PSAG12-IPT overexpression in eggplant delays leaf senescence and induces abiotic stress tolerance

The isopentytransperase (IPT) gene, coupled to the SAG12 promoter, was successfully transferred into the eggplant (Solanum melongena L.) mediated by Agrobacterium tumefaciens. Four P-SAG12 IPT overexpressing transgenic plants were identified by Southern blotting. Reverse transcription polymerase chain reaction revealed that IPT was expressed in senescent leaves under the control of SAG12 promoter. Compared with wild type eggplants, the leaf senescence was significantly delayed and tolerance to drought and cold stress was enhanced in the T-1 generation of P-SAG12-IPT transgenic eggplants. The contents of chlorophyll, indoleacetic acid, zeatin riboside, and gibberellic acid in the transgenic eggplants were higher than those in the wild type eggplants. The activities of reactive oxygen species-scavenging enzymes in the transgenic eggplants were also higher than those in the wild type eggplants. Abscisic acid and malondialdehyde levels were lower in the transgenic plants than in the wild type plants. Also the vegetative growth rate and yield of the transgenic plants were higher than those of the wild type eggplant. Our study suggests that the P-SAG12-IPT expression cassette may be suitable for the genetic improvement of eggplant.