Overexpression of sugarcane SoTUA gene enhances cold tolerance in transgenic sugarcane

Alpha (alpha)-tubulin (TUA) is a primary unit of cytoskeleton microtubules. In recent years, more frequent frosts have caused considerable yield loss in sugarcane (Saccharum spp. hybrid) production. Temperature is one of the most influential abiotic factors affecting the microtubule polymerization state in plants. In this research, we developed overexpressing SoTUA transgenic sugarcane lines from the cold-susceptible cultivar ROC22. The transgene was confirmed by polymerase chain reaction (PCR) and quantificational real-time polymerase chain reaction (qRT-PCR) analysis, while the relative expression of SoTUA protein was verified by Western blot. Compared with the nontransformed control plants (wild type [WT]), the transgenic lines showed higher relative protein expression than the WT at 25 degrees C, which indicates the overexpression of SoTUA protein. The contents of soluble protein and sugar and the activity of peroxidase (POD) were higher while the content of maleicdialdehyde was lower in the transgenic plants than the WT plants under the chilling treatment. Meanwhile, the expression levels of cold-defense related genes (P5CS, WRKY, Cu/Zn-SOD, and POD1) were higher in the transgenic lines than in the WT. These results suggest that the SoTUA protein plays an important role in protecting plants during chilling stress. This positive effect is not affected by transgenic plant generations.

Automated summary

The overexpression of SoTUA gene in sugarcane enhances protein expression, cold resistance, growth, and yield. Transgenic plants have higher levels of soluble protein and sugar, lower levels of malondialdehyde, and increased expression of cold-defense genes compared to wild type. This positive effect of SoTUA protein on chilling stress protection is consistent across transgenic plant generations.