Group 6 Late Embryogenesis Abundant (LEA) Proteins in Monocotyledonous Plants: Genomic Organization and Transcript Accumulation Patterns in Response to Stress in Oryza sativa

In this study, group 6 Late Embryogenesis Abundant (LEA) proteins from monocot plants were identified along with a set of unique motifs that distinguished them from eudicot LEA6 proteins. Moreover, a LEA6 gene and its corresponding protein from Oryza sativa (OsLEA6) were also investigated. We found that the rice genome contains only one gene of this family, described its genomic organization, and discarded the possibility suggested in different databases that this gene was fused with an HSP90 gene forming a chimeric OsHSP90–LEA6 protein. We also showed that OsLEA6 transcript accumulates in response to water deficit conditions and that, using specific anti-OsLEA6 antibodies, its corresponding protein follows a similar accumulation pattern. The analysis of the OsLEA6 gene promoter sequence is also included, in which different drought and ABA response cis elements were identified. Accordingly, the ABA responsiveness of OsLEA6 protein is also shown. Thus, as previously shown for other LEA6 members present in eudicots, rice and other monocot LEA6 proteins are likely to participate in responses to stress conditions.