ARS | Publication request: EXPRESSION OF SOLUBLE INVERTASE IN TRANSFORMED CARROT

Submitted to: In Vitro Plant
Publication Type: Abstract Only
Publication Acceptance Date: June 4, 1998
Publication Date: N/A

Technical Abstract: The beta-fructofuanosidases (invertases) cleave sucrose and related sugars into fructose and glucose. This enzyme is present in most plant tissues in multiple forms. Carrots contain an insoluble invertase and soluble invertases. The Rs locus in carrot conditions the accumulation of sucrose, fructose, and glucose. Two different sizes of invertase isozyme ll bands have been identified from Rsl and rs/rs plants based on genomic DNA PCR amplification, 4 kb and 6 kb respectively. The inbreds B493, B4367 and B7262Yc are homozygous for the recessive allele (rs/rs) and accumulate high levels of sucrose, while most carrots accumulate glucose and fructose (Rsl-). Increased consumer interest in sweeter carrots requires greater understanding of sucrose metabolism and its biochemistry. We established a gene transformation system for carrots using an Agrobacterium-mediated method. Intact soluble invertase isozyme l and isozyme ll cDNAs were generated from B493 and B4367 via RT-PCR. The cDNA fragments were cloned into pBI121. B493 calli and tobacco plants were transformed by Agrobacterium rumefaciens LBA4404 containing the pBI121 vector driven by the 35S promoter. Transformed calli have been obtained and regenerated into plants. Invertase expression was compared in transformed and non-transformed rs/rs carrots. The expression of carrot invertase in other species (tobacco) will be studied. The results improve our understanding of the role of soluble invertase in sucrose metabolism of carrot.