Distribution, ecological fate, and risks of steroid estrogens in environmental matrices.

Over the past two decades, steroidal estrogens (SEs) such as 17α-ethylestradiol (EE2), 17ß-estradiol (E2),17α-estradiol (17α-E2), estriol (E3) and estrone (E1) have elicited worldwide attention due to their potentially harmful effects on human health and aquatic organisms even at low concentration ng/L. Natural steroidal estrogens exhibit greater endocrine disruption potency due to their high binding effect on nuclear estrogen receptors (ER). However, less has been explored regarding their associated environmental risks and fate. A comprehensive bibliometric study of the current research status of SEs was conducted using the Web of Science to assess the development trends and current knowledge of SEs in the last two decades, from 2001 to 2021 October. The number of publications has tremendously increased from 2003 to 2021. We summarized the contamination status and the associated ecological risks of SEs in different environmental compartments. The results revealed that SEs are ubiquitous in surface waters and natural SEs are most studied. We further carried out an in-depth evaluation and synthesis of major research hotspots and the dominant SEs in the matrices were E1, 17ß-E2, 17α-E2, E3 and EE2. Nonetheless, investigations of SEs in soils, groundwater, and sediments remain scarce. This study elucidates SEs distribution, toxicological risks, ecological fate and mitigation measures, which will be beneficial for future monitoring, management, and risk assessment. Further studies are recommended to assess the toxicological risks of different SEs in complex environmental matrices to pursue a more precise and holistic quantitative estimation of estrogenic risk.

Late embryogenesis abundant gene LEA3 (Gh_A08G0694) enhances drought and salt stress tolerance in cotton.

Plants have evolved a complex and organized response to abiotic stress that involves physiological and metabolic reprogramming, transcription control, epigenetic regulation, and expressions of thousand interacting genes for instance the late embryogenesis abundant (LEA) proteins are expressed in multiple environmental variables during the plant developmental period, and thus play critical role in enhancing drought and salt stress tolerance. A comprehensive molecular and functional characterization of the LEA3 gene was carried out in cotton under abiotic stress conditions in order to elucidate their functions. Seventy eight genes were identified in cotton, and were clustered into six clades moreover; the LEA genes were more upregulated in the tissues of the tetraploid cotton compared to the diploid type. A key gene, Gh_A08G0694 was the most upregulated, and was knocked in tetraploid cotton, the knocked out significantly increased the susceptibility of cotton plants to salinity and drought stresses, moreover, several ABA/stress-associated genes were down regulated. Similarly, overexpression of the key gene, significantly increased tolerance of the overexpressed plants to drought and salinity stress. The key gene is homologous to GhLEA3 protein, found to have strong interaction to key abiotic stress tolerance genes, voltage-dependent anion channel 1 (VDAC1) and glyceraldehyde-3-phosphate dehydrogenase A (gapA).

Functional Characterization of GhACX3 Gene Reveals Its Significant Role in Enhancing Drought and Salt Stress Tolerance in Cotton.

The acyl-coenzyme A oxidase 3 (ACX3) gene involved in the ß-oxidation pathway plays a critical role in plant growth and development as well as stress response. Earlier on, studies focused primarily on the role of ß-oxidation limited to fatty acid breakdown. However, ACX3 peroxisomal ß-oxidation pathways result in a downstream cascade of events that act as a transduction of biochemical and physiological responses to stress. A role that is yet to be studied extensively. In this study, we identified 20, 18, 22, 23, 20, 11, and 9 proteins in Gossypium hirsutum, G. barbadense, G. tomentosum, G. mustelinum, G. darwinii, G. arboretum, and G. raimondii genomes, respectively. The tetraploid cotton genome had protein ranging between 18 and 22, while diploids had between 9 and 11. After analyzing the gene family evolution or selection pressure, we found that this gene family undergoes purely segmental duplication both in diploids and tetraploids. W-Box (WRKY-binding site), ABRE, CAAT-Box, TATA-box, MYB, MBS, LTR, TGACG, and CGTCA-motif are abiotic stress cis-regulatory elements identified in this gene family. All these are the binding sites for abiotic stress transcription factors, indicating that this gene is essential. Genes found in G. hirsutum showed a clear response to drought and salinity stress, with higher expression under drought and salt stress, particularly in the leaf and root, according to expression analysis. We selected Gh_DO1GO186, one of the highly expressed genes, for functional characterization. We functionally characterized the GhACX3 gene through overexpression and virus-induced gene silencing (VIGS). Overexpression of this gene enhanced tolerance under stress, which was exhibited by the germination assay. The overexpressed seed growth rate was faster relative to control under drought and salt stress conditions. The survival rate was also higher in overexpressed plants relative to control plants under stress. In contrast, the silencing of the GhACX3 gene in cotton plants resulted in plants showing the stress susceptibility phenotype and reduced root length compared to control. Biochemical analysis also demonstrated that GhACX3-silenced plants experienced oxidative stress while the overexpressed plants did not. This study has revealed the importance of the ACX3 family during stress tolerance and can breed stress-resilient cultivar.