Abstract
Background: Switchgrass ( Panicum virgatum L.) is a prime candidate for non-grain-based bioenergy feedstock production. Improved drought tolerance and higher water use efficiency are important for its successful field establishment and production, especially on marginal lands. Aquaporins are key channels and regulators for water transportation and maintenance of cellular water status. In this study, the functional role of an aquaporin gene, PvPIP2;9 , in switchgrass was studied. Results: Expression of PvPIP2;9 was regulated by diurnal oscillation and osmotic stress. Constitutive over-expressing PvPIP2;9 in switchgrass significantly improved its leaf length, plant height, above-ground biomass, biomass protein contents, and cellulose contents in stressed plants. Under 21 days of drought treatment, transgenic plants showed less electrolyte leakage rates, but higher relative water contents, photochemical efficiencies, and chlorophyll contents, indicating that PvPIP2;9 positively regulated plant drought tolerance and water use efficiency. Moreover, expression patterns of all 14 switchgrass PIP2 subfamily genes were checked during the drought treatment, and the result showed that over-expressing PvPIP2;9 also affected transcript levels of most other PIP2 genes. Conclusions: Together, this study showed that improved biomass yield, drought tolerance and higher water use efficiency can be achieved by manipulating the expression level of PvPIP2;9 and also suggested PIP2 subfamily genes were transcriptionally regulated in a coordinated manner.
Overexpression of an aquaporin gene
PvPIP2;9
improved biomass yield, protein content, drought tolerance and water use efficiency in switchgrass (
Panicum virgatum
L.)
