Os08g0535200

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Xa13 are Rice recessive resistance genes controlling of rice disease resistance and the reproductive growth .

Annotated Information

Function

The xa13 gene is fully recessive, conferring resistance only in the homozygous status.This gene specifically confers resistance to the Philippine Xoo race 6(PXO99).Thirty bacterial blight resistance(R) genes (21 dominant genes and 9 recessive gene) in rice have been identified. They are the main sources for the genetic improvement of rice for recessive R genes to XOO. However, xa13 is one of the known recessive R genes.It interacts strongly with other R genes such as xa5, Xa4 and Xa21.But small-scale gene expression studies and pathogen-induced subtractive cDNA library analysis have revealed that some defense-responsive genes activated in xa13-mediated resistance are not involved in resistance that is mediated by dominant R genes(Xa4, Xa10andXa26).These results suggest xa13 functions differently from other R genes[1][2].


After fine mapping Of xa13 to a 14.8kb DNA fragment.Sequence analysis of this fragment indicate that this region contained two complete open reading frames and the 5’ end of a predicted hypothetical gene.We found two candidate genes, a prime stretch class is rich in protein gene homologous gene proline, and the other is the nodule gene MtN3 homologous gene[3].Os8N3 is a member of the MtN3 gene family from plants and animals, is elevated upon infection by Xanthomonas oryzae pv. oryzae strain PXO99A and depends on the type III effector gene pthXo1. Os8N3 resides near xa13, and PXO99A failed to induce Os8N3 in rice lines with xa13. Silencing of Os8N3 by inhibitory RNA produced plants that were resistant to infection by strain PXO99A yet remained susceptible to other strains of the pathogen. The effector gene avrXa7 from strain PXO86 enabled PXO99A compatibility on either xa13- or Os8N3-silenced plants. The findings indicate that Os8N3 is a host susceptibility gene for bacterial blight targeted by the type III effector PthXo1. The results support the hypothesis that X. oryzae pv.oryzae commandeers the regulation of otherwise developmentally regulated host genes to induce a state of disease susceptibility[4].


Os-8N3 is a susceptibility (S) gene for Xanthomonas oryzae pv oryzae, the causal agent of bacterial blight, and the recessive allele is defeated by strains of the pathogen producing any one of the type III effectors. AvrXa7, PthXo2, or PthXo3, which are all members of the transcription activator-like (TAL) effector family. Both AvrXa7 and PthXo3 induce the expression of a second member of the N3 gene family, here named Os-11N3.Insertional mutagenesis or RNA-mediated silencing of Os-11N3 resulted in plants with loss of susceptibility specifically to strains of X. oryzae pv oryzae dependent on AvrXa7 or PthXo3 for virulence.AvrXa7 drives expression of Os-11N3 and that AvrXa7 interacts and binds specifically to an effector binding element within the Os-11N3 promoter, lending support to the predictive models for TAL effector binding specificity. The result indicates that variations in the TAL effector repetitive domains are driven by selection to overcome both dominant and recessive forms of resistance to bacterial blight in rice[5].


A contig map covering the xa13 region
Xoo resistance mediated by xa13 is not caused by this amino acid residue variation, but by alteration of promoter regions that leads to differences in the expression of xa13 and Xa13 in reaction to Xoo infection[5].


The dominant allele,Xa13, is required for both bacterial growth and pollen development.The resistant (recessive) and susceptible (dominant) alleles of xa13 can encode identical proteins, but have crucial sequence differences in their promoter regions. Suppressing expression of either the dominant or recessive allele of xa13 enhanced the resistance, but caused male sterility of the plants, indicating that the product of this gene acted both as a bacterial growth dependent modulator and as an essential constituent of pollen development[6].

Os8N3is amemberof theMtN3family
Association of Xa13 expression and pollen development
Sequence comparison of the promoter regions of xa13 and Xa13 from different rice lines.


Xa13 encodes an indispensable plasma membrane protein of the MtN3/saliva family, which is prevalent in eukaryotes with unknown biochemical function.XA13 protein cooperates with two other proteins, COPT1 and COPT5, to promote removal of copper from xylem vessels, where Xoo multiplies and spreads to cause disease.Copper, an essential micronutrient of plants and an important element for a number of pesticides in agriculture, suppresses Xoo growth. Xoo strain PXO99 is more sensitive to copper than other strains; its infection of rice is associated with activation of XA13, COPT1, and COPT5, which modulate copper redistribution in rice.[7]

Modulating COPT1, COPT5, or Xa13 Expression Influenced Rice Responses to Xoo Infection
AvrXa7 Drives TAL Effector-Specific Host Gene Induction.


Rice Os-11N3 Represents a Distinct Clade of the N3 Family.

Chen also found XA13 belongs SWEET family can transport from extracellular glucose within the cell , thus providing nutrients for the bacteria , beneficial bacteria growth and reproduction[8].

