S. citri elimination by somatic embryogenesis, from stigmas/styles (SES) and from undeveloped ovules of aborted seeds (SEO), was evaluated using DAS-ELISA and PCR. Different organs of the infected citrus species were tested for the presence of S. citri, which was detected in ovaries (100%), leaves (66.66%), columella (32.22%), non viable seeds (22.68%) and stigmas/styles (16.66%). Stigmas/styles (Navel orange) and undeveloped ovules (Navel and Valencia oranges) were cultured in MS medium supplemented with BAP and sucrose. The SES medium included also malt extract. Somatic embryos were produced with no callus formation from undeveloped ovules, 1 to 3 months after culture initiation, whereas later on callus surface in SES. The embryogenic response of Navel was 100% in SEO and 34.66% in SES. No significant difference was observed in the embryogenic response of Navel and Valencias using SEO.
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Despite the low infection rate of S. citri in stigmas/styles and callus, no infection resulted in regenerants from SES. Same results were obtained in regenerants from SEO. Considering the 22.68% of seed infection, viable seeds of infected fruits, belonging to lime, lemon and orange from Egypt were sown for seedling production. No transmission of S. citri was detected in the seedlings after 6 months of growth.
