Eggplant Lines Research Articles

Transgenic Resistance to the Colorado Potato Beetle in Bt-expressing Eggplant Fields

Colorado potato beetle (CPB; Leptinotarsa decemlineata-Say) is a serious pest because it has developed resistance against insecticides. Three transgenic eggplant (Solanum melongena L.) lines bearing a mutagenized Bacillus thuringiensis Berl. gene coding for the Cry3B toxin, and the nontransformed control DR2-line were tested in field trials to assess their insect resistance. The transgenic lines 3-2, 6-1, and 9-8 were tested at two different locations in a randomized complete-block design. Samples were taken biweekly to assess the level of CPB and the presence of other insects. At harvest, total yield and fruit number per plot were recorded. Two transgenic lines showed high levels of resistance at both locations, as measured by CPB abundance and yield. Fruit production was almost twice as great in the highly resistant lines (3-2 and 9-8) as in the nontransformed control. The 6-1 transgenic line showed an intermediate level of resistance; it was similar to the control under heavy CPB pressure and was comparable to the other transgenic lines under milder infestations. Analysis by double antibody sandwich–enzyme linked immunosorbent assay (DAS–ELISA), performed on different tissues, revealed a lower amount of Cry3B protein in the 6-1 transgenic line than in lines 3-2 and 9-8. No detrimental effects on nontarget arthropods (including the chrysomelid Altica) were evident. Field observations confirmed that Bt may be able to control CPB infestation in eggplant, representing a potential effective and environmentally safe means of pest control.

Salt-tolerance and proline accumulation: a comparative study in salt-tolerant and wild type cultured cells of eggplant

A NaCl-tolerant cell line of eggplant has been isolated, as a spontaneous variant, on agar solidified medium supplemented with 1% NaCl (Electrical conductivity -17.5 m mho/cm), a concentration lethal to the wild type cells. The stability of the altered response of the selected clone was confirmed by growing it on normal medium for 3 months and then bringing back to the stress medium. This cell line not only grew well on media containing upto 1% NaCl but also required 0.25% NaCl for its optimal growth. It is interesting to note that there is a certain concentration of NaCl (Critical point) above which the proline content of the cells rises sharply. A relationship between the NaCl stress and proline content has been found. The critical point in the wild type cultured cells (0.75% NaCl) lies below to that of the selected salt-tolerant variant (1.0% NaCl).