Arabidopsis HTT2 Improves Thermotolerance in Heading Chinese Cabbage

In Arabidopsis, the HEAT-INDUCED TAS1 TARGET2 (HTT2) is an important thermotolerance gene that is silenced by ta-siR255, an siRNA. This ta-siR255 siRNA is absent from heading Chinese cabbage (Brassica rapa ssp. pekinensis). The team of Jianxia Jiang from Chinese Academy of Sciences previously attempted to overexpress the heading Chinese cabbage BrpHTT2 gene but failed due to cosuppression.

The researchers aimed to overexpress an exogenous HTT2, the Arabidopsis HTT2, in heading Chinese cabbage to improve its thermotolerance. After transforming the Arabidopsis HTT2 to heading Chinese cabbage, the researchers evaluated the transformed plants under high-temperature (38°C) and heat-shock (46°C) conditions.

The survival rate of the transformed seedlings increased compared to wildtypes under heat shock. The hypocotyl length of the transformed seedlings were also increased under high temperature and heat shock. Several heat-shock factor genes were also found to be upregulated in the transformed plants under high-temperature and heat shock conditions. In the field, the transgenic plants appeared greener and formed leafy heads earlier than wildtypes.

The study provides a new approach to the genetic manipulation of thermotolerance in crops through the introduction of exogenous genes.

For more information, read the article in BMC Plant Biology.