Identification And Characterization Of A Rice Plasticity Gene RPL1

Organisms can adjust their phenotype in response to changing environmental conditions, and some new phenotypic characteristics will be passed on to their offspring, which we called acquired inheritance. In1942, British biologist Waddington coined "canalization" to help understand the genetic mechanism of acquired inheritance. However, few people care about his theory until that Rutherford and Lindquist found Drosophila heat shock protein HSP90acting as a molecular mechanism of canalization in1998.In this study, we isolated a rice (Oryza sativa L.) mutant, rice plasticity1(rpl1), which displayed increased environment-dependent phenotypic variations. The main results in this mutant are shown below.1. RPL1gene was a new gene, which comprised eight exons and seven introns. The open reading frame was813bp, encoding270amino acids.2. The rpll plants showed semidwarf phenotype with small panicles at maturity stage. By investigating some morphological traits, we found that mutants showed an obvious different phenotype in Lingshui than Wuhan, ie mutant plants were vulnerable to the growth environment.3. RT-PCR assay, in situ hybridization assay and transgenic plants with promoter construction indicated that PRL1gene was expressed in rice root, culm, leaves and panicles.4. Transient expression assay of RPL1gene in Arabidopsis and rice protoplasts showed that it is localized in the nucleus and may be associated with heterochromatin.5. The rpll mutation affected genome DNA methylation pattern and histone modification status.6. RPL1also affected DNA methylation and histone modification status of its own.7. RPL1did not interact with SDG728, OsSRTl, OsHDTl, or containing JmjC domain genes JMJ703, JMJ704, JMJ705, JMJ706or JMJ716in yeast8. The mutation of RPL1affected responses of the rice plant to phytohormones such as brassinosteroid, gibberellin and cytokinin. And the histone modification status of the rice BR receptor gene OsBRI1was changed in rpll.9. RPL1was plant specific.All results above demonstrated that RPL1was a plasticity gene regulating phenotypic plasticity in response to growth environments and might regulate phenotypic plasticity through affecting phytohormone signaling. Similar to HSP90, the mutation of RPL1would increase the phenotypic plasticity of plants and was involved in epigenetic process; Unlike HSP90, RPL1was only found in plants while HSP90was in organisms in all kingdoms of life except archaea. Thus, RPLl regulating phenotypic plasticity was important for rice evolution.