Drought is one of the major constraints to rain-fed agricultural production, especially under climate change conditions. Plants evolved an array of adaptive strategies that perceive stress stimuli and respond to these stress signals through specific mechanisms. Abscisic acid (ABA) is a premier signal for plants to respond to drought and plays a critical role in plant growth and development. ABA triggers a variety of physiological processes such as stomatal closure, root system modulation, organizing soil microbial communities, activation of transcriptional and post-transcriptional gene expression, and metabolic alterations. Thus, understanding the mechanisms of ABA-mediated drought responses in plants is critical for ensuring crop yield and global food security. In this review, we highlighted how plants adjust ABA perception, transcriptional levels of ABA- and drought-related genes, and regulation of metabolic pathways to alter drought stress responses at both cellular and the whole plant level. Understanding the synergetic role of drought and ABA will strengthen our knowledge to develop stress-resilient crops through integrated advanced biotechnology approaches. This review will elaborate on ABA-mediated drought responses at genetic, biochemical, and molecular levels in plants, which is critical for advancement in stress biology research.

Environmental stresses, such as temperature, heavy metals, drought, cold, and microbial infections adversely damage various aspects of plant growth and development. Salinity and drought are among major hazardous factors, which adversity affects plant growth and productivity. Transcription factors, such as basic helix-loop-helix play critical roles in regulating plant physiological processes under abiotic stresses. In this study, we presented the characterization of a tomato SlbHLH22 gene under abiotic stresses such as drought and salinity. Plants overexpressing SlbHLH22 showed short height with small leaves and enhanced flavonoid accumulation. In wild type (WT) plant, the elevated levels of SlbHLH22 were detected under salt and D-mannitol stresses. Subcellular localization analysis revealed that SlbHLH22 protein was targeted to the nucleus in onion epidermal cells. Transactivation assay in yeast demonstrated that SlbHLH22 had transcriptional activation ability. The transgenic plants overexpressing SlbHLH22 displayed enhanced vigor and more tolerant to drought and salinity than WT. Overexpression of SlbHLH22 significantly peaked the activities of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) to minimize the impacts of reactive oxygen species such as H₂O₂, which was reduced significantly in transgenic plants along with Malondialdehyde (MDA). Moreover, the expression levels of ROS defense genes (SlPOD, SlCAT, SlSOD), ABA biosynthesis genes, proline biosynthesis, and flavonoids synthesis genes were also activated under salinity and drought. Taken together, our study implies that the overexpression of SlbHLH22 improved tomato plant stress resistance by improving ROS scavenging system, increasing osmotic potential and enhanced accumulation of secondary metabolites in tomato plants.

• Gut microbial diversity dysbiosis leads to increased death in COVID-19. • High death tool in COVID-19 is due to microbiome disturbance in co-morbid patients. • More deaths in ICU Individual seems to be because of microbiome dysbiosis. • Probiotics can be a Supplementary Therapy to decrease death tool in COVID-19.

The MYB gene family is one of the largest groups of transcription factors (TFs) playing diverse roles in several biological processes.Hedychium coronarium(white ginger lily) is a renowned ornamental plant both in tropical and subtropical regions due to its flower shape and strong floral scent mainly composed of terpenes and benzenoids. However, there is no information available regarding the role of the MYB gene family inH. coronarium. In the current study, the MYB gene family was identified and extensively analyzed. The identified 253HcMYBgenes were unevenly mapped on 17 chromosomes at a different density. Promoter sequence analysis showed numerous phytohormones related tocis-regulatory elements. The majority ofHcMYBgenes contain two to three introns and motif composition analysis showed their functional conservation. Phylogenetic analysis revealed that HcMYBs could be classified into 15 distinct clades, and the segmental duplication events played an essential role in the expansion of theHcMYBgene family. Tissue-specific expression patterns ofHcMYBgenes displayed spatial and temporal expression. Furthermore, sevenHcMYB(HcMYB7/8/75/79/145/238/248) were selected for further investigation. Through RT-qPCR, the response of candidatesHcMYBgenes toward jasmonic acid methyl ester (MeJA), abscisic acid (ABA), ethylene, and auxin was examined. Yeast one-hybrid (Y1H) assays revealed that candidate genes directly bind to the promoter of bottom structural volatile synthesis genes (HcTPS1,HcTPS3,HcTPS10, andHcBSMT2). Moreover, yeast two-hybrid (Y2H) assay showed that HcMYB7/8/75/145/248 interact with HcJAZ1 protein. InHcMYB7/8/79/145/248-silenced flowers, the floral volatile contents were decreased and downregulated the expression of key structural genes, suggesting that these genes might play crucial roles in floral scent formation inH. coronariumby regulating the expression of floral scent biosynthesis genes. Collectively, these findings indicate thatHcMYBgenes might be involved in the regulatory mechanism of terpenoids and benzenoid biosynthesis inH. coronarium.