Localization

Xa13 is Located in the long arm of rice the chromosome 8.

Expression

xa13 expression levels in leaves is very low, but the high level of expression in the ear and anther. RNA interference by inhibiting the expression of xa13, enhanced xa13-mediated resistance, indicating that the absence of a dominant allele xa13 bacterial blight resistance is a must[9].

Knowledge Extention

Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xooc) cause bacterial blight (BB) and bacterial leaf streak (BLS) in rice (Oryza sativa), which constrain rice production in China and the world.According to bioinformatics of Xoo and other recent reports, there are 15~30 avrBs3/PthA (avr/pth) genes in Xoo and Xooc. Recent research results suggest that avr/pth genes are not only involved in virulence when there are no corresponding R genes in rice, but also in suppressing plant immunity for hypersensitive response, and in avirulence when there are matching R genes in rice. Although avr/pth genes exist in Xooc, no R genes are present for BLS in rice. Members of avr/pth family genes are remarkably similar. However, the main differences are the number and apparent nature of near-identical 102-base-pair direct repeats in the central portion of the coding sequence[10].


The type Ⅲ secretion system (T3SS) effector is considered as one of the key virulence factorsin Xanthomonas oryzae. X. oryzae pv. oryzae and X. oryzae pv. oryzicola cause bacterial leaf blight and bacterial leaf streak in rice, which are important bacterial diseases of rice[11].


TAL effectors are secreted through the TTSS and targeted to host nuclei, a process that is mediated by the conserved N-terminal and C-terminal regions, respectively.TAL effectors combined with a specific gene promoter DNA, similar to eukaryotic transcription factor gene expression in plants start to control the physiological and biochemical processes of plants[12].

Labs working on this gene

  • National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Hua zhong Agricultural University, Wuhan 430070, China
  • Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, Iowa 50011
  • National Key Laboratory of Crop Biology ShanDong Provincial, Key Laboratory of Agricultural Microbiology ,Shandong Agricultural University ,Tai an 271018, Shandong

References

  1. ↑ Chu ZH, Fu YB,Hong Y, et al.Targeting xa13, a recessive gene for bacterial blight resistance in rice.Theoretical and Applied Genetics, 2006, 112(3): 455-461
  2. ↑ Zhou B,Peng K,Chu Z,et al.The defense responsive genes showing enhance and repressive expression after pathogen infection in rice.Sci China C 45:449-467
  3. ↑ Zhang G, E.R. Angeles, M.L.C,et al.RAPD and RFLP mapping of the bacterial blight resistance gene xa-13 in rice.Theoretical and Applied Genetics, 1996, 93(1-2): 65-70
  4. ↑ Bing Yang, Akiko Sugio*, and Frank F. White†.Os8N3 is a host disease-susceptibility gene for bacterial blight of rice.PNAS July 5, 2006 �vol. 103 �no. 27 �10503–10508
  5. ↑ 5.0 5.1 Ginny Antony,Zhou Junhui ,Huang Sheng,et al.Rice xa13 Recessive Resistance to Bacterial Blight Is Defeated by Induction of the Disease Susceptibility Gene Os-11N3 The Plant Cell, Vol. 22: 3864–3876 Cite error: Invalid <ref> tag; name "foo" defined multiple times with different content
  6. ↑ Chu, ZH., Yuan M, Yao J,et al.Promoter Mutations of an Essential Gene for Pollen Development Result in Disease Resistance in Rice." Genes Dev 20, no. 10 (2006): 1250-5.
  7. ↑ Yuan, M, Chu ZH, Li X,et al.The Bacterial Pathogen Xanthomonas Oryzae Overcomes Rice Defenses by Regulating Host Copper Redistribution. Plant Cell 22, no. 9 (2010): 3164-76.
  8. ↑ Chen L Q, Hou B H, Lalonde S, et al. Sugar transporters for intercellular exchange and nutrition of pathogens. Nature, 2010, 468: 527-532.
  9. ↑ Antony.G, Zhou J, Huang S, et al. Rice Xa13 Recessive Resistance to Bacterial Blight Is Defeated by Induction of the Disease Susceptibility Gene Os-11n3." Plant Cell 22, no. 11 (2010): 3864-76.
  10. ↑ 李玉蓉，邹丽芳，武晓敏,et al.水稻黄单胞菌avrBs3/PthA 家族基因研究进展.中国农业科学 2007,40(10):2193-2199
  11. ↑ 赵帅,张子宇,冯家勋.水稻黄单胞菌三型分泌系统效应物的研究进展.Microbiology China.DEC 20, 2011, 38(12): 1828−1842.
  12. ↑ T. OGAWA, LIN L , R. E. TABIEN .et al.A new recessive gene for resistance to bacterial blight of rice Rice Genetics Newsletters, 1987, 4(0): 98-100

Structured Information

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