Genome-wide analysis of C-repeat binding factor (CBF) family members in Pennisetum glaucum and the function of PgCBF21 under cold stress.

BACKGROUND

Pennisetum hybrid (Pennisetum glaucum x P. purpureum), a perennial forage grass of the Poaceae family, it has a well-developed root system, strong tillering ability, high biomass yield, and rich nutritional content, making it a premium forage grass. However, Pennisetum genera grasses are sensitive to low-temperature stress and lacks the ability to adapt to cold environments, severely limiting its cultivation in temperate and high-altitude regions. C-repeat binding factor (CBF) members belong to the AP2/ERF (APETALA2/ethylene-responsive element-binding factor) type transcription activators, which play important roles in plants' response to cold stress.

RESULTS

We identified 23 PgCBF genes, unevenly distributed across chromosomes 1 to 7. Physicochemical property analysis revealed that the amino acid count of PgCBF family members ranged from 187 to 324, with molecular weights between 19688.36 and 34271.70 Da and theoretical isoelectric points between 4.57 and 9.82. Promoter region analysis of PgCBF genes indicated the presence of various cis-acting elements involved in hormone response, tissue-specific expression, and stress response. Additionally, qRT-PCR results showed significant upregulation of PgCBF11 expression in stems following cold treatment, with increasing over 40-fold after 32 h of cold treatment and about 20-fold after 8 h of cold treatment. PgCBF21 exhibited a strong response in leaves after 8 h of cold treatment, with expression levels rising more than 37-fold. Furthermore, through the overexpression of PgCBF21, we ascertained its capacity to enhance cold tolerance in yeast.

CONCLUSION

This study analyzed the molecular characteristics of the PgCBF family members in P. glaucum and identified several candidate genes responsive to cold stress, providing a theoretical foundation for future research on the innovative utilization of cold-resistant resources.