Enhancing cold resistance in Banana (Musa spp.) through EMS-induced mutagenesis, L-Hyp pressure selection: phenotypic alterations, biomass composition, and transcriptomic insights.

BACKGROUND: The cultivation of bananas encounters substantial obstacles, particularly due to the detrimental effects of cold stress on their growth and productivity. A potential remedy that has gained attention is the utilization of ethyl mesylate (EMS)-induced mutagenesis technology, which enables the creation of a genetically varied group of banana mutants. This complex procedure entails subjecting the mutants to further stress screening utilizing L-Hyp in order to identify those exhibiting improved resistance to cold. This study conducted a comprehensive optimization of the screening conditions for EMS mutagenesis and L-Hyp, resulting in the identification of the mutant cm784, which exhibited remarkable cold resistance. Subsequent investigations further elucidated the physiological and transcriptomic responses of cm784 to low-temperature stress. RESULTS: EMS mutagenesis had a substantial effect on banana seedlings, resulting in modifications in shoot and root traits, wherein a majority of seedlings exhibited delayed differentiation and limited elongation. Notably, mutant leaves displayed altered biomass composition, with starch content exhibiting the most pronounced variation. The application of L-Hyp pressure selection aided in the identification of cold-resistant mutants among seedling-lethal phenotypes. The mutant cm784 demonstrated enhanced cold resistance, as evidenced by improved survival rates and reduced symptoms of chilling injury. Physiological analyses demonstrated heightened activities of antioxidant enzymes and increased proline production in cm784 when subjected to cold stress. Transcriptome analysis unveiled 946 genes that were differentially expressed in cm784, with a notable enrichment in categories related to 'Carbohydrate transport and metabolism' and 'Secondary metabolites biosynthesis, transport, and catabolism'. CONCLUSION: The present findings provide insights into the molecular mechanisms that contribute to the heightened cold resistance observed in banana mutants. These mechanisms encompass enhanced carbohydrate metabolism and secondary metabolite biosynthesis, thereby emphasizing the adaptive strategies employed to mitigate the detrimental effects induced by cold stress.

Firm-level carbon risk perception and ESG performance.

In a sustainable economy, each firm perceives different levels of carbon risk, but there are few studies on the relationship between a firm's carbon risk perception and Environmental, Social, and Governance (ESG) performance. This paper examines the impact of firm-level carbon risk perception on ESG performance using Chinese A-share listed firms during 2011-2020. We find a positive relationship between firm-level perception of carbon risk and firm ESG performance. Further analysis shows that analyst coverage and media attention exert a substantial moderating effect on the link between carbon risk perception and ESG performance. We identify three channels through which carbon risk perception affects ESG performance. First, rising carbon risk perception enables firms to take measures to reduce pollutants and greenhouse gas emissions and increases environmental (E) scores. Second, this perception encourages firms to take responsibility for social employment and increases social (S) scores. Finally, it improves firm sustainable governance and further increases governance (G) scores. Our research has an important guiding role in promoting firm ESG practice.