Abstract
Rice (Oryza sativa L.) is one of the most important food crops in the world. In plants, jasmonic acid (JA) plays essential roles in response to biotic and abiotic stresses. As one of the largest transcription factors (TFs), basic region/leucine zipper motif (bZIP) TFs play pivotal roles through the whole life of plant growth. However, the relationship between JA and bZIP TFs were rarely reported, especially in rice. In this study, we found two rice homologues of Arabidopsis VIP1 (VirE2-interacting protein 1), OsbZIP81, and OsbZIP84. OsbZIP81 has at least two alternative transcripts, OsbZIP81.1 and OsbZIP81.2. OsbZIP81.1 and OsbZIP84 are typical bZIP TFs, while OsbZIP81.2 is not. OsbZIP81.1 can directly bind OsPIOX and activate its expression. In OsbZIP81.1 overexpression transgenic rice plant, JA (Jasmonic Acid) and SA (Salicylic acid) were up-regulated, while ABA (Abscisic acid) was down-regulated. Moreover, Agrobacterium, Methyl Jasmonic Acid (MeJA), and PEG6000 can largely induce OsbZIP81. Based on ChIP-Seq and Random DNA Binding Selection Assay (RDSA), we identified a novel cis-element OVRE (Oryza VIP1 response element). Combining ChIP-Seq and RNA-Seq, we obtained 1332 targeted genes that were categorized in biotic and abiotic responses, including α-linolenic acid metabolism and fatty acid degradation. Together, these results suggest that OsbZIP81 may positively regulate JA levels by directly targeting the genes in JA signaling and metabolism pathway in rice.
Highlights
Rice (Oryza sativa L.) is a model species for monocotyledonous plants and cereals, which are the greatest source of food for the world’s population
Based on an analysis of the evolutionary relationship of all group IX subfamily members, we found that OsbZIP81 had the closest evolutionary relationship with OsbZIP84 (Figure 1A, black box), followed by VIP1 and RSG (Figure 1A, red box)
These results indicate that the members of the group IX subfamily in different plants have highly conserved protein sequences, and that OsbZIP81 and OsbZIP84 are homologues of Arabidopsis VIP1 in rice
Summary
Rice (Oryza sativa L.) is a model species for monocotyledonous plants and cereals, which are the greatest source of food for the world’s population. Transcription factors (TFs) are triggers for gene expression and they play important regulatory roles throughout the plant life time, especially in plant growth, development, and responses to abiotic and biotic stresses. VIP1 is involved in other functions in addition to its role in Agrobacterium-mediated transformation, including osmosensory signaling, low sulfur tolerance, metal-binding, touch response, Botrytis and salt stress responses, the ABA response, and transcriptional regulation [22,23,24,25,26,27,28,29,30]. We identified two pathogenesis-regulated (PR) proteins, PR10a/PBZ1 and RSOsPR10, and other stress response genes These results suggest that OsbZIP81 may positive regulate JA levels and may play a role in pathogen resistance
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
