Genome-wide identification of Miscanthus ASR gene family reveals that MsASR4 is linked to NaCl tolerance

Abscisic acid stress-ripening (ASR) genes are plant-specific gene families that play diverse roles in regulating development and stress responses of plants. Despite Miscanthus being a renowned energy crop globally, the comprehensive analysis of the entire genome of the Miscanthus ASR family remains unexplored. This knowledge gap hinders a thorough understanding of the functions and mechanisms of the Miscanthus ASR family in regulating abiotic stress. This study retrieved 12 MsASR gene family members in Miscanthus, namely, MsASR1 to MsASR12, which were categorized into I, II, III, and IV. The expansion of these family members primarily occurred through segmented repetition. Under NaCl stress, several MsASR genes in Miscanthus were upregulated. The overexpression of Miscanthus MsASR4 enhanced NaCl tolerance in Arabidopsis. In addition, MsASR4 overexpression increased the endogenous abscisic acid (ABA) contents, proline accumulation, and the antioxidant enzymatic activities and promoted the transcriptional levels of important marker genes involved in proline and ABA biosynthesis and the antioxidant defense under NaCl stress. An effector and reporter assay demonstrated that MsASR4 activated the promoter activity of important marker genes. The results of this study are the first to investigate MsASR genes in Miscanthus, enriching our knowledge of the ASR family in Miscanthus and providing candidate genes for future crop improvement.