Title : ABA-mediated stress response mechanism modulates stigmatic papillae development in Arabidopsis thaliana
Abstract:
Reproduction is an important process in the life cycle. Pollination is the first step in bringing together the male and female gametophytes for plant reproduction and starts when pollen grains land on the stigmatic papillae at the apex of gynoecium. While mechanism of pollination has been studied for many years, the development and elongation mechanisms of papillae remain largely unknown. In this study, we report developmental flexibility of papillae and their quick response mechanisms, in response to abiotic stress. There are many genes in the A. thaliana genome, and more than 15,000 genes are expressed in the stigmatic papillae for sustaining a reproduction and developmental functions, which includes a diversity of molecular players particularly those involved in metabolic, transcription and signaling processes. Through reverse genetic, in vitro, and transcriptome analyses, we found that the stigmatic papillae of A. thaliana changed their length rapidly in response to ambient conditions such as high humidity and salinity: NaCl treatment reduced the papillae length and ABA treatment induced papilla elongation, and that the key mechanism for the rapid response of papillae elongation is mediated by ABA pathway. The ABA-mediated response in papillae can be launched only when synthesized ABA precursor from the primary biosynthesis pathway is converted to an active form of ABA, by activation of the downstream biosynthesis pathway, enabling rapid response against ambient conditions. This is one of plant adaptations to the environment to maintain the chance of pollination for successful reproduction in Plants.
