The Effect And Mechanism Of BnHSFA4a On Desiccation Tolerance Of Seeds

Obtaining and losing of seed desiccation tolerance is associated with a variety of factors. Heat Shock transcription Factor (HSF), as a regulatory factor of galactinol synthase, plays an important role in response to seed dehydration. In this study, rape seed of different germination stages were dehydrated through artificial dehydration process (LiCl saturated salt solution). The results showed that the seeds were gradually sensitivity to dehydration with the increase of radicle length. Radicle length of 1 mm has stronger desiccation tolerance, whereas, desiccation tolerance is almost lost in seeds of 2.5 mm. The expression of BnHSFA4a was increasing to the peak where the radicle length of seeds was 1 mm, then gradually decline no matter before or after dehydration. And some kinds of antioxidant enzyme and RFO content are closely related to HSFA4a. Transient expression of GFP-BnHSFA4a in Arabidopsis protoplast found that under the normal condition, HSFA4a was located in the nucleus. Compared wild type with Athsfa4a mutant, RFO content, antioxidant capacity and desiccation tolerance of mutant seed are less intensive than wild type. Thus, it is confirmed that HSFA4a in seed is relative with desiccation tolerance. And we constructed a protocol for regeneration of transgenic rape after Agrobacterium-mediated transformation of hypocotyls from the spring B. napus "Precocity" cultivar and get T1 generation transgenic plants.