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Plant genes involved in drought tolerance and other stress responses

Hamill, J.D. Prof; Ph: (03) 9905 3850; Fax: (03) 9905 5537; john.hamill@sci.monash.edu.au

Neale, A.D. Dr; Ph: (03) 9905 3854; Fax: (03) 9905 5537; alan.neale@sci.monash.edu.au

Morgan, S.M. Ms; Ph: (03) 9314 6806

Research organisation: Monash University, Department of Biological Sciences (Genetics Section), Clayton Vic 3168

Sponsor: DRDC, Dairy Research and Development Corporation

Objective: To develop molecular mechanisms for controlling expression of introduced genes such as those conferring desiccation and salt tolerance under conditions of plant stress.

Methodology:

1. Isolate the cis acting control regions of plant gene promoters responding to the stress hormones such as ethylene, abscisic acid and salicylic acid.

2. Utilise the cis acting control regions to determine how plants perceive environmental signals at the molecular level.

3. Utilise this information to regulate the expression of introduced genes.

Progress:

The Plant Desiccation Tolerance Group was set up at Monash University Department of Biological Science in 1993 as a collaboration between Dr A.D.Neale, Dr Don Gaff and Professor John Hamill to study the molecular genetics of desiccation tolerance in resurrection plants. These plants are the "ultimate" drought-tolerant plants, having the remarkable ability to survive total water loss and remain viable for years in a dry state. Following rainfall, these resurrection plants rehydrate and recommence normal metabolism and growth within 24 hours.

The seed and pollen of most plants can also withstand severe desiccation. This has led the researchers to hypothesise that this ability has extended to root and leaf tissues in resurrection species. This implies that drought tolerance is inherent in the genetic constitution of the majority of plants, including most crop and pasture species. It is therefore likely that the introduction of a small number of regulatory genes, isolated from a resurrection plant, could induce drought tolerance in most plant species, by extending the ability to viably dehydrate to leaves and roots, without affecting other plant characteristics. This would be of major significance for reduction of crop losses and soil erosion during periods of drought.

The research group has utilised recently developed molecular biology techniques to isolate more than thirty genes from the resurrection grass Sporobolus stapfianus. So far more than twenty have been shown to be drought responsive. These genes include several regulatory genes encoding transcription factors, signal transduction components and a possible drought receptor. The group believes it is very close to being able to genetically introduce drought tolerance into drought sensitive plants, however additional funding is required to successfully achieve this.

Period: starting date 1993-02; completion date 1995-12

Status: completed

Keywords: drought tolerance, desiccation tolerance, molecular genetics, resurrection plants

Publications:

Kuang, J., Gaff, D., Gianello, R., Blomstedt, C., Neale, A. and Hamill, J. (1995). Changes in in vivo protein complements in drying leaves of the desiccation-tolerant grass Sporobolus stapfianus and the desiccation-sensitive Sporobolus pyramidalis. Australian Journal of Plant Physiology 22, 1027-34.

Blomstedt, C.K., Gianello, R.D., Hamill, J.D., Neale, A.D. and Gaff, D.F. (1997). Drought-stimulated genes correlated with desiccation tolerance of the resurrection grass Sporobolus stapfianus. Plant Growth Regulators 24, 153-161.

Blomstedt, C.K., Gianello, R.D., Gaff, D.F. Hamill, J.D. and Neale, A.D. (in press). Differential Gene Expression in Desiccation-Tolerant and Desiccation-Sensitive Tissue of the Resurrection Grass Sporobolus stapfianus.

  

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