The PYR/PYL/RCAR (PYL) gene family (Pyrabactin Resistance 1/PYR1-Like/Regulatory Component of ABA Receptor), as core receptors of abscisic acid (ABA), play a pivotal regulatory role in the signaling pathways of plant responses to abiotic stresses such as drought. Saccharum spontaneum L. (wild sugarcane), an important wild relative for sugarcane stress-resistant breeding, harbors abundant drought-tolerant genetic resources. However, systematic identification and functional analysis of its PYL gene family remain unreported to date. Based on the S. spontaneum genome data (Saccharum spontaneum Np-X2021), the study identified members of the SsPYL gene family using bioinformatics approaches, and systematically analyzed the physicochemical properties, chromosomal localization, phylogenetic relationships, gene structures, conserved motifs, and cis-acting elements in promoters. Additionally, quantitative real-time PCR (qRT-PCR) was employed to investigate the expression patterns of core members under drought stress. The results showed that 32 SsPYL genes, designated as SsPYL1 to SsPYL32, were identified in the S. spontaneum genome. The encoded proteins ranged in length from 149 to 385 amino acids, with most being acidic and hydrophilic proteins primarily localized in the cytoplasm. The secondary structure was dominated by α-helices and random coils. Furthermore, SsPYLs exhibited uneven distribution across chromosomes, and segmental duplication was the dominant mechanism driving family expansion. A total of 54 pairs of syntenic genes were identified between SsPYLs and rice OsPYL genes, reflecting the evolutionary conservation of this family among monocotyledonous plants. Phylogenetic analysis clustered the 32 SsPYLs into three subfamilies, with members of the same subfamily sharing similar conserved motif compositions and gene structures. All SsPYL proteins contained the signature PYR_PYL_RCAR_like domain. The promoter regions of SsPYL genes were enriched in hormone-responsive and abiotic stress-related cis-acting elements, such as ABRE (ABA-responsive element), ARE (anaerobic responsive element), and LTR (low-temperature responsive element). Under drought stress, the expression levels of eight SsPYL genes (SsPYL1, SsPYL3, SsPYL4, SsPYL6, SsPYL8, SsPYL14, SsPYL19 and SsPYL24) were extremely significantly upregulated (P<0.01), among which SsPYL8, SsPYL14 and SsPYL19 showed more than 5-fold upregulation. The genes are thus speculated to be key candidate genes regulating drought tolerance in S. spontaneum. The study represents the first systematic characterization of the molecular features and drought-responsive patterns of the SsPYL gene family in S. spontaneum. It would provide a theoretical basis for further exploring the functional mechanisms in ABA-mediated drought stress signaling pathways and offer important gene targets for the genetic improvement of drought tolerance in sugarcane.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |