CHARACTERIZATION OF PHOTOSYSTEM PARAMETERS OF TRANSPLASTOMIC LINES EXPRESSING VACCINE ANTIGENS

ALBARRACIN, R.; CORIGLIANO, M.; MAIALE, SJ; CLEMENTE, M.

Mar del Plata

Congreso; Sociedad Argentina de investigaciones Bioquímicas y Biología Molecular; 2015

SAIB

Chloroplasts transformation technology has emerged as an alternative platform for antigen expression in plants. In particular, we demonstrated that the fusion of Toxoplasma gondii SAG1 antigen to Leishmania infantum Hsp83 (LiHsp83-SAG1) significantly increased the level of SAG1 accumulation in chloroplasts compared to SAG1 alone. However, LiHsp83-SAG1 line showed chlorotic phenotype and growth retardation. In order to understand these unintended pleiotropic effects, we characterized the photosystem parameters of LiHsp83-SAG1 and compared them with SAG1 and GRA4 transplastomic lines versus wild type plants (WT). Completely developed leaves from 42 old-days plants were used to measure foliar area, chlorophyll content by chemical and spectrophotometry (SPAD) methods and chlorophyll fluorescence (OJIP). SAG1 foliar area was 17% bigger than WT, while LiHsp83-SAG1 was 23% smaller than WT. SPAD and chemical methods showed similar results, transplastomic lines had less chlorophyll content than WT. OJIP analysis showed no differences among SAG1, GRA4 and WT plants. On the other hand, LiHsp83-SAG1 revealed low values for most of the parameters measured, such as maximum quantum yield of primary photosystem II photochemistry and electron transport per excited cross section. This first approach suggests that photosystem parameters in LiHsp83-SAG1, especially those related to PSII, are damaged.