Os05g0542500

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The rice gene Os05g0542500 was reported as OsLEA3-1 in 2007[1], OsLEA3 in 1997[2], respectively.

Annotated Information

Gene Symbol

  • Os05g0542500 <=> OsLEA3-1, OsLea3-1, LEA3, OsLEA3, OsLEA19, OsLEA19a, OsLEA19b, OsLEA3, Oslea3, oslea3

Function

  • The promoter of OsLEA3-1 isolated from the upland rice IRAT109 exhibits strong activity under drought- and salt-stress conditions[1]. Overexpression of FON1 could upregulate LEA3 and OsbZIP46[3].
  • At the transcription level, several stress-related and ABA-responsive genes, including LEA3, OsbZIP46, APX3, APX5, and CATB, were upregulated in transgenic plants overexpressing FON1, but correspondingly downregulated in RNAi plants[3].

Mutation

  • Three constructs[1]:
    • OsLEA3-S
    • OsLEA3-A
    • OsLEA3-H
    • They were generated by fusing the cDNA of the OsLEA3-1 gene with CaMV 35S, Actin1 and HVA1-like promoter in the backbone vectors pCAMBIA1301S, pCAMBIA1301A, and pCAMBIA1301H, respectively.
    • Drought resistance pre-screening of T1 families at anthesis stage revealed that the over-expressing families with OsLEA3-S and OsLEA3-H constructs had significantly higher relative yield than the wild type under drought stress conditions, although a yield penalty existed in T1 families under normal growth conditions.
    • Nine homozygous families, exhibiting over-expression of a single-copy of the transgene and relatively low yield penalty in the T1 generation, were tested in the field for drought resistance in the T2 and T3 generations and in the PVC pipes for drought tolerance in the T2 generation.
    • Except for two families, all the other families (transformed with OsLEA3-S and OsLEA3-H constructs) had higher grain yield than the wild type under drought stress in both the field and the PVC pipes conditions. No significant yield penalty was detected for these T2 and T3 families.


Expression

  • OsLEA3-1 is induced by drought, salt and abscisic acid (ABA), but not by cold stress. Drought resistance of transgenic lines over-expressing the OsLEA3-1 gene can be improved through selections in terms of the relative yield in the T1generation or yield in the T2 or later generations under the field conditions[1].
  • Transgenic rice with significantly enhanced drought resistance and without yield penalty can be generated by over expressing OsLEA3-1 gene with appropriate promoters and following a bipartite (stress and non-stress) in-field screening protocol[1].
  • The OSLEA3 protein characteristically contains ten imperfect 11-mer amino acid repeats. Exogenous application of ABA and exposure to salt shock rapidly induces a de novo, abundant oslea3 transcript accumulation. The stress-induced oslea3

transcript gradually declined upon prolonged salt shock, as wilting-induced damage became irreversible[2].

  • oslea3 expression was compared for the salt-tolerant variety Pokkali and the salt-sensitive cultivar Taichung N1. Higher maximal mRNA levels were found in roots of the tolerant variety, also declining less rapidly upon sustained salt shock, concomitant with a delayed drop in shoot water content. DNA blot analysis indicated the existence of a small oslea3 gene family in rice with an equal gene number in both ecotypes[2].

Evolution

  • OsLEA3-1 protein sequence has 97% identity to OsLEA3 in rice and OsLEA3-1 is considered to be an allele of OsLEA3 based on its location in the rice genome. The OsLEA3-1 protein has 56% identity to HVA1 from barley, 52% identity to group 3 LEA protein MGL3 from maize, and 53% identity to group 3 LEA protein pMA2005 from wheat as revealed by ClustalW[1].
  • Oslea3 has an ORF of 603 bp extending from position 83 to position 685, containing three peptide sequences that are in complete agreement with the determined aa sequences of the internal peptides[2].

Knowledge Extension

  • The levels of dehydrins and group 3 LEA proteins were significantly higher in roots from tolerant compared with sensitive varieties. Endogenous ABA levels showed a transient increase in roots exposed to osmotic shock[4].
  • Group 3 LEA proteins are composed principally of tandem repeats of an 11-mer amino acid motif, forming an amphiphilic helix that readily binds ions. LEA genes are suggested to be involved in tolerance to cellular dehydration upon desiccation, salt stress, or cold, although direct evidence is still lacking[4].

Labs working on this gene

  • National Center of Plant Gene Research (Wuhan), National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
  • Laboratorium voor Genetica, Department of Genetics, Flanders Interuniversity Institute for Biotechnology (VIB), Universiteit Gent, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Xiao B, Huang Y, Tang N, et al. Over-expression of a LEA gene in rice improves drought resistance under the field conditions[J]. Theoretical and Applied Genetics, 2007, 115(1): 35-46.
  2. 2.0 2.1 2.2 2.3 Moons A, De Keyser A, Van Montagu M. A group 3 LEA cDNA of rice, responsive to abscisic acid, but not to jasmonic acid, shows variety-specific differences in salt stress response[J]. Gene, 1997, 191(2): 197-204.
  3. 3.0 3.1 Feng L, Gao Z, Xiao G, et al. Leucine-rich repeat receptor-like kinase FON1 regulates drought stress and seed germination by activating the expression of ABA-responsive genes in rice[J]. Plant Molecular Biology Reporter, 2014, 32(6): 1158-1168.
  4. 4.0 4.1 Moons A, Bauw G, Prinsen E, et al. Molecular and physiological responses to abscisic acid and salts in roots of salt-sensitive and salt-tolerant Indica rice varieties[J]. Plant Physiology, 1995, 107(1): 177-186.

Structured Information