Accumulation of storage compounds during seed development plays an important
role in the life cycle of oilseed plants. These compounds provide carbon and
energy resources to support the growth of seedlings. The team of Yanli Guo
from Huazhong Agricultural University aims to study the BnCIPK9 gene, which
is strongly induced by wounding stress, in canola (Brassica napus) tissues.
The overexpression of BnCIPK9 during seed development reduced oil synthesis
in transgenic B. napus, leading to lower seed oil content (OC) compared to
wild-type (WT) plants. On the other hand, OC in Arabidopsis thaliana
Atcipk9-knockout mutants was higher than that of WT plants. However,
seedlings of Atcipk9-knockout mutants also failed to establish roots on a
sugar-free medium, but could be rescued by supplementation of sucrose or
glucose. Moreover, the phenotype of the supplemented transgenic lines was
similar to that of WT plants when grown on sugar-free medium.
These results show that BnCIPK9 and AtCIPK9 are involved in sugar-related
response and play important roles in the regulation of energy reserves.
AtCIPK9 negatively regulates lipid accumulation and affects early seedling
establishment in Arabidopsis. This study on CIPK9 provides insights into its
regulation of OC, and might be used for improving OC in canola.