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The rice gene Os03g0230500 was reported as DSM3 in 2011[1], OsITPK2(OsITP5/6K-2) in 2007[2], respectively.

Annotated Information


  • DSM3 is predicted to encode a putative ITPK with 349 amino acids and a predicted molecular mass of 38.8 kDa. DSM3/ OsITPK2 is an important member of the OsITPK family for stress responses, and an optimal expression level is essential for drought and salt tolerance in rice[1].
  • According to the predicted function of DSM3 as an ITPK and the downstream genes affected, DSM3 may contribute significantly in inositol phosphate–mediated stress signal transductions, although its biochemical characteristics and transcriptional regulation related to other physiological substrates and products remain to be identified[1].
  • Disruption or overexpression of DSM3 can affect the expression of some stress-responsive genes and some of the homologous genes[1]:
    • Two peroxidase genes (OsPOX8.1 and OsPOX22.3) showed slightly higher expression levels in both the mutant and overexpression lines than in the WT' before drought stress, but their drought-induced expression levels were lower than that in the WT'.
    • Du et al. checked a few osmotic adjustment–related genes (OsP5CS, OsLEA3, OsRAB16b, and OsGDSL) and the results showed that the OsP5CS and OsGDSL had significantly lower levels in both the mutant and overexpression lines under drought stress conditions.


  • a drought- and salt-hypersensitive mutant dsm3[1]:
    • The mutant phenotype was caused by a T-DNA insertion in a gene encoding a putative inositol 1,3,4-trisphosphate 5/6-kinase previously named OsITPK2 with unknown function.
    • Under drought stress conditions, the mutant had significantly less accumulation of osmolytes such as proline and soluble sugar and showed significantly reduced root volume, spikelet fertility, biomass, and grain yield; however, malondialdehyde level was increased in the mutant.
    • A few genes related to osmotic adjustment and reactive oxygen species scavenging were down-regulated in the mutant and overexpression lines.
  • positive and negative lines[1]:
    • Three positive (DSM3-suppressed) artificial miRNA lines
      • ai-1
      • ai-9
      • ai-14
    • three negative lines
      • ai-3
      • ai-4
      • ai-13
    • They were selected for drought and salt stress testing. The results showed that the positive lines were hypersensitive to drought and salt stresses , which is in agreement with the phenotype of the dsm3 mutant.
    • The survival rate of the positive amiR-DSM3 lines was only 5–15%, significantly lower than that of the control (50–70%).
    • In the salt treatment, the plant height of the positive amiR-DSM3 lines was significantly lower than that of the control.


  • Overexpression of DSM3 (OsITPK2) in rice resulted in drought- and salt-hypersensitive phenotypes and physiological changes similar to those in the mutant. Inositol trisphosphate (IP3) level was decreased in the overexpressors under normal condition and drought stress[1].
  • The expression level of DSM3 promoter-driven b-glucuronidase (GUS) reporter gene in rice was induced by drought, salt and abscisic acid. Transcript level analysis of OsITPK genes revealed that they had different tempo-spatial expression patterns, and the responses of DSM3 to abiotic stresses, including drought, salinity, cold, and high temperature, were distinct from the other five members in rice[1].

Subcellular localization

ER localization of DSM3 was confirmed by transient expression in Arabidopsis mesophyll protoplasts. The result of ER localization of the DSM3 was consistent with its biological process as a functional ITPK in rice[1].


Figure 1. Phylogenetic analysis of ITPK families and exon–intron structures of OsITPK genes.(from reference [1]).

Sequence analysis revealed six putative ITPKs in rice[1][2].

  • Phylogenetic analysis[1]:
    • Phylogenetic analysis based on the deduced protein sequences revealed three subgroups for these ITPKs (Fig. 1a).
      • OsITPKs are distributed in all the three subgroups. OsITPK1, OsITPK2, and OsITPK3 were clustered in subgroup I.
      • OsITPK4 and OsITPK5 were classified into 'subgroup II.
      • OsITPK6 resided in subgroup III, in which ITPKs from vertebrates were predominant (Fig. 1a).
    • The ITPKs from Arabidopsis were also distributed in all three subgroups.
  • the exon–intron structures of the OsITPK genes and their chromosomal locations[1]:
    • OsITPK4 and OsITPK5 belonging to subgroup II (Fig. 1A), have no intron (Fig. 1b).
    • OsITPK6 contained 12 exons and 11 introns and belongs to subgroup III.
    • The other three rice ITPKs (OsITPK1 to OsITPK3) belong to subgroup I, with each containing 10 exons and 9 introns with very similar intron phases (Fig. 1b).
    • The exon–intron organization structures of the OsITPK genes suggest that OsITPK1, OsITPK2, and OsITPK3 are similar to each other (Fig. 1b).

Labs working on this gene

  • National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, 430070 Wuhan, China


  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 Du H, Liu L, You L, et al. Characterization of an inositol 1, 3, 4-trisphosphate 5/6-kinase gene that is essential for drought and salt stress responses in rice[J]. Plant molecular biology, 2011, 77(6): 547-563.
  2. 2.0 2.1 Cite error: Invalid <ref> tag; no text was provided for refs named ref2

Structured Information