Genetically modified pollen resistant to abiotic stress

The method allows the transformation of pollen with an expression vector containing the DSUP protein from the tardigrade (Ramazzottius varieornatus), or its functional units, to confer resistance to desiccation and radiation damage (UV-B), both of which are stressful conditions naturally present in some regions of the Earth's surface.

The transformation of the construct into pollen was achieved by biolistic bombardment with small DNA-coated inert metal spheres. The presence of the pollen-specific LAT52 promoter in the vector allows for DSUP expression in pollen tubes after germination.

Pollen tube length, a parameter used to evaluate the effect of abiotic stress or potentially cytotoxic substances, remained unchanged in DSUP+ pollen compared to untransformed pollen. Furthermore, when subjected to radiation stress post-germination, DSUP+ pollen retained pollen tube length at the end of germination comparably to that of unstressed pollen.

It was also observed that the distance between the pollen tube tip and the male germinal unit was 10 times closer in DSUP+ pollen than in irradiated DSUP- pollen. Finally, DSUP+ pollen tubes exposed to UV-B radiation exhibited high antioxidant content, particularly polyphenols.

The method is suitable for pollinating edible spermatophyte plants of economic interest (Solanaceae, Gramineae, and Legumes), allows control of transgenic pollen dispersal into the environment, and does not require plant transformation and regeneration.