Improved germination under osmotic stress of tobacco plantsoverexpressing a cell wall peroxidase

Abstract

The cell wall is a fundamental component in theresponse of plants to environmental changes. To directly assessthe role of the cell wall we have increased the expression andactivity of a cell wall associated peroxidase (TPX2), an enzymeinvolved in modifying cell wall architecture. Overexpression ofTPX2 had no effect on wild-type development, but greatlyincreased the germination rate under high salt or osmotic stress.Differential scanning calorimetry showed that transgenic seedswere able to retain more water available for germination thanwild-type seeds. Thermoporometry calculations indicated thatthis could be due to a lower mean pore size in the walls oftransgenic seeds. Therefore, the higher capacity of transgenicseeds in retaining water could result in higher germination ratesin conditions where the availability of water is restricted.