RNA interference of Arabidopsis beta-amylase8 prevents maltose accumulation upon cold shock and increases sensitivity of PSII photochemical efficiency to freezing stress
Article first published online: 9 NOV 2005
The Plant Journal
Volume 44, Issue 5, pages 730–743, December 2005
How to Cite
Kaplan, F. and Guy, C. L. (2005), RNA interference of Arabidopsis beta-amylase8 prevents maltose accumulation upon cold shock and increases sensitivity of PSII photochemical efficiency to freezing stress. The Plant Journal, 44: 730–743. doi: 10.1111/j.1365-313X.2005.02565.x
- Issue published online: 9 NOV 2005
- Article first published online: 9 NOV 2005
- Received 9 June 2005; revised 2 August 2005; accepted 24 August 2005.
- environmental stress;
- temperature stress
It has been suggested that beta-amylase (BMY) induction during temperature stress in Arabidopsis could lead to starch-dependent maltose accumulation, and that maltose may contribute to protection of the electron transport chain and proteins in the chloroplast stroma during acute stress. A time-course transcript profiling analysis for cold shock at 4°C revealed that BMY8 (At4g17090) was induced specifically in response to cold shock, while major induction was not observed for any of the other eight beta-amylases. A parallel metabolite-profiling analysis revealed a robust transient maltose accumulation during cold shock. BMY8 RNAi lines with lower BMY8 expression exhibited a starch-excess phenotype, and a dramatic decrease in maltose accumulation during a 6-h cold shock at 4°C. The decreased maltose content was also accompanied by decreased glucose, fructose and sucrose content in the BMY8 RNAi plants, consistent with the roles of beta-amylase and maltose in transitory starch metabolism. BMY8 RNAi lines with reduced soluble sugar content exhibited diminished chlorophyll fluorescence as Fv/Fm ratio compared with wild type, suggesting that PSII photochemical efficiency was more sensitive to freezing stress. Together, carbohydrate analysis and freezing stress results of BMY8 RNAi lines indicate that increased maltose content, by itself or together through a maltose-dependent increase in other soluble sugars, contributes to the protection of the photosynthetic electron transport chain during freezing stress.