Salt Tolerance and Yield
Enhancement in Rice Plants via
Fungal Symbiosis - 2007

 

 

Home.gif (3162 bytes)

Back.gif (3162 bytes)

Project Leader and Principal  Investigators

Regina Redman, research professor, Dept. of Microbiology, Montana state University, Bozeman, MT

 

This new project is examining methods for improving salt tolerance in rice with an innovative fungal technique. Research in 2007 involved laboratory, greenhouse, and field studies with collaborating investigators at UC Davis. Encouraging results are reported with “symbiotic” plants outperforming untreated controls. The following summarizes highlights of this work.

Initially, 16 different commercial cultivars were examined in growth chamber and greenhouse studies. In this pilot phase of the study, research showed improved salt and drought tolerance, and increased plant biomass production and seed yield in plants treated with a Fusarium species. This process confers desirable traits by decreasing water consumption, increasing metabolic efficiency (photosynthetic carbon conversion to plant biomass) and by preventing detrimental impacts of sodium on plants. Although the specific mechanisms are not yet known, research is under way to elucidate the process. The California variety M-206 was found to be the best candidate for this procedure.

A second objective of this work was to develop a commercially adaptable procedure for fungal colonization. Researchers successfully developed a sterilization protocol for seed and report a 100% effective liquid colonization process. This process involves adding fungal spores as the final step in seed soaking that is designed to also ensure optimal seed sterilization and high germination levels.

Field and parallel greenhouse experiments were also conducted to examine the effect of gradually increasing levels of salt over a three-month period on symbiotic rice plants. Compared to untreated controls in the greenhouse study, the technique produced a statistically significant growth response, enhanced seed yields and plant biomass in both young seedlings and mature plants. Significant differences occurred in shoot number, weight, and root weight, with the highest differences in seed yield.

Salinity experiments were also conducted under paddy rice conditions with M-206. This part of the study showed statistically significant differences in plant biomass (60%) and plant viability (35%) in treated plants exposed to a high salt concentration. Because of the late planting date for this part of the study, no data on seed yield biomass is available. The parallel greenhouse experiments indicate, however, a likelihood that symbiotic plants would have outperformed the untreated.

Researchers also report that in the absence of salt stress, there were other notable differences. The symbiotic plants were visibly greener, more robust, and had a higher number of stems per plant compared to non-symbiotic plants. Future studies will look at the physiological, biochemical, molecular, and nutritional differences between symbiotic and non-symbiotic plants.

 

Home.gif (3162 bytes)Back.gif (3162 bytes)