Strigolactones (SLs) are considered to be a novel class of phytohormone involved in plant defense responses. Currently, their relationships with other plant hormones, such as abscisic acid (ABA), during responses to salinity stress are largely unknown. In this study, the relationship between SL and ABA during the induction of H2O2 – mediated tolerance to salt stress were studied in arbuscular mycorrhizal (AM) Sesbania cannabina seedlings. The SL levels increased after ABA treatments and decreased when ABA biosynthesis was inhibited in AM plants. Additionally, the expression levels of SL-biosynthesis genes in AM plants increased following treatments with exogenous ABA and H2O2. Furthermore, ABA-induced SL production was blocked by a pre-treatment with dimethylthiourea, which scavenges H2O2. In contrast, ABA production was unaffected by dimethylthiourea. Abscisic acid induced only partial and transient increases in the salt tolerance of TIS108 (a SL synthesis inhibitor) treated AM plants, whereas SL induced considerable and prolonged increases in salt tolerance after a pre-treatment with tungstate. These results strongly suggest that ABA is regulating the induction of salt tolerance by SL in AM S. cannabina seedlings.
Rhizosphere microbiota are conducive to soil nutrient cycling for plant growth. Long-term and excessive application of chemical fertilizer is harmful to agriculture. Seaweed extract is a good organic substitute for rhizosphere ecosystem and plant growth. We supplemented 5‰ seaweed extract powder to chemical fertilizer, and then studied its effect on rhizosphere bacteria of japonica rice (Oryza sativa L. subsp. japonica). In a short-term experiment, we compared the changes in rhizosphere bacteria among four treatments, i.e., no fertilizer (T1), chemical fertilizer only (T2), chemical fertilizer with 5‰ seaweed extract (T3), and less chemical fertilizer with 5‰ seaweed extract (80% of that of T3) (T4). Results show that seaweed extract supplement could affect the bacterial community in tillering and heading stages; the α-diversity of rhizosphere bacteria in the heading stage was obviously improved. In addition, seaweed extract supplement improved significantly the content of nitrate nitrogen (N), available phosphorus (P), and available potassium (K) in rhizosphere soil in the tillering stage, and, finally, increased the rice yield and quality mildly. Therefore, the seaweed extract supplement is shown to be a potential strategy to enrich the diversity of rhizosphere bacteria, which enhanced soil nutrient level, increased rice yield and quality, and also saved the use of chemical fertilizer.
Macroalgal blooms (Green tides) are occurring more frequently in many regions of the world because of the combined effects of increasingly intense human activity and climate change. In the last decade, the world's largest Ulva prolifera green tide has become a recurrent phenomenon, appearing every summer in the southern Yellow Sea, China. Green tides can hurt coastal tourism and eradicate aquaculture and artisanal fishing. Eutrophication in nearshore waters is the ultimate explanation for the explosive growth of the macroalgal biomass, but the specific course of each nearshore green tide is often complex and requires in-depth and extensive research to develop effective mitigation strategies. Researchers have undertaken extensive studies on the prevention, control and mitigation of large-scale green algal blooms, and felicitated the utilization of green tide harmful biomass through bio-refining, bioconversion and other measures. However, due to the large-scale and trans-regional nature of the green tide, the government's administrative coordination measures are also essential for effective control. Nevertheless, it is becoming increasingly urgent to prevent and control the bloom at the early stage, and efficiently salvage and use these valuable raw materials.
Marine endophytes are prolific sources of structurally diverse secondary metabolites with significant pharmaceutical potential, including anticancer, antimicrobial, and antioxidant agents. However, their commercial utilization is hindered by genomic instability in axenic cultures and inconsistent metabolite yields. While current studies focus on symbiotic interactions and compound discover, critical gaps persist in harnessing their biosynthetic capabilities. This review synthesizes knowledge on marine fungal metabolites and proposes a paradigm shift toward resource-driven research. It addresses strain improvement limitations and suggests strategies like mutagenesis, protoplast fusion, and metabolic engineering to bolster production stability and efficiency. The paper also discusses biological process optimization, including fermentation tuning, inducer and precursor addition, and adsorbent use, to enhance natural product synthesis. By identifying these research gaps and proposing a strategic roadmap, the review advances the stable and scalable production of bioactive metabolites, unlocking the commercial and therapeutic potential of marine endophytic fungi.