PROJECT TITLE : Molecular manipulation and engineering of rice for resistance to diseases (tungro and sheath blight).

Background

An increase in rice production has to be sustained in order to support the growing human population. Over the years the industry has been continually affected by diseases, weeds and unfavourable weather conditions that limit production. Due to several limitations such as limited availability of desirable genes in rich germplasm, on alternative non-conventional rice improvement technology must be employees, injecting new and more powerful approaches to rice improvement.

Biotechnology could contribute significantly to sustainable development by improvement in food production. It complements breeding programs in producing new varieties, which have improved characters such as disease resistance. Tungro and sheath blight are two serious disease of rice which are affecting rice production. Tungro disease can cause significant yield loses (US$342.7 million per year in Southeast Asia). Efforts to breed for resistance to the infection has been hampered by the lack of a natural gene for resistance (Khush, 1977). Various strategies have been used successfully to engineer for resistance against viruses in other crop plants. These strategies include the use of the use of the coat protein gene from the virus (Powell et al., 1986), utilisation of replicase (an enzyme involved in viral replication) (W. Kaniewshi and C. Law Son, unpublished), disfunctioning movement protein which interferes with cell-to-cell movement of the virus (Lapidot et al., 1993). The strategy that will be taken by this mega project are (1) the coat-protein mediated resistance by the MARDI's group and (2) the protease-mediated approach by the UKM's group. Both strategies utilize genes from the virus to engineer for resistant transgenic rice.

Another major disease threatening our rice industry now is sheath blight disease (US$46.6million per year in Southeast Asia),which is caused by the fungus Rhizoctonia solani. Several proteins in plants are known to be toxic to fungi.

These include lectins, chitinase and thonin. The strategy proposed by this mega project is to use thionin which can inhibit fungal growth. Since the gene for thionin has been cloned in rice, the initial effort of the project is to isolate and prepare gene contract for use in rice transformation. This is a joint effort by the MARDI and UPM groups.

A spin off that can be achieved from this project is the development of local expertise, skilland experience in engineering of rice. Based on current developments in this areaof research elsewhere, it is anticipated that biotechnology will play a greater role in corp in corp improvement. Engaging ourselves in this activity will give high divident in the future.

Objective of the project

To develop transgenic rice with resistance to tungro and sheath blight disease.

Objective Achived

Transgenic rice that is resistant to one of the tungro virus (RTSV) has been developed.

Activities of the project

1) Isolation of disease resistance genes:
a) Tungro resistance gene (coat protein gene from tungro virus - RTSV & RTBV)
b) Sheath blight resistance gene (thionin and other plant defense genes)

 

 

2) Transformation and regeneration of the Malaysian rice with
a) The coat protein gene from the Malaysian RTSV and RTBV
b) The protease gene from RTBV.

3) Screening for transgenic/resistance.
a) Screening for successful transformed rice plants.
b) Screening for resistance among the transgenic rice.

4) Isolation of thionin and other plant defense genes against Sheath Blight:
a) Development of a cDNA library of rice.
b) Screening for thionin and other plant defense genes.
c) Characterization of thionin and other plant defense genes.
d) Gene construction with the isolated genes.

Benefits of the Project

1) National expertise built within the institutions involved (MARDI and UKM) to genetically engineer rice. With this expertise, the Malaysian rice varieties can be improved for disease resistance (as in the current project) ; As well as for other characters in the future.

2) Seed producers will be getting new source of improved rice varieties for marketing.

3) Rice growers will be receiving rice varieties with built-in resistance against diseases.

• Outputs of the project and potential bcneficiaries

1) Isolated (or cloned) resistance genes for the diseases:
o The coat-protein , polymcrase and movement protein genes for tungro virus diseases.
o The chitinase and g1ucanase genes for shcath blight disease
Potential beneficiaries from these outputs are biotechnology researchers who are working for disease resistance in plants, especially rice.

2) A routine and efficient gene transfer and regeneration system for rice. Potential beneficiaries from these outputs are biotechnology researchers who are genetically engineering rice for improvement.

3) Data and information on the possibility of using the isolated genes above to derive resistance against the two diseases in rice. Potential beneficiaries from these outputs are the biotechnology researchers who arc genetically engineering rice for improvement, as well as the rice industry later on.

• Organisational Outcomes

The expertise built within the institutions involved (MARDI and UKM) to genetically engineer rice. With this expertise, the Malaysian rice varieties can be improved for disease resistance (as in the current project) as well as for other characters in the future.

The material derived from this project will be used as a released variety or can be used as parents in future breeding programs by the institutions involved.

• National Impacts

The national rice industry will have better rice varieties with characters that have been improved through biotechnology .A number of problems in production is beyond the reach of conventional technology. Biotechnology approaches as designed by this project will offer an alternative solution to those problems.

Status Project

- Completed