43-). The present study involved the execution of germination tests on municipal solid waste leachate. Lens culinaris and Medicago sativa seeds were exposed to leachate at different dilutions of 1%, 3%, 5%, 7%, and 10%, with tap water as control, for about 72 h in the dark at room temperature. Severe toxicity was observed for the 7% and 10% concentrations, observing that L. culinaris and M. sativa showed a mean value of germination index inferior to 50%. These results can be explained by the presence of inhibitor elements in the leachate such as heavy metals (Pb and Hg) and sodium. Lead (Pb) and mercury (Hg) have mean concentrations of 0.2276 ppm and 0.0159 ppm, respectively, while sodium (Na) exhibits an average concentration of 359.942 ppm. In addition, for the biochemical parameters, we noted a decrease in alpha-amylase activity proportionally to the germination index. In conclusion, this work highlights the significant metabolic disturbances induced by leachate, harming the germination of L. culinaris and M. sativa seeds. The present results highlight the potential deleterious effects of leachate pollution on agricultural activities and the ecosystem. However, it may also be possible to take advantage of the leachate's richness in organic matter and nutrient salts to fertilize agricultural land. Our next investigations will aim to verify whether the use of leachate as fertilizer will cause damage to crops and soil.
Under natural conditions, crops typically suffer from severe challenges due to the increasing of abiotic and biotic stresses which severely affect plant growth and reduc crop yield. The present study investigated the single and combined impacts of Sclerotinia sclerotiorum and salinity stress on common bean (Phaseolus vulgaris L.) seedling which is scarcely studied. The study evaluated the in vitro and in vivo influence of two salinity tolerant Trichoderma isolates, T. koningii and T. harzianum against S. sclerotiorum under salinity stress. The results showed the ability of T. koningii and T. harzianum to grow and sporulate at high levels of salinity, 80 mM NaCl, without significantly impacting their ability to produce cell wall degrading enzymes, cellulase and chitinase. Amylase and proteinase (Prb1) genes were detected in T. harzianum. The in vitro assay revealed that both isolates could inhibit the growth of S. sclerotiorum under high salinity concentrations. In a greenhouse experiment, both Trichoderma isolates ameliorated the damaging impacts of S. sclerotiorum under salinity stress on common bean seedlings' germination and growth characteristics compared to their untreated control. Both bioagents significantly attenuated the damping-off and collar/stem rot percentages of infected common bean under salinity stress. Salinity stress intensified the effect of S. sclerotiorum on photosynthetic pigments, induced oxidative and nitrative stress, hampered ionic homeostasis, and deactivated antioxidants and defense-related molecules. On the other hand, Trichoderma isolates restrained the reduction of chlorophylls and carotenoids, ascorbate, reduced glutathione, flavonoids, phenolics, and various antioxidant enzymes, especially for single stresses and T. harzianum. All these upregulations reflected in keeping the cell membranes of common beans seedling more stable where the levels of lipid peroxidation and methylglyoxal due to the reduction of reactive oxygen species and upregulation of nitric oxide, which expressed better growth under pathogen attack or/and saline. The tested isolates, T. koningii and T. harzianum could be used as effective biological control against S. sclerotiorum on common beans in saline soils or areas irrigated with saline water.