Figure 3

Expression of GRAS genes in vegetative Pinus radiata organs and at the embryonic-postembryonic develop mental transition. A) Organs from 35-day-old pine seedlings. qRT-PCR was performed using RNAs from roots (R), hypocotyls (H), cotyledons (C) or shoot apex nodal segments (A). B) Embryo development. qRT-PCR was performed using RNAs from embryogenic masses at 7 (P7) and 14 (P14) days of proliferation, early-maturation embryo (M1) and late-maturation embryo (M3). C) Embryonic-postembryonic development. qRT-PCR was performed using RNAs from embryogenic masses at 7 (P7) days of proliferation, rooting-competent hypocotyls (H21) and non-competent hypocotyls (H90) or epicotyls (E90) from seedlings of 21- and 90-day-old seedlings, respectively. A total of 1 μg RNA was reverse transcribed, and 12.5 ng of cDNA was amplified with 400 nM of specific primers. Pine Ri18S was used as the control. Results are expressed as mean values of the relative expression to roots (A) or P7 (B and C) ± SE from at least three biological replicates. Insets in B show details of early developmental stages. Results of PrSHR expression in C are expressed as mean values of relative expression to H21. Expression levels of PrSCL1 and PrSHR had already been measured in organs during vegetative development [16],[17]. Expression of PrSCL16 was not detected in any of the RNA samples tested. SCL, SCARECROW-LIKE; SHR, SHORT-ROOT.