[Intellectual Contribution]

Cloning of the brown planthopper resistance gene BPH26 from indica rice cultivar induces sucking inhibition

Yasumori Tamura1, Makoto Hattori1, Akira Takahashi2, Jianzhong Wu3, Naoki Sentoku4
1Insect-Plant Interaction Research Unit, 2Disease Resistant Crops Research Unit, 3Advanced Genomics Laboratory, 4Functional Plant Research Unit
[Abstract]
Brown planthopper (BPH) is a serious pest of rice. A BPH-resistance gene, BPH26, was cloned from an indica rice cultivar. It was revealed that although the stylet of BPH could reach the phloem, it could not suck the phloem sap from the rice plants carrying BPH26 and subsequently died from starvation.
[Keywords]
Keywords: indica rice cultivar, brown planthopper, Nilaparvata lugens Stål, BPH resistance gene, sucking inhibition, BPH26, NBS-LRR

[Background]

The brown planthopper (BPH), Nilaparvata lugens Stål, is an important pest of rice (Fig. 1), which causes serious damage to rice cultivation by sucking the phloem sap until the plant dies. Since BPH strains showing resistance to insecticides such as imidacloprid have emerged, the issue of BPH damage to rice cultivation has become more serious. Although it has been reported that BPH26 could confer resistance to BPH which has recently migrated to Japan because of the coexistence of BPH25, the BPH26 has not been cloned yet. Development and utilization of BPH-resistant rice varieties will promote environment-friendly and low-cost agricultural practices involving limited use of pesticides.

[Results and Discussion]
  1. The chromosomal location and nucleotide sequences, and functions of BPH26 were analyzed, and DNA markers of BPH26 were developed for marker-assisted breeding.
  2. The BPH26 was identified using transgenic rice lines with the gene. It was revealed that BPH could not suck the phloem sap from rice varieties carrying BPH26 and died from starvation, although the stylet could reach the phloem (Fig. 2). When BPH was released on two varieties, one with BPH26 and the other without BPH26, only the variety with BPH26 survived the insect infestation (Fig. 3 and Fig. 4).
  3. The BPH26 protein closely resembles rice NBS-LRR proteins, which are involved in signal perception and transduction during infection by pathogens. This suggests that BPH26 protein is a receptor involved in the signal perception and transduction activated during BPH attack.
[Future prospects]
  1. The BPH26 gene in coexistence of BPH25 conferred resistance to the BPH biotype that neither BPH26 nor BPH25 was effective against.
  2. DNA markers of BPH25 for marker-assisted breeding are currently under development. A broad-spectrum BPH-resistant variety against some BPH biotypes can be developed by using two DNA markers for the two genes (BPH25 and BPH26).

Fig. 1. A brown planthopper sucking rice phloem sap.
The rice plant dies because of the loss of nutrient content in the phloem sap.

 

Fig. 2. Total duration of phloem ingestion in the two rice lines during a 10-hour measurement period.

 

Fig. 3. Rice seedlings after one week of BPH release.
Although the susceptible japonica rice variety (left) was almost wilted, the rice variety carrying BPH26 (right) grew vigorously.

 

Fig. 4. Diagram showing BPH26 induced resistance.
BPH cannot suck the phloem sap and subsequently dies from starvation.

 

[Collaborators]

Hideshi Yasui (Kyushu University), Hirofumi Yoshioka, Miki Yoshioka (Nagoya University)

[Reference]

  1. amura Y, Hattori M, Yoshioka H, Yoshioka M, Takahashi A, Wu J, Sentoku N, Yasui H (2014) Map-based cloning and characterization of a brown planthopper resistance gene BPH26 from Oryza sativa L. ssp. indica cultivar ADR52 Scientific Reports 4:5872
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