Polypeptides associated with the induction and maturation of direct somatic embryogenesis in peanut (Arachis hypogaea L.)

Analysis of protein patterns in mature zygotic embryo axes and somatic embryos by two-dimensional gel electrophoresis revealed that protein of spot no. E-4 (37 kDa, pI 9.5) and E-5 (37 kDa, pI 9.8) are present only in the 6 day old culture indicating their importance for induction of somatic embryogenesis. Proteins of spot no. E-1 (53 kDa, pI 8.2), E-2 (53 kDa, pI 8.3) and E-3 (37 kDa, pI 9.3) expressed in 6 day-old immature zygotic embryo axis cultures were also present in globular staged somatic embryos and these proteins are possibly associated with early stages of somatic embryogenesis. Proteins of 65 kDa separated into different spots of C-1, C-2, C-3, C-4 with pI values ranging from 6.3-9.6 on two-dimensional gel are present only in zygotic embryos. Proteins of C-2 (65 kDa, pI 7.5), C-8 (22 kDa, pI 7.8), C-10 (20 kDa, pI 5.3) C-11 (20 kDa, pI 5.5) were specifically expressed in mature zygotic embryo axes and are possibly associated with storage or late embryonic proteins. A few proteins showed differential expression during various stages of somatic embryos and many proteins that expressed in cotyledonary somatic embryos and were also present in immature and mature zygotic embryo axes.