Climate change not only leads to high temperatures, droughts, floods, storms and declining soil quality, but it also affects the spread and mutation of pests and diseases, which directly influences plant growth and constitutes a new challenge to food security. Numerous hormones like auxin, ethylene and melatonin, regulate plant growth and development as well as their resistance to environmental stresses. To mitigate the impact of diverse biotic and abiotic stressors on crops, single or multiple phytohormones in combination have been applied. Melatonin is a multifunctional signaling molecule engaged in the development and stress response of plants. In the current review, we discuss the synthesis and action of melatonin, as well as its utilization for plant resistance to different stresses from the perspective of practical application. Simultaneously, we elucidate the regulatory effects and complex mechanisms of melatonin and other plant hormones on the growth of plants, explore the practical applications of melatonin in combination with other phytohormones in crops. This will aid in the planning of management strategies to protect plants from damage caused by environmental stress.

A rich diversity of radiation-resistant (Rr) and desiccation-resistant (Dr) bacteria has been found in arid habitats of the world. Evidence from scientific research has linked their origin to reactive oxygen species (ROS) intermediates. Rr and Dr. bacteria of arid regions have the potential to regulate imbalance radicals and evade a higher dose of radiation and oxidation than bacterial species of non-arid regions. Photochemical-activated ROS in Rr bacteria is run through photo-induction of electron transfer. A hypothetical model of the biogeochemical cycle based on solar radiation and desiccation. These selective stresses generate oxidative radicals for a short span with strong reactivity and toxic effects. Desert-inhibiting Rr bacteria efficiently evade ROS toxicity with an evolved antioxidant system and other defensive pathways. The imbalanced radicals in physiological disorders, cancer, and lung diseases could be neutralized by a self-sustaining evolved Rr bacteria antioxidant system. The direct link of evolved antioxidant system with intermediate ROS and indirect influence of radiation and desiccation provide useful insight into richness, ecological diversity, and origin of Rr bacteria capabilities. The distinguishing features of Rr bacteria in deserts present a fertile research area with promising applications in the pharmaceutical industry, genetic engineering, biological therapy, biological transformation, bioremediation, industrial biotechnology, and astrobiology.

Strigolactones (SLs), the newest group of phytohormones, are involved in a wide range of functions, including the regulation of plant growth and physiology. Besides, emerging evidence suggests that SLs also participate in the promotion of plant environmental stress resilience through mediation of different metabolic genes/pathways. However, thus far little is known about SL-mediated transcriptional changes in rice (Oryza sativa), compared to other model plants. To meet this objective, we analyzed the RNA-seq-based comparative transcriptome data sets of rice SL-deficient dwarf l7 (d17) mutant line and its respective wild-type (WT), obtained from the National Center for Biotechnology Information GenBank. Both, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed, in order to identify genes/pathways which function downstream of SLs. With respect to the WT, a large number of functional GO terms, mainly stress-associated terms such as 'response to stress', 'response to stimulus', 'response to chemical', 'response to oxidative stress' and 'reactive oxygen species metabolic process' were significantly suppressed in the d17 mutant plants. In addition, KEGG metabolic pathways such as cvaline, leucine and isoleucine degradation', 'plant hormone signal transduction', 'galactose metabolism', 'fatty acid degradation' and 'phenylalanine metabolism' were also remarkably undermined in the d17 lines relative to the WT. These results imply a possible involvement of rice SLs in the regulation of distinct stress-related metabolic genes/pathways, which may function in environmental stress tolerance of plants. Taken together, the study provides new opportunities to broaden our limited understanding of SL-regulated downstream pathways, especially in rice.