Transgenic citrus plants expressing the p35 anti-apoptotic gene have altered response to abiotic stress

Transgenic plants of the citrus rootstock Carrizo citrange cultivar [Citrus sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf.] expressing a p35 anti-apoptotic gene were exposed to three types of abiotic stress. The responses of plants from the three transgenic lines, p35-1, p35-2, and p35-4 were compared to those of wild-type (WT) plants, revealing consistent improvements in the ability of leaf explants from p35-2 transgenic plants to withstand freezing. When exposed to drought stress, plants transformed with p35 gene exhibited similar elongation growth and branching to WT plants. The stem water potential (SWP) in drought-stressed p35-2 and p35-4 plants was significantly lower than SWP measured in WT plants in one experiment, but in a repeat experiment, the SWP of WT and transgenic plants were similar. The ability to withstand salt stress was similar in all four genotypes. The introduction of anti apoptotic genes with beneficial effects in plant stress resilience into citrus, such as p35, may lead to the production of cultivars more tolerant to freezing conditions or other types of abiotic stress.